Journal ArticleComput Biol Med · August 2024
Registering the head and estimating the scalp surface are important for various biomedical procedures, including those using neuronavigation to localize brain stimulation or recording. However, neuronavigation systems rely on manually-identified fiducial h ...
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Journal ArticleJ Autism Dev Disord · June 2024
We report preliminary results of computer vision analysis of caregiver-child interactions during free play with children diagnosed with autism (N = 29, 41-91 months), attention-deficit/hyperactivity disorder (ADHD, N = 22, 48-100 months), or combined autis ...
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ConferenceConference on Human Factors in Computing Systems - Proceedings · May 11, 2024
Autism, characterized by challenges in socialization and communication, benefits from early detection for prompt and timely intervention. Traditional autism screening questionnaires often exhibit reduced accuracy in primary care settings and significantly ...
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Journal ArticleCerebellum (London, England) · April 2024
Dysarthria is a common manifestation across cerebellar ataxias leading to impairments in communication, reduced social connections, and decreased quality of life. While dysarthria symptoms may be present in other neurological conditions, ataxic dysarthria ...
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Journal ArticlePLoS One · 2024
BACKGROUND: While early autism intervention can significantly improve outcomes, gaps in implementation exist globally. These gaps are clearest in Africa, where forty percent of the world's children will live by 2050. Task-sharing early intervention to non- ...
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ConferenceProceedings of Machine Learning Research · January 1, 2024
Group distributional robustness optimization methods (GDRO) learn models that guarantee performance across a broad set of demographics. GDRO is often framed as a minimax game where an adversary proposes data distributions under which the model performs poo ...
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ConferenceProceedings of Machine Learning Research · January 1, 2024
Causal inference on networks faces challenges posed in part by violations of standard identification assumptions due to dependencies between treatment units. Although graph geometry fundamentally influences such dependencies, the potential of geometric too ...
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Journal Articlenpj Digital Medicine · December 1, 2023
Heart rate (HR) response to workout intensity reflects fitness and cardiorespiratory health. Physiological models have been developed to describe such heart rate dynamics and characterize cardiorespiratory fitness. However, these models have been limited t ...
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Journal ArticleNat Med · October 2023
Early detection of autism, a neurodevelopmental condition associated with challenges in social communication, ensures timely access to intervention. Autism screening questionnaires have been shown to have lower accuracy when used in real-world settings, su ...
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ConferenceClin Image Based Proced Fairness AI Med Imaging Ethical Philos Issues Med Imaging (2023) · October 2023
The localization and tracking of neurocranial landmarks is essential in modern medical procedures, e.g., transcranial magnetic stimulation (TMS). However, state-of-the-art treatments still rely on the manual identification of head targets and require setti ...
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Journal ArticleScience advances · September 2023
Nudges are interventions promoting healthy behavior without forbidding options or substantial incentives; the Apple Watch, for example, encourages users to stand by delivering a notification if they have been sitting for the first 50 minutes of an hour. On ...
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Journal ArticleJ Biomed Inform · August 2023
Recent work has shown that predictive models can be applied to structured electronic health record (EHR) data to stratify autism likelihood from an early age (<1 year). Integrating clinical narratives (or notes) with structured data has been shown to impro ...
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Journal ArticleAutism Res · July 2023
Early behavioral markers for autism include differences in social attention and orienting in response to one's name when called, and differences in body movements and motor abilities. More efficient, scalable, objective, and reliable measures of these beha ...
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Journal ArticleSci Rep · May 3, 2023
Differences in social attention are well-documented in autistic individuals, representing one of the earliest signs of autism. Spontaneous blink rate has been used to index attentional engagement, with lower blink rates reflecting increased engagement. We ...
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Journal ArticleNPJ Digit Med · February 3, 2023
Increasing evidence suggests that early motor impairments are a common feature of autism. Thus, scalable, quantitative methods for measuring motor behavior in young autistic children are needed. This work presents an engaging and scalable assessment of vis ...
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Journal ArticleJAMA Netw Open · February 1, 2023
IMPORTANCE: Autism detection early in childhood is critical to ensure that autistic children and their families have access to early behavioral support. Early correlates of autism documented in electronic health records (EHRs) during routine care could all ...
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Journal ArticleIEEE Trans Affect Comput · 2023
Atypical facial expression is one of the early symptoms of autism spectrum disorder (ASD) characterized by reduced regularity and lack of coordination of facial movements. Automatic quantification of these behaviors can offer novel biomarkers for screening ...
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Journal ArticleJ Child Psychol Psychiatry · January 2023
BACKGROUND: Early differences in sensorimotor functioning have been documented in young autistic children and infants who are later diagnosed with autism. Previous research has demonstrated that autistic toddlers exhibit more frequent head movement when vi ...
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Journal ArticleMedical image analysis · January 2023
We present a method for suppressing motion artifacts in anatomical magnetic resonance acquisitions. Our proposed technique, termed MOTOR-MRI, can recover and salvage images which are otherwise heavily corrupted by motion induced artifacts and blur which re ...
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Journal ArticleComput Biol Med · August 2024
Registering the head and estimating the scalp surface are important for various biomedical procedures, including those using neuronavigation to localize brain stimulation or recording. However, neuronavigation systems rely on manually-identified fiducial h ...
Full textLink to itemCite
Journal ArticleJ Autism Dev Disord · June 2024
We report preliminary results of computer vision analysis of caregiver-child interactions during free play with children diagnosed with autism (N = 29, 41-91 months), attention-deficit/hyperactivity disorder (ADHD, N = 22, 48-100 months), or combined autis ...
Full textLink to itemCite
ConferenceConference on Human Factors in Computing Systems - Proceedings · May 11, 2024
Autism, characterized by challenges in socialization and communication, benefits from early detection for prompt and timely intervention. Traditional autism screening questionnaires often exhibit reduced accuracy in primary care settings and significantly ...
Full textCite
Journal ArticleCerebellum (London, England) · April 2024
Dysarthria is a common manifestation across cerebellar ataxias leading to impairments in communication, reduced social connections, and decreased quality of life. While dysarthria symptoms may be present in other neurological conditions, ataxic dysarthria ...
Full textCite
Journal ArticlePLoS One · 2024
BACKGROUND: While early autism intervention can significantly improve outcomes, gaps in implementation exist globally. These gaps are clearest in Africa, where forty percent of the world's children will live by 2050. Task-sharing early intervention to non- ...
Full textLink to itemCite
ConferenceProceedings of Machine Learning Research · January 1, 2024
Group distributional robustness optimization methods (GDRO) learn models that guarantee performance across a broad set of demographics. GDRO is often framed as a minimax game where an adversary proposes data distributions under which the model performs poo ...
Cite
ConferenceProceedings of Machine Learning Research · January 1, 2024
Causal inference on networks faces challenges posed in part by violations of standard identification assumptions due to dependencies between treatment units. Although graph geometry fundamentally influences such dependencies, the potential of geometric too ...
Cite
Journal Articlenpj Digital Medicine · December 1, 2023
Heart rate (HR) response to workout intensity reflects fitness and cardiorespiratory health. Physiological models have been developed to describe such heart rate dynamics and characterize cardiorespiratory fitness. However, these models have been limited t ...
Full textCite
Journal ArticleNat Med · October 2023
Early detection of autism, a neurodevelopmental condition associated with challenges in social communication, ensures timely access to intervention. Autism screening questionnaires have been shown to have lower accuracy when used in real-world settings, su ...
Full textLink to itemCite
ConferenceClin Image Based Proced Fairness AI Med Imaging Ethical Philos Issues Med Imaging (2023) · October 2023
The localization and tracking of neurocranial landmarks is essential in modern medical procedures, e.g., transcranial magnetic stimulation (TMS). However, state-of-the-art treatments still rely on the manual identification of head targets and require setti ...
Full textLink to itemCite
Journal ArticleScience advances · September 2023
Nudges are interventions promoting healthy behavior without forbidding options or substantial incentives; the Apple Watch, for example, encourages users to stand by delivering a notification if they have been sitting for the first 50 minutes of an hour. On ...
Full textCite
Journal ArticleJ Biomed Inform · August 2023
Recent work has shown that predictive models can be applied to structured electronic health record (EHR) data to stratify autism likelihood from an early age (<1 year). Integrating clinical narratives (or notes) with structured data has been shown to impro ...
Full textLink to itemCite
Journal ArticleAutism Res · July 2023
Early behavioral markers for autism include differences in social attention and orienting in response to one's name when called, and differences in body movements and motor abilities. More efficient, scalable, objective, and reliable measures of these beha ...
Full textLink to itemCite
Journal ArticleSci Rep · May 3, 2023
Differences in social attention are well-documented in autistic individuals, representing one of the earliest signs of autism. Spontaneous blink rate has been used to index attentional engagement, with lower blink rates reflecting increased engagement. We ...
Full textLink to itemCite
Journal ArticleNPJ Digit Med · February 3, 2023
Increasing evidence suggests that early motor impairments are a common feature of autism. Thus, scalable, quantitative methods for measuring motor behavior in young autistic children are needed. This work presents an engaging and scalable assessment of vis ...
Full textOpen AccessLink to itemCite
Journal ArticleJAMA Netw Open · February 1, 2023
IMPORTANCE: Autism detection early in childhood is critical to ensure that autistic children and their families have access to early behavioral support. Early correlates of autism documented in electronic health records (EHRs) during routine care could all ...
Full textLink to itemCite
Journal ArticleIEEE Trans Affect Comput · 2023
Atypical facial expression is one of the early symptoms of autism spectrum disorder (ASD) characterized by reduced regularity and lack of coordination of facial movements. Automatic quantification of these behaviors can offer novel biomarkers for screening ...
Full textLink to itemCite
Journal ArticleJ Child Psychol Psychiatry · January 2023
BACKGROUND: Early differences in sensorimotor functioning have been documented in young autistic children and infants who are later diagnosed with autism. Previous research has demonstrated that autistic toddlers exhibit more frequent head movement when vi ...
Full textLink to itemCite
Journal ArticleMedical image analysis · January 2023
We present a method for suppressing motion artifacts in anatomical magnetic resonance acquisitions. Our proposed technique, termed MOTOR-MRI, can recover and salvage images which are otherwise heavily corrupted by motion induced artifacts and blur which re ...
Full textCite
Journal ArticleAutism · August 2022
Many studies of autism look at the differences in how autistic research participants look at certain types of images. These studies often focus on where research participants are looking within the image, but that does not tell us everything about how much ...
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ConferenceACM International Conference Proceeding Series · June 21, 2022
Federated learning is an increasingly popular paradigm that enables a large number of entities to collaboratively learn better models. In this work, we study minimax group fairness in federated learning scenarios where different participating entities may ...
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Journal ArticleInt J Comput Assist Radiol Surg · March 2022
PURPOSE: Reconstructive surgeries to treat a number of musculoskeletal conditions, from arthritis to severe trauma, involve implant placement and reconstructive planning components. Anatomically matched 3D-printed implants are becoming increasingly patient ...
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Journal ArticleInt J Eat Disord · January 2022
OBJECTIVE: To characterize helpful parent feeding strategies using reflections on childhood eating experiences of adults with symptoms of Avoidant/Restrictive Food Intake Disorder (ARFID). METHOD: We explored a unique text-based dataset gathered from a pop ...
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Journal ArticleIEEE access : practical innovations, open solutions · January 2022
Eye movement assessments have the potential to help in diagnosis and tracking of neurological disorders. Cerebellar ataxias cause profound and characteristic abnormalities in smooth pursuit, saccades, and fixation. Oculomotor dysmetria (i.e., hypermetric a ...
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Journal ArticleJournal of Machine Learning Research · January 1, 2022
Encoding the scale information explicitly into the representation learned by a convolutional neural network (CNN) is beneficial for many computer vision tasks especially when dealing with multiscale inputs. We study, in this paper, a scaling-translation-eq ...
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Journal ArticleFront Psychiatry · 2022
Diffusion tensor imaging (DTI) has been used as an outcome measure in clinical trials for several psychiatric disorders but has rarely been explored in autism clinical trials. This is despite a large body of research suggesting altered white matter structu ...
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Journal ArticleBME frontiers · January 2022
Objective and Impact Statement. We use deep learning models to classify cervix images-collected with a low-cost, portable Pocket colposcope-with biopsy-confirmed high-grade precancer and cancer. We boost classification performance on a screened-posi ...
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Journal ArticleJ Child Psychol Psychiatry · September 2021
BACKGROUND: This study is part of a larger research program focused on developing objective, scalable tools for digital behavioral phenotyping. We evaluated whether a digital app delivered on a smartphone or tablet using computer vision analysis (CVA) can ...
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Journal ArticleJAMA Pediatr · August 1, 2021
IMPORTANCE: Atypical eye gaze is an early-emerging symptom of autism spectrum disorder (ASD) and holds promise for autism screening. Current eye-tracking methods are expensive and require special equipment and calibration. There is a need for scalable, fea ...
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Journal ArticleHuman brain mapping · June 2021
Deep brain stimulation (DBS) surgery has been shown to dramatically improve the quality of life for patients with various motor dysfunctions, such as those afflicted with Parkinson's disease (PD), dystonia, and essential tremor (ET), by relieving motor sym ...
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ConferenceIEEE Computer Society Conference on Computer Vision and Pattern Recognition Workshops · June 1, 2021
Image retrieval relies heavily on the quality of the data modeling and the distance measurement in the feature space. Building on the concept of image manifold, we first propose to represent the feature space of images, learned via neural networks, as a gr ...
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Journal ArticleAutism Res · March 2021
Commonly used screening tools for autism spectrum disorder (ASD) generally rely on subjective caregiver questionnaires. While behavioral observation is more objective, it is also expensive, time-consuming, and requires significant expertise to perform. As ...
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Journal ArticleIEEE Trans Affect Comput · 2021
Observational behavior analysis plays a key role for the discovery and evaluation of risk markers for many neurodevelopmental disorders. Research on autism spectrum disorder (ASD) suggests that behavioral risk markers can be observed at 12 months of age or ...
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Journal ArticleIEEE Trans Affect Comput · 2021
Autism spectrum disorder (ASD) is associated with deficits in the processing of social information and difficulties in social interaction, and individuals with ASD exhibit atypical attention and gaze. Traditionally, gaze studies have relied upon precise an ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · January 2021
Spoofing attacks are critical threats to modern face recognition systems, and most common countermeasures exploit 2D texture features as they are easy to extract and deploy. 3D shape-based methods can substantially improve spoofing prevention, but extracti ...
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ConferenceICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · January 1, 2021
Deep neural networks models are generally designed and trained for a specific type and quality of data. In this work, we address this problem in the context of nested learning. For many applications, both the input data, at training and testing, and the pr ...
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ConferenceProceedings - IEEE International Conference on Robotics and Automation · January 1, 2021
In this paper, we introduce Cirrus, a new long-range bi-pattern LiDAR public dataset for autonomous driving tasks such as 3D object detection, critical to highway driving and timely decision making. Our platform is equipped with a high-resolution video cam ...
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ConferenceProceedings of Machine Learning Research · January 1, 2021
Much of the work in the field of group fairness addresses disparities between predefined groups based on protected features such as gender, age, and race, which need to be available at train, and often also at test, time. These approaches are static and re ...
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Journal ArticleAutism · October 2020
This was a project in primary care for young children (1-2 years old). We tested a parent questionnaire on a tablet. This tablet questionnaire asked questions to see whether the child may have autism. We compared the paper and pencil version of the questio ...
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Journal ArticleScientific reports · October 2020
Eye movements are disrupted in many neurodegenerative diseases and are frequent and early features in conditions affecting the cerebellum. Characterizing eye movements is important for diagnosis and may be useful for tracking disease progression and respon ...
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Journal ArticleAutism Res · August 2020
To improve early identification of autism spectrum disorder (ASD), we need objective, reliable, and accessible measures. To that end, a previous study demonstrated that a tablet-based application (app) that assessed several autism risk behaviors distinguis ...
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Journal ArticleProc Mach Learn Res · August 2020
Seizures are a common emergency in the neonatal intesive care unit (NICU) among newborns receiving therapeutic hypothermia for hypoxic ischemic encephalopathy. The high incidence of seizures in this patient population necessitates continuous electroencepha ...
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Journal ArticleSci Rep · July 2, 2020
Ollivier-Ricci curvature is a method for measuring the robustness of connections in a network. In this work, we use curvature to measure changes in robustness of brain networks in children with autism spectrum disorder (ASD). In an open label clinical tria ...
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Journal ArticleIEEE transactions on pattern analysis and machine intelligence · July 2020
Active illumination is a prominent complement to enhance 2D face recognition and make it more robust, e.g., to spoofing attacks and low-light conditions. In the present work we show that it is possible to adopt active illumination to enhance state-of-the-a ...
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ConferenceAnnual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference · July 2020
We apply feature-extraction and machine learning methods to multiple sources of contrast (acetic acid, Lugol's iodine and green light) from the white Pocket Colposcope, a low-cost point of care colposcope for cervical cancer screening. We combine features ...
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Journal ArticleSci Rep · February 5, 2020
Autism Spectrum Disorder (ASD) is characterized by early attentional differences that often precede the hallmark symptoms of social communication impairments. Development of novel measures of attentional behaviors may lead to earlier identification of chil ...
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Journal ArticleSci Rep · January 14, 2020
An amendment to this paper has been published and can be accessed via a link at the top of the paper. ...
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Journal ArticleAdvances in Neural Information Processing Systems · January 1, 2020
In this paper, we consider domain-invariant deep learning by explicitly modeling domain shifts with only a small amount of domain-specific parameters in a Convolutional Neural Network (CNN). By exploiting the observation that a convolutional filter can be ...
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Journal ArticleIEEE Transactions on Signal Processing · January 1, 2020
Following a comment correspondence paper, we agree that there is a mistake in one of the formulas in the paper "Deep Neural Networks with Random Gaussian Weights: A Universal Classification Strategy? "We show that this error only impacts one claim in the o ...
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Conference8th International Conference on Learning Representations, ICLR 2020 · January 1, 2020
While generative adversarial networks (GANs) have revolutionized machine learning, a number of open questions remain to fully understand them and exploit their power. One of these questions is how to efficiently achieve proper diversity and sampling of the ...
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ConferenceProceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition · January 1, 2020
Deep neural networks (DNNs) are notorious for their vulnerability to adversarial attacks, which are small perturbations added to their input images to mislead their prediction. Detection of adversarial examples is, therefore, a fundamental requirement for ...
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Conference37th International Conference on Machine Learning, ICML 2020 · January 1, 2020
In this work we formulate and formally characterize group fairness as a multi-objective optimization problem, where each sensitive group risk is a separate objective. We propose a fairness criterion where a classifier achieves minimax risk and is Pareto-ef ...
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ConferenceAdvances in Neural Information Processing Systems · January 1, 2020
Agents trained via deep reinforcement learning (RL) routinely fail to generalize to unseen environments, even when these share the same underlying dynamics as the training levels. Understanding the generalization properties of RL is one of the challenges o ...
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Journal ArticleProceedings - 2019 International Conference on Computer Vision Workshop, ICCVW 2019 · October 1, 2019
LiDAR-based 3D object detection plays a crucial role in modern autonomous driving systems. LiDAR data often exhibit severe changes in properties across different observation ranges. In this paper, we explore cross-range adaptation for 3D object detection u ...
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Journal ArticleProceedings - 2019 International Conference on Computer Vision Workshop, ICCVW 2019 · October 1, 2019
Traditional gaze estimation methods typically require explicit user calibration to achieve high accuracy. This process is cumbersome and recalibration is often required when there are changes in factors such as illumination and pose. To address this challe ...
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Journal ArticleScientific reports · September 2019
Fragile X Syndrome (FXS), a common inheritable form of intellectual disability, is known to alter neocortical circuits. However, its impact on the diverse synapse types comprising these circuits, or on the involvement of astrocytes, is not well known. We u ...
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ConferenceProceedings - International Conference on Image Processing, ICIP · September 1, 2019
Extracting the instantaneous heart rate (iHR) from face videos has been well studied in recent years. It is well known that changes in skin color due to blood flow can be captured using conventional cameras. One of the main limitations of methods that rely ...
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Journal ArticleIEEE Trans Biomed Eng · August 2019
GOAL: In this paper, we propose methods for (1) automatic feature extraction and classification for acetic acid and Lugol's iodine cervigrams and (2) methods for combining features/diagnosis of different contrasts in cervigrams for improved performance. ME ...
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Journal ArticleAutism · April 2019
To demonstrate the capability of computer vision analysis to detect atypical orienting and attention behaviors in toddlers with autism spectrum disorder. One hundered and four toddlers of 16-31 months old (mean = 22) participated in this study. Twenty-two ...
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Journal ArticleNeurosurgery · March 2019
BackgroundDeep brain stimulation (DBS) of the subthalamic nucleus (STN) is a proven and effective therapy for the management of the motor symptoms of Parkinson's disease (PD). While accurate positioning of the stimulating electrode is critical for ...
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Journal ArticleCurr Opin Biomed Eng · March 2019
Despite significant recent advances in molecular genetics and neuroscience, behavioral ratings based on clinical observations are still the gold standard for screening, diagnosing, and assessing outcomes in neurodevelopmental disorders, including autism sp ...
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Journal ArticleHuman brain mapping · February 2019
Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has shown clinical potential for relieving the motor symptoms of advanced Parkinson's disease. While accurate localization of the STN is critical for consistent across-patients effective DBS, cl ...
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Journal ArticleIEEE Access · January 1, 2019
Fluctuation-based dispersion entropy (FDispEn) is a new approach to estimate the dynamical variability of the fluctuations of signals. It is based on Shannon entropy and fluctuation-based dispersion patterns. To quantify the physiological dynamics over mul ...
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Journal ArticleFrontiers in neuroscience · January 2019
The use of Artificial Intelligence and machine learning in basic research and clinical neuroscience is increasing. AI methods enable the interpretation of large multimodal datasets that can provide unbiased insights into the fundamental principles of brain ...
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Conference36th International Conference on Machine Learning, ICML 2019 · January 1, 2019
Data collection and sharing are pervasive aspects of modern society. This process can either be voluntary, as in the case of a person taking a facial image to unlock his/her phone, or incidental, such as traffic cameras collecting videos on pedestrians. An ...
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Journal ArticleProceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition · December 14, 2018
Deep neural networks have proved very successful on archetypal tasks for which large training sets are available, but when the training data are scarce, their performance suffers from overfitting. Many existing methods of reducing overfitting are data-inde ...
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Journal ArticleProceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition · December 14, 2018
Deep neural networks trained using a softmax layer at the top and the cross-entropy loss are ubiquitous tools for image classification. Yet, this does not naturally enforce intra-class similarity nor inter-class margin of the learned deep representations. ...
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Journal ArticleSci Rep · November 19, 2018
Evidence suggests that differences in motor function are an early feature of autism spectrum disorder (ASD). One aspect of motor ability that develops during childhood is postural control, reflected in the ability to maintain a steady head and body positio ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · September 10, 2018
Multi-image alignment, bringing a group of images into common register, is an ubiquitous problem and the first step of many applications in a wide variety of domains. As a result, a great amount of effort is being invested in developing efficient multi-ima ...
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ConferenceICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · September 10, 2018
Diagnosis of melanoma is fraught with uncertainty, and discordance rates among physicians remain high because of the lack of a definitive criterion. Motivated by this challenge, this paper first introduces the Patch Weyl transform (PWT), a 2-dimensional va ...
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ConferenceICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · September 10, 2018
Accelerating iterative algorithms for solving inverse problems using neural networks have become a very popular strategy in the recent years. In this work, we propose a theoretical analysis that may provide an explanation for its success. Our theory relies ...
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Journal ArticleStructure (London, England : 1993) · June 2018
The advent of direct electron detectors has enabled the routine use of single-particle cryo-electron microscopy (EM) approaches to determine structures of a variety of protein complexes at near-atomic resolution. Here, we report the development of methods ...
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Journal ArticleIEEE Transactions on Signal Processing · April 1, 2018
Solving inverse problems with iterative algorithms is popular, especially for large data. Due to time constraints, the number of possible iterations is usually limited, potentially affecting the achievable accuracy. Given an error one is willing to tolerat ...
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Journal ArticleJ Neurosci · February 14, 2018
With ever-increasing advancements in technology, neuroscientists are able to collect data in greater volumes and with finer resolution. The bottleneck in understanding how the brain works is consequently shifting away from the amount and type of data we ca ...
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Journal ArticleNeuroImage · February 2018
We present a sparse Bayesian unmixing algorithm BusineX: Bayesian Unmixing for Sparse Inference-based Estimation of Fiber Crossings (X), for estimation of white matter fiber parameters from compressed (under-sampled) diffusion MRI (dMRI) data. BusineX comb ...
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Journal ArticleLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · January 1, 2018
In this paper, we introduce a random forest semantic hashing scheme that embeds tiny convolutional neural networks (CNN) into shallow random forests. A binary hash code for a data point is obtained by a set of decision trees, setting ‘1’ for the visited tr ...
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Journal Article35th International Conference on Machine Learning, ICML 2018 · January 1, 2018
Filters in a Convolutional Neural Network (CNN) contain model parameters learned from enormous amounts of data. In this paper, we suggest to decompose convolutional filters in CNN as a truncated expansion with pre-fixed bases, namely the Decomposed Convolu ...
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Journal ArticlePLoS One · 2018
Volitional exploration and learning are key to adaptive behavior, yet their characterization remains a complex problem for cognitive science. Exploration has been posited as a mechanism by which motivation promotes memory, but this relationship is not well ...
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Journal ArticlePloS one · January 2018
Understanding how groups of neurons interact within a network is a fundamental question in system neuroscience. Instead of passively observing the ongoing activity of a network, we can typically perturb its activity, either by external sensory stimulation ...
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ConferenceProgress in Biomedical Optics and Imaging - Proceedings of SPIE · January 1, 2018
The world health organization recommends visual inspection with acetic acid (VIA) and/or Lugol's Iodine (VILI) for cervical cancer screening in low-resource settings. Human interpretation of diagnostic indicators for visual inspection is qualitative, subje ...
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Journal ArticleFrontiers in neuroanatomy · January 2018
Application-specific validation of antibodies is a critical prerequisite for their successful use. Here we introduce an automated framework for characterization and screening of antibodies against synaptic molecules for high-resolution immunofluorescence a ...
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Journal ArticlePloS one · January 2018
ObjectiveDeep brain stimulation (DBS) requires accurate localization of the anatomical target structure, and the precise placement of the DBS electrode within it. Ultra-high field 7 Tesla (T) MR images can be utilized to create patient-specific an ...
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Journal ArticleNPJ Digit Med · 2018
Current tools for objectively measuring young children's observed behaviors are expensive, time-consuming, and require extensive training and professional administration. The lack of scalable, reliable, and validated tools impacts access to evidence-based ...
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Journal ArticleProceedings - 30th IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2017 · November 6, 2017
Surveillance cameras today often capture NIR (near infrared) images in low-light environments. However, most face datasets accessible for training and verification are only collected in the VIS (visible light) spectrum. It remains a challenging problem to ...
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Journal ArticleProceedings - 30th IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2017 · November 6, 2017
In this paper, a self-learning approach is proposed towards solving scene-specific pedestrian detection problem without any human' annotation involved. The self-learning approach is deployed as progressive steps of object discovery, object enforcement, and ...
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ConferenceProceedings - 30th IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2017 · November 6, 2017
Motion blur from camera shake is a major problem in videos captured by hand-held devices. Unlike single-image deblurring, video-based approaches can take advantage of the abundant information that exists across neighboring frames. As a result the best perf ...
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ConferenceProceedings - 30th IEEE Conference on Computer Vision and Pattern Recognition, CVPR 2017 · November 6, 2017
In this work, we introduce a highly efficient algorithm to address the nonnegative matrix underapproximation (NMU) problem, i.e., nonnegative matrix factorization (NMF) with an additional underapproximation constraint. NMU results are interesting as, compa ...
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ConferenceMedical image computing and computer-assisted intervention : MICCAI ... International Conference on Medical Image Computing and Computer-Assisted Intervention · September 2017
We propose a sparse Bayesian learning algorithm for improved estimation of white matter fiber parameters from compressed (under-sampled q-space) multi-shell diffusion MRI data. The multi-shell data is represented in a dictionary form using a non-monoexpone ...
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Conference2017 12th International Conference on Sampling Theory and Applications, SampTA 2017 · September 1, 2017
Understanding the generalization properties of deep learning models is critical for their successful usage in many applications, especially in the regimes where the number of training samples is limited. We study the generalization properties of deep neura ...
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Journal ArticleIEEE Transactions on Signal Processing · August 15, 2017
The generalization error of deep neural networks via their classification margin is studied in this paper. Our approach is based on the Jacobian matrix of a deep neural network and can be applied to networks with arbitrary nonlinearities and pooling layers ...
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ConferenceProceedings - 2017 IEEE International Conference on Computer Vision Workshops, ICCVW 2017 · July 1, 2017
Deep Neural Networks (DNNs) that achieve state-of-the-art results are still prone to suffer performance degradation when deployed in many real-world scenarios due to shifts between the training and deployment domains. Limited data from a given setting can ...
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ConferenceProceedings - 2017 IEEE International Conference on Computer Vision Workshops, ICCVW 2017 · July 1, 2017
Privacy and fairness are critical in computer vision applications, in particular when dealing with human identification. Achieving a universally secure, private, and fair systems is practically impossible as the exploitation of additional data can reveal p ...
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Journal ArticleJ Pediatr · April 2017
OBJECTIVES: To assess changes in quality of care for children at risk for autism spectrum disorders (ASD) due to process improvement and implementation of a digital screening form. STUDY DESIGN: The process of screening for ASD was studied in an academic p ...
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Journal ArticlePLoS computational biology · April 2017
Deeper exploration of the brain's vast synaptic networks will require new tools for high-throughput structural and molecular profiling of the diverse populations of synapses that compose those networks. Fluorescence microscopy (FM) and electron microscopy ...
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Conference2016 6th International Conference on Image Processing Theory, Tools and Applications, IPTA 2016 · January 17, 2017
Recent studies validated the feasibility of estimating heart rate from human faces in RGB video. However, test subjects are often recorded under controlled conditions, as illumination variations significantly affect the RGB-based heart rate estimation accu ...
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Journal ArticlePloS one · January 2017
BackgroundDeep brain stimulation (DBS) is an established clinical therapy and computational models have played an important role in advancing the technology. Patient-specific DBS models are now common tools in both academic and industrial research ...
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ConferenceProceedings of the 20th International Conference on Artificial Intelligence and Statistics, AISTATS 2017 · January 1, 2017
Copyright 2017 by the author(s). This paper studies the generalization error of invariant classifiers. In particular, we consider the common scenario where the classification task is invariant to certain transformations of the input, and that the classifie ...
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ConferenceProceedings of the 20th International Conference on Artificial Intelligence and Statistics, AISTATS 2017 · January 1, 2017
This paper studies the generalization error of invariant classifiers. In particular, we consider the common scenario where the classification task is invariant to certain transformations of the input, and that the classifier is constructed (or learned) to ...
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Journal ArticleBiomed Opt Express · December 1, 2016
Patient motion artifacts are often visible in densely sampled or large wide field-of-view (FOV) retinal optical coherence tomography (OCT) volumes. A popular strategy for reducing motion artifacts is to capture two orthogonally oriented volumetric scans. H ...
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Journal ArticleIEEE transactions on pattern analysis and machine intelligence · November 2016
Finding an informative subset of a large collection of data points or models is at the center of many problems in computer vision, recommender systems, bio/health informatics as well as image and natural language processing. Given pairwise dissimilarities ...
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Journal ArticleIEEE Transactions on Signal Processing · November 1, 2016
The performance of multiimage alignment, bringing different images into one coordinate system, is critical in many applications with varied signal-to-noise ratio (SNR) conditions. A great amount of effort is being invested into developing methods to solve ...
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ConferenceProceedings of the IEEE Sensor Array and Multichannel Signal Processing Workshop · September 15, 2016
The interest in problems related to graph inference has been increasing significantly during the last decade. However, the vast majority of the problems addressed are either static, or systems where changes in one node are immediately reflected in other no ...
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Journal ArticleIEEE Transactions on Signal Processing · July 1, 2016
Three important properties of a classification machinery are i) the system preserves the core information of the input data; ii) the training examples convey information about unseen data; and iii) the system is able to treat differently points from differ ...
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ConferenceICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · May 18, 2016
The short-time Fourier transform (STFT) is widely used to analyze the spectra of temporal signals that vary through time. Signals defined over graphs, due to their intrinsic complexity, exhibit large variations in their patterns. In this work we propose a ...
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Journal ArticleIEEE Transactions on Signal Processing · May 1, 2016
Nonnegative matrix factorization (NMF) has an established reputation as a useful data analysis technique in numerous applications. However, its usage in practical situations is undergoing challenges in recent years. The fundamental factor to this is the in ...
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Journal ArticleIEEE Transactions on Signal Processing · April 1, 2016
The Weyl transform is introduced as a rich framework for data representation. Transform coefficients are connected to the Walsh-Hadamard transform of multiscale autocorrelations, and different forms of dyadic periodicity in a signal are shown to appear as ...
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Journal ArticleIEEE transactions on pattern analysis and machine intelligence · January 2016
Graph matching-aligning a pair of graphs to minimize their edge disagreements-has received wide-spread attention from both theoretical and applied communities over the past several decades, including combinatorics, computer vision, and connectomics. Its at ...
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ConferenceCommunications in Computer and Information Science · January 1, 2016
Gaze analysis has gained much popularity over the years due to its relevance in a wide array of applications, including humancomputer interaction, fatigue detection, and clinical mental health diagnosis. However, accurate gaze estimation from low resolutio ...
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Journal ArticlePLoS One · 2016
Early childhood anxiety disorders are common, impairing, and predictive of anxiety and mood disorders later in childhood. Epidemiological studies over the last decade find that the prevalence of impairing anxiety disorders in preschool children ranges from ...
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Chapter · January 1, 2016
We present a novel sparse modeling approach to non-rigid shape matching using only the ability to detect repeatable regions. As the input to our algorithm, we are given only two sets of regions in two shapes; no descriptors are provided so the corresponden ...
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ConferenceProceedings - International Conference on Image Processing, ICIP · December 9, 2015
This paper presents a prediction framework of brain subcortical structures which are invisible on clinical low-field MRI, learning detailed information from ultrahigh-field MR training data. Volumetric segmentation of Deep Brain Stimulation (DBS) structure ...
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ConferenceProceedings - International Conference on Image Processing, ICIP · December 9, 2015
A common task in video processing is the binary separation of a video's content into either background or moving foreground. However, many situations require a foreground analysis with a finer temporal granularity, in particular for objects or people which ...
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ConferenceProceedings - International Conference on Image Processing, ICIP · December 9, 2015
In this work, we present a dictionary learning based framework for robust, cross-modality, and pose-invariant facial expression recognition. The proposed framework first learns a dictionary that i) contains both 3D shape and morphological information as we ...
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Journal ArticleIEEE Transactions on Computational Imaging · December 1, 2015
Videos captured with hand-held cameras often suffer from a significant amount of blur, mainly caused by the inevitable natural tremor of the photographer's hand. In this work, we present an algorithm that removes blur due to camera shake by combining infor ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · November 2015
Numerous recent approaches attempt to remove image blur due to camera shake, either with one or multiple input images, by explicitly solving an inverse and inherently ill-posed deconvolution problem. If the photographer takes a burst of images, a modality ...
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ConferenceProceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition · October 14, 2015
Numerous recent approaches attempt to remove image blur due to camera shake, either with one or multiple input images, by explicitly solving an inverse and inherently ill-posed deconvolution problem. If the photographer takes a burst of images, a modality ...
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Chapter · October 2015
The RubiX [1] algorithm combines high SNR characteristics of low resolution data with high spacial specificity of high resolution data, to extract microstructural tissue parameters from diffusion MRI. In this paper we focus on estimating crossing fiber ori ...
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Journal ArticleIEEE transactions on pattern analysis and machine intelligence · September 2015
Parsimony, including sparsity and low rank, has been shown to successfully model data in numerous machine learning and signal processing tasks. Traditionally, such modeling approaches rely on an iterative algorithm that minimizes an objective function with ...
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ConferenceICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · August 4, 2015
High dimensional data is modeled using low-rank subspaces, and the probability of misclassification is expressed in terms of the principal angles between subspaces. The form taken by this expression motivates the design of a new feature extraction method t ...
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ConferenceProceedings - International Symposium on Biomedical Imaging · July 21, 2015
The subthalamic nucleus (STN) within the sub-cortical region of the Basal ganglia is a crucial targeting structure for Parkinson's Deep brain stimulation (DBS) surgery. Volumetric segmentation of such small and complex structure, which is elusive in clinic ...
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Journal ArticleSignificance · April 1, 2015
Recent press reports would have you believe that cancer develops randomly, and healthy living makes little difference. But that is a gross misinterpretation of a recent scientific paper, as Joseph E. Lucas and Guillermo Sapiro explain. ...
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Journal ArticleInformation and Inference · March 1, 2015
Problems related to graph matching and isomorphisms are very important both from a theoretical and practical perspective, with applications ranging from image and video analysis to biological and biomedical problems. The graph matching problem is challengi ...
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ConferenceProceedings of the IEEE International Conference on Computer Vision · February 17, 2015
Many recent efforts have been devoted to designing sophisticated deep learning structures, obtaining revolutionary results on benchmark datasets. The success of these deep learning methods mostly relies on an enormous volume of labeled training samples to ...
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Journal ArticleJournal of Machine Learning Research · February 1, 2015
A low-rank transformation learning framework for subspace clustering and classification is proposed here. Many high-dimensional data, such as face images and motion sequences, approximately lie in a union of low-dimensional subspaces. The corresponding sub ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · January 2015
Compressive sensing of signals drawn from a Gaussian mixture model (GMM) admits closed-form minimum mean squared error reconstruction from incomplete linear measurements. An accurate GMM signal model is usually not available a priori, because it is difficu ...
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ConferenceLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · January 1, 2015
This work introduces a robust framework for predicting Deep Brain Stimulation (DBS) target structures which are not identifiable on standard clinical MRI. While recent high-field MR imaging allows clear visualization of DBS target structures, such high-fie ...
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ConferenceAdvances in Neural Information Processing Systems · January 1, 2015
This paper proposes a framework for learning features that are robust to data variation, which is particularly important when only a limited number of training samples are available. The framework makes it possible to tradeoff the discriminative value of l ...
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ConferenceLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · January 1, 2015
Given a universe of local communities of a large network, we aim at identifying the meaningful and consistent communities in it. We address this from a new perspective as the process of obtaining consensual community detections and formalize it as a bi-clu ...
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Conference · January 1, 2015
Video camera architects must design cameras capable of high-quality, dynamic event capture, while adhering to power and communications constraints. Though modern imagers are capable of both simultaneous spatial and temporal resolutions at micrometer and mi ...
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Chapter · January 1, 2015
Source separation is a widely studied problem in signal processing. Despite the permanent progress reported in the literature it is still considered a significant challenge. This chapter first reviews the use of non-negative matrix factorization (NMF) algo ...
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Conference3rd International Conference on Learning Representations, ICLR 2015 - Workshop Track Proceedings · January 1, 2015
The Weyl transform is introduced as a rich framework for data representation. Transform coefficients are connected to the Walsh-Hadamard transform of multiscale autocorrelations, and different forms of dyadic periodicity in a signal are shown to appear as ...
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Conference3rd International Conference on Learning Representations, ICLR 2015 - Workshop Track Proceedings · January 1, 2015
Hash codes are a very efficient data representation needed to be able to cope with the ever growing amounts of data. We introduce a random forest semantic hashing scheme with information-theoretic code aggregation, showing for the first time how random for ...
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Conference3rd International Conference on Learning Representations, ICLR 2015 - Workshop Track Proceedings · January 1, 2015
In this work we study the properties of deep neural networks (DNN) with random weights. We formally prove that these networks perform a distance-preserving embedding of the data. Based on this we then draw conclusions on the size of the training data and t ...
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Journal ArticleSIAM Journal on Imaging Sciences · November 25, 2014
We consider grouping as a general characterization for problems such as clustering, community detection in networks, and multiple parametric model estimation. We are interested in merging solutions from different grouping algorithms, distilling all their g ...
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Journal ArticleMagnetic resonance in medicine · November 2014
PurposeDiffusion MRI provides important information about the brain white matter structures and has opened new avenues for neuroscience and translational research. However, acquisition time needed for advanced applications can still be a challenge ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · November 2014
A Gaussian mixture model (GMM)-based algorithm is proposed for video reconstruction from temporally compressed video measurements. The GMM is used to model spatio-temporal video patches, and the reconstruction can be efficiently computed based on analytic ...
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ConferenceProceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition · September 24, 2014
A simple and inexpensive (low-power and low-bandwidth) modification is made to a conventional off-the-shelf color video camera, from which we recover multiple color frames for each of the original measured frames, and each of the recovered frames can be fo ...
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Journal ArticleIEEE journal of biomedical and health informatics · September 2014
Volumetric segmentation of subcortical structures, such as the basal ganglia and thalamus, is necessary for noninvasive diagnosis and neurosurgery planning. This is a challenging problem due in part to limited boundary information between structures, simil ...
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Journal ArticleNeuroImage · August 2014
We introduce a framework for population analysis of white matter tracts based on diffusion-weighted images of the brain. The framework enables extraction of fibers from high angular resolution diffusion images (HARDI); clustering of the fibers based partly ...
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Journal ArticlePLoS biology · March 2014
Candida albicans, the most prevalent human fungal pathogen, is generally diploid. However, 50% of isolates that are resistant to fluconazole (FLC), the most widely used antifungal, are aneuploid and some aneuploidies can confer FLC resistance. To ask if FL ...
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Conference2014 IEEE International Conference on Image Processing, ICIP 2014 · January 28, 2014
Learning a transformation-based dimension reduction, thereby compressive, technique for classification is here proposed. High-dimensional data often approximately lie in a union of low-dimensional subspaces. We propose to perform dimension reduction by lea ...
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Conference2014 IEEE International Conference on Image Processing, ICIP 2014 · January 28, 2014
A low-rank transformation learning framework for subspace clustering and classification is here proposed. Many high-dimensional data, such as face images and motion sequences, approximately lie in a union of low-dimensional subspaces. The corresponding sub ...
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Conference2014 IEEE International Conference on Image Processing, ICIP 2014 · January 28, 2014
We present a simple and powerful technique for testing with a prescribed precision whether a set of 2D lines meet at a given point. The method is based on a probabilistic framework and has a fundamental geometric interpretation. We use this technique for d ...
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Journal ArticleAutism Res Treat · 2014
The early detection of developmental disorders is key to child outcome, allowing interventions to be initiated which promote development and improve prognosis. Research on autism spectrum disorder (ASD) suggests that behavioral signs can be observed late i ...
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Journal Article2014 4th Joint Workshop on Hands-Free Speech Communication and Microphone Arrays, HSCMA 2014 · January 1, 2014
Traditionally, NMF algorithms consist of two separate stages: a training stage, in which a generative model is learned; and a testing stage in which the pre-learned model is used in a high level task such as enhancement, separation, or classification. As a ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · January 1, 2014
Early detection and treatment of psychiatric disorders on children has shown significant impact in their subsequent development and quality of life. The assessment of psychopathology in childhood is commonly carried out by performing long comprehensive int ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · January 1, 2014
Given an universe of distinct, low-level communities of a network, we aim at identifying the 'meaningful' and consistent communities in this universe. We address this as the process of obtaining consensual community detections and formalize it as a bi-clus ...
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ConferenceMathematics and Visualization · January 1, 2014
The ‘rich club’ is a relatively new concept in brain connectivity analysis, which identifies a core of densely interconnected high-degree nodes. Establishing normative measures for rich club organization is vital, as is understanding how scanning parameter ...
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ConferenceProceeding of the International Congress of Mathematicans, ICM 2014 · January 1, 2014
In this paper we briefly present some of Stanley Osher's contributions in the areas of high resolution shock capturing methods, level set methods, partial differential equation (PDE) based methods in computer vision and image processing, and optimization. ...
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Conference2nd International Conference on Learning Representations, ICLR 2014 - Conference Track Proceedings · January 1, 2014
In recent years, a lot of attention has been devoted to efficient nearest neighbor search by means of similarity-preserving hashing. One of the plights of existing hashing techniques is the intrinsic trade-off between performance and computational complexi ...
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Conference2nd International Conference on Learning Representations, ICLR 2014 - Conference Track Proceedings · January 1, 2014
This work introduces a transformation-based learner model for classification forests. The weak learner at each split node plays a crucial role in a classification tree. We propose to optimize the splitting objective by learning a linear transformation on s ...
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Journal ArticleInternational Journal of Pattern Recognition and Artificial Intelligence · January 1, 2014
We present a computer-aided detection pipeline for polyp detection in Computer tomographic colonography. The first stage of the pipeline consists of a simple colon segmentation technique that enhances polyps, which is followed by an adaptive-scale candidat ...
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Journal ArticleLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · December 1, 2013
Computer tomographic colonography, combined with computer-aided detection, is a promising emerging technique for colonic polyp analysis. We present a complete pipeline for polyp detection, starting with a simple colon segmentation technique that enhances p ...
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Journal ArticleIEEE International Conference on Intelligent Robots and Systems · December 1, 2013
Presented are results demonstrating that, in developing a system with its first objective being the sustained detection of adults and young children as they move and interact in a normal preschool setting, the direct application of the straightforward RGB- ...
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Journal ArticleLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · December 1, 2013
We cast the problem of discovering the community structure in networks as the composition of community candidates, obtained from several community detection base algorithms, into a coherent structure. In turn, this composition can be cast into a maximum-we ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · October 18, 2013
A method for removing impulse noise from audio signals by fusing multiple copies of the same recording is introduced in this paper. The proposed algorithm exploits the fact that while in general multiple copies of a given recording are available, all shari ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · October 18, 2013
In this paper we present a framework for real time enhancement of speech signals. Our method leverages a new process-centric approach for sparse and parsimonious models, where the representation pursuit is obtained applying a deterministic function or proc ...
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Journal ArticleProceedings - 2013 3rd International Workshop on Pattern Recognition in Neuroimaging, PRNI 2013 · October 15, 2013
We consider the problem of improving the accuracy and reliability of probabilistic white matter tractography methods by improving the built-in sampling scheme, which randomly draws, from a diffusion model such as the orientation distribution function (ODF) ...
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Journal ArticleNeuroImage · October 2013
The Human Connectome Project (HCP) is a collaborative 5-year effort to map human brain connections and their variability in healthy adults. A consortium of HCP investigators will study a population of 1200 healthy adults using multiple imaging modalities, ...
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Journal ArticleNeuroImage · October 2013
The Human Connectome Project (HCP) relies primarily on three complementary magnetic resonance (MR) methods. These are: 1) resting state functional MR imaging (rfMRI) which uses correlations in the temporal fluctuations in an fMRI time series to deduce 'fun ...
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Journal ArticleIEEE transactions on pattern analysis and machine intelligence · August 2013
Unsupervised multilayered (“deep”) models are considered for imagery. The model is represented using a hierarchical convolutional factor-analysis construction, with sparse factor loadings and scores. The computation of layer-dependent model p ...
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Journal Article · August 1, 2013
We propose a low-rank transformation-learning framework to robustify subspace
clustering. Many high-dimensional data, such as face images and motion
sequences, lie in a union of low-dimensional subspaces. The subspace clustering
problem has been extensivel ...
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Journal Article · August 1, 2013
We present a low-rank transformation approach to compensate for face
variations due to changes in visual domains, such as pose and illumination. The
key idea is to learn discriminative linear transformations for face images
using matrix rank as the optimiz ...
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Journal ArticleMagnetic resonance in medicine · June 2013
PurposeIn diffusion MRI, a technique known as diffusion spectrum imaging reconstructs the propagator with a discrete Fourier transform, from a Cartesian sampling of the diffusion signal. Alternatively, it is possible to directly reconstruct the or ...
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Journal Article · May 29, 2013
Video object segmentation is a challenging problem due to the presence of
deformable, connected, and articulated objects, intra- and inter-object
occlusions, object motion, and poor lighting. Some of these challenges call for
object models that can locate ...
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Journal ArticleHuman brain mapping · May 2013
Human brains are highly convoluted surfaces with multiple folds. To characterize the complexity of these folds and their relationship with neurological and psychiatric conditions, different techniques have been developed to quantify the folding patterns, a ...
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Journal ArticleOptics express · May 2013
We use mechanical translation of a coded aperture for code division multiple access compression of video. We discuss the compressed video's temporal resolution and present experimental results for reconstructions of > 10 frames of temporal data per coded s ...
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Journal ArticleProceedings of the National Academy of Sciences of the United States of America · March 2013
Rapid antigenic variation of HA, the major virion surface protein of influenza A virus, remains the principal challenge to the development of broader and more effective vaccines. Some regions of HA, such as the stem region proximal to the viral membrane, a ...
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Journal ArticleJ Struct Biol · February 2013
The limitation of using low electron doses in non-destructive cryo-electron tomography of biological specimens can be partially offset via averaging of aligned and structurally homogeneous subsets present in tomograms. This type of sub-volume averaging is ...
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Journal ArticleIEEE Transactions on Signal Processing · January 21, 2013
A framework for adaptive and non-adaptive statistical compressive sensing is developed, where a statistical model replaces the standard sparsity model of classical compressive sensing. We propose within this framework optimal task-specific sensing protocol ...
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Journal ArticleAdvances in Neural Information Processing Systems · January 1, 2013
Graph matching is a challenging problem with very important applications in a wide range of fields, from image and video analysis to biological and biomedical problems. We propose a robust graph matching algorithm inspired in sparsity-related techniques. W ...
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Journal Article2013 IEEE International Conference on Image Processing, ICIP 2013 - Proceedings · January 1, 2013
A Gaussian Mixture Model (GMM)-based algorithm is proposed for video reconstruction from temporal compressed measurements. The GMM is used to model spatio-temporal video patches, and the reconstruction can be efficiently computed based on analytic expressi ...
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Journal Article2013 IEEE International Conference on Image Processing, ICIP 2013 - Proceedings · January 1, 2013
Splines are a popular and attractive way of smoothing noisy data. Computing splines involves minimizing a functional which is a linear combination of a fitting term and a regularization term. The former is classically computed using a (sometimes weighted) ...
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Journal ArticleAdvances in Neural Information Processing Systems · January 1, 2013
In this paper, we propose a new computationally efficient framework for learning sparse models. We formulate a unified approach that contains as particular cases models promoting sparse synthesis and analysis type of priors, and mixtures thereof. The super ...
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Journal ArticleProceedings of the IEEE International Conference on Computer Vision · January 1, 2013
In many image/video/web classification problems, we have access to a large number of unlabeled samples. However, it is typically expensive and time consuming to obtain labels for the samples. Active learning is the problem of progressively selecting and an ...
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ConferenceProceedings of the 14th International Society for Music Information Retrieval Conference, ISMIR 2013 · January 1, 2013
In this work, we propose a trainable sparse model for automatic polyphonic music transcription, which incorporates several successful approaches into a unified optimization framework. Our model combines unsupervised synthesis models similar to latent compo ...
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Journal ArticleIEEE transactions on pattern analysis and machine intelligence · January 2013
Unsupervised multi-layered ("deep") models are considered for general data, with a particular focus on imagery. The model is represented using a hierarchical convolutional factor-analysis construction, with sparse factor loadings and scores. The computatio ...
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Journal ArticleBrain connectivity · January 2013
The quest to map brain connectivity is being pursued worldwide using diffusion imaging, among other techniques. Even so, we know little about how brain connectivity measures depend on the magnetic field strength of the scanner. To investigate this, we scan ...
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Journal ArticleComputer Graphics Forum · January 1, 2013
We present a novel sparse modeling approach to non-rigid shape matching using only the ability to detect repeatable regions. As the input to our algorithm, we are given only two sets of regions in two shapes; no descriptors are provided so the corresponden ...
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Journal ArticleInternational journal of biomedical imaging · January 2013
The acquisition of high angular resolution diffusion MRI is particularly long and subject motion can become an issue. The orientation distribution function (ODF) can be reconstructed online incrementally from diffusion-weighted MRI with a Kalman filtering ...
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Journal Article2013 IEEE International Conference on Image Processing, ICIP 2013 - Proceedings · January 1, 2013
This paper introduces the concept of adaptive temporal compressive sensing (CS) for video. We propose a CS algorithm to adapt the compression ratio based on the scene's temporal complexity, computed from the compressed data, without compromising the qualit ...
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Journal ArticleFrontiers in neuroscience · January 2013
Registration of diffusion-weighted magnetic resonance images (DW-MRIs) is a key step for population studies, or construction of brain atlases, among other important tasks. Given the high dimensionality of the data, registration is usually performed by rely ...
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Journal ArticleACM International Conference Proceeding Series · December 19, 2012
Extracting sentiment from Twitter data is one of the fundamental problems in social media analytics. Twitter's length constraint renders determining the positive/negative sentiment of a tweet difficult, even for a human judge. In this work we present a gen ...
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Journal ArticleStructure (London, England : 1993) · December 2012
Cryo-electron microscopy (cryo-EM) is a powerful technique for 3D structure determination of protein complexes by averaging information from individual molecular images. The resolutions that can be achieved with single-particle cryo-EM are frequently limit ...
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Journal ArticleInformation and Inference · December 1, 2012
We address the problems of multi- and single-domain regression based on distinct and unpaired labeled training sets for each of the domains and a large unlabeled training set from all domains. We formulate these problems as a Bayesian estimation with parti ...
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ConferenceInternational Geoscience and Remote Sensing Symposium (IGARSS) · December 1, 2012
Several studies suggest that the use of geometric features along with spectral information improves the classification and visualization quality of hyperspectral imagery. These studies normally make use of spatial neighborhoods of hyperspectral pixels for ...
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ConferenceProceedings of the 13th International Society for Music Information Retrieval Conference, ISMIR 2012 · December 1, 2012
Separating the leading vocals from the musical accompaniment is a challenging task that appears naturally in several music processing applications. Robust principal component analysis (RPCA) has been recently employed to this problem producing very success ...
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Conference2012 IEEE International Conference on Development and Learning and Epigenetic Robotics, ICDL 2012 · December 1, 2012
The early detection of developmental disorders is key to child outcome, allowing interventions to be initiated that promote development and improve prognosis. Research on autism spectrum disorder (ASD) suggests behavioral markers can be observed late in th ...
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ConferenceIEEE International Conference on Intelligent Robots and Systems · December 1, 2012
Early intervention in mental disorders can dramatically increase an individual's quality of life. Additionally, when symptoms of mental illness appear in childhood or adolescence, they represent the later stages of a process that began years earlier. One g ...
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Journal ArticleProceedings - International Conference on Image Processing, ICIP · December 1, 2012
A simple motion estimation algorithm, light-weighted both in memory and in time, is presented in this paper. This simplicity is achieved by decoupling the matching and the regularization stages in the estimation process. Experiments show that the obtained ...
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Journal ArticleAdvances in Neural Information Processing Systems · December 1, 2012
Graphical models are a very useful tool to describe and understand natural phenomena, from gene expression to climate change and social interactions. The topological structure of these graphs/networks is a fundamental part of the analysis, and in many case ...
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Journal ArticleAdvances in Neural Information Processing Systems · December 1, 2012
Given pairwise dissimilarities between data points, we consider the problem of finding a subset of data points, called representatives or exemplars, that can efficiently describe the data collection. We formulate the problem as a row-sparsity regularized t ...
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Journal Article · October 25, 2012
The early detection of developmental disorders is key to child outcome,
allowing interventions to be initiated that promote development and improve
prognosis. Research on autism spectrum disorder (ASD) suggests behavioral
markers can be observed late in th ...
Open AccessLink to itemCite
Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · October 23, 2012
A framework for learning sensing kernels adapted to signals that follow a Gaussian mixture model (GMM) is introduced in this paper. This follows the paradigm of statistical compressive sensing (SCS), where a statistical model, a GMM in particular, replaces ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · October 23, 2012
A new framework for representing quasi-harmonic signals, and its application to score-informed single channel musical instruments separation, is introduced in this paper. In the proposed approach, the signal's pitch and spectral envelope are modeled separa ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · October 23, 2012
We address the problems of multi-domain and single-domain regression based on distinct labeled training sets for each of the domains and a large unlabeled training set from all domains. We formulate these problems as ones of Bayesian estimation with partia ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · October 23, 2012
Robust low-rank matrix estimation is a topic of increasing interest, with promising applications in a variety of fields, from computer vision to data mining and recommender systems. Recent theoretical results establish the ability of such data models to re ...
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Journal ArticleProceedings of the 29th International Conference on Machine Learning, ICML 2012 · October 10, 2012
We present a comprehensive framework for structured sparse coding and modeling extending the recent ideas of using learnable fast regressors to approximate exact sparse codes. For this purpose, we propose an efficient feed forward architecture derived from ...
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Journal ArticleInternational Journal of Computer Vision · October 1, 2012
An efficient sparse modeling pipeline for the classification of human actions from video is here developed. Spatio-temporal features that characterize local changes in the image are first extracted. This is followed by the learning of a class-structured di ...
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Journal ArticleProceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition · October 1, 2012
We consider the problem of finding a few representatives for a dataset, i.e., a subset of data points that efficiently describes the entire dataset. We assume that each data point can be expressed as a linear combination of the representatives and formulat ...
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Journal Article · September 27, 2012
In this paper we present a comprehensive framework for learning robust
low-rank representations by combining and extending recent ideas for learning
fast sparse coding regressors with structured non-convex optimization
techniques. This approach connects ro ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · September 2012
Sparse data models, where data is assumed to be well represented as a linear combination of a few elements from a dictionary, have gained considerable attention in recent years, and their use has led to state-of-the-art results in many signal and image pro ...
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Journal Article · August 27, 2012
A framework for unsupervised group activity analysis from a single video is
here presented. Our working hypothesis is that human actions lie on a union of
low-dimensional subspaces, and thus can be efficiently modeled as sparse linear
combinations of atoms ...
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Journal Article · August 10, 2012
Splines are a popular and attractive way of smoothing noisy data. Computing
splines involves minimizing a functional which is a linear combination of a
fitting term and a regularization term. The former is classically computed
using a (weighted) L2 norm wh ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · July 2012
A collaborative convex framework for factoring a data matrix X into a nonnegative product AS , with a sparse coefficient matrix S, is proposed. We restrict the columns of the dictionary matrix A to coincide with certain columns of the data matrix X ...
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Journal ArticleIEEE transactions on information technology in biomedicine : a publication of the IEEE Engineering in Medicine and Biology Society · July 2012
Catheters are routinely inserted via vessels to cavities of the heart during fluoroscopic image guided interventions for electrophysiology (EP) procedures such as ablation. During such interventions, the catheter undergoes nonrigid deformation due to physi ...
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Journal ArticleIEEE Transactions on Signal Processing · June 1, 2012
The power of sparse signal modeling with learned overcomplete dictionaries has been demonstrated in a variety of applications and fields, from signal processing to statistical inference and machine learning. However, the statistical properties of these mod ...
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Journal ArticleProceedings of IEEE Workshop on Applications of Computer Vision · May 11, 2012
In developmental disorders such as autism and schizophrenia, observing behavioral precursors in very early childhood can allow for early intervention and can improve patient outcomes. While such precursors open the possibility of broad and large-scale scre ...
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Journal ArticleJ Struct Biol · May 2012
We have previously used cryo-electron tomography combined with sub-volume averaging and classification to obtain 3D structures of macromolecular assemblies in cases where a single dominant species was present, and applied these methods to the analysis of a ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · May 2012
In this paper, the problem of denoising and occlusion restoration of 3-D range data based on dictionary learning and sparse representation methods is explored. We apply these techniques after converting the noisy 3-D surface into one or more images. We pre ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · May 2012
A general framework for solving image inverse problems with piecewise linear estimations is introduced in this paper. The approach is based on Gaussian mixture models, which are estimated via a maximum a posteriori expectation-maximization algorithm. A dua ...
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Journal ArticleMagnetic resonance in medicine · April 2012
Hardware constraints, scanning time limitations, patient movement, and signal-to-noise ratio (SNR) considerations, restrict the slice-selection and the in-plane resolutions of MRI differently, generally resulting in anisotropic voxels. This nonuniform samp ...
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Journal ArticleParagraph · March 2012
Bourdieu's concept of the literary field aimed to overcome the opposition between internal and external analysis of literary works. This paper examines its theoretical and methodological implications by exploring the notion of mediations between t ...
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Journal ArticleSIAM Journal on Imaging Sciences · February 13, 2012
We consider analysis of noisy and incomplete hyperspectral imagery, with the objective of removing the noise and inferring the missing data. The noise statistics may be wavelength dependent, and the fraction of data missing (at random) may be substantial, ...
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Journal ArticleNeuroImage · February 2012
Modern non-invasive brain imaging technologies, such as diffusion weighted magnetic resonance imaging (DWI), enable the mapping of neural fiber tracts in the white matter, providing a basis to reconstruct a detailed map of brain structural connectivity net ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · January 2012
Nonparametric Bayesian methods are considered for recovery of imagery based upon compressive, incomplete, and/or noisy measurements. A truncated beta-Bernoulli process is employed to infer an appropriate dictionary for the data under test and also for imag ...
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Journal ArticlePLoS Pathog · 2012
HIV-1 infection begins with the binding of trimeric viral envelope glycoproteins (Env) to CD4 and a co-receptor on target T-cells. Understanding how these ligands influence the structure of Env is of fundamental interest for HIV vaccine development. Using ...
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Journal ArticlePloS one · January 2012
The advantages of ultra-high magnetic field (7 Tesla) MRI for basic science research and neuroscience applications have proven invaluable. Structural and functional MR images of the human brain acquired at 7 T exhibit rich information content with potentia ...
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Journal ArticlePloS one · January 2012
Basal ganglia circuits are affected in neurological disorders such as Parkinson's disease (PD), essential tremor, dystonia and Tourette syndrome. Understanding the structural and functional connectivity of these circuits is critical for elucidating the mec ...
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Journal ArticleAnnual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference · January 2012
We consider the problem of tracking white matter fibers in high angular resolution diffusion imaging (HARDI) data while simultaneously estimating the local fiber orientation profile. Prior work showed that an unscented Kalman filter (UKF) can be used for t ...
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Journal ArticleProceedings. IEEE International Symposium on Biomedical Imaging · January 2012
The presence of noise in High Angular Resolution Diffusion Imaging (HARDI) data of the brain can limit the accuracy with which fiber pathways of the brain can be extracted. In this work, we present a variational model to denoise HARDI data corrupted by Ric ...
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Journal ArticleProceedings - IEEE International Conference on Robotics and Automation · January 1, 2012
Clinical studies confirm that mental illnesses such as autism, Obsessive Compulsive Disorder (OCD), etc. show behavioral abnormalities even at very young ages; the early diagnosis of which can help steer effective treatments. Most often, the behavior of su ...
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ConferenceProceedings of the 12th SIAM International Conference on Data Mining, SDM 2012 · January 1, 2012
We propose a new matrix completion algorithm| Kernelized Probabilistic Matrix Factorization (KPMF), which effectively incorporates external side information into the matrix factorization process. Unlike Probabilistic Matrix Factorization (PMF) [14], which ...
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Journal Article · December 26, 2011
A framework of online adaptive statistical compressed sensing is introduced
for signals following a mixture model. The scheme first uses non-adaptive
measurements, from which an online decoding scheme estimates the model
selection. As soon as a candidate m ...
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Journal ArticleJournal of Machine Learning Research · December 1, 2011
A dependent hierarchical beta process (dHBP) is developed as a prior for data that may be represented in terms of a sparse set of latent features, with covariate-dependent feature usage. The dHBP is applicable to general covariates and data models, imposin ...
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Journal ArticleIEEE Transactions on Signal Processing · December 1, 2011
A novel framework of compressed sensing, namely statistical compressed sensing (SCS), that aims at efficiently sampling a collection of signals that follow a statistical distribution, and achieving accurate reconstruction on average, is introduced. SCS bas ...
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Journal ArticleProceedings - International Conference on Image Processing, ICIP · December 1, 2011
Sparse representation theory has been increasingly used in signal processing and machine learning. In this paper we introduce a hierarchical sparse modeling approach which integrates information from the image patch level to derive a mid-level invariant im ...
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Journal ArticleProceedings - International Symposium on Biomedical Imaging · November 2, 2011
Diffusion tensor imaging has accelerated the study of brain connectivity, but single-tensor diffusion models are too simplistic to model fiber crossing and mixing. Hybrid diffusion imaging (HYDI) samples the radial and angular structure of local diffusion ...
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Journal ArticleProceedings - International Symposium on Biomedical Imaging · November 2, 2011
Cortical connectivity is associated with cognitive and behavioral traits that are thought to vary between sexes. Using high-angular resolution diffusion imaging at 4 Tesla, we scanned 234 young adult twins and siblings (mean age: 23.4 2.0 SD years) with 94 ...
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Journal ArticleProceedings - International Symposium on Biomedical Imaging · November 2, 2011
The orientation distribution function (ODF) can be reconstructed online incrementally from diffusion-weighted MRI with a Kalman filtering framework. This online reconstruction can provide real-time feedback to the practitioner, especially appreciated for l ...
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Journal ArticleProceedings - International Symposium on Biomedical Imaging · November 2, 2011
High angular resolution diffusion imaging (HARDI) allows population studies of fiber integrity and connectivity. Tractography can extract individual fibers. For group studies, fibers must be clustered into recognizable bundles found consistently across sub ...
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Journal ArticleIEEE Transactions on Geoscience and Remote Sensing · November 1, 2011
A method is presented for subpixel modeling, mapping, and classification in hyperspectral imagery using learned block-structured discriminative dictionaries, where each block is adapted and optimized to represent a material in a compact and sparse manner. ...
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Journal ArticleProceedings of the 28th International Conference on Machine Learning, ICML 2011 · October 7, 2011
A new nonparametric Bayesian model is developed to integrate dictionary learning and topic model into a unified framework. The model is employed to analyze partially annotated images, with the dictionary learning performed directly on image patches. Effici ...
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Journal ArticleProceedings of the 28th International Conference on Machine Learning, ICML 2011 · October 7, 2011
A convolutional factor-analysis model is developed, with the number of filters (factors) inferred via the beta process (BP) and hierarchical BP, for single-task and multi-task learning, respectively. The computation of the model parameters is implemented w ...
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Journal ArticleIEEE transactions on information technology in biomedicine : a publication of the IEEE Engineering in Medicine and Biology Society · September 2011
Cardiac ablation involves the risk of serious complications when thermal injury to the esophagus occurs. This paper proposes to reduce the risk of such injuries by a proactive visualization technique, improving physician awareness of the esophagus location ...
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Journal ArticleIEEE Transactions on Signal Processing · September 1, 2011
Sparse modeling is a powerful framework for data analysis and processing. Traditionally, encoding in this framework is performed by solving an ℓ1-regularized linear regression problem, commonly referred to as Lasso or Basis Pursuit. In this work we combine ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · August 18, 2011
A dependent hierarchical beta process (dHBP) is developed as a prior for data that may be represented in terms of a sparse set of latent features (dictionary elements), with covariate-dependent feature usage. The dHBP is applicable to general covariates an ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · August 18, 2011
The power of sparse signal coding with learned overcomplete dictionaries has been demonstrated in a variety of applications and fields, from signal processing to statistical inference and machine learning. However, the statistical properties of these model ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · August 18, 2011
A general framework based on Gaussian models and a MAPEM algorithm is introduced in this paper for solving matrix/ table completion problems. The numerical experiments with the standard and challenging movie ratings data show that the proposed approach, ba ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · August 18, 2011
A collaborative framework for detecting the different sources in mixed signals is presented in this paper. The approach is based on C-HiLasso, a convex collaborative hierarchical sparse model, and proceeds as follows. First, we build a structured dictionar ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · August 18, 2011
A new framework of compressive sensing (CS), namely statistical compressive sensing (SCS), that aims at efficiently sampling a collection of signals that follow a statistical distribution and achieving accurate reconstruction on average, is introduced. For ...
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Journal ArticleMedical image analysis · August 2011
A global probabilistic fiber tracking approach based on the voting process provided by the Hough transform is introduced in this work. The proposed framework tests candidate 3D curves in the volume, assigning to each one a score computed from the diffusion ...
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Journal ArticleInternational Journal of Computer Vision · July 1, 2011
In this paper concepts from continuum mechanics are used to define geodesic paths in the space of shapes, where shapes are implicitly described as boundary contours of objects. The proposed shape metric is derived from a continuum mechanical notion of visc ...
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Journal ArticleInternational Journal of Computer Vision · July 1, 2011
Non-local methods for image denoising and inpainting have gained considerable attention in recent years. This is in part due to their superior performance in textured images, a known weakness of purely local methods. Local methods on the other hand have de ...
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Journal ArticleCommunications of the ACM · May 1, 2011
Deriving appropriate regularization terms, priors or models, has occupied the research community since the early days of digital image processing. Different image models can be appropriate for different types of images; for example, MRI and natural images ...
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Journal ArticleProceedings. IEEE International Symposium on Biomedical Imaging · April 2011
High angular resolution diffusion imaging (HARDI) allows in vivo analysis of the white matter structure and connectivity. Based on orientation distribution functions (ODFs) that represent the directionality of water diffusion at each point in the br ...
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Journal Article · March 12, 2011
This paper addresses the problem of simultaneous signal recovery and
dictionary learning based on compressive measurements. Multiple signals are
analyzed jointly, with multiple sensing matrices, under the assumption that the
unknown signals come from a uni ...
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Journal ArticleIEEE Signal Processing Magazine · January 1, 2011
The problem of finding and exploiting low-dimensional structures in high-dimensional data is taking on increasing importance in image, video, or audio processing; Web data analysis/search; and bioinformatics, where data sets now routinely lie in observatio ...
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Journal ArticleProceedings - International Conference on Image Processing, ICIP · December 1, 2010
Recent advances in sparse modeling and dictionary learning for discriminative applications show high potential for numerous classification tasks. In this paper, we show that highly accurate material classification from hyperspectral imagery (HSI) can be ob ...
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Journal ArticleProceedings - International Conference on Image Processing, ICIP · December 1, 2010
We present a Bayesian model for image interpolation and dictionary learning that uses two nonparametric priors for sparse signal representations: the beta process and the Dirichlet process. Additionally, the model uses spatial information within the image ...
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Journal ArticleProceedings - International Conference on Image Processing, ICIP · December 1, 2010
An image representation framework based on structured sparsemodel selection is introduced in this work. The corresponding modeling dictionary is comprised of a family of learned orthogonal bases. For an image patch, a model is first selected from this dict ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · October 2010
Inpainting is the art of modifying an image in a form that is not detectable by an ordinary observer. There are numerous and very different approaches to tackle the inpainting problem, though as explained in this paper, the most successful algorithms are b ...
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Journal ArticleInternational Journal of Computer Vision · September 1, 2010
In this paper, the problem of non-rigid shape recognition is studied from the perspective of metric geometry. In particular, we explore the applicability of diffusion distances within the Gromov-Hausdorff framework. While the traditionally used geodesic di ...
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Journal ArticleProceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition · August 31, 2010
A clustering framework within the sparse modeling and dictionary learning setting is introduced in this work. Instead of searching for the set of centroid that best fit the data, as in k-means type of approaches that model the data as distributions around ...
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Journal Article2010 7th IEEE International Symposium on Biomedical Imaging: From Nano to Macro, ISBI 2010 - Proceedings · August 9, 2010
The diffusion orientation distribution function (ODF) can be reconstructed from q-ball imaging (QBI) to map the complex intravoxel structure of water diffusion. As acquisition time is particularly large for high angular resolution diffusion imaging (HARDI) ...
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Journal ArticleMagnetic resonance in medicine · August 2010
q-Ball imaging is a high-angular-resolution diffusion imaging technique that has been proven very successful in resolving multiple intravoxel fiber orientations in MR images. The standard computation of the orientation distribution function (the probabilit ...
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Journal Article2010 44th Annual Conference on Information Sciences and Systems, CISS 2010 · June 24, 2010
Sparse modeling is a powerful framework for data analysis and processing. Traditionally, encoding in this framework is done by solving an ℓ1-regularized linear regression problem, usually called Lasso. In this work we first combine the sparsity-inducing pr ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · March 2010
Shape models (SMs), capturing the common features of a set of training shapes, represent a new incoming object based on its projection onto the corresponding model. Given a set of learned SMs representing different objects classes, and an image with a new ...
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Journal ArticleJournal of Machine Learning Research · February 22, 2010
Sparse coding-that is, modelling data vectors as sparse linear combinations of basis elements-is widely used in machine learning, neuroscience, signal processing, and statistics. This paper focuses on the large-scale matrix factorization problem that consi ...
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Journal ArticleBrain and cognition · February 2010
Gyrification is the process by which the brain undergoes changes in surface morphology to create sulcal and gyral regions. The period of greatest development of brain gyrification is during the third trimester of pregnancy, a period of time in which the br ...
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Journal ArticleJournal of Geophysical Research: Earth Surface · January 1, 2010
[1] A geometric framework for the automatic extraction of channels and channel networks from high-resolution digital elevation data is introduced in this paper. The proposed approach incorporates nonlinear diffusion for the preprocessing of the data, both ...
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Journal ArticleProceedings of the IEEE · January 1, 2010
Techniques from sparse signal representation are beginning to see significant impact in computer vision, often on nontraditional applications where the goal is not just to obtain a compact high-fidelity representation of the observed signal, but also to ex ...
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Journal ArticleAnnual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference · January 2010
Computer Tomographic Colonography, combined with computer-aided detection (CAD), is a promising emerging technique for colonic polyp analysis. We present a CAD scheme for polyp flagging based on new texture and geometric features that consider both the inf ...
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Journal ArticleLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · January 1, 2010
Accurately modeling object colors, and features in general, plays a critical role in video segmentation and analysis. Commonly used color models, such as global Gaussian mixtures, localized Gaussian mixtures, and pixel-wise adaptive ones, often fail to acc ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · January 1, 2010
Sparse representation theory has been increasingly used in the fields of signal processing and machine learning. The standard sparse models are not invariant to spatial transformations such as image rotations, and the representation is very sensitive even ...
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Journal ArticleICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings · January 1, 2010
A clustering framework within the sparse modeling and dictionary learning setting is introduced in this work. Instead of searching for the set of centroid that best fit the data, as in k-means type of approaches that model the data as distributions around ...
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Journal ArticleJournal of Geophysical Research: Earth Surface · 2010
[1] A geometric framework for the automatic extraction of channels and channel networks from high-resolution digital elevation data is introduced in this paper. The proposed approach incorporates nonlinear diffusion for the preprocessing of the data, both ...
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Journal ArticleMedical image computing and computer-assisted intervention : MICCAI ... International Conference on Medical Image Computing and Computer-Assisted Intervention · January 2010
By revealing complex fiber structure through the orientation distribution function (ODF), q-ball imaging has recently become a popular reconstruction technique in diffusion-weighted MRI. In this paper, we propose an analytical dimension reduction approach ...
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Journal ArticleProceedings of the 26th International Conference On Machine Learning, ICML 2009 · December 9, 2009
The k q-flats algorithm is a generalization of the popular k-means algorithm where q dimensional best fit affine sets replace centroids as the cluster prototypes. In this work, a modification of the k q-flats framework for pattern classification is introdu ...
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Journal ArticleProceedings of the IEEE International Conference on Computer Vision · December 1, 2009
We propose in this paper to unify two different approaches to image restoration: On the one hand, learning a basis set (dictionary) adapted to sparse signal descriptions has proven to be very effective in image reconstruction and classification tasks. On t ...
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Journal ArticleCAMSAP 2009 - 2009 3rd IEEE International Workshop on Computational Advances in Multi-Sensor Adaptive Processing · December 1, 2009
Sparse data models, where data is assumed to be well represented as a linear combination of a few elements from a dictionary, have gained considerable attention in recent years, and their use has led to state-of-the-art results in many signal and image pro ...
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Journal ArticleLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · November 6, 2009
A nonlocal variational formulation for interpolating a sparsely sampled image is introduced in this paper. The proposed variational formulation, originally motivated by image inpainting problems, encourages the transfer of information between similar image ...
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Journal ArticleLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · November 6, 2009
A variational approach to defining geodesics in the space of implicitly described shapes is introduced in this paper. The proposed framework is based on the time discretization of a geodesic path as a sequence of pairwise matching problems, which is strict ...
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Journal ArticleLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · November 6, 2009
Non-local methods for image denoising and inpainting have gained considerable attention in recent years. This is in part due to their superior performance in textured images, a known weakness of purely local methods. Local methods on the other hand have de ...
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Journal ArticleHuman brain mapping · October 2009
Estimating the thickness of the cerebral cortex is a key step in many brain imaging studies, revealing valuable information on development or disease progression. In this work, we present a framework for measuring the cortical thickness, based on minimizin ...
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Journal ArticleACM International Conference Proceeding Series · September 15, 2009
Sparse coding - that is, modelling data vectors as sparse linear combinations of basis elements - is widely used in machine learning, neuroscience, signal processing, and statistics. This paper focuses on learning the basis set, also called dictionary, to ...
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Journal ArticleACM International Conference Proceeding Series · September 15, 2009
The k q-flats algorithm is a generalization of the popular k-means algorithm where q dimensional best fit affine sets replace centroids as the cluster prototypes. In this work, a modification of the k q-flats framework for pattern classification is introdu ...
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Journal ArticleÉtudes littéraires · September 1, 2009
La reparution de La nouvelle revue française sous l’Occupation allemande en France pose la question à la fois théorique et pratique de la continuité des institutions. La NRF de Drieu La Rochelle ...
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Journal ArticleInternational Journal of Computer Vision · August 1, 2009
Recently, the Sobolev metric was introduced to define gradient flows of various geometric active contour energies. It was shown that the Sobolev metric outperforms the traditional metric for the same energy in many cases such as for tracking where the coar ...
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Journal ArticleACM Transactions on Graphics · July 27, 2009
Although tremendous success has been achieved for interactive object cutout in still images, accurately extracting dynamic objects in video remains a very challenging problem. Previous video cutout systems present two major limitations: (1) reliance on glo ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · July 2009
Sparse signal representation, analysis, and sensing have received a lot of attention in recent years from the signal processing, optimization, and learning communities. On one hand, learning overcomplete dictionaries that facilitate a sparse representation ...
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Journal ArticleProceedings. IEEE International Symposium on Biomedical Imaging · June 2009
Q-ball imaging (QBI) is a high angular resolution diffusion imaging (HARDI) technique which has been proven very successful in resolving multiple intravoxel fiber orientations in MR images. The standard computation of the orientation distribution function ...
Full textCite
Journal ArticleProceedings. IEEE International Symposium on Biomedical Imaging · June 2009
Studies of cerebral asymmetry can open doors to understanding the functional specialization of each brain hemisphere, and how this is altered in disease. Here we examined hemispheric asymmetries in fiber architecture using diffusion tensor imaging (DTI) in ...
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Journal ArticleInternational Journal of Computer Vision · April 1, 2009
An interactive framework for soft segmentation and matting of natural images and videos is presented in this paper. The proposed technique is based on the optimal, linear time, computation of weighted geodesic distances to user-provided scribbles, from whi ...
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Journal ArticleNeuroImage · March 2009
In this article, we review recent mathematical models and computational methods for the processing of diffusion Magnetic Resonance Images, including state-of-the-art reconstruction of diffusion models, cerebral white matter connectivity analysis, and segme ...
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Journal ArticleCortex; a journal devoted to the study of the nervous system and behavior · March 2009
It has long been acknowledged that planar hand drawing movements conform to a relationship between movement speed and shape, such that movement speed is inversely proportional to the curvature to the power of one-third. Previous literature has detailed pot ...
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Journal ArticleAlgorithms for molecular biology : AMB · February 2009
BackgroundComputing the distance between two RNA secondary structures can contribute in understanding the functional relationship between them. When used repeatedly, such a procedure may lead to finding a query RNA structure of interest in a datab ...
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Journal Article · January 1, 2009
In this chapter the authors go beyond traditional sparse modeling, and address collaborative structured sparsity to add stability and prior information to the representation. In structured sparse modeling, instead of considering the dictionary atoms as sin ...
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Journal ArticleAdvances in Neural Information Processing Systems 22 - Proceedings of the 2009 Conference · January 1, 2009
Non-parametric Bayesian techniques are considered for learning dictionaries for sparse image representations, with applications in denoising, inpainting and com-pressive sensing (CS). The beta process is employed as a prior for learning the dictionary, and ...
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Journal ArticleAdvances in Neural Information Processing Systems 21 - Proceedings of the 2008 Conference · January 1, 2009
It is now well established that sparse signal models are well suited for restoration tasks and can be effectively learned from audio, image, and video data. Recent research has been aimed at learning discriminative sparse models instead of purely reconstru ...
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Journal ArticleProceedings - International Conference on Image Processing, ICIP · January 1, 2009
Shape models (SMs), capturing the common features of a set of training shapes, represent a new incoming object based on its projection onto the corresponding model. Given a set of learned SMs representing different objects, and an image with a new shape, t ...
Full textCite
Journal ArticleProceedings of the 26th International Conference On Machine Learning, ICML 2009 · January 1, 2009
Sparse coding - that is, modelling data vectors as sparse linear combinations of basis elements - is widely used in machine learning, neuroscience, signal processing, and statistics. This paper focuses on learning the basis set, also called dictionary, to ...
Cite
Journal ArticleGraphical Models · January 1, 2009
A geometric framework for the recognition of three-dimensional objects represented by point clouds is introduced in this paper. The proposed approach is based on comparing distributions of intrinsic measurements on the point cloud. In particular, intrinsic ...
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Journal ArticleMedical image computing and computer-assisted intervention : MICCAI ... International Conference on Medical Image Computing and Computer-Assisted Intervention · January 2009
Q-ball imaging (QBI) is a high angular resolution diffusion imaging (HARDI) technique which has been proven very successful in resolving multiple intravoxel fiber orientations in MR images. The standard computation of the orientation distribution function ...
Full textCite
Journal ArticleSIAM Journal on Imaging Sciences · January 1, 2009
Many problems in image processing are addressed via the minimization of a cost functional. The most prominently used optimization technique is gradient-descent, often used due to its simplicity and applicability where other techniques, e.g., those coming f ...
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ConferenceProceedings of the IEEE International Conference on Computer Vision · January 1, 2009
A general framework simultaneously addressing pose estimation, 2D segmentation, object recognition, and 3D reconstruction from a single image is introduced in this paper. The proposed approach partitions 3D space into voxels and estimates the voxel states ...
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Journal ArticleInternational Journal of Computer Vision · December 1, 2008
A framework for the regularized and robust estimation of non-uniform dimensionality and density in high dimensional noisy data is introduced in this work. This leads to learning stratifications, that is, mixture of manifolds representing different characte ...
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Journal ArticleProceedings - International Conference on Image Processing, ICIP · December 1, 2008
Many problems in image processing are solved via the minimization of a cost functional. The most widely used optimization technique is the gradient descent, often used due to its simplicity and applicability where other optimization techniques, e.g., those ...
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Journal ArticleJ Struct Biol · October 2008
Tomograms of biological specimens derived using transmission electron microscopy can be intrinsically noisy due to the use of low electron doses, the presence of a "missing wedge" in most data collection schemes, and inaccuracies arising during 3D volume r ...
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Journal Article26th IEEE Conference on Computer Vision and Pattern Recognition, CVPR · September 23, 2008
Sparse signal models have been the focus of much recent research, leading to (or improving upon) state-of-the-art results in signal, image, and video restoration. This article extends this line of research into a novel framework for local image discriminat ...
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Journal Article2008 IEEE Computer Society Conference on Computer Vision and Pattern Recognition Workshops, CVPR Workshops · September 22, 2008
A framework for scene learning from a single still video camera is presented in this work. In particular, the camera transformation and the direction of the shadows are learned using information extracted from pedestrians walking in the scene. The proposed ...
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Journal Article2008 IEEE Computer Society Conference on Computer Vision and Pattern Recognition Workshops, CVPR Workshops · September 22, 2008
A geometric framework for the recognition of three-dimensional objects represented by point clouds is introduced in this paper The proposed approach is based on comparing distributions of intrinsic measurements on the point cloud. In particular, intrinsic ...
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Journal Article2008 IEEE Computer Society Conference on Computer Vision and Pattern Recognition Workshops, CVPR Workshops · September 22, 2008
Online virtual globe applications such as Google Earth and Maps, Microsoft Virtual Earth, and Yahoo! Maps, allow users to explore realistic models of the Earth. To provide the ground-level detail of interest to users, it is necessary to serve and render hi ...
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Journal Article2008 5th IEEE International Symposium on Biomedical Imaging: From Nano to Macro, Proceedings, ISBI · September 10, 2008
A stratification and manifold learning approach for analyzing High Angular Resolution Diffusion Imaging (HARDI) data is introduced in this paper. HARDI data provides high-dimensional signals measuring the complex microstructure of biological tissues, such ...
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Journal Article2008 5th IEEE International Symposium on Biomedical Imaging: From Nano to Macro, Proceedings, ISBI · September 10, 2008
Estimating the thickness of cerebral cortex is a key step in many MR brain imaging studies, revealing valuable information on development or disease progression. In this work we present a new approach to measure the cortical thickness, based on minimizing ...
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Journal Article2008 5th IEEE International Symposium on Biomedical Imaging: From Nano to Macro, Proceedings, ISBI · September 10, 2008
In limited data tomography, with applications such as electron microscopy and medical imaging, the scanning views are within an angular range that is often both limited and sparsely sampled. In these situations, standard algorithms produce reconstructions ...
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Journal ArticleNature · September 4, 2008
The envelope glycoproteins (Env) of human and simian immunodeficiency viruses (HIV and SIV, respectively) mediate virus binding to the cell surface receptor CD4 on target cells to initiate infection. Env is a heterodimer of a transmembrane glycoprotein (gp ...
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Journal ArticleComputer Vision and Image Understanding · September 1, 2008
Geometric approaches for filling-in surface holes are introduced and studied in this paper. The basic principle is to choose the completing surface as one which minimizes a power of the mean curvature. We interpret this principle in a level set formulation ...
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Journal ArticleIEEE Transactions on Geoscience and Remote Sensing · August 1, 2008
A fast algorithm for multiscale representation and segmentation of hyperspectral imagery is introduced in this paper. The multiscale/scale-space representation is obtained by solving a nonlinear diffusion partial differential equation (PDE) for vector-valu ...
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Journal ArticleProceedings of SPIE - The International Society for Optical Engineering · June 17, 2008
In this work, we study unsupervised classification algorithms for hyperspectral images based on band-by-band scalar histograms and vector-valued generalized histograms, obtained by vector quantization. The corresponding histograms are compared by dissimila ...
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Journal ArticleChemtracts · June 1, 2008
A critical step in human and simian immunodeficiency virus (HIV and SIV, respectively) pathogenesis is entry into the target cell. The process of infection is mediated by envelope glycoproteins, Env, which assemble in a trim- eric form on the surface of th ...
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Journal ArticleJournal of vision · June 2008
Information in the cortex is thought to be represented by the joint activity of neurons. Here we describe how fundamental questions about neural representation can be cast in terms of the topological structure of population activity. A new method, based on ...
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Journal ArticleJournal of structural biology · June 2008
Strategies for the determination of 3D structures of biological macromolecules using electron crystallography and single-particle electron microscopy utilize powerful tools for the averaging of information obtained from 2D projection images of structurally ...
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Journal ArticleIEEE transactions on pattern analysis and machine intelligence · April 2008
A framework for robust foreground detection that works under difficult conditions such as dynamic background and moderately moving camera is presented in this paper. The proposed method includes two main components: coarse scene representation as the union ...
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Journal ArticleMultiscale Modeling and Simulation · January 1, 2008
This paper presents a framework for learning multiscale sparse representations of color images and video with overcomplete dictionaries. A single-scale K-SVD algorithm was introduced in [M. Aharon, M. Elad, and A. M. Bruckstein, IEEE Trans. Signal Process. ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · January 2008
Sparse representations of signals have drawn considerable interest in recent years. The assumption that natural signals, such as images, admit a sparse decomposition over a redundant dictionary leads to efficient algorithms for handling such sources of dat ...
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Journal ArticleIEEE/ACM transactions on computational biology and bioinformatics · January 2008
When accounting for structural fluctuations or measurement errors, a single rigid structure may not be sufficient to represent a protein. One approach to solve this problem is to represent the possible conformations as a discrete set of observed conformati ...
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Journal ArticleProceedings of the IEEE International Conference on Computer Vision · December 1, 2007
The problem of motion estimation and restoration of objects in a blurred video sequence is addressed in this paper. Fast movement of the objects, together with the aperture time of the camera, result in a motion-blurred image. The direct velocity estimatio ...
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Journal ArticleAdvances in Neural Information Processing Systems · December 1, 2007
The study of point cloud data sampled from a stratification, a collection of manifolds with possible different dimensions, is pursued in this paper. We present a technique for simultaneously soft clustering and estimating the mixed dimensionality and densi ...
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Journal ArticleProceedings of the IEEE International Conference on Computer Vision · December 1, 2007
An interactive framework for soft segmentation and matting of natural images and videos is presented in this paper. The proposed technique is based on the optimal, linear time, computation of weighted geodesic distances to the user-provided scribbles, from ...
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Journal ArticleProceedings of the IEEE International Conference on Computer Vision · December 1, 2007
An approach for incremental learning of a 3D scene from a single static video camera is presented in this paper. In particular, we exploit the presence of casual people walking in the scene to infer relative depth, learn shadows, and segment the critical g ...
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Journal Article2007 4th IEEE International Symposium on Biomedical Imaging: From Nano to Macro - Proceedings · November 27, 2007
Advances in automated data acquisition in electron tomography have led to an explosion in the amount of data that can be obtained about the spatial architecture of a variety of biologically and medically relevant objects with resolutions in the "nano" rang ...
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Journal Article2007 4th IEEE International Symposium on Biomedical Imaging: From Nano to Macro - Proceedings · November 27, 2007
In limited angle tomography, with applications such as electron microscopy, medical imaging, and industrial testing, the object of interest is scanned over a limited angular range, which is less than the full 180° mathematically required for density recons ...
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Journal Article2007 4th IEEE International Symposium on Biomedical Imaging: From Nano to Macro - Proceedings · November 27, 2007
Electron tomography provides opportunities to determine diree-dimensional cellular architecture at resolutions high enough to identify individual macromolecules such as proteins. Image analysis of such data poses a challenging problem due to the extremely ...
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Journal ArticleProceedings of SPIE - The International Society for Optical Engineering · November 15, 2007
This paper presents an algorithm that generates a scale-space representation of hyperspectral imagery using Algebraic Multigrid (AMG) solvers. The scale-space representation is obtained by solving with AMG a vector-valued anisotropic diffusion equation, wi ...
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Scholarly Edition · October 27, 2007
Данная статья, основанная на разработанной Пьером Бурдье теории поля и на эмпирических исследованиях о писателях во Франции, представляет принципы структурирования французского поля литературы с конца XIX в. по начало 1970-х гг. Структура французского поля ...
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Journal ArticleProceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition · October 11, 2007
Kernel methods have been widely studied in the field of pattern recognition. These methods implicitly map, "the kernel trick," the data into a space which is more appropriate for analysis. Many manifold learning and dimensionality reduction techniques are ...
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Journal ArticleProceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition · October 11, 2007
A framework for the regularized estimation of non-uniform dimensionality and density in high dimensional data is introduced in this work. This leads to learning stratifications, that is, mixture of manifolds representing different characteristics and compl ...
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Journal ArticleGraphical Models · May 1, 2007
Point-based surface processing has developed into an attractive alternative to mesh-based processing tools for a number of geometric modeling applications. By working with point clouds directly, processing is based on the raw data and its underlying geomet ...
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Journal ArticleIEEE Geoscience and Remote Sensing Letters · April 1, 2007
The nonlinear dimensionality reduction and its effects on vector classification and segmentation of hyperspectral images are investigated in this letter. In particular, the way dimensionality reduction influences and helps classification and segmentation i ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · April 2007
An interactive algorithm for soft segmentation of natural images is presented in this paper. The user first roughly scribbles different regions of interest, and from them, the whole image is automatically segmented. This soft segmentation is obtained via f ...
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Journal ArticleIEEE transactions on medical imaging · April 2007
Sulcal fundi are 3-D curves that lie in the depths of the cerebral cortex and, in addition to their intrinsic value in brain research, are often used as landmarks for downstream computations in brain imaging. In this paper, we present a geometric algorithm ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · February 2007
A framework for inpainting missing parts of a video sequence recorded with a moving or stationary camera is presented in this work. The region to be inpainted is general: it may be still or moving, in the background or in the foreground, it may occlude one ...
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Journal ArticleLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · January 1, 2007
Recently, the Sobolev metric was introduced to define gradient flows of various geometric active contour energies. It was shown that the Sobolev metric out-performs the traditional metric for the same energy in many cases such as for tracking where the coa ...
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Journal ArticleProceedings - International Conference on Image Processing, ICIP · January 1, 2007
In this work, we propose a framework for foreground representation, in video and illustrate it with a multi-camera people matching application. We first decompose the video into foreground and back-ground. A low-level coarse segmentation of the foreground ...
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Journal ArticleProceedings - International Conference on Image Processing, ICIP · January 1, 2007
An interactive algorithm for soft segmentation and matting of natural Images and videos is presented in this paper. The technique follows and extends [10], where the user first roughly scribbles/labels different regions of interest, and from them the whole ...
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Journal Article · December 1, 2006
Inpainting, the technique of modifying an image in an undetectable form, is as ancient as art itself. The goals and applications of inpainting are numerous, from the restoration of damaged paintings, photographs and films, to the removal of selected undesi ...
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Journal ArticleProceedings - International Conference on Image Processing, ICIP · December 1, 2006
This paper introduces a new framework for learning multiscale sparse representations of natural images with overcomplete dictionaries. Our work extends the K-SVD algorithm [1], which learns sparse single-scale dictionaries for natural images. Recent work h ...
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Journal ArticleIEEE Transactions on Geoscience and Remote Sensing · December 1, 2006
In this paper, a framework for smoothing gridlike digital terrain elevation data, which achieves a fair shape bymeans of minimizing an energy functional, is presented. The minimization is performed under the side condition of hard constraints, which comes ...
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Journal Article2006 3rd IEEE International Symposium on Biomedical Imaging: From Nano to Macro - Proceedings · November 17, 2006
Sulcal fundi are 3D curves that lie in the depths of the cerebral cortex and are often used as landmarks for downstream computations in brain imaging. We present a sequence of geometric algorithms which automatically extract the sulcal fundi from magnetic ...
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Journal ArticleJournal of Computational Physics · July 20, 2006
We extend a recently introduced method for numerically solving partial differential equations on implicit surfaces [M. Bertalmío, L.T. Cheng, S. Osher, G. Sapiro. Variational problems and partial differential equations on implicit surfaces, J. Comput. Phys ...
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Journal ArticleThe Journal of organic chemistry · July 2006
The topography of antibody binding sites has been classified into five types that evoke familiar geomorphic features of the Earth. The 229 antibody crystal structures from the Protein Data Bank were analyzed and classified into these classes. Relationships ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · May 2006
Colorization, the task of coloring a grayscale image or video, involves assigning from the single dimension of intensity or luminance a quantity that varies in three dimensions, such as red, green, and blue channels. Mapping between intensity and color is, ...
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Journal ArticleProceedings of SPIE - The International Society for Optical Engineering · April 17, 2006
In this paper we present an algorithm for 3D medical image segmentation based on an affine invariant flow. The algorithm is simple to implement and semi-automatic. The technique is based on active contours evolving in time according to intrinsic geometric ...
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Journal ArticleJournal of Computational Physics · March 1, 2006
In this note we present an implementation of the fast marching algorithm for solving Eikonal equations that in practice reduces the original run-time from O(N log N) to linear. This lower run-time cost is obtained while keeping an error bound of the same o ...
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Chapter · January 1, 2006
Point clouds are one of the most primitive and fundamental manifold representations. A popular source of point clouds are three-dimensional shape acquisition devices such as laser range scanners. Another important field where point clouds are found is the ...
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ConferenceNIPS 2006: Proceedings of the 19th International Conference on Neural Information Processing Systems · January 1, 2006
The study of point cloud data sampled from a stratification, a collection of manifolds with possible different dimensions, is pursued in this paper. We present a technique for simultaneously soft clustering and estimating the mixed dimensionality and densi ...
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Journal ArticleIEEE Geoscience and Remote Sensing Letters · January 1, 2006
A framework for geometric regularization of elevation maps is introduced in this letter. The framework takes into account errors in the data, which form part of standard elevation maps specifications, as well as possible additional user/application-depende ...
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Journal ArticleIEEE/ACM transactions on computational biology and bioinformatics · January 2006
Local conformation is an important determinant of RNA catalysis and binding. The analysis of RNA conformation is particularly difficult due to the large number of degrees of freedom (torsion angles) per residue. Proteins, by comparison, have many fewer deg ...
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Journal ArticleIEEE Signal Processing Letters · December 1, 2005
In this letter, improvements to the nonlocal means image denoising method introduced by Buades et al. are presented. The original nonlocal means method replaces a noisy pixel by the weighted average of pixels with related surrounding neighborhoods. While p ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · December 2005
Steganography is the art of secret communication. Its purpose is to hide the presence of information, using, for example, images as covers. We experimentally investigate if stego-images, bearing a secret message, are statistically "natural." For this purpo ...
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Journal ArticleProceedings - International Conference on Image Processing, ICIP · December 1, 2005
We present a basic technique to fill-in missing parts of a video sequence taken from a static camera. Two important cases are considered. The first case is concerned with the removal of non-stationary objects that occlude stationary background. We use a pr ...
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Journal ArticleProceedings - International Conference on Image Processing, ICIP · December 1, 2005
We present an algorithm for tracking moving objects using intrinsic minimal surfaces which handles particularly well the presence of severe and total occlusions even in the presence of weak object boundaries. We adopt an edge based approach and find the se ...
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Journal ArticleProceedings - International Conference on Image Processing, ICIP · December 1, 2005
A framework for automatic image colorization, the art of adding color to a monochrome image or movie, is presented in this paper. The approach is based on considering the geometry and structure of the monochrome luminance input, given by its gradient infor ...
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Journal ArticleProceedings of the IEEE Visualization Conference · December 1, 2005
Level set methods, an important class of partial differential equation (PDE) methods, define dynamic surfaces implicitly as the level set (iso-surface) of a sampled, evolving nD function. This course is targeted for researchers interested in learning about ...
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Journal ArticleSIAM Journal on Applied Mathematics · September 30, 2005
A theoretical and computational framework for computing intrinsic distance functions and geodesics on submanifolds of ℝ d given by point clouds is introduced and developed in this paper. The basic idea is that, as shown here, intrinsic distance functions a ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · September 2005
Electron tomography allows for the determination of the three-dimensional structures of cells and tissues at resolutions significantly higher than that which is possible with optical microscopy. Electron tomograms contain, in principle, vast amounts of inf ...
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Journal ArticleFoundations of Computational Mathematics · July 1, 2005
Point clouds are one of the most primitive and fundamental manifold representations. Popular sources of point clouds are three-dimensional shape acquisition devices such as laser range scanners. Another important field where point clouds are found is in th ...
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Journal ArticleGraphical Models · July 1, 2005
A paradigm for automatic three-dimensional shape and geometry rendering from multiple images is introduced in this paper. In particular, non-photorealistic rendering (NPR) techniques in the style of pen-and-ink illustrations are addressed, while the underl ...
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Journal Article · January 1, 2005
This chapter deals with an efficient and accurate approach in image segmentation: active contours. The general idea behind this technique is to apply partial differential equations (PDEs) to deform a curve or a surface toward the boundaries of the objects ...
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Journal ArticleInternational journal of computer vision · December 2004
A new definition of affine invariant medial axis of planar closed curves is introduced. A point belongs to the affine medial axis if and only if it is equidistant from at least two points of the curve, with the distance being a minimum and given by the ...
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Journal ArticleProceedings - International Conference on Image Processing, ICIP · December 1, 2004
A new paradigm for automatic non-photorealistic rendering (NPR) is introduced in this paper. Existing NPR approaches can be categorized in two groups depending on the type of input they use: image based and object based. Using multiple images as input to t ...
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Journal ArticleACM International Conference Proceeding Series · December 1, 2004
Point clouds are one of the most primitive and fundamental surface representations. A popular source of point clouds are three dimensional shape acquisition devices such as laser range scanners. Another important field where point clouds are found is in th ...
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Journal ArticleProceedings - International Conference on Image Processing, ICIP · December 1, 2004
The decomposition of an image into its primitive components, such as cartoon plus texture, is a fundamental problem in image processing. In [11, 16], the authors proposed a technique to achieve this decomposition into structure and texture. These two compo ...
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Journal ArticleProceedings - International Conference on Image Processing, ICIP · December 1, 2004
A light field is a 4D function representing radiance as a function of ray position and direction in 3D space. In this paper we describe a method for recovering gaps in light fields of scenes that contain significant occluders. In these situations, although ...
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Journal Article2004 2nd IEEE International Symposium on Biomedical Imaging: Macro to Nano · December 1, 2004
Electron tomography allows determination of the three-dimensional structures of cells and tissues at resolutions significantly higher than is possible with optical microscopy. Electron tomograms contain, in principle, vast amounts of information on the loc ...
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Journal ArticleJournal of Computational Physics · September 1, 2004
We investigate the problem of determining visible regions given a set of (moving) obstacles and a (moving) vantage point. Our approach to this problem is through an implicit framework, where the obstacles are represented by a level set function. The visibi ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · September 2004
Two complementary geometric structures for the topographic representation of an image are developed in this work. The first one computes a description of the Morse-topological structure of the image, while the second one computes a simplified version of it ...
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ConferenceACM SIGGRAPH 2004 Course Notes, SIGGRAPH 2004 · August 8, 2004
Level set methods, an important class of partial differential equation (PDE) methods, define dynamic surfaces implicitly as the level set (iso-surface) of a sampled, evolving nD function. The course begins with preparatory material that introduces the conc ...
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Journal ArticleJournal of Computational Physics · March 20, 2004
A framework for solving variational problems and partial differential equations that define maps onto a given generic manifold is introduced in this paper. We discuss the framework for arbitrary target manifolds, while the domain manifold problem was addre ...
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Journal ArticleNeuroImage · January 2004
We describe how implicit surface representations can be used to solve fundamental problems in brain imaging. This kind of representation is not only natural following the state-of-the-art segmentation algorithms reported in the literature to extract the di ...
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Journal ArticleMultiscale Modeling and Simulation · January 1, 2004
A geometric representation for images is studied in this work. This is based on two complementary geometric structures for the topographic representation of an image. The first one computes a description of the Morse structure, while the second one compute ...
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Journal ArticleIEEE International Conference on Image Processing · December 17, 2003
Two complementary geometric structures for the topographic representation of an image are developed in this work. The first one computes a description of the Morse structure of the image, while the second one computes a simplified version of its drainage s ...
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Journal ArticleIEEE International Conference on Image Processing · December 17, 2003
An algorithm for filling-in surface holes is introduced in this paper. The basic idea is to represent the surface of interest in implicit form, and fill-in the holes with a system of geometric partial differential equations derived from image inpainting al ...
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Journal ArticleIEEE International Conference on Image Processing · December 17, 2003
In this paper we propose an extension of grayscale histogram equalization for color images. For aesthetic reasons, previously proposed color histogram equalization techniques do not generate uniform color histograms. Our method will always generate an almo ...
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Journal ArticleIEEE International Conference on Image Processing · December 16, 2003
In this paper, we present a technique for automatic color image inpainting, the art of modifying an image-region in a non-detectable form. The main algorithm is based on the theory of projections onto convex sets (POCS). The image and its wavelet transform ...
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Journal ArticleIEEE International Conference on Image Processing · December 16, 2003
An algorithm for the simultaneous filling-in of texture and structure in regions of missing image information is presented in this paper. The basic idea is to first decompose the image into the sum of two functions with different basic characteristics, and ...
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Journal ArticleIEEE Transactions on Visualization and Computer Graphics · October 1, 2003
Considerable evidence suggests that a viewer's perception of the 3D shape of a polygonally-defined object can be significantly affected (either masked or enhanced) by the presence of a surface texture pattern. However, investigations into the specific mech ...
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Journal ArticleProceedings of SPIE - The International Society for Optical Engineering · September 15, 2003
Knowledge of brain aneurysm dimensions is essential during the planning stage of minimally invasive surgical interventions using Guglielmi Detachable Coils (GDC). These parameters are obtained in clinical routine using 2D Maximum Intensity Projection image ...
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Journal ArticleJournal of Computational Physics · March 1, 2003
In this paper we review the algorithm development and applications in high resolution shock capturing methods, evel set methods, and PDE based methods in computer vision and image processing. The emphasis is on Stanley Osher's contribution in these areas a ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · January 2003
An algorithm for the simultaneous filling-in of texture and structure in regions of missing image information is presented in this paper. The basic idea is to first decompose the image into the sum of two functions with different basic characteristics, and ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · January 2003
An approach for filling-in blocks of missing data in wireless image transmission is presented. When compression algorithms such as JPEG are used as part of the wireless transmission process, images are first tiled into blocks of 8 x 8 pixels. When such ima ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · January 2003
A novel paradigm for information visualization in high dynamic range images is presented in this paper. These images, real or synthetic, have luminance with typical ranges many orders of magnitude higher than that of standard output/viewing devices, thereb ...
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Journal ArticleLecture Notes in Computer Science · January 1, 2003
Knowledge of brain aneurysm dimensions is essential in minimally invasive surgical interventions using Guglielmi Detachable Coils. These parameters are obtained in clinical routine using 2D maximum intensity projection images. Automated quantification of t ...
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Journal ArticleProceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition · 2003
An algorithm for the simultaneous filling-in of texture and structure in regions of missing image information is presented in this paper. The basic idea is to first decompose the image into the sum of two functions with different basic characteristics, and ...
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Journal ArticleJournal of Vision · December 1, 2002
If we could design the perfect texture pattern to apply to any smooth surface in order to enable observers to more accurately perceive the surface's shape in a static monocular image taken from an arbitrary generic viewpoint under standard lightingconditio ...
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Journal ArticleIEEE International Conference on Image Processing · January 1, 2002
A novel paradigm for information visualization in high dynamic range images is presented in this paper. These images, real or synthetic, have luminance with typical ranges many orders of magnitude higher than that of standard output devices, thereby requir ...
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Journal ArticleIEEE International Conference on Image Processing · January 1, 2002
An approach for filling-in blocks of missing data in wireless image transmission is presented in this paper. When compression algorithms such as JPEG are used as part of the wireless transmission process, images are first tiled into blocks of 8 × 8 pixels. ...
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Journal ArticleIEEE International Conference on Image Processing · January 1, 2002
A fast scheme for wavelet-domain interpolation of lost image blocks in wireless image transmission is presented in this paper. In the transmission of block-coded images, fading in wireless channels and congestion in packet-switched networks can cause entir ...
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Journal ArticleJournal of Computational Physics · December 10, 2001
A novel framework for solving variational problems and partial differential equations for scalar and vector-valued data defined on surfaces is introduced in this paper. The key idea is to implicitly represent the surface as the level set of a higher dimens ...
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Journal ArticleProceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition · December 1, 2001
Image inpainting involves filling in part of an image or video using information from the surrounding area. Applications include the restoration of damaged photographs and movies and the removal of selected objects. In this paper, we introduce a class of a ...
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Journal ArticleJournal of Computational Physics · November 1, 2001
An algorithm for the computationally optimal construction of intrinsic weighted distance functions on implicit hyper-surfaces is introduced in this paper. The basic idea is to approximate the intrinsic weighted distance by the Euclidean weighted distance c ...
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Journal ArticleIEEE Transactions on Geoscience and Remote Sensing · October 1, 2001
The compression of elevation data is studied in this paper. The performance of JPEG-LS, the new international ISO/ITU standard for lossless and near-lossless (controlled-lossy) still-image compression, is investigated both for data from the USGS digital el ...
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Journal ArticleHuman brain mapping · September 2001
In this study, a computational optimal system for the generation of curves on triangulated surfaces representing 3D brains is described. The algorithm is based on optimally computing geodesics on the triangulated surfaces following Kimmel and Sethian ([199 ...
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Journal ArticlePattern Recognition · May 1, 2001
In this paper we discuss a new approach to compute discrete skeletons of planar shapes which is based on affine distances, being therefore affine invariant. The method works with generic curves that may contain concave sections, A dynamical interpretation ...
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Journal ArticleIEEE Signal Processing Letters · April 1, 2001
A method for isotropic and anisotropic diffusion of vector probabilities in general, and posterior probabilities in particular, is introduced. The technique is based on diffusing via coupled partial differential equations restricted to the semi-hyperplane ...
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Journal ArticleIEEE transactions on medical imaging · February 2001
A novel method for denoising functional magnetic resonance imaging temporal signals is presented in this note. The method is based on progressively enhancing the temporal signal by means of adaptive anisotropic spatial averaging. This average is based on a ...
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Journal ArticleComputer Vision and Image Understanding · January 1, 2001
Ridge and valley structures are important image features, especially in oriented textures. Usually, the extraction of these structures requires a prefiltering step to regularize the source image. In this paper, we show that classical diffusion-based filter ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · January 2001
A variational approach for filling-in regions of missing data in digital images is introduced. The approach is based on joint interpolation of the image gray levels and gradient/isophotes directions, smoothly extending in an automatic fashion the isophote ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · January 2001
A novel approach for color image denoising is proposed in this paper. The algorithm is based on separating the color data into chromaticity and brightness, and then processing each one of these components with partial differential equations or diffusion fl ...
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Journal ArticleIEEE International Conference on Image Processing · January 1, 2001
In this paper, we apply a knowledge-based segmentation method developed for still and video images to the problem of tracking missiles and high speed projectiles. Since we are only interested in segmenting a portion of the missile (namely, the nose cone), ...
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Journal ArticleProceedings of the IEEE International Conference on Computer Vision · January 1, 2001
A variational approach for filling-in regions of missing data in gray-level and color images is introduced in this paper. The approach is based on joint interpolation of the image gray-levels and gradient/isophotes directions, smoothly extending in an auto ...
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Journal ArticleProceedings of the IEEE International Conference on Computer Vision · January 1, 2001
A new definition of affine invariant erosion of 3D surfaces is introduced. Instead of being based in terms of Euclidean distances, the volumes enclosed between the surface and its chords are used. The resulting erosion is insensitive to noise, and by const ...
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ConferenceProceedings - IEEE Workshop on Variational and Level Set Methods in Computer Vision, VLSM 2001 · January 1, 2001
A novel framework for solving variational problems and partial differential equations for scalar and vector-valued data defined on surfaces is introduced. The key idea is to implicitly represent the surface as the level set of a higher dimensional function ...
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Journal ArticleIEEE International Conference on Image Processing · December 1, 2000
In this paper, a PDE-based system for detecting the boundary of skin lesions in digital clinical skin images is presented. The image is first-processed via contrast-enhancement and anisotropic diffusion. If the lesion is covered by hairs, a PDE-based conti ...
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Journal ArticleIEEE International Conference on Image Processing · December 1, 2000
A new approach for improving the detection of pixels associated with neural activity in functional magnetic resonance imaging (fMRI) is presented. We propose to use anisotropic diffusion to exploit the spatial correlation between the active pixels in funct ...
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Journal ArticleIEEE Signal Processing Letters · September 1, 2000
In this letter, we extend the concept of level lines of scalar images to vector-valued data. Consistent with the scalar case, we define the level-lines of vector-valued images as the integral curves of the directions of minimal vectorial change. This direc ...
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Journal ArticleIEEE transactions on medical imaging · July 2000
In this paper, a partial-differential equations (PDE)-based system for detecting the boundary of skin lesions in digital clinical skin images is presented. The image is first preprocessed via contrast-enhancement and anisotropic diffusion. If the lesion is ...
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Journal ArticleIEEE Transactions on Pattern Analysis and Machine Intelligence · July 1, 2000
A method for deforming curves in a given image to a desired position in a second image is introduced in this paper. The algorithm is based on deforming the first image toward the second one via a Partial Differential Equation (PDE), while tracking the defo ...
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Journal ArticleSIGGRAPH 2000 - Proceedings of the 27th Annual Conference on Computer Graphics and Interactive Techniques · July 1, 2000
Inpainting, the technique of modifying an image in an undetectable form, is as ancient as art itself. The goals and applications of inpainting are numerous, from the restoration of damaged paintings and photographs to the removal/replacement of selected ob ...
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Journal ArticleIEEE Transactions on Visualization and Computer Graphics · April 1, 2000
In this paper, we give an explicit method for mapping any simply connected surface onto the sphere in a manner which preserves angles. This technique relies on certain conformal mappings from differential geometry. Our method provides a new way to automati ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · January 2000
LOCO-I (LOw COmplexity LOssless COmpression for Images) is the algorithm at the core of the new ISO/ITU standard for lossless and near-lossless compression of continuous-tone images, JPEG-LS. It is conceived as a "low complexity projection" of the universa ...
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Journal ArticleIEEE International Conference on Image Processing · January 1, 2000
A novel approach for color image denoising is proposed in this paper. The algorithm is based on separating the color data into chromaticity and brightness, and then processing each one of these components with partial differential equations or diffusion fl ...
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Journal ArticleIEEE International Conference on Image Processing · 2000
A method for isotropic and anisotropic diffusion of vector probabilities in general, and posterior probabilities in particular, is introduced. The technique is based on diffusing via coupled partial differential equations restricted to the semi-hyperplane ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · January 2000
An approach for the segmentation of still and video synthetic aperture radar (SAR) images is described. A priori knowledge about the objects present in the image, e.g., target, shadow and background terrain, is introduced via Bayes' rule. Posterior probabi ...
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Journal ArticleIEEE International Conference on Image Processing · January 1, 2000
A simple approach to compute the skeletons of gray-scale images using partial differential equations is presented in this paper. The proposed scheme works directly on the gray-scale images, without the necessity of pre-segmentation (binarization), or the a ...
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Journal ArticleInternational Journal of Computer Vision · January 1, 2000
In a number of disciplines, directional data provides a fundamental source of information. A novel framework for isotropic and anisotropic diffusion of directions is presented in this paper. The framework can be applied both to denoise directional data and ...
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Journal ArticleJournal of Mathematical Imaging and Vision · January 1, 2000
In this paper, we formally connect between vector median filters, inf-sup morphological operations, and geometric partial differential equations. Considering a lexicographic order, which permits to define an order between vectors in IRN, we first show that ...
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ConferenceLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · January 1, 2000
A new definition of affine invariant skeletons for shape re- presentation is introduced. A point belongs to the affine skeleton if and only if it is equidistant from at least two points of the curve, with the distance being a minima and given by the areas ...
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Journal ArticleIEEE International Conference on Image Processing · December 1, 1999
LOCO-I (LOw COmplexity LOssless COmpression for Images) is the algorithm at the core of the new ISO/ITU standard for lossless and near-lossless compression of continuous-tone images, JPEG-LS. The algorithm was conceived as a `low complexity projection' of ...
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Journal ArticleIEEE International Conference on Image Processing · December 1, 1999
In this paper, we formally connect between vector median filters, morphological operators, and geometric partial differential equations. Considering a lexicographic order, which permits to define an order between vectors in IRN, we first show that the vect ...
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Journal ArticleIEEE Transactions on Pattern Analysis and Machine Intelligence · December 1, 1999
A gsometric-vision approach to color constancy and illuminant estimation is presented in this paper. We show a general framework, based on ideas from the generalized probabilistic Hough translorm, to estimate the illuminant and reflectance ot natural image ...
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Journal ArticleIEEE transactions on medical imaging · May 1999
Since the work by Osher and Sethian on level-sets algorithms for numerical shape evolutions, this technique has been used for a large number of applications in numerous fields. In medical imaging, this numerical technique has been successfully used, for ex ...
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Journal ArticleActa Applicandae Mathematicae · January 1, 1999
In this paper we undertake a systematic investigation of affine invariant object detection and image denoising. Edge detection is first presented from the point of view of the affine invariant scale-space obtained by curvature based motion of the image lev ...
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Journal ArticleProceedings of the IEEE International Conference on Computer Vision · January 1, 1999
In a number of disciplines, directional data provides a fundamental source of information. A novel framework for isotropic and anisotropic diffusion of directions is presented in this paper. The framework can be applied both to regularize directional data ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · January 1999
A novel approach for shape preserving contrast enhancement is presented in this paper. Contrast enhancement is achieved by means of a local histogram equalization algorithm which preserves the level-sets of the image. This basic property is violated by com ...
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ConferenceLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · January 1, 1999
In this paper we present and briefly describe a Windows user-friendly system designed to assist with the analysis of images in general, and biomedical images in particular. The system, which is being made publicly available to the research community, imple ...
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ConferenceLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · January 1, 1999
A method for deforming curves in a given image to a desired position in a second image is introduced in this paper. The algorithm is based on deforming the first image toward the second one via a partial differential equation, while tracking the deformatio ...
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ConferenceLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · January 1, 1999
Since the work by Osher and Sethian on level-sets algorithms for numerical shape evolutions, this technique has been used for a large number of applications in numerous fields. In medical imaging, this numerical technique has been successfully used for exa ...
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ConferenceLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · January 1, 1999
Edges are viewed as statistical outliers with respect to local image gradient magnitudes. Within local image regions we compute a robust statistical measure of the gradient variation and use this in an anisotropic diffusion framework to determine a spatial ...
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Journal ArticleIEEE International Conference on Image Processing · December 1, 1998
A method for deforming curves in a given image to a desired position in a second image is introduced in this paper. The algorithm is based on deforming the first image toward the second one via a partial differential equation, while tracking the deformatio ...
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Journal ArticleProceedings of the IEEE International Conference on Computer Vision · December 1, 1998
Affine invariant medial axes and symmetry sets of planar shapes are introduced and studied in this paper. Two different approaches are presented. The first one is based on affine invariant distances, and defines the symmetry set, a set containing the media ...
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Journal ArticleProceedings of the IEEE International Conference on Computer Vision · December 1, 1998
A geometric-vision approach to solve bilinear problems in general, and the color constancy and illuminant estimation problem in particular, is presented in this paper. We show a general framework, based on ideas from the generalized (probabilistic) Hough t ...
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Journal ArticleProceedings of the IEEE International Conference on Computer Vision · December 1, 1998
We describe a system that is being used to segment gray matter and create connected cortical representations from MRI. The method exploits knowledge of the anatomy of the cortex and incorporates structural constraints into the segmentation. First, the whit ...
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Journal ArticleIEEE International Conference on Image Processing · December 1, 1998
A new approach for the segmentation of still and video SAR images is described in this paper. A priori knowledge about the objects present in the image, e.g., target, shadow, and background terrain, is introduced via Bayes' rule. Posterior probabilities ob ...
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Journal ArticleIEEE International Conference on Image Processing · December 1, 1998
In this paper we describe a system that is being used for the segmentation of neurons in images obtained from electronic microscopy. These images are extremely noisy, and ordinary active contours techniques detect spurious objects and fail to detect the ne ...
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Journal Article · November 1, 1998
LOCO-I (LOw COmplexity LOssless COmpression for Images) is the algorithm at the core of the new ISO/ITU standard for lossless and near-lossless compression of continuous-tone images, JPEG-LS. It is conceived as a `low complexity projection' of the universa ...
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Journal ArticleGeometriae Dedicata · January 1, 1998
Affine invariant symmetry sets of planar curves are introduced and studied in this paper. Two different approaches are investigated. The first one is based on affine invariant distances, and defines the symmetry set as the closure of the locus of points on ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · January 1998
Relations between anisotropic diffusion and robust statistics are described in this paper. Specifically, we show that anisotropic diffusion can be seen as a robust estimation procedure that estimates a piecewise smooth image from a noisy input image. The " ...
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Journal ArticleIEEE International Conference on Image Processing · December 1, 1997
Recently, we proposed an efficient image segmentation technique that anisotropically smoothes the homogeneous posterior probabilities before independent pixelwise MAP classification is carried out. In this paper, we develop the mathematical theory underlyi ...
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Journal ArticleIEEE International Conference on Image Processing · December 1, 1997
A novel approach for shape preserving contrast enhancement is presented in this paper. Contrast enhancement is achieved by means of a local histogram equalization algorithm which preserves the level-sets of the image. This basic property is violated by com ...
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Journal ArticleIEEE International Conference on Image Processing · December 1, 1997
Relations between anisotropic diffusion and robust statistics are described in this paper. We show that anisotropic diffusion can be seen as a robust estimation procedure that estimates a piecewise smooth image from a noisy input image. The `edge-stopping' ...
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Journal ArticleIEEE transactions on medical imaging · December 1997
We describe a system that is being used to segment gray matter from magnetic resonance imaging (MRI) and to create connected cortical representations for functional MRI visualization (fMRI). The method exploits knowledge of the anatomy of the cortex and in ...
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Journal ArticleIEEE Transactions on Pattern Analysis and Machine Intelligence · December 1, 1997
A geometric approach for 3D object segmentation and representation is presented. The segmentation is obtained by deformable surfaces moving towards the objects to be detected in the 3D image. The model is based on curvature motion and the computation of su ...
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Journal ArticleVision research · September 1997
A new discrete-time reverse-correlation scheme for the study of visual neurons is proposed. The visual stimulus is generated by drawing with uniform probability, at each refresh time, an image from a finite set S of orthonormal images. We show that if the ...
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Journal ArticleJournal of Differential Equations · April 10, 1997
The explicit use of partial differential equations (PDEs) in image processing became a major research topic in the past years. In this work we present a framework for histogram (pixel-value distribution) modification via ordinary and partial differential e ...
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Journal Article · April 1, 1997
A novel approach for shape preserving contrast enhancement is presented in this paper. Contrast enhancement is achieved by means of a local histogram equalization algorithm which preserves the level-sets of the image. This basic property is violated by com ...
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Journal ArticleVision research · February 1997
Numerous studies have shown that the power of 1/3 is important in relating Euclidean velocity to radius of curvature (R) in the generation and perception of planar movement. Although the relation between velocity and curvature is clear and very intuitive, ...
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ConferenceLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · January 1, 1997
Relations between anisotropic diffusion and robust statistics are described in this paper. We show that anisotropic diffusion can be seen as a robust estimation procedure that estimates a piecewise smooth image from a noisy input image. The "edge-stopping" ...
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Journal ArticleInternational Journal of Computer Vision · January 1, 1997
A novel scheme for the detection of object boundaries is presented. The technique is based on active contours evolving in time according to intrinsic geometric measures of the image. The evolving contours naturally split and merge, allowing the simultaneou ...
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Journal ArticleGraphical Models and Image Processing · January 1, 1997
A framework for contrast enhancement via image evolution flows and variational formulations is introduced in this paper. First, an algorithm for histogram modification via image evolution equations is presented. We show that the image histogram can be modi ...
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Journal ArticleComputer Vision and Image Understanding · January 1, 1997
A framework for object segmentation in vector-valued images is presented in this paper. The first scheme proposed is based on geometric active contours moving toward the objects to be detected in the vector-valued image. Object boundaries are obtained as g ...
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Journal ArticleNumerische Mathematik · January 1, 1997
A novel geometric approach for three dimensional object segmentation is presented. The scheme is based on geometric deformable surfaces moving towards the objects to be detected. We show that this model is related to the computation of surfaces of minimal ...
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Journal ArticleSIAM Journal on Applied Mathematics · January 1, 1997
The study of geometric flows for smoothing, multiscale representation, and analysis of two- and three-dimensional objects has received much attention in the past few years. In this paper, we first survey the geometric smoothing of curves and surfaces via g ...
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Journal ArticleHP Laboratories Technical Report · January 1, 1997
We describe a system that is being used to segment gray matter from volumetric representations of the human cortex obtained using magnetic resonance imaging. The segmentation algorithm identifies gray matter voxels and computes their connectivity. The meth ...
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Journal ArticleJournal of Mathematical Imaging and Vision · January 1, 1997
Multiscale representations and progressive smoothing constitute an important topic in different fields as computer vision, CAGD, and image processing. In this work, a multiscale representation of planar shapes is first described. The approach is based on c ...
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Journal ArticleIEEE International Conference on Image Processing · December 1, 1996
A partial-differential-equations (PDE') based geometric framework for segmentation of vector-valued images is described in this paper. The first component of this approach is based on two dimensional geometric active contours deforming from their initial p ...
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Journal ArticleIEEE International Conference on Image Processing · December 1, 1996
In this paper, we present mathematical and qualitative relations between a number of partial differential equations frequently used in image processing and computer vision. We show for example that classical active contours introduced for object detection ...
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Journal ArticleHP Laboratories Technical Report · June 1, 1996
This work aims to present and study symmetry sets which are affine invariant. Two alternatives to affine invariant symmetry sets are presented. The first one is based on a definition of affine invariant distances. The second approach is based on affine bit ...
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Journal ArticleInvestigative Ophthalmology and Visual Science · February 15, 1996
Purpose. The standard approach to generalize the white-noise technique to neural systems with multiple inputs consists of using a spatio-temporal white noise stimulus. A drawback of this methodology is that the input space to be explored is huge, and only ...
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Journal ArticleIEEE transactions on image processing : a publication of the IEEE Signal Processing Society · January 1996
A general framework for anisotropic diffusion of multivalued images is presented. We propose an evolution equation where, at each point in time, the directions and magnitudes of the maximal and minimal rate of change in the vector-image are first evaluated ...
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Journal ArticleProceedings of the Workship on Mathematical Methods in Biomedical Image Analysis · January 1, 1996
A geometric scheme for detecting, representing, and measuring 3D medical data is presented. The technique is based on deforming 3D surfaces, represented via level-sets, towards the medical objects, according to intrinsic geometric measures of the data. The ...
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Journal ArticleProceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition · January 1, 1996
In this paper we undertake a systematic investigation of affine invariant object detection. Edge detection is first presented from the point of view of the affine invariant scale-space obtained by curvature based motion of the image level-sets. In this cas ...
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Journal ArticleProceedings of SPIE - The International Society for Optical Engineering · January 1, 1996
A new approach for anisotropic diffusion processing of color images is proposed. The main idea of the algorithm is to facilitate diffusion of the image in the direction parallel to color edges. The direction of maximal and minimal color change at each poin ...
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Journal ArticleProceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition · January 1, 1996
A framework for object segmentation in vector-valued images is presented in this paper. The first scheme proposed is based on geometric active contours moving towards the objects to be detected in the vector-valved image. Objects boundaries are obtained as ...
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Journal ArticleData Compression Conference Proceedings · January 1, 1996
LOCO-I (LOw COmplexity LOssless COmpression for Images) is a novel lossless compression algorithm for continuous-tone images which combines the simplicity of Huffman coding with the compression potential of context models, thus 'enjoying the best of both w ...
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ConferenceLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · January 1, 1996
A novel geometric approach for 3D object segmentation and representation is presented. The scheme is based on geometric deformable surfaces moving towards the objects to be detected. We show that this model is equivalent to the computation of surfaces of m ...
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Journal ArticleIEEE International Conference on Image Processing · December 1, 1995
In this paper I briefly discuss the main characteristics of the use of partial differential equations and curve/surface evolution theory in computer vision and image processing. I will describe the approach and its main advantages, together with a number o ...
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Journal ArticleIEEE International Conference on Image Processing · December 1, 1995
An algorithm for histogram modification via image evolution equations is first presented in this paper. We show that the image histogram can be modified to achieve any given distribution as the steady state solution of this partial differential equation. W ...
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ConferenceProceedings of SPIE - The International Society for Optical Engineering · September 1, 1995
An algorithm for histogram modification via image evolution equations is first presented in this paper. We show that the image histogram can be modified to achieve any given distribution as the steady state solution of this partial differential equation. W ...
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ConferenceProceedings of SPIE - The International Society for Optical Engineering · August 11, 1995
The explicit use of partial differential equations (PDE's) in image processing became a major topic of study in the last years. In this work we present an algorithm for histogram modification via PDE's. We show that the histogram can be modified to achieve ...
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ConferenceProceedings of SPIE - The International Society for Optical Engineering · August 11, 1995
A novel scheme for performing detection and measurements in medical images is presented. The technique is based on active contours evolving in time according to intrinsic geometric measures of the image. The evolving contours naturally split and merge, all ...
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Journal ArticleActa Applicandae Mathematicae · February 1, 1995
We discuss three different affine invariant evolution processes for smoothing planar curves. The first one is derived from a geometric heat-type flow, both the initial and the smoothed curves being differentiable. The second smoothing process is obtained f ...
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Journal ArticleInternational Journal of Pattern Recognition and Artificial Intelligence · January 1, 1995
Evolutions of closed planar polygons are studied in this work. In the first part of the paper, the general theory of linear polygon evolutions is presented, and two specific problems are analyzed. The first one is a polygonal analog of a novel affine-invar ...
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Journal ArticleComputers and Mathematics with Applications · January 1, 1995
In this paper, a curve evolution approach for the computation of geodesic curves on 3D surfaces is presented. The algorithm is based on deforming, via the curve shortening flow, an arbitrary initial curve ending at two given surface points. The 3D curve sh ...
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Journal ArticleInternational Journal of Pattern Recognition and Artificial Intelligence · 1995
Evolutions of closed planar polygons are studied in this work. In the first part of the paper, the general theory of linear polygon evolutions is presented, and two specific problems are analyzed. The first one is a polygonal analog of a novel affine-invar ...
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Journal ArticleIEEE Transactions on Pattern Analysis and Machine Intelligence · January 1, 1995
In this paper, area preserving multi-scale representations of planar curves are described. This allows smoothing without shrinkage at the same time preserving all the scale-space properties. The representations are obtained deforming the curve via geometri ...
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Journal ArticleIEEE International Conference on Computer Vision · January 1, 1995
A novel scheme for the detection of object boundaries is presented. The technique is based on active contours deforming according to intrinsic geometric measures of the image. The evolving contours naturally split and merge, allowing the simultaneous detec ...
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ConferenceProceedings of SPIE - The International Society for Optical Engineering · October 25, 1994
Based on modern invariant theory and symmetry groups, a high level way of defining invariant geometricflows for a given Lie group is described in this work. We then analyze in more detail different subgroups ofthe projective group, which are of special int ...
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Journal ArticleJournal of Functional Analysis · January 1, 1994
An affine invariant curve evolution process is presented in this work. The evolution studied is the affine analogue of the Euclidean Curve Shortening flow. Evolution equations, for both affine and Euclidean invariants, are developed. An affine version of t ...
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Journal ArticleJournal of Visual Communication and Image Representation · January 1, 1994
A new approach for gray-level image coding using binary morphological operations on the image bit-planes is presented. This approach is based on a Geometric Sampling Theorem (GST), and on a modified morphological skeleton. The theorem, which is proved in t ...
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ConferenceProceedings - International Conference on Image Processing, ICIP · January 1, 1994
In this paper we experiments with geometric algorithms for image smoothing. Examples are given for MRI and ATR data. We emphasize experiments with the affine invariant geometric smoother or affine heat equation, originally developed for binary shape smooth ...
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ConferenceLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) · January 1, 1994
In this paper, area preserving geometric multi-scale representations of planar curves are described. This allows geometric smoothing without shrinkage at the same time preserving all the scale-space properties. The representations are obtained deforming th ...
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Journal ArticleInternational Journal of Computer Vision · August 1, 1993
A new affine invariant scale-space for planar curves is presented in this work. The scale-space is obtained from the solution of a novel nonlinear curve evolution equation which admits affine invariant solutions. This flow was proved to be the affine analo ...
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Journal ArticleProceedings of SPIE - The International Society for Optical Engineering · January 1, 1993
We describe a geometric method for formulating planar curve evolution equations which are invariant under a certain transformation group. The approach is based on concepts from the classical theory of differential invariants. The flows we obtain are geomet ...
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Journal ArticlePattern Recognition · January 1, 1993
A new approach to digital implementation of continuous-scale mathematical morphology is presented. The approach is based on discretization of evolution equations associated with continuous multiscale morphological operations. Those equations, and their cor ...
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ConferenceProceedings - 17th Convention of Electrical and Electronics Engineers in Israel, EEIS 1991 · January 1, 1991
A new approach for image coding based on bit-plane decomposition and binary morphological operations is presented. The image is first processed by an errordiffusion technique in order to reduce the number of bitplanes without a significant quality degradat ...
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