David J. Brady

Journal article Optics express · May 2026 We demonstrate a snapshot 3D and texture imaging method based on structured illumination. A calibrated projector-camera system is modeled using a differentiable projector-camera image formation model, enabling physics-guided, unsupervised learning to joint ... Full text Cite

Polarization unlocks scene-level 3D imaging

Journal article Opto Electronic Advances · April 1, 2026 Scene-level high-precision 3D imaging remains a key challenge due to the trade-offs between imaging distance and accuracy. While polarization-based 3D imaging offers potential, it offers a focus on "discontinuous" targets—environments where multiple object ... Full text Cite

Radiometric sensitivity and resolution of synthetic tracking imaging for orbital debris monitoring.

Journal article Optics express · February 2026 We consider sampling and detection strategies for solar-illuminated space debris. We argue that the lowest detectable debris cross-sectional area (corresponding to a factor of 3-10x in diameter) may be reduced by 10-100x by analysis of stacks of image fram ... Full text Cite

Sparse Transformer for Ultra-Sparse Sampled Video Compressive Sensing

Journal article IEEE Transactions on Multimedia · January 1, 2026 Digital cameras consume ∼ 0.1 microjoule per pixel to capture and encode video, resulting in a power usage of ∼ 20 W for a 4 K sensor operating at 30 fps. Imagining gigapixel cameras operating at 100-1000 fps, the current processing model is unsustainable. ... Full text Cite

Space-time imaging

Journal article Handbook of Statistics · January 1, 2026 This chapter provides a survey of space-time imaging, focusing on the evolution from traditional frame-based video to modern computational imaging. It addresses the fundamental challenge of capturing high-dimensional dynamic scenes under the constraints of ... Full text Cite

Multiscale aperture synthesis imager.

Journal article Nature communications · November 2025 Synthetic aperture imaging has enabled breakthrough observations from radar to astronomy. However, optical implementation remains challenging due to stringent wavefield synchronization requirements among multiple receivers. Here we present the multiscale a ... Full text Cite

Divide and conquer: parallel processing in computational imaging

Journal article Advanced Photonics · September 1, 2025 Parallel processing in array cameras enables improvements in field of view, depth of field as well as color and polarization sampling. A recent study by Zhang et al. expands on this theme with the demonstration of SpeedShot, which uses a small camera array ... Full text Cite

Design and implementation of a snapshot ptychographic wavefront camera array.

Journal article Optics express · July 2025 We describe and demonstrate a ptychographic wavefront camera array for snapshot complex field estimation. A 2-dimensional diffraction grating in the entrance aperture enables programmable overlap between the effective apertures of the 3×3 camera array. We ... Full text Cite

Computational imaging with meta-optics

Journal article Optica · June 20, 2025 Sub-wavelength diffractive meta-optics have emerged as a versatile platform to manipulate light fields at will, due to their ultra-small form factor and flexible multifunctionalities. However, miniaturization and multimodality are typically compromised by ... Full text Cite

Interferometric focal planes.

Journal article Optics express · May 2025 We propose arrays of integrated interferometers to characterize the mutual intensity on focal planes. While focal coherence measurement does not increase the aperture-limited spatial bandpass, it can increase Shannon information capacity relative to irradi ... Full text Cite

A Decade Review of Video Compressive Sensing: A Roadmap to Practical Applications

Journal article Engineering · March 1, 2025 It has been over a decade since the first coded aperture video compressive sensing (CS) system was reported. The underlying principle of this technology is to employ a high-frequency modulator in the optical path to modulate a recorded high-speed scene wit ... Full text Cite

CardiacField: computational echocardiography for automated heart function estimation using two-dimensional echocardiography probes

Journal article European Heart Journal Digital Health · January 1, 2025 Aims: Accurate heart function estimation is vital for detecting and monitoring cardiovascular diseases. While two-dimensional echocardiography (2DE) is widely accessible and used, it requires specialized training, is prone to inter-observer variability, an ... Full text Cite

Differentiable Imaging: Progress, Challenges, and Outlook

Journal article Advanced Devices and Instrumentation · January 1, 2025 Differentiable imaging has emerged as a transformative paradigm in computational imaging by enabling end-to-end optimization of integrated optical-computational systems.This review examines how differentiable frameworks bridge the persistent gap between ph ... Full text Cite

Continuous 3D Myocardial Motion Tracking via Echocardiography.

Journal article IEEE transactions on medical imaging · December 2024 Myocardial motion tracking stands as an essential clinical tool in the prevention and detection of cardiovascular diseases (CVDs), the foremost cause of death globally. However, current techniques suffer from incomplete and inaccurate motion estimation of ... Full text Cite

Ptychographic wavefront cameras.

Journal article Optics letters · December 2024 We introduce a snapshot wavefront camera capable of reconstructing the complex field of an object with near quantum-limited accuracy. This system incorporates a diffraction grating at the entrance aperture and an array of cameras positioned to align with t ... Full text Cite

Multifocal array camera system design

Journal article Applied Optics · September 1, 2024 Traditional cameras rely on focusing mechanisms for high-performance imaging over a large depth range. However, focusing mechanisms are usually complicated, bulky, and costly. Here we consider multifocal array cameras that eliminate the need for focusing m ... Full text Cite

Reflective signatures of unresolved objects.

Journal article Optics express · July 2024 We present a method for identifying, classifying, and distinguishing unresolved reflective objects. A forward model is developed to predict how the radiance field from a specular surface will be angularly distributed and how samples detected from that fiel ... Full text Cite

Integrated photonic encoder for low power and high-speed image processing.

Journal article Nature communications · May 2024 Modern lens designs are capable of resolving greater than 10 gigapixels, while advances in camera frame-rate and hyperspectral imaging have made data acquisition rates of Terapixel/second a real possibility. The main bottlenecks preventing such high data-r ... Full text Cite

Roadmap for Optical Metasurfaces

Journal article ACS Photonics · March 20, 2024 Metasurfaces have recently risen to prominence in optical research, providing unique functionalities that can be used for imaging, beam forming, holography, polarimetry, and many more, while keeping device dimensions small. Despite the fact that a vast ran ... Full text Cite

Synthetic Aperture Scatter Imaging

Journal article IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing · January 1, 2024 Diffraction limits the minimum resolvable feature on remotely observed targets to $\lambda R_{c}/A_{c}$, where $\lambda$ is the operating wavelength, $R_{c}$ is the range to the target and $A_{c}$ is the diameter of the observing aperture. Resolution is of ... Full text Cite

Computational Imaging and Artificial Intelligence: The Next Revolution of Mobile Vision

Journal article Proceedings of the IEEE · December 1, 2023 Signal capture is at the forefront of perceiving and understanding the environment; thus, imaging plays a pivotal role in mobile vision. Recent unprecedented progress in artificial intelligence (AI) has shown great potential in the development of advanced ... Full text Cite

Compressive video via IR-pulsed illumination.

Journal article Optics express · November 2023 We propose and demonstrate a compressive temporal imaging system based on pulsed illumination to encode temporal dynamics into the signal received by the imaging sensor during exposure time. Our approach enables >10x increase in effective frame rate withou ... Full text Cite

Sampling for Snapshot Compressive Imaging

Journal article Intelligent Computing · January 1, 2023 In this study, we compare interlaced and multiscale sampling of smooth manifolds for snapshot compressive imaging. With a particular focus on spectral, spatial, and temporal focal photographic imaging systems, we show that structured transformer networks e ... Full text Cite

From compressive sampling to compressive tasking: retrieving semantics in compressed domain with low bandwidth

Journal article Photonix · December 1, 2022 High-throughput imaging is highly desirable in intelligent analysis of computer vision tasks. In conventional design, throughput is limited by the separation between physical image capture and digital post processing. Computational imaging increases throug ... Full text Cite

Target discrimination in the extended shortwave infrared band (2 to 2.5 μm) compared with visible, near-infrared, and SWIR in degraded visual environments

Journal article Optical Engineering · November 1, 2022 Long-range target identification is well studied in the visible (Vis) and near-infrared (NIR) bands and more recently in the shortwave infrared (SWIR). The longer wavelength of SWIR (1 to 1.7 μm) improves target detection for both long ranges and under cha ... Full text Cite

Array Camera Image Fusion using Physics-Aware Transformers

Journal article Journal of Imaging Science and Technology · November 1, 2022 We demonstrate a physics-aware transformer for feature-based data fusion from cameras with diverse resolution, color spaces, focal planes, focal lengths, and exposure. We also demonstrate a scalable solution for synthetic training data generation for the t ... Full text Cite

Lens sensitivity to aberration: Scaling rules

Journal article Optical Engineering · October 1, 2022 We show that aberration sensitivities are independent of lens scaling when the perturbation amount is kept the same. This behavior is in agreement with the results of actual calculation. Further, we point out that aberration sensitivities scale in the same ... Full text Cite

Split achromatic doublet problem and lens element centering in a drop-in barrel

Journal article Optical Engineering · October 1, 2022 A split doublet is more sensitive to aberration because the inner surfaces are typically strong in curvature and can independently misalign. To improve the centering of a lens element, we discuss using a strip of material inserted in the gap between the le ... Full text Cite

Editorial: Introduction to the Special Issue on Deep Learning for High-Dimensional Sensing

Journal article IEEE Journal on Selected Topics in Signal Processing · June 1, 2022 Full text Cite

Snapshot ptychography on array cameras.

Journal article Optics express · January 2022 We use convolutional neural networks to recover images optically down-sampled by 6.7 × using coherent aperture synthesis over a 16 camera array. Where conventional ptychography relies on scanning and oversampling, here we apply decompressive neural estimat ... Full text Cite

A modular hierarchical array camera

Journal article Light Science and Applications · December 1, 2021 Array cameras removed the optical limitations of a single camera and paved the way for high-performance imaging via the combination of micro-cameras and computation to fuse multiple aperture images. However, existing solutions use dense arrays of cameras t ... Full text Cite

CrossNet++: Cross-Scale Large-Parallax Warping for Reference-Based Super-Resolution.

Journal article IEEE transactions on pattern analysis and machine intelligence · December 2021 The ability of camera arrays to efficiently capture higher space-bandwidth product than single cameras has led to various multiscale and hybrid systems. These systems play vital roles in computational photography, including light field imaging, 360 VR came ... Full text Cite

Review of bio-optical imaging systems with a high space-bandwidth product

Journal article Advanced Photonics · July 1, 2021 Optical imaging has served as a primary method to collect information about biosystems across scales-from functionalities of tissues to morphological structures of cells and even at biomolecular levels. However, to adequately characterize a complex biosyst ... Full text Cite

Photon-limited bounds for phase retrieval.

Journal article Optics express · May 2021 We show that the optimal Cramér-Rao lower bound on the mean-square error for the estimation of a coherent signal from photon-limited intensity measurements is equal to the number of signal elements, or the number of signal elements minus one when we accoun ... Full text Cite

Snapshot Compressive Imaging: Theory, Algorithms, and Applications

Journal article IEEE Signal Processing Magazine · March 1, 2021 Capturing high-dimensional (HD) data is a long-term challenge in signal processing and related fields. Snapshot compressive imaging (SCI) uses a 2D detector to capture HD (≥3D) data in a snapshot measurement. Via novel optical designs, the 2D detector samp ... Full text Cite

Deep Learning for Camera Autofocus

Journal article IEEE Transactions on Computational Imaging · January 1, 2021 Most digital cameras use specialized autofocus sensors, such as phase detection, lidar or ultrasound, to directly measure focus state. However, such sensors increase cost and complexity without directly optimizing final image quality. This paper proposes a ... Full text Cite

Compressive Sampling for Array Cameras

Journal article SIAM Journal on Imaging Sciences · January 1, 2021 While design of high-performance lenses and image sensors has long been the focus of camera development, the size, weight, and power of image data processing components are currently the primary barriers to radical improvements in camera resolution. Here w ... Full text Cite

A coded aperture microscope for X-ray fluorescence full-field imaging.

Journal article Journal of synchrotron radiation · November 2020 The design and construction of an instrument for full-field imaging of the X-ray fluorescence emitted by a fully illuminated sample are presented. The aim is to produce an X-ray microscope with a few micrometers spatial resolution, which does not need to s ... Full text Cite

Resolution and sampling analysis in digital in-line holography with spherical wave illumination

Journal article Optical Engineering · October 1, 2020 The resolution optimization and sampling strategies in practical digital in-line holography (DIH) with spherical wave illumination are analytically studied by optimizing system parameters. Optimal parameters of holographic recording, including illumination ... Full text Cite

Distributed focus and digital zoom

Journal article Engineering Research Express · September 1, 2020 We explore integrated microcamera focus systems for array cameras. Array cameras enable wide field of view 90° to 360° high resolution (10-100 μrad) imaging with small exit apertures (≈10mm). Small exit apertures enable compact focus mechanisms with fast a ... Full text Cite

Noise suppression for ballistic-photons based on compressive in-line holographic imaging through an inhomogeneous medium.

Journal article Optics express · March 2020 Noise suppression is one of the most important tasks in imaging through inhomogeneous mediums. Here, we proposed a denoising approach based on compressive in-line holography for imaging through an inhomogeneous medium. A reference-beam-free system with a l ... Full text Cite

View Synthesis from multi-view RGB data using multilayered representation and volumetric estimation

Journal article Virtual Reality and Intelligent Hardware · February 1, 2020 Background: Aiming at free-view exploration of complicated scenes, this paper presents a method for interpolating views among multi RGB cameras. Methods: In this study, we combine the idea of cost volume, which represent 3D information, and 2D semantic seg ... Full text Cite

Deep learning for camera data acquisition, control, and image estimation

Journal article Advances in Optics and Photonics · January 1, 2020 We review the impact of deep-learning technologies on camera architecture. The function of a camera is first to capture visual information and second to form an image. Conventionally, both functions are implemented in physical optics. Throughout the digita ... Full text Cite

Rank Minimization for Snapshot Compressive Imaging.

Journal article IEEE transactions on pattern analysis and machine intelligence · December 2019 Snapshot compressive imaging (SCI) refers to compressive imaging systems where multiple frames are mapped into a single measurement, with video compressive imaging and hyperspectral compressive imaging as two representative applications. Though exciting re ... Full text Cite

Field of view in monocentric multiscale cameras.

Journal article Applied optics · August 2018 Conventionally, the field of view of a camera is understood as the angular extent of a convex circular or rectangular region. Parallel camera architectures with computational image stitching, however, allow implementation of a field of view with an arbitra ... Full text Cite

Twin-Image-Free Holography: A Compressive Sensing Approach.

Journal article Physical review letters · August 2018 Holographic reconstruction is troubled by the phase-conjugate wave front arising from Hermitian symmetry of the complex field. The so-called twin image obfuscates the reconstruction in solving the inverse problem. Here we quantitatively reveal how and how ... Full text Cite

Parallel cameras

Journal article Optica · February 20, 2018 Parallel lens systems and parallel image signal processing enable cost efficient and compact cameras to capture gigapixel scale images. This paper reviews the context of such cameras in the developing field of computational imaging and discusses how parall ... Full text Cite

Full field-of-view digital lens-free holography for weak-scattering objects based on grating modulation.

Journal article Applied optics · January 2018 Grating-based single-shot digital lens-free holography with spatial spectral multiplexing is proposed to realize full field-of-view (FOV) imaging for weak-scattering objects. Multiple object waves are generated by a one-dimensional grating that is placed i ... Full text Cite

Efficient block-wise algorithm for compressive holography.

Journal article Optics express · October 2017 Compressive holography is a relatively time-consuming image estimation in convex optimized problem. We propose an efficient block-wise algorithm to limit the searching space and reduce the calculation time while keeping the reconstruction quality. The effe ... Full text Cite

High-resolution spectral video acquisition

Journal article Frontiers of Information Technology and Electronic Engineering · September 1, 2017 Compared with conventional cameras, spectral imagers provide many more features in the spectral domain. They have been used in various fields such as material identification, remote sensing, precision agriculture, and surveillance. Traditional imaging spec ... Full text Cite

Galilean monocentric multiscale optical systems.

Journal article Optics express · August 2017 The first generation of monocentric multiscale gigapixel cameras used Keplerian designs to enable full field coverage. This paper considers alternative designs that remove the requirement that adjacent subimages overlap. Removing this constraint enables Ga ... Full text Cite

Coded Apertures in Mass Spectrometry.

Journal article Annual review of analytical chemistry (Palo Alto, Calif.) · June 2017 The use of coded apertures in mass spectrometry can break the trade-off between throughput and resolution that has historically plagued conventional instruments. Despite their very early stage of development, coded apertures have been shown to increase thr ... Full text Cite

Heterogeneous camera array for multispectral light field imaging.

Journal article Optics express · June 2017 Multispectral light field acquisition is challenging due to the increased dimensionality of the problem. In this paper, inspired by anaglyph theory (i.e. the ability of human eyes to synthesize colored stereo perception from color-complementary (such as re ... Full text Cite

Compressive sensing and adaptive sampling applied to millimeter wave inverse synthetic aperture imaging.

Journal article Optics express · February 2017 In order to improve speed and efficiency over traditional scanning methods, a Bayesian compressive sensing algorithm using adaptive spatial sampling is developed for single detector millimeter wave synthetic aperture imaging. The application of this algori ... Full text Open Access Cite

Large Metasurface Aperture for Millimeter Wave Computational Imaging at the Human-Scale.

Journal article Scientific reports · February 2017 We demonstrate a low-profile holographic imaging system at millimeter wavelengths based on an aperture composed of frequency-diverse metasurfaces. Utilizing measurements of spatially-diverse field patterns, diffraction-limited images of human-sized subject ... Full text Cite

Computational Snapshot Multispectral Cameras: Toward dynamic capture of the spectral world

Journal article IEEE Signal Processing Magazine · September 1, 2016 Multispectral cameras collect image data with a greater number of spectral channels than traditional trichromatic sensors, thus providing spectral information at a higher level of detail. Such data are useful in various fields, such as remote sensing, mate ... Full text Cite

Efficient patch-based approach for compressive depth imaging.

Journal article Applied optics · September 2016 We present efficient camera hardware and algorithms to capture images with extended depth of field. The camera moves its focal plane via a liquid lens and modulates the scene at different focal planes by shifting a fixed binary mask, with synchronization a ... Full text Cite

Snapshot fan beam coded aperture coherent scatter tomography.

Journal article Optics express · August 2016 We use coherently scattered X-rays to measure the molecular composition of an object throughout its volume. We image a planar slice of the object in a single snapshot by illuminating it with a fan beam and placing a coded aperture between the object and th ... Full text Cite

Range performance of the DARPA AWARE wide field-of-view visible imager.

Journal article Applied optics · June 2016 In a prior paper, we described a new imaging architecture that addresses the need for wide field-of-view imaging combined with the resolution required to identify targets at long range. Over the last two years substantive improvements have been made to the ... Full text Cite

Characterization of the AWARE 40 wide-field-of-view visible imager

Journal article Optica · December 18, 2015 High-resolution, wide-field-of-view photography has undergone substantial improvements since the advent of multiscale lens design. Here, we present and evaluate a multiscale camera capable of a 10 μrad instantaneous field of view over a 36° field of view. ... Full text Cite

Compressive tomography

Journal article Advances in Optics and Photonics · November 19, 2015 Compressive tomography consists of estimation of high-dimensional objects from lower dimensional measurements. We review compressive tomography using radiation fields, including geometric, wave, and statistical field models. We find coded apertures most ap ... Full text Cite

Feedback stitching for gigapixel video

Journal article Journal of Electronic Imaging · November 1, 2015 Methods of stitching static panoramas are unsuitable for video-rate stitching from camera arrays, because these methods are too computationally intensive for real-time operation and do not take advantage of prior knowledge of camera positions or the cohere ... Full text Cite

Alternating minimization algorithm with automatic relevance determination for transmission tomography under poisson noise

Journal article SIAM Journal on Imaging Sciences · September 30, 2015 We propose a globally convergent alternating minimization (AM) algorithm for image reconstruction in transmission tomography, which extends automatic relevance determination (ARD) to Poisson noise models with Beer’s law. The algorithm promotes solutions th ... Full text Cite

Image translation for single-shot focal tomography

Journal article Optica · September 20, 2015 Focus and depth of field are conventionally addressed by adjusting longitudinal lens position. More recently, combinations of deliberate blur and computational processing have been used to extend depth of field. Here we show that dynamic control of transve ... Full text Cite

Signal recovery and system calibration from multiple compressive poisson measurements

Journal article SIAM Journal on Imaging Sciences · September 17, 2015 The measurement matrix employed in compressive sensing typically cannot be known precisely a priori and must be estimated via calibration. One may take multiple compressive measurements, from which the measurement matrix and underlying signals may be estim ... Full text Cite

Order of Magnitude Signal Gain in Magnetic Sector Mass Spectrometry Via Aperture Coding.

Journal article Journal of the American Society for Mass Spectrometry · September 2015 Miniaturizing instruments for spectroscopic applications requires the designer to confront a tradeoff between instrument resolution and instrument throughput [and associated signal-to-background-ratio (SBR)]. This work demonstrates a solution to this trade ... Full text Cite

Compressive hyperspectral imaging with side information

Journal article IEEE Journal on Selected Topics in Signal Processing · September 1, 2015 A blind compressive sensing algorithm is proposed to reconstruct hyperspectral images from spectrally-compressed measurements. The wavelength-dependent data are coded and then superposed, mapping the three-dimensional hyperspectral datacube to a two-dimens ... Full text Cite

Spectral-temporal compressive imaging.

Journal article Optics letters · September 2015 This Letter presents a compressive camera that integrates mechanical translation and spectral dispersion to compress a multi-spectral, high-speed scene onto a monochrome, video-rate detector. Experimental reconstructions of 17 spectral channels and 11 temp ... Full text Cite

Single-sensor multispeaker listening with acoustic metamaterials.

Journal article Proceedings of the National Academy of Sciences of the United States of America · August 2015 Designing a "cocktail party listener" that functionally mimics the selective perception of a human auditory system has been pursued over the past decades. By exploiting acoustic metamaterials and compressive sensing, we present here a single-sensor listeni ... Full text Cite

Spatial light modulator based color polarization imaging.

Journal article Optics express · May 2015 We describe a compressive snapshot color polarization imager that encodes spatial, spectral, and polarization information using a liquid crystal modulator. We experimentally show that polarization imaging is compressible by multiplexing polarization states ... Full text Cite

Compressive sensing in the EO/IR.

Journal article Applied optics · March 2015 We investigate the utility of compressive sensing (CS) to electro-optic and infrared (EO/IR) applications. We introduce the field through a discussion of historical antecedents and the development of the modern CS framework. Basic economic arguments (in th ... Full text Cite

Two-dimensional aperture coding for magnetic sector mass spectrometry.

Journal article Journal of the American Society for Mass Spectrometry · February 2015 In mass spectrometer design, there has been a historic belief that there exists a fundamental trade-off between instrument size, throughput, and resolution. When miniaturizing a traditional system, performance loss in either resolution or throughput would ... Full text Cite

Compressive sensing by learning a Gaussian mixture model from measurements.

Journal article IEEE 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 ... Full text Cite

Millimeter wave surface and reflectivity estimation based on sparse time of flight measurements

Journal article International Conference on Infrared Millimeter and Terahertz Waves Irmmw Thz · November 13, 2014 We present a novel active millimeter wave imaging technique that can be used to estimate target surface and reflectivity. This technique requires no mechanical scanning but requires only a sparse array of detectors. The illumination beam requires no focusi ... Full text Cite

Video compressive sensing using Gaussian mixture models.

Journal article IEEE 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 ... Full text Cite

Metamaterial microwave holographic imaging system.

Journal article Journal of the Optical Society of America. A, Optics, image science, and vision · October 2014 We demonstrate a microwave imaging system that combines advances in metamaterial aperture design with emerging computational imaging techniques. The flexibility inherent to guided-wave, complementary metamaterials enables the design of a planar antenna tha ... Full text Cite

An X-ray scatter system for material identification in cluttered objects: A Monte Carlo simulation study

Journal article Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms · September 15, 2014 The analysis of X-ray scatter patterns has been demonstrated as an effective method of identifying specific materials in mixed object environments, for both biological and non-biological applications. Here we describe an X-ray scatter imaging system for ma ... Full text Cite

Complementary coded apertures for 4-dimensional x-ray coherent scatter imaging.

Journal article Optics express · September 2014 X-ray scattering has played a key role in non-destructive materials characterization due to the material-specific coherent scattering signatures. In the current energy dispersive coherent scatter imaging systems, including selected volume tomography and co ... Full text Cite

Compressive mass analysis on quadrupole ion trap systems.

Journal article Journal of the American Society for Mass Spectrometry · July 2014 Conventionally, quadrupole ion trap mass spectrometers eject ions of different mass-to-charge ratio (m/z) in a sequential fashion by performing a scan of the rf trapping voltage amplitude. Due to the inherent sparsity of most mass spectra, the detector mea ... Full text Cite

Compressed sampling strategies for tomography.

Journal article Journal of the Optical Society of America. A, Optics, image science, and vision · July 2014 We investigate new sampling strategies for projection tomography, enabling one to employ fewer measurements than expected from classical sampling theory without significant loss of information. Inspired by compressed sensing, our approach is based on the u ... Full text Cite

Adaptive millimeter-wave synthetic aperture imaging for compressive sampling of sparse scenes.

Journal article Optics express · June 2014 We apply adaptive sensing techniques to the problem of locating sparse metallic scatterers using high-resolution, frequency modulated continuous wave W-band RADAR. Using a single detector, a frequency stepped source, and a lateral translation stage, invers ... Full text Open Access Cite

Echelle crossed grating millimeter wave beam scanner.

Journal article Optics express · June 2014 We present a two-dimensional, active, millimeter-wave, electronic beam scanner, with Doppler capabilities for stand-off imaging. The two-dimensional scan is achieved by mapping the millimeter wave spectrum to space using a pair of crossed gratings. The act ... Full text Cite

Characterization of the AWARE 10 two-gigapixel wide-field-of-view visible imager.

Journal article Applied optics · May 2014 System requirements for many military electro-optic and IR camera systems reflect the need for both wide-field-of-view situational awareness as well as high-resolution imaging for target identification. In this work we present a new imaging system architec ... Full text Cite

Compressive acoustic imaging with metamaterials.

Journal article The Journal of the Acoustical Society of America · April 2014 Compressive imaging has brought revolutionary design methodologies to imaging systems. By shuffling and multiplexing the object information space, the imaging system compresses data on the physical layer and enables employing fewer sensors and acquiring le ... Full text Cite

Structured illumination for tomographic X-ray diffraction imaging.

Journal article The Analyst · February 2014 Tomographic imaging of the molecular structure of an object is important for a variety of applications, ranging from medical and industrial radiography to security screening. X-ray diffraction imaging is the preeminent technique for performing molecular an ... Full text Cite

Optical performance test and validation of microcameras in multiscale, gigapixel imagers.

Journal article Optics express · February 2014 Wide field-of-view gigapixel imaging systems capable of diffraction-limited resolution and video-rate acquisition have a broad range of applications, including sports event broadcasting, security surveillance, astronomical observation, and bioimaging. The ... Full text Cite

Compressive coded aperture spectral imaging: An introduction

Journal article IEEE Signal Processing Magazine · January 1, 2014 Maging spectroscopy involves the sensing of a large amount of spatial information across a multitude of wavelengths. Conventional approaches to hyperspectral sensing scan adjacent zones of the underlying spectral scene and merge the results to construct a ... Full text Cite

Compressive single-pixel snapshot x-ray diffraction imaging.

Journal article Optics letters · January 2014 We present a method for realizing snapshot, depth-resolved material identification using only a single, energy-sensitive pixel. To achieve this result, we employ a coded aperture with subpixel features to modulate the energy spectrum of coherently scattere ... Full text Cite

Coded aperture x-ray scatter tomography

Journal article Proceedings of SPIE the International Society for Optical Engineering · January 1, 2014 We present a system for X-ray tomography using a coded aperture. A fan beam illuminates a 2D cross-section of an object and our coded aperture system produces a tomographic image from each static snapshot; as such, we can reconstruct either a static object ... Full text Cite

Structured illumination for compressive x-ray diffraction tomography

Journal article Proceedings of SPIE the International Society for Optical Engineering · January 1, 2014 Coherent x-ray scatter (also know as x-ray diffraction) has long been used to non-destructively investigate the molecular structure of materials for industrial, medical, security, and fundamental purposes. Unfortunately, molecular tomography based on coher ... Full text Cite

X-ray coherent scatter imaging for surgical margin detection: A Monte Carlo study

Journal article Progress in Biomedical Optics and Imaging Proceedings of SPIE · January 1, 2014 Instead of having the entire breast removed (a mastectomy), breast cancer patients often receive a breast con-serving surgery (BCS) for removal of only the breast tumor. If post-surgery analysis reveals ta missed margin around the tumor tissue excised thro ... Full text Cite

Compressive millimeter wave and X-ray tomography

Journal article Optics InfoBase Conference Papers · January 1, 2014 Compressive tomography consists of estimation of high dimensional objects from measurements distributed over lower dimensions. Examples include reconstruction of 3D spectral data cubes from 2D focal planes and reconstruction of 3D volumes from 2D x-ray pro ... Cite

Roadmap for commercial gigapixel cameras

Journal article Optics InfoBase Conference Papers · January 1, 2014 Multiscale array cameras allow 10-100x improvements in commercial camera resolution. This talk discussed the optical manufacturing, electronic processing and communications and cloud software ecosystem that enables economical multiscale cameras. © 2014 OSA ... Cite

Coding and sampling for compressive x-ray diffraction tomography

Journal article Proceedings of SPIE the International Society for Optical Engineering · December 9, 2013 Coded apertures and energy resolving detectors may be used to improve the sampling efficiency of x-ray tomography and increase the physical diversity of x-ray phenomena measured. Coding and decompressive inference enable increased molecular specificity, re ... Full text Cite

Imaging of diffuse objects with dispersive imagers

Journal article International Conference on Infrared Millimeter and Terahertz Waves Irmmw Thz · December 1, 2013 Dispersive imagers measure multiple speckle realizations of the object to be estimated. This poses a challenge for coherent imaging as classically objects are backpropagated and then despeckled. We present initial findings on an intensity based method for ... Full text Cite

Coded apertures for x-ray scatter imaging.

Journal article Applied optics · November 2013 We examine coding strategies for coded aperture scatter imagers. Scatter imaging enables tomography of compact regions from snapshot measurements. We present coded aperture designs for pencil and fan beam geometries, and compare their singular value spectr ... Full text Cite

Autofocus for a multiscale gigapixel camera.

Journal article Applied optics · November 2013 In recent studies, the advanced wide field of view architectures for image reconstruction and exploitation (AWARE) multiscale camera, which is composed of a monocentric objective lens and an array of microcameras, was developed for the realization of snaps ... Full text Cite

Design of a spherical focal surface using close-packed relay optics: erratum.

Journal article Optics express · November 2013 A coding error was found in calculating the optimal packing distribution of our geodesic array. The error was corrected and the new optimization results in slightly improved packing density. The overall approach and algorithm remain unchanged. ... Full text Cite

Snapshot molecular imaging using coded energy-sensitive detection.

Journal article Optics express · October 2013 We demonstrate a technique for measuring the range-resolved coherent scatter form factors of different objects from a single snapshot. By illuminating the object with an x-ray pencil beam and placing a coded aperture in front of a linear array of energy-se ... Full text Cite

Metamaterial apertures for coherent computational imaging on the physical layer.

Journal article Journal of the Optical Society of America. A, Optics, image science, and vision · August 2013 We introduce the concept of a metamaterial aperture, in which an underlying reference mode interacts with a designed metamaterial surface to produce a series of complex field patterns. The resonant frequencies of the metamaterial elements are randomly dist ... Full text Cite

Coded hyperspectral imaging and blind compressive sensing

Journal article SIAM Journal on Imaging Sciences · July 15, 2013 Blind compressive sensing (CS) is considered for reconstruction of hyperspectral data imaged by a coded aperture camera. The measurements are manifested as a superposition of the coded wavelength-dependent data, with the ambient three-dimensional hyperspec ... Full text Cite

Snapshot 2D tomography via coded aperture x-ray scatter imaging.

Journal article Appl Opt · July 1, 2013 This paper describes a fan beam coded aperture x-ray scatter imaging system that acquires a tomographic image from each snapshot. This technique exploits the cylindrical symmetry of the scattering cross section to avoid the scanning motion typically requir ... Full text Link to item Cite

Monte-Carlo simulations of a coded-aperture X-ray scatter imaging system for molecular imaging

Journal article Progress in Biomedical Optics and Imaging Proceedings of SPIE · June 3, 2013 In this work, we demonstrate the ability to determine the material composition of a sample by measuring coherent scatter diffraction patterns generated using a coded-aperture x-ray scatter imaging (CAXSI) system. Most materials are known to exhibit unique ... Full text Cite

Wide-field compact catadioptric telescope spanning 0.7-14 μm wavelengths.

Journal article Applied optics · June 2013 We present a wide-field compact f-1.2, f-1.6 effective illumination catadioptric telescope that spans the wavelengths 0.7-14.0 μm. Such a telescope replaces several telescopes designed for different infrared bands, while having a track length shorter than ... Full text Cite

Coded aperture compressive temporal imaging.

Journal article Optics 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 ... Full text Open Access Cite

Wide-field astronomical multiscale cameras

Journal article Astronomical Journal · May 1, 2013 In order to produce sufficiently low aberrations with a large aperture, telescopes have a limited field of view. Because of this narrow field, large areas of the sky at a given time are unobserved. We propose several telescopes based on monocentric reflect ... Full text Cite

A testbed for wide-field, high-resolution, gigapixel-class cameras.

Journal article Rev Sci Instrum · May 2013 The high resolution and wide field of view (FOV) of the AWARE (Advanced Wide FOV Architectures for Image Reconstruction and Exploitation) gigapixel class cameras present new challenges in calibration, mechanical testing, and optical performance evaluation. ... Full text Link to item Cite

Automated calibration and optical testing of the AWARE-2 gigapixel multiscale camera

Journal article Proceedings of SPIE the International Society for Optical Engineering · April 11, 2013 Gigapixel-class cameras present new challenges in calibration, mechanical testing, and optical performance evaluation. The AWARE-2 gigapixel camera has nearly one-hundred micro-cameras covering a 120 degree wide by 40 degree tall field of view, with one pi ... Full text Cite

Petapixel photography and the limits of camera information capacity

Journal article Proceedings of SPIE the International Society for Optical Engineering · April 10, 2013 The monochromatic single frame pixel count of a camera is limited by diffraction to the space-bandwidth product, roughly the aperture area divided by the square of the wavelength. We have recently shown that it is possible to approach this limit using mult ... Full text Cite

Coded aperture snapshot spectral polarization imaging.

Journal article Applied optics · April 2013 We describe a single-shot polarization spectral imager that combines two birefringent crystals with a binary coded aperture to encode the spatial, spectral and polarization data cube for compressive sampling on a two-dimensional (2D) detector array. We use ... Full text Cite

Optomechanical design of multiscale gigapixel digital camera.

Journal article Applied optics · March 2013 Recent developments in multiscale imaging systems have opened up the possibility for commercially viable wide-field gigapixel cameras. While multiscale design principles allow tremendous simplification of the optical design, they place increased emphasis o ... Full text Cite

Big snapshot stitching with scarce overlap

Journal article 2013 IEEE High Performance Extreme Computing Conference Hpec 2013 · January 1, 2013 We address certain properties that arise in gigapixel-scale image stitching for snapshot images captured with a novel micro-camera array system, AWARE-2. This system features a greatly extended field of view and high optical resolution, offering unique sen ... Full text Cite

Gaussian mixture model for video compressive sensing

Journal article 2013 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 ... Full text Cite

Multiscale, dictionary-based speckle denoising

Journal article Optics InfoBase Conference Papers · January 1, 2013 We propose a multiscale, dictionary-based, data-adaptive estimation method to recover intensities from multiplicative, speckle data. The proposed method preserves the edges and textures in the underlying image while smoothing intensities in homogenous regi ... Cite

Adaptive scanning for synthetic aperture imagers

Journal article Optics InfoBase Conference Papers · January 1, 2013 Synthetic aperture imagers measure the space-bandwidth product of full-apertures by moving a single detector. We show results from an adaptive sensing experiment that demonstrate a three times speedup over full-scans. © 2013 Optical Society of America. ... Cite

Optical design for computational imaging instruments (invited paper)

Journal article Optics Infobase Conference Papers · January 1, 2013 Using electronic sensors and computation, optical instruments that acquire images solely for algorithmic interpretation are increasingly frequent. High depth of focus, high resolution, and wide fields are simultaneously achieved with joint optical and comp ... Cite

A wide-field catadioptric monocentric multiscale telescope with all-spherical glass optics

Journal article Optics InfoBase Conference Papers · January 1, 2013 Monocentric multiscale design combines a common objective optic with an array of secondary apertures to enable wide field of view high resolution imaging. Here we describe a 15o field of view with 1.1 arcsecond ifov. © OSA 2013. ... Cite

Compressive sensing for video using a passive coding element

Journal article Optics InfoBase Conference Papers · January 1, 2013 We present a prototype system that utilizes mechanical translation of a passive coding element to compress high-speed temporal information into low-framerate video sequences. Reconstructions of 148 frames per experimental coded snapshot are reported. © OSA ... Cite

Color image formation for multiscale gigapixel imaging

Journal article Optics InfoBase Conference Papers · January 1, 2013 We present the current development of the image formation pipeline for color gigapixel images obtained by the AWARE-10 multiscale camera.We introduce a camera simulator, the modifications to the scalable pipeline, and the challenges for creating seamless c ... Cite

Efficient model-based tonemapping of high dynamic range gigapixel images

Journal article Optics InfoBase Conference Papers · January 1, 2013 We present a technique to address the tonemapping of high dynamic range (HDR) gigapixel images. The proposed method relies on extracting low-dimensional models from lowresolution proxy images, and can be efficiently implemented in a parallel manner. © OSA ... Cite

Coding for X-ray scatter imaging

Journal article Optics InfoBase Conference Papers · January 1, 2013 We present coding strategies for x-ray scatter imaging, with focus on pencil and fan beam geometries. Coded apertures spatially modulate the scatter signal prior to measurement, and appropriate reconstruction algorithms recover the tomographic images. © OS ... Cite

Coded aperture snapshot spectral imager based on liquid crystal spatial light modulator

Journal article Optics InfoBase Conference Papers · January 1, 2013 We describe the use of a liquid crystal on silicon modulator to jointly code spatial and spectral features for snapshot spectral imaging. We demonstrate compressive measurement of megapixel multispectral image with 5 nm resolution. © OSA 2013. ... Cite

Determining the optimum grid-connected photovoltaic inverter size

Journal article Solar Energy · January 1, 2013 This paper discusses the practical factors that may influence the inverter sizing strategy. Effects of various factors are studied separately by isolating parameters in the simulations. These factors include irradiance and temperature conditions of the pho ... Full text Cite

Metamaterial apertures for computational imaging.

Journal article Science (New York, N.Y.) · January 2013 By leveraging metamaterials and compressive imaging, a low-profile aperture capable of microwave imaging without lenses, moving parts, or phase shifters is demonstrated. This designer aperture allows image compression to be performed on the physical hardwa ... Full text Cite

Adaptive temporal compressive sensing for video

Journal article 2013 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 ... Full text Open Access Cite

Wide-field microscopy using microcamera arrays

Journal article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · 2013 A microcamera is a relay lens paired with image sensors. Microcameras are grouped into arrays to relay overlapping views of a single large surface to the sensors to form a continuous synthetic image. The imaged surface may be curved or irregular as each ca ... Full text Cite

Efficient testing methodologies for microcameras in a gigapixel imaging system

Journal article Proceedings of SPIE - The International Society for Optical Engineering · 2013 Multiscale parallel imaging - based on a monocentric optical design - promises revolutionary advances in diverse imaging applications by enabling high resolution, real-time image capture over a wide field-of-view (FOV), including sport broadcast, wide-fiel ... Full text Cite

Oversampled triangulation of AWARE-10 monocentric ball lens using an auto-stigmatic microscope

Journal article Optics Express · 2013 In our development of multiscale, gigapixel camera architectures, there is a need for an accurate three-dimensional position alignment of large monocentric lenses relative to hemispherical dome structures. In this work we describe a method for estimating t ... Full text Cite

A common scalable microcamera design for 2, 10, and 40 gigapixel class multiscale cameras

Journal article Frontiers in Optics Fio 2012 · December 1, 2012 Gigapixel camera economics favors reutilization of design components including optics, optomechanics, and electronics. We show microcamera designs for multiscale architectures that only change optical surface profiles that span orders of magnitude of gigap ... Cite

Distributed binary geometric sensor arrays for low-data-throughput human gait biometrics

Journal article Proceedings of the IEEE Sensor Array and Multichannel Signal Processing Workshop · October 12, 2012 We present a novel sensing paradigm of measuring human gait. The goal of the research is to achieve low-cost gait biometrics systems with minimum data throughput for various sensing modalities. The binary measurements of the system are achieved by using bo ... Full text Cite

Development of a scalable image formation pipeline for multiscale gigapixel photography.

Journal article Optics express · September 2012 We report on the image formation pipeline developed to efficiently form gigapixel-scale imagery generated by the AWARE-2 multiscale camera. The AWARE-2 camera consists of 98 "microcameras" imaging through a shared spherical objective, covering a 120° x 50° ... Full text Cite

Engineering a gigapixel monocentric multiscale camera

Journal article OPTICAL ENGINEERING · August 2012 Full text Link to item Cite

Pencil beam coded aperture x-ray scatter imaging

Journal article Optics Express · July 16, 2012 We use coded aperture x-ray scatter imaging to interrogate scattering targets with a pencil beam. Observations from a single x-ray exposure of a flat-panel scintillation detector are used to simultaneously determine the along-beam positions and momentum tr ... Full text Cite

Design and scaling of monocentric multiscale imagers.

Journal article Applied optics · July 2012 Monocentric multi-scale (MMS) lenses are a new approach to high-resolution wide-angle imaging, where a monocentric objective lens is shared by an array of identical rotationally symmetric secondary imagers that each acquire one overlapping segment of a mos ... Full text Cite

Design and fabrication of an ultraviolet-visible coded aperture snapshot spectral imager

Journal article Optical Engineering · July 1, 2012 We describe the design and performance of a coded aperture spectral imager with a wide spectral range of 320 to 700nm over 87 channels and 1988-by-1988 pixels of spatial resolution. A custom-designed relay lens was designed and built for the system, includ ... Full text Cite

Computer experiment and global optimization of layered monocentric lens systems

Journal article Optik · July 1, 2012 In this paper we derive a general analytical solution for a monocentric lens system and present a global optimization method combining sequential design for global optimization and an expected improvement algorithm for global optimization for the design an ... Full text Cite

3D imaging spectroscopy for measuring hyperspectral patterns on solid objects

Journal article ACM Transactions on Graphics · July 1, 2012 Sophisticated methods for true spectral rendering have been developed in computer graphics to produce highly accurate images. In addition to traditional applications in visualizing appearance, such methods have potential applications in many areas of scien ... Full text Cite

Computational imaging

Journal article Optical Engineering · July 1, 2012 Full text Cite

SU-E-I-77: X-Ray Coherent Scatter Diffraction Pattern Modeling in GEANT4.

Journal article Med Phys · June 2012 PURPOSE: To model X-ray coherent scatter diffraction patterns in GEANT4 for simulating experiments involving material detection through diffraction pattern measurement. Although coherent scatter cross-sections are modeled accurately in GEANT4, diffraction ... Full text Link to item Cite

Multiscale gigapixel photography.

Journal article Nature · June 2012 Pixel count is the ratio of the solid angle within a camera's field of view to the solid angle covered by a single detector element. Because the size of the smallest resolvable pixel is proportional to aperture diameter and the maximum field of view is sca ... Full text Cite

Terahertz interferometric synthetic aperture tomography for confocal imaging systems.

Journal article Optics letters · April 2012 Terahertz (THz) interferometric synthetic aperture tomography (TISAT) for confocal imaging within extended objects is demonstrated by combining attributes of synthetic aperture radar and optical coherence tomography. Algorithms recently devised for interfe ... Full text Cite

Statistical performance bounds for coded-aperture compressive spectral-polarimetric imaging

Journal article Computational Optical Sensing and Imaging Cosi 2012 · January 1, 2012 We apply statistical information and Bayesian estimation theories to calculate certain fundamental bounds on the reconstruction of segment boundaries, material type, and surface texture of sparse objects from their coded-aperture compressive spectral-polar ... Full text Cite

Challenges in gigapixel multiscale image formation

Journal article Imaging Systems and Applications ISA 2012 · January 1, 2012 We present new results from the image formation team on the AWARE Wide-Field project. We will report on new strategies prompted by new challenges encountered in experiments with two prototype AWARE Wide-Field systems. © 2012 OSA. ... Full text Cite

Focus in multiscale imaging systems

Journal article Computational Optical Sensing and Imaging Cosi 2012 · January 1, 2012 We consider first order lens design for microcamera-based focus in multiscale cameras, we compare focal and spectral tomography and we compare dynamic focal scanning with alternative EDoF and focal stacking strategies. © 2012 OSA. ... Full text Cite

Challenges in gigapixel multiscale image formation

Journal article Imaging Systems and Applications, ISA 2012 · 2012 Cite

Challenges in gigapixel multiscale image formation

Journal article Imaging Systems and Applications, ISA 2012 · January 1, 2012 We present new results from the image formation team on the AWARE Wide-Field project. We will report on new strategies prompted by new challenges encountered in experiments with two prototype AWARE Wide-Field systems. © 2012 OSA. ... Cite

Bringing You More Than the Weekend: Union Membership and Self-Rated Health in the U.S.

Journal article Social Forces · 2012 Link to item Cite

Coded-aperture Raman imaging for standoff explosive detection

Journal article Proceedings of SPIE the International Society for Optical Engineering · January 1, 2012 This paper describes the design of a deep-UV Raman imaging spectrometer operating with an excitation wavelength of 228 nm. The designed system will provide the ability to detect explosives (both traditional military explosives and home-made explosives) fro ... Full text Cite

Coded aperture spectroscopy with denoising through sparsity.

Journal article Optics express · January 2012 We compare noise and classification metrics for three aperture codes in dispersive spectroscopy. In contrast with previous theory, we show that multiplex codes may be advantageous even in systems dominated by Poisson noise. Furthermore, ill-conditioned cod ... Full text Cite

Reconstructing and segmenting hyperspectral images from compressed measurements

Journal article Workshop on Hyperspectral Image and Signal Processing Evolution in Remote Sensing · December 28, 2011 A joint reconstruction and segmentation model for hyperspectral data obtained from a compressive measurement system is proposed, and some preliminary tests are described. Although hyperspectral imaging (HSI) technology has incredible potential, its utility ... Full text Cite

Joint segmentation and reconstruction of coded aperture hyperspectral data

Journal article Optics InfoBase Conference Papers · December 1, 2011 This work presents experimental verification of a joint segmentation reconstruc- tion algorithm on real data from a snapshot hyperspectral imager. Accurate spectra can be computed for any pixel location in the data cube. © 2011 Optical Society of America. ... Cite

Optical testing of the AWARE wide field 2-gigapixel multiscale camera

Journal article Optics Infobase Conference Papers · December 1, 2011 Testing a 2-Gigapixel 8 arcsec IFOV, 120° FOV camera requires integration of precision mechanical automation, optical instrumentation, image diagnostics, electronics and networking hardware. We detail the ongoing AWARE Wide Field Camera efforts. © 2011 OSA ... Cite

Image formation in multiscale optical systems

Journal article Optics Infobase Conference Papers · December 1, 2011 We present image formation (IF) strategies developed for multiscale imaging systems. In this context, IF takes advantage of significant prior knowledge of array geometry and relies on parallelizable algorithms to handle the high data bandwidth. © 2011 OSA. ... Cite

In-line holographic CARS microscopy

Journal article Optics Infobase Conference Papers · December 1, 2011 We investigated inline holographic CARS microscopy, in which the reference generated from a nonlinear medium co-propagates with the CARS signal produced from a specimen. We show that this technique has 3D chemical selective imaging capability. © 2010 Optic ... Cite

A multiscale, wide field, gigapixel camera

Journal article Optics Infobase Conference Papers · December 1, 2011 Recent investigations into high pixel count imaging using multiscale optics have led to a novel optical design for a wide field, gigapixel camera. We review the mechanical design and optical performance of this imager. © 2011 OSA. ... Cite

Sparse aperture holographic synthesis with multiple speckle realizations

Journal article Optics Infobase Conference Papers · December 1, 2011 Sparse aperture holographic synthesis enables large scale high resolution imaging with sources in variable states of coherence. Using incoherent sources increases bandpass coverage and reduces speckle effects. © 2011 Optical Society of America. ... Cite

Image coding for compressive focal tomography

Journal article Optics Infobase Conference Papers · December 1, 2011 We consider image coding to alias high spatial frequencies in a focused image into low-frequency components which survive low-pass defocusing. Coding before defocusing is shown to structure measurements appropriately for decompressive inference. © 2011 OSA ... Cite

Dennis healy, ISP, MONTAGE and MOSAIC

Journal article Optics Infobase Conference Papers · December 1, 2011 Through a series of DARPA programs, Dennis Healy's unique grasp of the mathematical and physical structure of data and his equally unique tolerance for implausible ideas revolutionized the theory of image acquisition. © 2011 OSA. ... Cite

High pixel count holography

Journal article Optics Infobase Conference Papers · December 1, 2011 Relatively low cost focal arrays and the availability of high performance digital processing enable computational holographic imaging on unprecedented scale. This talk describes recent progress in registration and optimization algorithm. © 2011 Optical Soc ... Cite

Design and fabrication of a UV-visible coded aperture spectral imager (CASI)

Journal article Optics Infobase Conference Papers · December 1, 2011 CASI is a snapshot capable UV-visible spectral imager for measuring bird plumage. Near apochromatic UV-visible optics were designed and built with an MTF for a 4Mpx detector. Wide-spectral bandwidth data from CASI is then presented. © 2011 Optical Society ... Cite

Optimizing microcamera aperture in gigapixel monocentric multiscale cameras

Journal article Optics Infobase Conference Papers · December 1, 2011 Multiscale designs divide the imaging task between a simple objective and many complex microcameras. We study imaging quality as the microcamera aperture size varies from 0.375 to 36 mm with 2 and 50 gigapixel objectives. © 2011 Optical Society of America. ... Cite

Coded aperture spectroscopy with regularization via convex optimization

Journal article Optics Infobase Conference Papers · December 1, 2011 Three coded aperture spectrometers are compared for performance. The classic understanding of performance under Poisson noise is shown to be incomplete through simulation. The slit spectrometer code is not the optimal code for compressible signals. © 2011 ... Cite

An implementation of collaborative adaptation of cognitive radio parameters using an ontology and policy based approach

Journal article Analog Integrated Circuits and Signal Processing · December 1, 2011 The main objective of this paper is to demonstrate the feasibility of the ontology and policy based approach to realize collaborative, automatic adaptation of cognitive radio parameters in the transmitter and receiver. The ontology and policy based approac ... Full text Cite

Sampling and processing for compressive holography [Invited].

Journal article Applied optics · December 2011 Compressive holography applies sparsity priors to data acquired by digital holography to infer a small number of object features or basis vectors from a slightly larger number of discrete measurements. Compressive holography ... Full text Cite

Sampling geometries and resolution limits for compressive MMW and terahertz imaging

Journal article Irmmw Thz 2011 36th International Conference on Infrared Millimeter and Terahertz Waves · December 1, 2011 Compressive measurement enables image formation from sparse and irregular arrays. In MMW and terahertz imaging, compressive measurement may lead to a preference for fewer but more complex transceivers over dense arrays of simple transceivers (e.g. conventi ... Full text Cite

Microcamera aperture scale in monocentric gigapixel cameras.

Journal article Applied optics · October 2011 Multiscale cameras achieve wide-angle, high-resolution imaging by combining coarse image formation by a simplified wide-field objective with localized aberration correction in an array of narrow field microcameras. Microcamera aperture size is a critical p ... Full text Cite

Joint segmentation and reconstruction of hyperspectral images from a single snapshot

Journal article Proceedings of SPIE the International Society for Optical Engineering · September 26, 2011 This work describes numerical methods for the joint reconstruction and segmentation of spectral images taken by compressive sensing coded aperture snapshot spectral imagers (CASSI). In a snapshot, a CASSI captures a two-dimensional (2D) array of measuremen ... Full text Cite

In-line holographic CARS microscopy

Journal article 2011 Conference on Lasers and Electro Optics Laser Science to Photonic Applications CLEO 2011 · September 1, 2011 We investigated inline holographic CARS microscopy, in which the reference generated from a nonlinear medium co-propagates with the CARS signal produced from a specimen. We show that this technique has 3D chemical selective imaging capability. © 2011 OSA. ... Cite

Gigapixel holography

Journal article 2011 Ico International Conference on Information Photonics Ip 2011 · August 22, 2011 Relatively low cost focal plane arrays and the availability of high performance digital memory and processing enable computational holographic imaging on unprecedented scale. Recent progress in registration and optimization enables coherent imaging over re ... Full text Cite

Design of a spherical focal surface using close-packed relay optics.

Journal article Opt Express · August 15, 2011 This paper presents a design strategy for close-packing circular finite-conjugate optics to create a spherical focal surface. Efficient packing of circles on a sphere is commonly referred to as the Tammes problem and various methods for packing optimizatio ... Full text Link to item Cite

Thin holographic camera with integrated reference distribution.

Journal article Applied optics · August 2011 Off-axis digital holography typically uses a beam splitter to combine reference and object waves at an angle matched to the sampling period of the sensor array. The beam splitter determines the thickness of the recording system. This paper describes and de ... Full text Cite

Coding for compressive focal tomography.

Journal article Applied optics · August 2011 We consider the capabilities and limits of strategies for single-aperture three-dimensional and extended depth of field optical imaging. We show that reduced spatial resolution is implicit in forward models for light field sampling and that reduced modulat ... Full text Cite

Joint segmentation and reconstruction of hyperspectral data with compressed measurements.

Journal article Applied optics · August 2011 This work describes numerical methods for the joint reconstruction and segmentation of spectral images taken by compressive sensing coded aperture snapshot spectral imagers (CASSI). In a snapshot, a CASSI captures a two-dimensional (2D) array of measuremen ... Full text Cite

Image formation challenges in the MOSAIC platform

Journal article Proceedings of SPIE the International Society for Optical Engineering · July 21, 2011 The DARPA MOSAIC program applies multiscale optical design (shared objective lens and parallel array of microcameras) to the acquisition of high pixel count images. Interestingly, these images present as many challenges as opportunities. The imagery is acq ... Full text Cite

Image-based registration for synthetic aperture holography.

Journal article Optics express · June 2011 High pixel count apertures for digital holography may be synthesized by scanning smaller aperture detector arrays. Characterization and compensation for registration errors in the detector array position and pitch and for phase instability between the refe ... Full text Cite

Equivalent quasi-static estimation of dynamic penetration force for near surface soil characterization

Journal article Geotechnical Special Publication · May 27, 2011 This paper describes the application of maximum log-likelihood estimation to estimate the average force during a dynamic penetration. It is used to obtain a quasi- static equivalent of the dynamic force in Rapid Soil Characterization System (RapSochs). The ... Full text Cite

Optimum inverter sizing in consideration of irradiance pattern and PV incentives

Journal article Conference Proceedings IEEE Applied Power Electronics Conference and Exposition APEC · May 13, 2011 This paper proposes a general method of sizing the inverter for a PV system. The method evaluates effects of PV incentive policies, inverter efficiency curves, and inverter protection schemes on optimum inverter sizing through system-level cost analysis. S ... Full text Cite

Metallic nano-structures for polarization-independent multi-spectral filters.

Journal article Nanoscale research letters · May 2011 Cross-shaped-hole arrays (CSHAs) are selected for diminishing the polarization-dependent transmission differences of incident plane waves. We investigate the light transmission spectrum of the CSHAs in a thin gold film over a wide range of features. It is ... Full text Cite

Reply to "Comments on multiple aperture cameras

Journal article Applied Optics · April 10, 2011 In response to "Comments on 'Design and characterization of thin multiple aperture infrared cameras,'" Appl. Opt. 50, 1584 (2011), I explain how aliasing and regularization impact noise scaling in multiple aperture imagers. © 2011 Optical Society of Americ ... Full text Cite

Video-rate compressive holographic microscopic tomography.

Journal article Optics express · April 2011 Compressive holography enables 3D reconstruction from a single 2D holographic snapshot for objects that can be sparsely represented in some basis. The snapshot mode enables tomographic imaging of microscopic moving objects. We demonstrate video-rate tomogr ... Full text Cite

Close-up imaging using microcamera arrays for focal plane synthesis

Journal article Optical Engineering · March 1, 2011 Conventional close-up imaging uses lens arrays to form a continuous image of an extended object on a single focal plane sensor or photographic film. By imaging using microcamera arrays onto many separate sensors rather than a single large sensor, the subfi ... Full text Cite

Image formation in multiscale optical systems

Journal article Optics Infobase Conference Papers · January 1, 2011 We present image formation (IF) strategies developed for multiscale imaging systems. In this context, IF takes advantage of significant prior knowledge of array geometry and relies on parallelizable algorithms to handle the high data bandwidth. © 2011 OSA. ... Full text Cite

A multiscale, wide field, gigapixel camera

Journal article Optics InfoBase Conference Papers · 2011 Cite

Optimizing microcamera aperture in gigapixel monocentric multiscale cameras

Journal article Optics InfoBase Conference Papers · 2011 Cite

A multiscale, wide field, gigapixel camera

Journal article Optics InfoBase Conference Papers · 2011 Recent investigations into high pixel count imaging using multiscale optics have led to a novel optical design for a wide field, gigapixel camera. We review the mechanical design and optical performance of this imager. © 2011 OSA. ... Cite

Image formation in multiscale optical systems

Journal article Optics InfoBase Conference Papers · 2011 We present image formation (IF) strategies developed for multiscale imaging systems. In this context, IF takes advantage of significant prior knowledge of array geometry and relies on parallelizable algorithms to handle the high data bandwidth. © 2011 OSA. ... Cite

Optimizing microcamera aperture in gigapixel monocentric multiscale cameras

Journal article Optics InfoBase Conference Papers · 2011 Multiscale designs divide the imaging task between a simple objective and many complex microcameras. We study imaging quality as the microcamera aperture size varies from 0.375 to 36 mm with 2 and 50 gigapixel objectives. © 2011 Optical Society of America. ... Cite

Controlling a lamprey-based robot with an electronic nervous system

Journal article Smart Structures and Systems · 2011 We are developing a biomimetic robot based on the Sea Lamprey. The robot consists of a cylindrical electronics bay propelled by an undulatory body axis. Shape memory alloy (SMA) actuators generate propagating flexion waves in five undulatory segments of a ... Cite

Controlling a lamprey-based robot with an electronic nervous system

Sparse aperture coding for compressive sampling

Journal article Proceedings of SPIE the International Society for Optical Engineering · December 13, 2010 For many years, the basic goal of sparse aperture design has been to maximize the support of the modulation transfer function (MTF). Golay apertures and related nonredundant arrays are typically used to achieve this objective. Unfortunately, maximizing the ... Full text Cite

Gigagon: A monocentric lens design imaging 40 gigapixels

Journal article Optics InfoBase Conference Papers · December 1, 2010 The Gigagon is a f/2.5 five element monocentric lens resolving under 2 arcsec over a 120 degree field of view intended to image onto megapixel sensors tiled over the focal surface. © 2010 Optical Society of America. ... Cite

Compressive holographic microscopy

Journal article Optics Infobase Conference Papers · December 1, 2010 We demonstrate a snapshot 3D holographic microscopy using decompressive inference to infer a tomographic image from a Gabor hologram and to remove autocorrelation and twin-image terms. © 2009 Optical Society of America. ... Cite

Integrated nano-hole array surface plasmon resonance biochemical sensor

Journal article Optics InfoBase Conference Papers · December 1, 2010 We have demonstrated a super-periodic metallic nano-hole array surface plasmon device for integrated biochemical sensing. The super-periodic nano-hole array device combines functions of sensing and surface plasmon resonance spectral analysis on a single de ... Cite

Compressive holography of di®use scatterers

Journal article Optics Infobase Conference Papers · December 1, 2010 We image the incoherent 3D scattering density of objects from the covariance of 2D scattered speckle -eld measurements using forward model regularization and constrained optimization. 3D resolution consistent with spatial bandlimits is demonstrated. © 2009 ... Cite

Sparse fourier sampling in millimeter-wave compressive holography

Journal article Optics InfoBase Conference Papers · December 1, 2010 We analyze the impact of sparse sampling on millimeter-wave (MMW) two-dimensional (2D) holographic measurements for three-dimensional (3D) object reconstruction. Simulations address 3D object estimation efficacy. We present 3D object reconstructions from e ... Cite

Compressive holography of diffuse objects.

Journal article Applied optics · December 2010 We propose an estimation-theoretic approach to the inference of an incoherent 3D scattering density from 2D scattered speckle field measurements. The object density is derived from the covariance of the speckle field. The inference is performed by a constr ... Full text Open Access Cite

Multiframe image estimation for coded aperture snapshot spectral imagers.

Journal article Applied optics · December 2010 A coded aperture snapshot spectral imager (CASSI) estimates the three-dimensional spatiospectral data cube from a snapshot two-dimensional coded projection, assuming that the scene is spatially and spectrally sparse. For less spectrally sparse scenes, we s ... Full text Cite

Cramer-rao study of scattering systems in one-dimensional space

Journal article Proceedings of the IASTED International Conference on Antennas Radar and Wave Propagation Arp 2010 · December 1, 2010 A Cramer-Rao bound (CRB) study is developed to characterize the information content about scattering parameters that is contained in reflective (R), transmissive (T), and combined R plus T wave scattering data. The analysis is developed for scalar wave sca ... Full text Cite

Computational photography and compressive holography

Journal article 2010 IEEE International Conference on Computational Photography Iccp 2010 · November 17, 2010 As lasers, photosensors, and computational imaging techniques improve, holography becomes an increasingly attractive approach for imaging applications largely re- served for photography. For the same illumination energy, we show that holography and photogr ... Full text Cite

The impact of irradiance time behaviors on inverter sizing and design

Journal article 2010 IEEE 12th Workshop on Control and Modeling for Power Electronics COMPEL 2010 · October 22, 2010 This paper investigates the time behavior of over-irradiance events in which the photovoltaic (PV) array outputs more power than the rated power of the inverter. A new dynamic interpretation of such events is proposed and is compared to the conventional st ... Full text Cite

Light propagating in metal sub-wavelength-hole arrays

Journal article Nano · October 1, 2010 We investigate the light propagating through a sub-wavelength-hole array in a thin gold film. The extraordinary light transmission (ELT) of the metallic array is observed. This ELT is due to the localized plasmon polaritons, whose production are dependent ... Full text Cite

Generalized sampling using a compound-eye imaging system for multi-dimensional object acquisition.

Journal article Optics express · August 2010 In this paper, we propose generalized sampling approaches for measuring a multi-dimensional object using a compact compound-eye imaging system called thin observation module by bound optics (TOMBO). This paper shows the proposed system model, physical exam ... Full text Open Access Cite

Analytic-domain lens design with proximate ray tracing.

Journal article Journal of the Optical Society of America. A, Optics, image science, and vision · August 2010 We have developed an alternative approach to optical design which operates in the analytical domain so that an optical designer works directly with rays as analytical functions of system parameters rather than as discretely sampled polylines. This is made ... Full text Open Access Cite

Millimeter-wave compressive holography.

Journal article Applied optics · July 2010 We describe an active millimeter-wave holographic imaging system that uses compressive measurements for three-dimensional (3D) tomographic object estimation. Our system records a two-dimensional (2D) digitized Gabor hologram by translating a single pixel i ... Full text Open Access Cite

Sparse sampling and enhanced axial resolution in millimeter-wave holographic imaging

Journal article Proceedings of SPIE the International Society for Optical Engineering · June 21, 2010 This paper describes an active millimeter-wave (MMW) holographic imaging system used for the study of compressive measurement for concealed weapons detection. We record a digitized on-axis, Gabor hologram using a single pixel incoherent receiver that is tr ... Full text Cite

Identification of fluorescent beads using a coded aperture snapshot spectral imager.

Journal article Applied optics · April 2010 We apply a coded aperture snapshot spectral imager (CASSI) to fluorescence microscopy. CASSI records a two-dimensional (2D) spectrally filtered projection of a three-dimensional (3D) spectral data cube. We minimize a convex quadratic function with total va ... Full text Open Access Cite

Compressive video sensors using multichannel imagers.

Journal article Applied optics · April 2010 We explore the possibilities of obtaining compression in video through modified sampling strategies using multichannel imaging systems. The redundancies in video streams are exploited through compressive sampling schemes to achieve low power and low comple ... Full text Open Access Cite

Inline holographic coherent anti-Stokes Raman microscopy.

Journal article Optics express · April 2010 We demonstrate a simple approach for inline holographic coherent anti-Stokes Raman scattering (CARS) microscopy, in which a layer of uniform nonlinear medium is placed in front of a specimen to be imaged. The reference wave created by four-wave mixing in t ... Full text Open Access Cite

Imaging through turbulence using compressive coherence sensing.

Journal article Optics letters · March 2010 Previous studies have shown that the isoplanatic distortion due to turbulence and the image of a remote object may be jointly estimated from the 4D mutual intensity across an aperture. This Letter shows that decompressive inference on a 2D slice of the 4D ... Full text Open Access Cite

Point of dispense drug verification using coded aperture raman spectroscopy and image analysis

Journal article Optics InfoBase Conference Papers · January 1, 2010 Coded aperture Raman spectroscopy enables standoff through container classification of wide classes of dispensed pharmaceuticals. Sensitivity relative to conventional Raman systems is increased by nearly an order of magnitude, enabling efficient integratio ... Cite

Point of dispense drug verification using coded aperture raman spectroscopy and image analysis

Journal article Optics Infobase Conference Papers · January 1, 2010 Coded aperture Raman spectroscopy enables standoff through container classification of wide classes of dispensed pharmaceuticals. Sensitivity relative to conventional Raman systems is increased by nearly an order of magnitude, enabling efficient integratio ... Full text Cite

Coding and signal inference in compressive holography

Journal article Optics InfoBase Conference Papers · December 1, 2009 Compressive sensing enables highly accurate signal reconstruction from fewer measurements than the number of samples in a signal to be estimated. This paper describes a theoretical framework for 3D tomographic reconstruction from 2D holographic measurement ... Cite

Experimental demonstrations of compressive holography

Journal article Optics InfoBase Conference Papers · December 1, 2009 We demonstrate 3D object reconstruction from a single 2D data plane using compressive holography in Gabor and Leith-Upatneiks geometries. © 2009 Optical Society of America. ... Cite

Multiscale optical systems

Journal article Optics InfoBase Conference Papers · December 1, 2009 Cameras capturing gigapixel or even terapixel images are enabled by lens systems combining single aperture objectives with arrays of smaller scale processing optics. © 2009 Optical Society of America. ... Cite

Aberration correction in multiscale lenses

Journal article Optics InfoBase Conference Papers · December 1, 2009 Multiscale lens design splits the field into subregions and attempts to correct the local wavefront error in each subfield rather than the global error. We review the aberration theory underlying the approach. © 2009 Optical Society of America. ... Cite

Compressive coherence sensing

Journal article Optics Infobase Conference Papers · December 1, 2009 The 4D cross spectral density function is recovered using 2D rotational shear interferometer measurements and a matrix completion algorithm for low rank matrices. Imaging of point sources through turbulence is demonstrated. © 2009 Optical Society of Americ ... Cite

Millimeter-wave imaging using k-space compression

Journal article Optics InfoBase Conference Papers · December 1, 2009 We apply compression in the spatial frequency domain to generate millimeter wave images. Simulations indicate the efficacy of the approach. We are in the process of testing the system experimentally. © 2009 Optical Society of America. ... Cite

Coded aperture computed tomography

Journal article Proceedings of SPIE the International Society for Optical Engineering · December 1, 2009 Diverse physical measurements can be modeled by X-ray transforms. While X-ray tomography is the canonical example, reference structure tomography (RST) and coded aperture snapshot spectral imaging (CASSI) are examples of physically unrelated but mathematic ... Full text Cite

Cramer-Rao study of one-dimensional scattering systems: Part II: Computer simulations

Journal article Proceedings of the 6th IASTED International Conference on Antennas Radar and Wave Propagation Arp 2009 · December 1, 2009 This paper is the second of a two-part paper aimed at studying fundamental limits in estimation in 1D scattering systems via the Cramer-Rao bound. In this paper we provide and discuss computer simulation results illustrating the theory in the first paper. ... Cite

Cramer-Rao study of one-dimensional scattering systems: Part I: Formulation

Journal article Proceedings of the 6th IASTED International Conference on Antennas Radar and Wave Propagation Arp 2009 · December 1, 2009 A Cramer-Rao bound (CRB) study is developed in one-dimensional (1D) space which sheds fundamental insight onto the information about multiply scattering point-like scatterers that is contained in scattering field data corresponding to transmissive, reflect ... Cite

Joint transmitter/receiver I/Q imbalance compensation for direct conversion OFDM in packet-switched multipath environments

Journal article IEEE Transactions on Signal Processing · November 4, 2009 This correspondence presents an algorithm for compensation of I/Q imbalance for a direct-conversion packet-switched orthogonal frequency-division-multiplexing (OFDM) communications system, which accounts for transmitter I/Q imbalance, receiver I/Q imbalanc ... Full text Cite

Three-dimensional multipath shape factors for spatial modeling of wireless channels

Journal article IEEE Transactions on Wireless Communications · November 1, 2009 This paper develops a generalized theory of multipath shape factors used to study the small-scale fading statistics in three-dimensional non-omnidirectional multipath channels. Previous results for horizontal propagation channels are special cases of the p ... Full text Cite

Off-axis sparse aperture imaging using phase optimization techniques for application in wide-area imaging systems.

Journal article Applied optics · October 2009 Sparse apertures find imaging applications in diverse fields such as astronomy and medicine. We are motivated by the design of a wide-area imaging system where sparse apertures can be used to construct novel and efficient optical designs. Specifically, we ... Full text Cite

Coded aperture DUV spectrometer for standoff Raman spectroscopy

Journal article Proceedings of SPIE the International Society for Optical Engineering · September 7, 2009 We have designed and constructed a coded aperture spectrometer for use in the deep UV range. The Czerny- Turner design provides sufficient spectral resolution to observe Raman scattering features, while the use of a coded aperture provides a greatly improv ... Full text Cite

Rich Democracies, Poor People: How Politics Explain Poverty

Journal article Rich Democracies Poor People how Politics Explain Poverty · September 1, 2009 This book advances a political argument for poverty. This argument is developed from explaining cross-national and historical variation in poverty across affluent democracies since the late 1960s. Specifically, institutionalized power relations theory is p ... Full text Cite

Multipath directivity and spatial selectivity in three-dimensional wireless channels

Journal article IEEE Transactions on Antennas and Propagation · August 5, 2009 A generalized definition is presented of multipath angular spread, used to study the spatial correlation of the signal envelope in a three-dimensional wireless channel, both in the cases of a three-dimensional and a horizontal travel direction. Previous re ... Full text Cite

Compressive holography.

Journal article Optics express · July 2009 Compressive sampling enables signal reconstruction using less than one measurement per reconstructed signal value. Compressive measurement is particularly useful in generating multidimensional images from lower dimensional data. We demonstrate single frame ... Full text Cite

Fluorescence microscopy with a coded aperture snapshot spectral imager

Journal article Progress in Biomedical Optics and Imaging Proceedings of SPIE · June 12, 2009 This paper describes the application of a dual-dispersive (DD) coded aperture snapshot spectral imager (CASSI) to fluorescence microscopy. CASSI records an interleaved spatially varying, spectrally filtered map of an object onto a two-dimensional (2D) foca ... Full text Cite

Multiscale lens design.

Journal article Optics express · June 2009 While lenses of aperture less than 1000lambda frequently form images with pixel counts approaching the space-bandwidth limit, only heroic designs approach the theoretical information capacity at larger scales. We propose to use the field processing capabil ... Full text Cite

Resolution and interpolation of multichannel long wave infrared camera data

Journal article Proceedings of SPIE the International Society for Optical Engineering · May 25, 2009 We evaluate the performance of a multiple aperture camera with a target projector testbed and compare it to a single lens LWIR camera with a similar field of view and pixel count. We measure a noise equivalent temperature difierence of 131 mK for the multi ... Full text Cite

Design and characterization of thin multiple aperture infrared cameras.

Journal article Applied optics · April 2009 We describe a multiple-aperture long-wave infrared camera built on an uncooled microbolometer array with the objective of decreasing camera thickness. The 5 mm thick optical system is an f/1.2 design with a 6.15 mm effective focal length. An integrated ima ... Full text Cite

Video rate spectral imaging using a coded aperture snapshot spectral imager.

Journal article Optics express · April 2009 We have previously reported on coded aperture snapshot spectral imagers (CASSI) that can capture a full frame spectral image in a snapshot. Here we describe the use of CASSI for spectral imaging of a dynamic scene at video rate. We describe significant adv ... Full text Cite

A static multiplex Fabry-Perot spectrometer

Journal article Proceedings of SPIE the International Society for Optical Engineering · March 24, 2009 We demonstrate a static multiplex spectrometer based on a Fabry-Perot interferometric filter for measuring the mean spectral content of diffuse sources. By replacing the slit of a low-dispersion grating spectrometer with a Fabry-Perot interferometric filte ... Full text Cite

Optically multiplexed imaging with superposition space tracking

Journal article Optics Express · 2009 We describe a novel method to track targets in a large field of view. This method simultaneously images multiple, encoded sub-fields of view onto a common focal plane. Sub-field encoding enables target tracking by creating a unique connection between targe ... Full text Cite

Spatio-temporal sampling for video

Journal article Proceedings of SPIE the International Society for Optical Engineering · December 17, 2008 With this work we propose spatio-temporal sampling strategies for video using a lenslet array computational imaging system and explore the opportunities and challenges in the design of compressive video sensors and corresponding processing algorithms. The ... Full text Cite

Spectral image estimation for coded aperture snapshot spectral imagers

Journal article Proceedings of SPIE the International Society for Optical Engineering · December 17, 2008 This paper describes numerical estimation techniques for coded aperture snapshot spectral imagers (CASSI). In a snapshot, a CASSI captures a two-dimensional (2D) array of measurements that is an encoded representation of both spectral information and 2D sp ... Full text Cite

Superimposed video disambiguation for increased field of view.

Journal article Opt Express · October 13, 2008 Many infrared optical systems in wide-ranging applications such as surveillance and security frequently require large fields of view (FOVs). Often this necessitates a focal plane array (FPA) with a large number of pixels, which, in general, is very expensi ... Full text Link to item Cite

Optical Imaging and Spectroscopy

Journal article Optical Imaging and Spectroscopy · August 12, 2008 An essential reference for optical sensor system design This is the first text to present an integrated view of the optical and mathematical analysis tools necessary to understand computational optical system design. It presents the foundations of computat ... Full text Cite

Multi-excitation Raman spectroscopy technique for fluorescence rejection.

Journal article Optics express · July 2008 Multi-excitation Raman spectroscopy filters out Raman signals from a fluorescent background by sequentially using multiple excitation frequencies. The filtering method exploits the shift of the Raman spectra with excitation frequency and the static respons ... Full text Cite

High-throughput, multiplexed pushbroom hyperspectral microscopy.

Journal article Optics express · July 2008 We describe a high-throughput hyperspectral microscope. The system replaces the slit of conventional pushbroom spectral imagers with a static coded aperture mask. We present the theoretical underpinnings of the aperture coded spectral engine and describe t ... Full text Cite

Single disperser design for coded aperture snapshot spectral imaging.

Journal article Applied optics · April 2008 We present a single disperser spectral imager that exploits recent theoretical work in the area of compressed sensing to achieve snapshot spectral imaging. An experimental prototype is used to capture the spatiospectral information of a scene that consists ... Full text Cite

Thin infrared imaging systems through multichannel sampling.

Journal article Applied optics · April 2008 The size of infrared camera systems can be reduced by collecting low-resolution images in parallel with multiple narrow-aperture lenses rather than collecting a single high-resolution image with one wide-aperture lens. We describe an infrared imaging syste ... Full text Cite

Computational optical sensing and imaging: introduction to the feature issue.

Journal article Applied optics · April 2008 Full text Cite

Robust, common path, phase shifting interferometer and optical profilometer.

Journal article Applied optics · April 2008 We describe an improved implementation of our previously reported common-path, phase shifting, and shearing interferometer. Using a time-multiplexed phase shifting scheme, we demonstrate higher sampling resolution, better light sensitivity, and use of arbi ... Full text Cite

Multichannel sampling schemes for optical imaging systems.

Journal article Applied optics · April 2008 We introduce a framework of focal-plane coding schemes for multichannel sampling in optical systems. A particular objective is to develop an ultrathin imager without compromising image resolution. We present a complete f/2.1 optical system with a thickness ... Full text Cite

Quantitative performance metrics with long wave infrared multiple aperture cameras

Journal article Optics InfoBase Conference Papers · January 1, 2008 We characterize a long wave infrared multiple aperture imaging system by experimentally measuring its Noise Equivalent Temperature Difference and modulation transfer function. These results are compared with a conventional system. © 2008 Optical Society of ... Cite

Reinventing the camera

Journal article Optics and Photonics News · January 1, 2008 The workshop for the Microsystems Technology Office at the Defense Advanced Research Projects Agency (DARPA), 'Camera Ab Initio', in April, 2003 challenged the attendees to rethink the architecture of a camera, or an imaging sensor. The workshop resulted i ... Full text Cite

Compression at the physical interface: The A-to-I and MONTAGE programs

Journal article IEEE Signal Processing Magazine · January 1, 2008 Progresses in physical compressive sampling under the Defense Advanced Research Agency's Analog-to-Information (A-to-I) and Multiple Optical Non-Redundant Aperture Generalized Sensors (MONTAGE) programs are more about finding aggressive forms of generalize ... Full text Cite

Fast disambiguation of superimposed images for increased field of view

Journal article Proceedings - International Conference on Image Processing, ICIP · 2008 Many infrared optical systems in wide-ranging applications such as surveillance and security frequently require large fields of view. Often this necessitates a focal plane array (FPA) with a large number of pixels, which, in general, is very expensive. In ... Full text Cite

Optically multiplexed imaging with superposition space tracking

Journal article Proceedings of SPIE - The International Society for Optical Engineering · 2008 We describe a novel method to track targets in a large field of view. This method simultaneously images multiple, encoded sub-fields of view onto a common focal plane. Sub-field encoding enables target tracking by creating a unique connection between targe ... Full text Cite

Very-high-resolution tandem Fabry-Perot etalon cylindrical beam volume hologram spectrometer for diffuse source spectroscopy.

Journal article Optics letters · January 2008 We demonstrate a compact and slitless spectrometer with high resolution formed by cascading a Fabry-Perot etalon (FPE) and a cylindrical beam volume hologram (CBVH). The most significant advantage of this combined spectrometer is that we can independently ... Full text Cite

High-throughput, multiplex aperture-coded raman spectrometer for biomedical diagnostics

Journal article Biomedical Optics Biomed 2008 · January 1, 2008 Over the past couple of years, we have developed an aperture coded Raman spectrometer whose performance is optimized for extended, incoherent sources. We describe results conveying the potential for in vivo biomedical diagnostics. ©2007 Optical Society of ... Full text Cite

An ultra-high resolution spectrometer with successive combination of a Fabry-Perot etalon and a cylindrical beam volume hologram

Journal article Conference on Lasers and Electro Optics 2007 CLEO 2007 · December 1, 2007 We have designed a compact spectrometer by cascading a simple Fabry-Perot etalon and a cylindrical beam volume hologram. The combination of these two elements results in a twodimensional spatial-spectral mapping in the output plane. Using this spectrometer ... Full text Cite

IR performance study of an adaptive coded aperture "diffractive imaging" system employing MEMS "eyelid shutter" technologies

Journal article Proceedings of SPIE the International Society for Optical Engineering · December 1, 2007 Adaptive coded aperture sensing is an emerging technology enabling real time, wide-area IR/visible sensing and imaging. Exploiting unique imaging architectures, adaptive coded aperture sensors achieve wide field of view, near-instantaneous optical path rep ... Full text Cite

Single-shot compressive spectral imaging with a dual-disperser architecture.

Journal article Optics express · October 2007 This paper describes a single-shot spectral imaging approach based on the concept of compressive sensing. The primary features of the system design are two dispersive elements, arranged in opposition and surrounding a binary-valued aperture code. In contra ... Full text Cite

Localization using boundary sensors: An analysis based on graph theory

Journal article ACM Transactions on Sensor Networks · October 1, 2007 We consider sensors, such as fibers, lasers, and pyroelectric motion detectors, that fire when objects cross a boundary. A moving object can be localized by analyzing sequences of boundary crossings. We consider the number of distinct sequences and object ... Full text Cite

Multiscale reconstruction for computational spectral imaging

Journal article Proceedings of SPIE the International Society for Optical Engineering · August 31, 2007 In this work we develop a spectral imaging system and associated reconstruction methods that have been designed to exploit the theory of compressive sensing. Recent work in this emerging field indicates that when the signal of interest is very sparse (i.e. ... Full text Cite

Performance comparison of aperture codes for multimodal, multiplex spectroscopy.

Journal article Applied optics · August 2007 We experimentally evaluate diverse static independent column codes in a coded aperture spectrometer. The performance of each code is evaluated based on the signal-to-noise ratio (SNR), defined as the peak value in the spectrum to the standard deviation of ... Full text Cite

Longwave infrared (LWIR) coded aperture dispersive spectrometer.

Journal article Optics express · April 2007 We describe a static aperture-coded, dispersive longwave infrared (LWIR) spectrometer that uses a microbolometer array at the detector plane. The two-dimensional aperture code is based on a row-doubled Hadamard mask with transmissive and opaque openings. T ... Full text Cite

Multiple order coded aperture spectrometer.

Journal article Optics express · April 2007 We introduce a multiple order coded aperture (MOCA) spectrometer. The MOCA is a system that uses a multiplex hologram and a coded aperture to increase the spectral range and throughput of the system over conventional spectrometers while maintaining spectra ... Full text Cite

A pyroelectric infrared biometric system for real-time walker recognition by use of a maximum likelihood principal components estimation (MLPCE) method.

Journal article Optics express · March 2007 This paper presents a novel biometric system for real-time walker recognition using a pyroelectric infrared sensor, a Fresnel lens array and signal processing based on the linear regression of sensor signal spectra. In the model training stage, the maximum ... Full text Cite

A snap-shot dual-disperser imager for compressive hyperspectral imaging

Journal article Optics Infobase Conference Papers · January 1, 2007 We demonstrate a single-shot, dual-disperser spectral imaging system using coded apertures to perform compressive imaging. We also describe associated multiscale reconstruction algorithms to retrieve hyperspectral data from single-shot image. We show simul ... Full text Cite

Hyperspectral imager based on coded-aperture spectroscopy

Journal article Optics Infobase Conference Papers · January 1, 2007 A hyperspectral imager based on coded-aperture spectroscopy has excellently generated 3-D data cube that provides 2-D images of a sample with high selectivity of wavelength as well as spectrum with meaningful spectral features. © 2007 Optical Society of Am ... Full text Cite

Optical designs for compressive single shot spectral imaging

Journal article Optics Infobase Conference Papers · January 1, 2007 Static mask coded aperture spectral imaging enables compact, programmable coding for single shot measurements. We review recent demonstrations of spectral imaging systems in the DISP lab and describes trade-offs in dispersion and coding system design. © 20 ... Full text Cite

An ultra-high resolution spectrometer with successive combination of a Fabry-Perot etalon and a cylindrical beam volume hologram

Journal article Optics Infobase Conference Papers · January 1, 2007 We have designed a compact spectrometer by cascading a simple Fabry-Perot etalon and a cylindrical beam volume hologram. The combination of these two elements results in a twodimensional spatial-spectral mapping in the output plane. Using this spectrometer ... Cite

Coded-excitation Raman spectroscopy for Raman signal estimation in highly fluorescent media

Journal article Optics InfoBase Conference Papers · January 1, 2007 Raman signal estimation in highly fluorescent media is investigated using multiple excitation lasers and an iterative EM spectral reconstruction algorithm. Results from an 8-laser system show estimation performance increases with the number of excitation l ... Cite

The MONTAGE least gradient image reconstruction

Journal article Optics InfoBase Conference Papers · January 1, 2007 We introduce an image reconstruction algorithm for the Compressive Optical MONTAGE Photography Initiative, for recovering the resolution of an image from a set of aliased subimages acquired by a lenslet array optical system. © 2007 Optical Society of Ameri ... Cite

Multidimensional spatial and coherence imaging using single shot spectral imagers

Journal article Optics InfoBase Conference Papers · January 1, 2007 A spectral imaging system may efficiently sense 10-100 spectral channels but the full data cube is often redundant. We propose to exploit this redundancy to computationally expand depth of field or obtain multidimensional spatial images. © 2007 Optical Soc ... Cite

An ultra-high resolution volume holographic spectrometer

Journal article Optics InfoBase Conference Papers · January 1, 2007 We have designed a compact spectrometer by cascading a simple Fabry-Perot etalon and a cylindrical beam volume hologram. The combination of these two elements results in a twodimensional spatial-spectral mapping in the output plane. Using this spectrometer ... Cite

An ultra-high resolution tandem fabry-perot etalon cylindrical beam volume hologram spectrometer

Compressive measurements for video

Journal article Optics InfoBase Conference Papers · January 1, 2007 Redundancies present in video streams could be used to implement compressive sampling to achieve low power video sensors. We explore the possibilities of using this in the design of compressive video sensors and corresponding algorithms. © 2007 Optical Soc ... Cite

Depth of field with multi-aperture LWIR imagers

Journal article Optics InfoBase Conference Papers · January 1, 2007 We use a multiaperture approach to design a thin LWIR camera. Having a shorter focal length, the microlens array provides an extended depth of field over the conventional system. © 2007 Optical Society of America. ... Cite

Multiplexed point spread functions for image formation with application to large area sensing and surveillance

Journal article Optics InfoBase Conference Papers · January 1, 2007 Cite

On the design of SAR apertures using the Cramér-Rao bound

Journal article IEEE Transactions on Aerospace and Electronic Systems · January 1, 2007 The Cramér-Rao inequality is applied to the likelihood function of the synthetic aperture radar (SAR) scatterer parameter vector to relate the choice of flight path to estimation performance. Estimation error bounds for the scatterer parameter vector (incl ... Full text Cite

Dispersion multiplexing with broadband filtering for miniature spectrometers.

Journal article Applied optics · January 2007 We replace the traditional grating used in a dispersive spectrometer with a multiplex holographic grating to increase the spectral range sensed by the instrument. The multiplexed grating allows us to measure three different, overlapping spectral bands on a ... Full text Cite

Dynamic aperture optical arrays based on polymeric MEMS actuators for large scale coding elements with application in visible to MWIR

Journal article Proceedings of SPIE - The International Society for Optical Engineering · 2007 Extension of coded apertures to the MWIR introduces the effects of diffraction and other distortions not observed in shorter wavelength systems. A new approach is being developed under the DARPA/SPO funded LACOSTE (Large Area Coverage Optical search-while ... Full text Cite

Single-shot subpixel response measurement with an aperture array pixel mask.

Journal article Optics letters · December 2006 We first point out that the subpixel response function is another kernel function in digital imaging. Then we show that the subpixel response function of CMOS imaging sensor pixels can be measured with an aperture array pixel mask in a single-shot image ca ... Full text Cite

Human tracking with wireless distributed pyroelectric sensors

Journal article IEEE Sensors Journal · December 1, 2006 This paper presents a wireless pyroelectric sensor system, composed of sensing modules (slaves), a synchronization and error rejection module (master), and a data fusion module (host), to perform human tracking. The computation workload distribution among ... Full text Cite

Evaluation and tuning of a SAR detector using sparse-array spotlight mode simulations

Journal article 2006 IEEE Sensor Array and Multichannel Signal Processing Workshop Proceedings SAM 2006 · December 1, 2006 We describe a method of tuning a simple detection process of stationary targets in SAR images. The tuning metric accounts for the squared-error performance of prescient estimators of target location and reflectivity. The efficiencies of these prescient est ... Full text Cite

Information systems for biosensing

Journal article · December 1, 2006 Full text Cite

Biosensing: International research and development

Journal article Biosensing · December 1, 2006 The goal of this book is to disseminate information on the worldwide status and trends in biosensing R&D to government decisionmakers and the research community. The contributors critically analyze and compare biosensing research in the United States with ... Full text Cite

Microlens fabrication using HEBS glass for compact high-resolution IR imaging system

Journal article Proceedings of SPIE the International Society for Optical Engineering · November 23, 2006 Under the DARPA COMP-I (Compressive Optical MONTAGE Photography Initiative) program, the goal of this project is to significantly reduce the volume and form factor of infrared imaging systems without loss of resolution. The approach taken is to use an arra ... Full text Cite

Leith-Upatnieks holography in computational sensors

Journal article Proceedings of SPIE the International Society for Optical Engineering · November 13, 2006 Holographic optical elements are a critically enabling component of modern spectroscopy and spectral imaging systems. While the most common holographic elements are essentially those discovered in 1962 by Leith and Upatnieks, several decades passed prior t ... Full text Cite

Ultra-thin Multiple-channel LWIR Imaging Systems

Journal article Proceedings of SPIE the International Society for Optical Engineering · November 6, 2006 Infrared camera systems may be made dramatically smaller by simultaneously collecting several low-resolution images with multiple narrow aperture lenses rather than collecting a single high-resolution image with one wide aperture lens. Conventional imaging ... Full text Cite

Segmenting object space by geometric reference structures

Journal article ACM Transactions on Sensor Networks · November 1, 2006 A model for segmentation of an object space by an array of binary, radiation-field sensors and geometric reference structures is described. Given a family of binary, radiation-field sensors and a geometric reference structure, we refer to the set of sensor ... Full text Cite

Human-tracking systems using pyroelectric infrared detectors

Journal article Optical Engineering · October 1, 2006 We design and develop a low-cost pyroelectric detector-based IR motion-tracking system. We study the characteristics of the detector and the Fresnel lenses that are used to modulate the visibility of the detectors. We build sensor clusters in different con ... Full text Cite

Compressive imaging sensors

Journal article Proceedings of SPIE the International Society for Optical Engineering · September 18, 2006 This paper describes a compressive sensing strategy developed under the Compressive Optical MONTAGE Photography Initiative. Multiplex and multi-channel measurements are generally necessary for compressive sensing. In a compressive imaging system described ... Full text Cite

Reconstruction of reflectance spectra using robust nonnegative matrix factorization

Journal article IEEE Transactions on Signal Processing · September 1, 2006 In this correspondence, we present a robust statistics-based nonnegative matrix factorization (RNMF) approach to recover the measurements in reflectance spectroscopy. The proposed algorithm is based on the minimization of a robust cost function and yields ... Full text Cite

Compressive imaging spectrometers using coded apertures

Journal article Proceedings of SPIE the International Society for Optical Engineering · August 23, 2006 A spectral imager provides a 3-D data cube in which the spatial information (2-D) of the image is comple-mented by spectral information (1-D) about each spatial location. Typically, these systems are operated in a fully-determined (or overdetermined) manne ... Full text Cite

Real-time human identification using a pyroelectric infrared detector array and hidden Markov models.

Journal article Optics express · July 2006 This paper proposes a real-time human identification system using a pyroelectric infrared (PIR) detector array and hidden Markov models (HMMs). A PIR detector array with masked Fresnel lens arrays is used to generate digital sequential data that can repres ... Full text Cite

Multimodal multiplex Raman spectroscopy optimized for in vivo chemometrics

Journal article Progress in Biomedical Optics and Imaging Proceedings of SPIE · June 29, 2006 We have designed and constructed a multimodal multiplex Raman spectrometer which uses multi-wavelength excitation to better detect signals in the presence of fluorescence by taking advantage of the shift-variance of the Raman signal with respect to excitat ... Full text Cite

High-throughput hyperspectral microscopy

Journal article Proceedings of SPIE the International Society for Optical Engineering · May 8, 2006 A hyperspectral imager provides a 3-D data cube in which the spatial information (2-D) of the image is complemented by spectral information (1-D) about each spatial location. A static, high-throughput spectrometer design previously developed by our group c ... Full text Cite

Multitaper scan-free spectrum estimation using a rotational shear interferometer.

Journal article Applied optics · May 2006 Multitaper methods for a scan-free spectrum estimation that uses a rotational shear interferometer are investigated. Before source spectra can be estimated the sources must be detected. A source detection algorithm based upon the multitaper F-test is propo ... Full text Cite

Analysis of slitless holographic spectrometers implemented by spherical beam volume holograms.

Journal article Applied optics · May 2006 The analysis of a slitless volume holographic spectrometer is presented in detail. The spectrometer is based on a spherical beam volume hologram followed by a Fourier-transforming lens and a CCD. It is shown that the spectrometer is not sensitive to the in ... Full text Cite

Task-specific sensing--introduction.

Journal article Applied optics · May 2006 Full text Cite

Lightweight biometric detection system for human classification using pyroelectric infrared detectors.

Journal article Applied optics · May 2006 We use pyroelectric detectors that are differential in nature to detect motion in humans by their heat emissions. Coded Fresnel lens arrays create boundaries that help to localize humans in space as well as to classify the nature of their motion. We design ... Full text Cite

Thin digital imaging systems using focal plane coding

Journal article Proceedings of SPIE the International Society for Optical Engineering · April 17, 2006 With this work we show the use of focal plane coding to produce nondegenerate data between subapertures of an imaging system. Subaperture data is integrated to form a single high resolution image. Multiple apertures generate multiple copies of a scene on t ... Full text Cite

Nonadaptive group testing based fiber sensor deployment for multiperson tracking

Journal article IEEE Sensors Journal · April 1, 2006 We demonstrate a novel use of nonadaptive group testing in the design and implementation of a fiber sensor floor web for the localization and tracking of multiple individuals. We validate our design with a floor web woven with optical fiber threads that fo ... Full text Cite

Longwave infrared (LWIR) coded aperture dispersive spectrometer

Journal article Optics Infobase Conference Papers · January 1, 2006 We describe a static aperture-coded, dispersive longwave infrared (LWIR) spectrometer that uses a microbolometer array as the detector plane. We present experimental results of absorption spectroscopy for a variety of sources. © 2006 Optical Society of Ame ... Full text Cite

Longwave infrared (LWIR) coded aperture dispersive spectrometer

Multiple order coded aperture (MOCA) spectrometer

Journal article Optics Infobase Conference Papers · January 1, 2006 We introduce a Multiple Order Coded Aperture (MOCA) spectrometer that uses a crossdispersive hologram and a coded aperture to achieve improved spectral range over traditional dispersive spectrometers at comparable resolution. © 2006 OSA. ... Full text Cite

Pushbroom hyperspectral imaging with a coded aperture

Journal article Optics Infobase Conference Papers · January 1, 2006 We describe a hyperspectral camera which operates by translating a scene across the entrance of a coded aperture spectrometer. This applies a sequence of unique codes to the image, allowing full reconstruction of the datacube. © 2006 Optical Society of Ame ... Full text Cite

Longwave infrared (LWIR) coded aperture dispersive spectrometer

Journal article Optics InfoBase Conference Papers · January 1, 2006 We describe a static aperture-coded, dispersive longwave infrared (LWIR) spectrometer that uses a microbolometer array as the detector plane. We present experimental results of absorption spectroscopy for a variety of sources. © 2006 Optical Society of Ame ... Cite

Evaluation of aperture codes for high throughput spectroscopy

Journal article Optics Infobase Conference Papers · January 1, 2006 A coded aperture spectrometer maintains the spectral resolution of a traditional slit spectrometer while dramatically increasing the throughput. Here we evaluate the performance of different aperture codes for spectroscopy of weak, incoherent sources. © 20 ... Full text Cite

Longwave infrared (LWIR) coded aperture dispersive spectrometer

Dual-disperser design for single-shot computational spectral imaging

Journal article Optics Infobase Conference Papers · January 1, 2006 We describe a dual-disperser approach to computational spectral imaging. This approach enables flexible code design and avoids problems present in single-disperser systems. We will report on a prototype single-shot spectral imager based on these ideas. © 2 ... Full text Cite

Super-resolution mapping of flow velocity distribution in nanofluidic channels

Journal article Optics Infobase Conference Papers · January 1, 2006 We will show a super-resolution mapping technique for measuring the flow velocity distribution in nanofluidic channels. The mapping resolution can be much smaller than the diffraction limit of the optical imaging system. © 2006 Optical Society of America. ... Cite

Super-resolution mapping of flow velocity distribution in nanofluidic channels

Journal article Optics InfoBase Conference Papers · January 1, 2006 We will show a super-resolution mapping technique for measuring the flow velocity distribution in nanofluidic channels. The mapping resolution can be much smaller than the diffraction limit of the optical imaging system. © 2006 Optical Society of America. ... Cite

A compact fabry-perot grating cascaded spectrometer

Journal article Optics Infobase Conference Papers · January 1, 2006 We have designed a compact spectrometer by cascading a simple Fabry-Perot etalon and a grating. The grating expands the limited spectral range of the Fabry-Perot and the combination of both elements results in a powerful spectrometer with good two-dimensio ... Cite

A compact fabry-perot grating cascaded spectrometer

A compact Fabry-Perot grating cascaded spectrometer

Journal article Optics InfoBase Conference Papers · January 1, 2006 We have designed a compact spectrometer by cascading a simple Fabry-Perot etalon and a grating. The grating expands the limited spectral range of the Fabry-Perot and the combination of both elements results in a powerful spectrometer with good two-dimensio ... Cite

Coded-excitation Raman spectroscopy for ethanol chemometrics of tissue

Journal article Optics InfoBase Conference Papers · January 1, 2006 Raman spectroscopy of bulk tissue is challenging due to sample auto-fluorescence and weak Raman cross-sections of most molecules. We investigate the use of coded-excitation Raman spectroscopy coupled with an iterative algorithm for Raman signal estimation. ... Cite

Super-resolution mapping of flow velocity distribution in nanofluidic channels

Compressive sampling in spectral imaging systems

Journal article Optics InfoBase Conference Papers · January 1, 2006 Optical prefilters shape the analog-digital interface in imaging systems to implement generalized spatio-spectral sampling. The Duke Imaging and Spectroscopy Program explores generalized sampling systems, this talk focuses specifically on spectral encoding ... Cite

Ultra-thin multi-aperture LWIR imagers

Journal article Optics InfoBase Conference Papers · January 1, 2006 We design and implement an ultra-thin LWIR camera by replacing the conventional lens system with a micro-lens array. The resulting low resolution images can be used to reconstruct a high resolution image by post processing. © 2006 Optical Society of Americ ... Cite

Diffuse spectroscopy for inhomogeneous metal nanoparticle assays

Journal article Proceedings of SPIE - The International Society for Optical Engineering · 2006 We describe a compact computational spectroscopy platform optimized for molecular recognition using metal nanoparticle assays. The objective is motivated by the urgent need for low-cost, portable and high-throughput sensors for point-of-care (POC) clinical ... Full text Link to item Cite

Surface-stabilized holography in an azo-dye-doped liquid crystal

Journal article Opt. Lett. (USA) · 2006 Holograms are recorded by a 514-nm laser polarized parallel to the molecular director in an azo-dye-doped nematic liquid crystal. For some surface treatments, the recorded holograms persist in the dark. For glass surfaces, exposure to light polarized norma ... Cite

Micro-optics and megapixels

Journal article Optics and Photonics News · January 1, 2006 New sampling and measurement methods are proposed for spectrometers and imagers that are shrinking the size and boosting the performance of optical devices for several applications. Costs are reduced because less plastic, glass, and metal is used in each i ... Full text Cite

Coded aperture Raman spectroscopy for quantitative measurements of ethanol in a tissue phantom

Journal article Applied Spectroscopy · 2006 Coded aperture spectroscopy allows for sources of large etendue to be efficiently coupled into dispersive spectrometers by replacing the traditional input slit with a patterned mask. We describe a coded aperture spectrometer optimized for Raman spectroscop ... Full text Link to item Cite

Compressive sampling strategies for integrated microspectrometers

Journal article Proceedings of SPIE - The International Society for Optical Engineering · 2006 We consider compressive sensing in the context of optical spectroscopy. With compressive sensing, the ratio between the number of measurements and the number of estimated values is less than one, without compromising the fidelity in estimation. A compressi ... Full text Link to item Cite

Path-dependent human identification using a pyroelectric infrared sensor and fresnel lens arrays.

Journal article Optics express · January 2006 This paper presents a design and development of a low power consumption, and low cost, human identification system using a pyroelectric infrared (PIR) sensor whose visibility is modulated by a Fresnel lens array. The optimal element number of the lens arra ... Full text Cite

Static two-dimensional aperture coding for multimodal, multiplex spectroscopy

Journal article Applied Optics · 2006 We propose a new class of aperture-coded spectrometer that is optimized for the spectral characterization of diffuse sources. The instrument achieves high throughput and high spectral resolution by replacing the slit of conventional dispersive spectrometer ... Full text Link to item Cite

A Tandem Fabry-Perot volume hologram spectrometer with high resolution

Journal article Conference Proceedings Lasers and Electro Optics Society Annual Meeting LEOS · January 1, 2006 We have designed a compact spectrometer by cascading a simple Fabry-Perot etalon and a volume hologram. The volume hologram expands the limited spectral range of the Fabry-Perot and the combination of both elements results in a powerful spectrometer with g ... Full text Cite

Raman spectroscopy: Large-aperture raman spectroscopy for quantitative chemometrics

Journal article Optics and Photonics News · January 1, 2006 Full text Cite

Compressive optical montage photography

Journal article Proceedings of SPIE the International Society for Optical Engineering · December 1, 2005 The Compressive Optical MONTAGE Photography Initiative (COMP-I) is an initiative under DARPA's MONTAGE program. The goals of COMP-I are to produce 1 mm thick visible imaging systems and 5 mm thick IR systems without compromising pixel-limited resolution. I ... Full text Cite

Multi-dimensional aperture design and analysis for SAR using the Cramér-rao theorem

Journal article IEEE Camsap 2005 First International Workshop on Computational Advances in Multi Sensor Adaptive Processing · December 1, 2005 We are applying the Cramér-Rao theorem to synthetic aperture radar (SAR) processing in order to establish flight paths that permit height estimation and minimize errors in reflectivity measurements. The Cramér-Rao bound (CRB) establishes a lower bound on t ... Full text Cite

Diffraction-limited impulse response image reconstruction with a single imaging pixel

Journal article 2005 OSA Topical Meeting on Information Photonics Ip 2005 · December 1, 2005 In this paper, we will discuss two techniques to reconstruct diffraction-limited impulse response images by sub-pixel shifting the photodetector array and measuring the signal from a specific large area photodetector pixel. © 2005 Optical Society of Americ ... Cite

Sensor-layer image compression based on the quantized cosine transform

Journal article Proceedings of SPIE the International Society for Optical Engineering · November 15, 2005 We introduce a novel approach for compressive coding at the sensor layer for an integrated imaging system. Compression at the physical layer reduces the measurements-to-pixels ratio and the data volume for storage and transmission, without confounding imag ... Full text Cite

Biometric tracking with coded pyroelectric sensor clusters

Journal article Proceedings of SPIE the International Society for Optical Engineering · October 24, 2005 Human bodies are very good heat sources with peak emission wavelength of about 9μm. We use pyroelectric detectors that are differential in nature to detect human motion by their heat emissions. Coded Fresnel lens arrays create boundaries in space which hel ... Full text Cite

Inconsistencies between actual and estimated blood alcohol concentrations in a field study of college students: do students really know how much they drink?

Journal article Alcohol Clin Exp Res · September 2005 BACKGROUND: Alcohol use by college students is commonly measured through the use of surveys. The validity of such data hinge on the assumption that students are aware of how much alcohol they actually consume. Recent studies call this assumption into quest ... Full text Link to item Cite

Fiber-optic localization by geometric space coding with a two-dimensional gray code.

Journal article Applied optics · July 2005 With the objective of monitoring motion within a room, we segment the two-dimensional (2D) floor space into discrete cells and encode each cell with a binary code word generated by a fiber. We design a set of k-neighbor-local codes to localize an extended ... Full text Cite

Multimodal, multiplex, Raman spectroscopy of alcohol in diffuse, fluorescent media

Journal article Optics InfoBase Conference Papers · January 1, 2005 Optical diagnostics in biological materials are hindered by fluorescence and scattering. We have developed a multimodal, multiplex, coded-aperture Raman spectrometer to detect alcohol in a lipid tissue phantom solution. ©2005 Optical Society of America. ... Cite

Tomographic hyperspectral imaging without a missing-cone

Journal article Optics Infobase Conference Papers · January 1, 2005 We describe a hyperspectral imager combining coded aperture spectroscopy and tomographic spatial reconstruction. The throughput of the system is improved compared to scanning techniques while avoiding the missing-cone problem common to many spectral tomogr ... Full text Cite

Human motion tracking system using coded Fresnel lens arrays

Journal article Optics InfoBase Conference Papers · January 1, 2005 We have designed and developed a low-cost human motion tracking system using pyroelectric detectors and coded Fresnel lens arrays. We have deployed sensor clusters implementing an 8x8 Hadamard code variant and will demonstrate motion tracking. © 2005 Optic ... Cite

Compressive sampling for feature specific compact imagers

Journal article Optics InfoBase Conference Papers · January 1, 2005 We investigate the use of estimation methods with multi-aperture imaging hardware that are noise robust and able to provide high resolution images from limited measurements. © 2005 Optical Society of America. ... Cite

Design of a thin multi-aperture infrared imager

Journal article Optics InfoBase Conference Papers · January 1, 2005 We have designed a thin, multiplexed infrared imaging system that uses a diffractive element for generating shift-encoded images in each aperture. We present preliminary experimental results that demonstrate imager performance. © 2005 Optical Society of Am ... Cite

Multi-aperture visible high resolution thin imager

Journal article Optics InfoBase Conference Papers · January 1, 2005 We have designed and built a multi-aperture thin imager using a lenslet array and a CCD imager. The thickness of the imager is significantly reduced. We will present experimental results that demonstrate high resolution imaging. © 2005 Optical Society of A ... Cite

Multimodal, multiplex Raman spectrometer for weak, incoherent sources

Journal article Optics InfoBase Conference Papers · January 1, 2005 Raman spectroscopy in bio-materials is complicated by fluorescence and scattering. We have developed a multimodal, multiplex spectrometer that overcomes these difficulties. We are currently constructing a second generation prototype for in-vivo Raman spect ... Cite

Multiplex design for high-performance microspectrometers

Journal article Optics InfoBase Conference Papers · January 1, 2005 The volume of spectrometers can be drastically reduced through the use of multiplex measurement. Reductions of 3-5 orders of magnitude are possible. This has the potential to drastically effect manufacturing and deployment costs. ©2005 Optical Society of A ... Cite

Diffraction-limited impulse response image reconstruction with a single imaging pixel

Journal article Optics InfoBase Conference Papers · January 1, 2005 In this paper, we will discuss two techniques to reconstruct diffraction-limited impulse response images by sub-pixel shifting the photodetector array and measuring the signal from a specific large area photodetector pixel. © 2005 Optical Society of Americ ... Cite

Compact spectral diversity filters for diffuse source spectroscopy using spherical beam volume holograms

Journal article Optics InfoBase Conference Papers · January 1, 2005 We describe a new class of compact spectral diversity filters implemented using spherical beam volume holograms. Spectral diversity is improved by rotation multiplexing technique. Diffuse source spectroscopy enabled by using Fourier transform architecture ... Cite

Diffractive generation of non-redundant images for a multi-aperture, thin, high-resolution camera

Journal article Optics InfoBase Conference Papers · January 1, 2005 We have designed a diffractive element capable of generating shift-encoded images for a thin, multiplexed optical imaging system. We present simulations that validate the use of the element for high resolution imaging and preliminary experimental results o ... Cite

Large area pyroelectric motion tracking system

Journal article Optics InfoBase Conference Papers · January 1, 2005 Simple pyroelectric detectors and structured apertures are used to monitor motion in an area and report location and velocity of objects moving through the monitored area. © 2005 OSA/COSI 2005. ... Cite

The quantized cosine transform for sensor-layer image compression

Journal article Optics Infobase Conference Papers · January 1, 2005 We introduce a compressive encoding at the sensor layer based on the quantized cosine transform. Compression at the physical layer of integrated imaging systems reduces the measurements-to-pixels ratio, the data volume and accelerates image estimation. © 2 ... Cite

The quantized cosine transform for sensor-layer image compression

Journal article Optics InfoBase Conference Papers · January 1, 2005 We introduce a compressive encoding at the sensor layer based on the quantized cosine transform. Compression at the physical layer of integrated imaging systems reduces the measurements-to-pixels ratio, the data volume and accelerates image estimation. © 2 ... Cite

Compressive optical MONTAGE photography initiative: Noise and error analysis

Journal article Optics InfoBase Conference Papers · January 1, 2005 Image resolution is usually considered to be proportional to the focal plane sampling rate. However, as a result of Papoulis's generalized sampling theory [1], it is possible to reconstruct bandlimited images from sub-Nyquist sampled data provided multiple ... Cite

Diffraction-limited impulse response image reconstruction with a single imaging pixel

Journal article Optics Infobase Conference Papers · January 1, 2005 In this paper, we will discuss two techniques to reconstruct diffraction-limited impulse response images by sub-pixel shifting the photodetector array and measuring the signal from a specific large area photodetector pixel. © 2005 Optical Society of Americ ... Cite

Human characterization and tracking using pyroelectric sensors

Journal article Optics Infobase Conference Papers · January 1, 2005 A network of common pyroelectric motion sensors that can track and identify human targets has been developed using low-cost, commercially available components. Significantly cheaper than deploying infrared imag- ing systems and considerably more advanced t ... Cite

Role of recording geometry in the performance of spectral diversity filters with spherical beam volume holograms.

Journal article Optics letters · January 2005 We present experimental demonstrations of spectral diversity filters with spherical beam volume holograms for multimodal multiplex spectroscopy. Major properties of filters under diffuse-light illumination are discussed. The comparisons of spectral diversi ... Full text Cite

Standoff raman spectroscopy system for remote chemical detection

Journal article Proceedings of SPIE - The International Society for Optical Engineering · 2005 We have developed a class of aperture coding schemes for Remote Raman Spectrometers (RRS) that remove the traditional trade-off between throughput and spectral resolution. As a result, the size of the remote interrogation region can be driven by operationa ... Full text Link to item Cite

Multimodal optical spectrometers for remote chemical detection

Multimodal, multiplex, Raman spectroscopy of alcohol in diffuse, fluorescent media

Journal article Progress in Biomedical Optics and Imaging - Proceedings of SPIE · 2005 Optical diagnostics in biological materials are hindered by fluorescence and scattering. We have developed a multimodal, multiplex, coded-aperture Raman spectrometer to detect alcohol in a lipid tissue phantom solution. © 2005 SPIE and OSA. ... Cite

Efficient human pose tracking using multiplex sensing

Journal article Proceedings of SPIE the International Society for Optical Engineering · December 20, 2004 We design and calibrate an efficient human detection system, capable of detecting and tracking a single person while minimizing the number of required sensors. Our infrared detectors have a 2 meter range and a 250ms rise/fall time. We sample their signal u ... Full text Cite

Spherical beam volume holograms for spectroscopic applications: modeling and implementation.

Journal article Applied optics · December 2004 The spherical beam volume hologram, recorded by a plane wave and a spherical beam, is investigated for spectroscopic applications in detail. It is shown that both the diffracted and the transmitted beam can be used for spectroscopy when the hologram is rea ... Full text Cite

Measurement-efficient optical wavemeters.

Journal article Optics express · December 2004 We describe a method for efficiently determining the wavelength of a monochromatic source and provide an experimental proof-of-concept. The photomeasurement efficiency for a wavemeter can be written as eta(N,q) = (1 + logqN)/m, where N is the number of spe ... Full text Cite

Implementation of spectral diversity filters using spherical beam volume holograms

Journal article Conference Proceedings Lasers and Electro Optics Society Annual Meeting LEOS · December 1, 2004 We present experimental demonstrations of spectral diversity filters using spherical beam volume holograms. Major properties of filters under collimated and diffuse light will be presented. We also show rotation multiplexing can improve the spectral divers ... Cite

Reference structure tomography.

Journal article Journal of the Optical Society of America. A, Optics, image science, and vision · July 2004 Reference structure tomography (RST) uses multidimensional modulations to encode mappings between radiating objects and measurements. RST may be used to image source-density distributions, estimate source parameters, or classify sources. The RST paradigm p ... Full text Cite

Qualitative demonstration of spectral diversity filtering using spherical beam volume holograms.

Journal article Optics express · June 2004 We investigate the feasibility of designing spectral diversity filters using spherical beam volume holograms. Our experimental results qualitatively show the separation of the information of different incident wavelength channels using spherical beam volum ... Full text Cite

Spherical beam holograms for spectroscopic applications: Modeling and implementation

Journal article OSA Trends in Optics and Photonics Series · January 1, 2004 A new approach for analyzing spherical beam holograms is presented and tested. This method describes the diffraction effect in spherical beam holograms and its application in spectroscopy. The theoretical results are verified by experiments. © 2003 Optical ... Cite

A control system for a hybrid linear actuator for a flush deck hatch

Journal article Proceedings of the American Control Conference · January 1, 2004 This paper presents the control system design in the development of a hybrid linear actuator for opening the flush deck hatch CV/CVN ship class. We present a simple feedback control system for the hatch opening, which is described by a nonlinear model. The ... Full text Cite

Nonlinear estimation for interferometric imaging

Journal article Optics Communications · December 15, 2003 We conduct a comparative study between two types of imaging systems for distant point sources. One is a conventional focal plane system and the other, a multiplex system based on a rotational shearing interferometer (RSI). The RSI produces linear fringes i ... Full text Cite

Size and shape recognition using measurement statistics and random 3D reference structures.

Journal article Optics express · October 2003 Three dimensional (3D) reference structures segment source spaces based on whether particular source locations are visible or invisible to the sensor. A lensless 3D reference structure based imaging system measures projections of this source space on a sen ... Full text Cite

Imaging with random 3D reference structures.

Journal article Optics express · September 2003 We describe a sensor system based on 3D 'reference structures' which implements a mapping from a 3D source volume on to a 2D sensor plane. The reference structure used here is a random three dimensional distribution of polystyrene beads. We show how this b ... Full text Cite

Coded apertures for efficient pyroelectric motion tracking.

Journal article Optics express · September 2003 Coded apertures may be designed to modulate the visibility between source and measurement spaces such that the position of a source among N resolution cells may be discriminated using logarithm of N measurements. We use coded apertures as reference structu ... Full text Cite

Lensless sensor system using a reference structure.

Journal article Optics express · April 2003 We describe a reference structure based sensor system for tracking the motion of an object. The reference structure is designed to implement a Hadamard transformation over a range of angular perspectives. We implemented a reference structure with an angula ... Full text Cite

3D Optical Elements for Computational Sensors

Journal article OSA Trends in Optics and Photonics Series · January 1, 2003 3D Optical Elements for Computational Sensors. We discuss geometric segmentation of optical fields by volume optical elements and 3D photonic circuits and describe example systems. 3D elements include volume holograms, geometric filters and microcavity arr ... Cite

Three-dimensional imaging with the Argus sensor array

Journal article Proceedings of SPIE the International Society for Optical Engineering · December 1, 2002 The Argus project uses an array of computers and cameras as a means of investigating telepresence and real-time three-dimensional imaging. In this paper we will briefly discuss telepresence from an information flow and visualization perspective. The paper ... Full text Cite

High-resolution direction finding and scan-free spectrum estimation with rotational-shear interferometric sensor arrays

Journal article Proceedings of SPIE the International Society for Optical Engineering · December 1, 2002 In this paper we investigate the application of a rotational-shear interferometer, toward the problem of simultaneously estimating the directions of well-localized sources, and their spectral profiles. Rotational shear makes possible the acquisition of a s ... Full text Cite

Tracking and imaging humans on heterogeneous infrared sensor arrays for law enforcement applications

Journal article Proceedings of SPIE the International Society for Optical Engineering · December 1, 2002 We present a plan for the integration of geometric constraints in the source, sensor and analysis levels of sensor networks. The goal of geometric analysis is to reduce the dimensionality and complexity of distributed sensor data analysis so as to achieve ... Full text Cite

Sampling field sensor with anisotropic fan-out

Journal article Applied Optics · November 1, 2002 We describe a new common-path, phase-shift, and shearing interferometric device capable of single-shot detection of optical phase profiles. It samples the input field and uses birefringent plates to fan out phase-shifted copies of the samples in the empty ... Full text Cite

Digital refraction distortion correction with an astigmatic coherence sensor.

Journal article Applied optics · October 2002 We demonstrate the sensing and correction of an isoplanatic refractive distortion (not lens aberrations), using the complete measurement of the partially coherent field in an aperture that the previously described astigmatic coherence sensor provides. Isop ... Full text Cite

Integrated analysis and design of analog and digital processing in imaging systems: introduction to the feature issue.

Journal article Applied optics · October 2002 This feature presents themes arising from the Integrated Computational Imaging Systems topical meeting sponsored by the OSA in fall 2001. These themes revolve around joint design of digital and analog image processing to improve the specificity and efficie ... Full text Cite

Multiplex sensors and the constant radiance theorem.

Journal article Optics letters · January 2002 Coherent mode representation of the cross-spectral density is used to derive a modal analog of the constant radiance theorem with general applicability to linear optical systems. The theorem is used to consider the relationship between spatial detector geo ... Full text Cite

Tracking and imaging humans on heterogeneous infrared sensor array for tactical applications

Journal article Proceedings of SPIE the International Society for Optical Engineering · January 1, 2002 We recently implemented a heterogeneous network of infrared motion detectors and an infrared camera for the detection, localization, tracking, and identification of human targets. The network integrates dense deployments of low cost motion sensors for targ ... Full text Cite

The room is long and narrow

Journal article Research in Science Education · January 1, 2002 In this paper we analyse some of our experiences with peer review and argue that the process should be rethought. Rather than a gate-keeping device, the ideological function should be acknowledged as well as acknowledging that the true (idealistic) purpose ... Full text Cite

Tomographic processing on wireless ground sensor networks

Journal article Proceedings of SPIE the International Society for Optical Engineering · December 1, 2001 New opportunities for battlefield surveillance and modeling are unfolding with the advent of smart sensors linked via digital wireless networks. One exciting prospect is the use of tomographic techniques in order to create real-time three-dimensional model ... Full text Cite

Multipath delay estimation using a superresolution PN-correlation method

Journal article IEEE Transactions on Signal Processing · May 1, 2001 This paper addresses the problem of high-resolution estimation of a multipath channel delay profile. We propose several improvements to the so-called superresolution pseudo-noise sequence correlation method (SPM) and analyze its performance on time-varying ... Full text Cite

Cone-beam tomography with a digital camera

Journal article Applied Optics · April 10, 2001 We show that x-ray computer tomography algorithms can be applied with minimal alteration to the three-dimensional reconstruction of visible sources. Diffraction and opacity affect visible systems more severely than x-ray systems. For camera-based tomograph ... Full text Cite

Wireless integrated sensing, processing and display networks for site security

Journal article Proceedings of SPIE the International Society for Optical Engineering · January 1, 2001 We consider data management on ad hoc networks of sensing and processing nodes. We describe the construction of simple nodes from off the shelf components (PC 104 single board computers with flash memory, video capture cards and 802.llb wireless interfaces ... Full text Cite

Multiplex optics for visual image processing

Journal article Proceedings of SPIE the International Society for Optical Engineering · January 1, 2001 Multiplex optical systems are designed to mix information channels on sensors. This paper considers the use of multiplex sensors to embed scene analysis in the optical layer of imaging systems. The goals of embedded analysis are to reduce the system data a ... Full text Cite

High depth of field microscopic imaging using an interferometric camera

Journal article Optics Express · January 1, 2001 We describe the design or a microscope combining rotational shear interferometer (RSI)-based coherence imaging with an objective lens to simultaneously obtain high numerical aperture and high depth of field imaging. We present experimental results showing ... Full text Cite

Constructing a space for developing a rich understanding of science through play

Journal article Journal of Curriculum Studies · January 1, 2001 Full text Cite

Astigmatic coherence sensor for digital imaging

Journal article Optics Letters · December 1, 2000 We present a novel sensor that measures the entire spatial coherence function within an aperture by use of a variable astigmatic lens. This sensor permits digital capture and processing of partially coherent fields. We demonstrate the sensor by sampling an ... Full text Cite

Optical processing for 3D digital imaging

Journal article Conference Proceedings Lasers and Electro Optics Society Annual Meeting LEOS · December 1, 2000 Alternative models for source coding are presented and shown to impact transformation transfer and conventional image quality measures. System performance when conventional image formation is unnecessary is demonstrated. ... Cite

A maximum-likelihood base caller for DNA sequencing.

Journal article IEEE transactions on bio-medical engineering · September 2000 The procedures used to sequence the human genome involve the electrophoretic separation of mixtures of dioxyribonucleic acid (DNA) fragments tagged with reporting groups, usually fluorescent dyes. Each fluorescent pulse which arrives from an optical detect ... Full text Cite

Information theory in optoelectronic systems: Introduction to the feature

Journal article Applied Optics · April 10, 2000 There has been an explosion of recent interest concerning information theory in optoelectronic (OE) systems. This interest has been motivated in part by (1) the accelerating deployment of OE components into digital systems, (2) the blurring of the analog-d ... Full text Cite

Fabrication of thin-film micropolarizer arrays for visible imaging polarimetry

Journal article Applied Optics · April 1, 2000 We describe a microfabrication process for fabricating micropolarizer devices with polarization thin film. The polarization film is less than a 0.5 µm thick and can have a polarization extinction ratio of ∼330 in the visible wavelength range. A single-stat ... Full text Cite

Spectral tomography from spatial coherence measurements

Journal article Proceedings of SPIE the International Society for Optical Engineering · January 1, 2000 We describe the use of non-focal interferometric cameras for reconstruction of the four-dimensional power spectral density of incoherent sources. We develop a 4D version of the generalized van Cittert-Zernike theorem to establish the Fourier transform rela ... Cite

Confocal imaging through scattering media with a volume holographic filter

Journal article Proceedings of SPIE the International Society for Optical Engineering · January 1, 2000 The use of a volume holographic filter as collector element in a confocal system imaging through scattering (turbid) material is described. We show that the penetration depth of the volume holographic system is de-coupled from the scatter noise discriminat ... Cite

Imaging through turbulence with the volume-holographic confocal microscope

Journal article Proc. SPIE - Int. Soc. Opt. Eng. (USA) · 2000 The confocal microscope with volume-holographic collector utilizes Bragg selectivity in order to achieve depth sectioning. The volume hologram is recorded by the interference of two beams, one of which originates as a point source at a reference depth. Whe ... Cite

Wave-front sensing with a sampling field sensor

Journal article Applied Optics · January 1, 2000 We present a new type of optical wave-front sensor: the sampling field sensor SFS!. The SFS attempts to solve the problem of real-time optical phase detection. It has a high space-bandwidth product and can be made compact and vibration insensitive. We desc ... Full text Cite

Tomographic imaging of foam

Journal article Optics Express · January 1, 2000 The morphology of three-dimensional foams is of interest to physicists, engineers, and mathematicians. It is desired to image the 3-dimensional structure of the foam. Many different techniques have been used to image the foam, including magnetic resonance ... Full text Cite

Multi-color fluorescence detection of ribosomal RNA in micro-channels

Journal article Proceedings of SPIE the International Society for Optical Engineering · January 1, 2000 A micro fluidic device capable of detecting the abundance of bacteria in an environmental solution is described. The micro channels are made of poly(dimethylsioxane) (PDMS) elastomer integrated with fused silica capillaries coated with Aluminum. The detect ... Cite

Gallium lanthanum sulphide fibers for infrared transmission

Journal article Fiber and Integrated Optics · 2000 Gallium lanthanum sulphide (GLS) glass and fiber have potential for use in both active and passive infrared applications. In this paper the optical, thermal, and other key properties, which are essential for understanding the applications and crucial in th ... Full text Link to item Cite

Sensing, communications and processing budgets for tomographic distributed ground sensor arrays

Journal article Proceedings of SPIE the International Society for Optical Engineering · January 1, 2000 A sensor array is tomographic if sensor modules share raw information to form a joint target model. Target identification is then implemented on the global model. This paper considers sensor head and sensor array resource budgets for tomographic ground sen ... Cite

Optical properties of surface micromachined mirrors with etch holes

Journal article Journal of Microelectromechanical Systems · December 1, 1999 We have investigated the optical properties of surface-micromachined polycrystalline silicon reflectors within the visible spectral range at five different wavelengths. The measurement results of the reflectivity of various microreflectors at four differen ... Full text Cite

Holographic 3D imaging of microstructures

Journal article Proceedings of SPIE the International Society for Optical Engineering · December 1, 1999 A volume holographic matched filter is used for three-dimensional imaging of silicon microstructures. The filter is designed by recording a hologram that is matched to the object depth, allowing confocal imaging of the structure. Confocal imaging of micro ... Cite

Three-dimensional surface reconstruction of optical Lambertian objects using cone-beam tomography

Journal article IEEE International Conference on Image Processing · December 1, 1999 We develop an approach to the determination of 3-D structure and reflectivity of Lambertian objects using a modification of cone-beam tomography. Like other tomographic imaging methods, our approach is entirely numerical and does not rely on heuristics. Fu ... Cite

Visible cone-beam tomography with a lensless interferometric camera

Journal article Science · June 25, 1999 Digital processing of optical coherence functions can reconstruct three- dimensional objects illuminated by incoherent light. It is shown that Fourier analysis of the mutual intensity of the field produces projections that are mathematically identical to t ... Full text Cite

Confocal microscopy with a volume holographic filter

Journal article Optics Letters · June 15, 1999 A confocal scanning microscopy in which a matched volume holographic filter replaces the pinhole is described. Hologram recording is such that the field generated by an in-focus object is maximally diffracted, whereas out-of-focus objects are filtered out ... Full text Cite

Distributed Bragg pulse shaper: Demonstration and model

Journal article Journal of Lightwave Technology · April 1, 1999 The distributed Bragg pulse-shaper (DBPS) is a series of electrically switchable Bragg mirrors on a semiconductor waveguide. The DBPS encodes data packets using parallel electrical signals to set the states of the Bragg mirrors. A broad-band source pulse t ... Full text Cite

Three-dimensional tomography using a cubic-phase plate extended depth-of-field system

Journal article Optics Letters · February 15, 1999 We use cubic-phase plate imaging to demonstrate an order-of-magnitude improvement in the transverse resolution of three-dimensional objects reconstructed by extended depth-of-field tomography. Our algorithm compensates for the range shear of the cubic-phas ... Full text Cite

Multidimensional Tomographie Imaging Using Volume Holography

Journal article Proceedings of the IEEE · January 1, 1999 We propose the application of volume holography to fourdimensional (4-D) spatiospectral imaging. The proposed systems use materials and techniques developed for holographic data storage and interconnections to capture three-dimensional (3-D) spatial and on ... Full text Cite

Optical amplifiers and lasers in infrared fibres

Journal article Proceedings of SPIE - The International Society for Optical Engineering · 1999 We are currently investigating two infrared glasses for active applications. Gallium lanthanum sulphide (GLS) glass is investigated as a potential host material for rare-earth doped mid-infrared fibre lasers. We have fabricated gallium lanthanum sulphide g ... Full text Link to item Cite

Volume holographic imaging of three-dimensional objects

Journal article Proceedings of SPIE the International Society for Optical Engineering · January 1, 1999 Spherical-reference volume holograms exhibit spatial selectivity to the location and color of the reconstructing beam. We show that this property enables tomographic operations on extended incoherent polychromatic objects, and derive the shapes and spectra ... Cite

Spatio-spectral tomography of luminescent objects with volume holograms

Journal article Proceedings of SPIE the International Society for Optical Engineering · January 1, 1999 Volume holograms as optical imaging elements provide maximum flexibility in the design of the optical response. For example, when a polychromatic incoherent object illuminates a spherical-reference volume hologram, the shift selectivity effect extracts onl ... Cite

Three-dimensional coherence imaging in the fresnel domain

Journal article Applied Optics · January 1, 1999 We show that three-dimensional incoherent primary sources can be reconstructed from finite-aperture Fresnel-zone mutual intensity measurements by means of coordinate and Fourier transformation. The spatial bandpass and impulse response for three-dimensiona ... Full text Cite

Unattended interferometric sensors

Journal article Proceedings of SPIE the International Society for Optical Engineering · January 1, 1999 We describe tomographic integration of visible and IR projections to form 3D models of object spaces. 3D modeling is a computationally efficient means of multiple sensor data reduction and a robust means of scene analysis. We consider how imaging system de ... Full text Cite

Quantum dot spectrometer

Journal article LEOS Summer Topical Meeting · January 1, 1999 An account is given on the simulations and experiments on an electrically-tunable spectrally-sensitive photodetector based on inhomogeneous absorption in a self-assembled quantum dot array and resonant tunneling through a coupled quantum well layer. The pr ... Cite

Optical properties of micromachined polysilicon reflective surfaces with etching holes

Journal article Proceedings of SPIE the International Society for Optical Engineering · December 1, 1998 MUMPS (Multi-User MEMS Process) is receiving increasingly wide use in micro optics. We have investigated the optical properties of the polysilicon reflective surface in a typical MUMPS chip within the visible light spectrum. The effect of etching holes on ... Full text Cite

Fresnel zone interferometric imaging

Journal article Conference Proceedings Lasers and Electro Optics Society Annual Meeting LEOS · December 1, 1998 Fourier analysis in projective coordinates shows similar inversion in the Fresnel zone. Since the longitudinal resolution of 3D coherence imaging falls inversely in the square of range in both the Fresnel and Fraunhofer zones, extension to the Fresnel zone ... Cite

Three-dimensional source reconstruction with a scanned pinhole camera

Journal article Optics Letters · June 1, 1998 We present a simple reconstruction algorithm for three-dimensional (3D) incoherent source distributions imaged by a laterally scanned pinhole camera. We consider digital sampling of multiple pinhole images for 3D reconstruction and implement an experimenta ... Full text Cite

Asymptotic multiuser efficiencies for decision-directed multiuser detectors

Journal article IEEE Transactions on Information Theory · January 1, 1998 The asymptotic multiuser efficiencies (AME's) are derived for various classes of decision-directed multiuser detectors, including multistage detectors, and decision-feedback detectors. Novel classes of soft-decision multistage detectors are proposed and an ... Full text Cite

The quantum dot spectrometer

Journal article Applied Physics Letters · December 15, 1997 We propose a novel photodetector capable of multi-spectral channel operation. The device makes use of the ability of a quantum dot plane to capture an optical spectrum, and of a resonant-tunneling structure to perform spectrally sensitive read-out. We pres ... Full text Cite

Multiuser detection in a horizontal underwater acoustic channel using array observations

Journal article IEEE Transactions on Signal Processing · December 1, 1997 We present a multisensor, multiuser receiver that is capable of operating in an underwater acoustic channel with severe niultipath. For each active user, the receiver consists of a multi-input, single-output array processing filter followed by a single-cha ... Full text Cite

Micro-optical lenslets by photo-expansion in chalcogenide glasses

Journal article Journal of Lightwave Technology · August 1, 1997 A detailed study of the wavelength dependence of the formation of lenslets by photo-expansion in chalcogenide glasses is reported. Photo-expansion in chalcogenide glasses offers a one-step fabrication process to record surface structures such as gratings a ... Full text Cite

Noise and information in interferometric cross correlators

Journal article Applied Optics · June 10, 1997 We consider optical interferometric cross correlators based on broadband light sources. We derive the signal-to-noise ratio from basic principles and supply experimental evidence that corroborates the theoretical analysis. Noise sources are discussed, and ... Full text Cite

Superresolved optical scanning using polychromatic light

Journal article Journal of the Optical Society of America A Optics and Image Science and Vision · January 1, 1997 Subwavelength detection of object displacement with use of a polychromatic interferometric imaging system is demonstrated experimentally. Object position detection with 50-nm lateral resolution is achieved. This result derives from and is consistent with i ... Full text Cite

Fabrication of high-resolution micropolarizer arrays

Journal article Optical Engineering · January 1, 1997 Procedures for creating high-resolution polarization filter arrays using multilayer polyvinyl alcohol (PVA) films are described. Two state polarization filter arrays with 25 μm resolution and three state polarization filter arrays with 48 μm resolution are ... Full text Cite

Superresolution through space-time control of two-level quantum systems

Journal article Journal of the Optical Society of America B Optical Physics · January 1, 1997 Spatial structure created by pulsed field interactions with two-level systems is considered. Superresolved pattern formation is possible by the use of extra degrees of freedom programmed in the time-domain field. In analogy with slice selection in magnetic ... Full text Cite

Fabrication and spectroscopy of erbium doped gallium lanthanum sulphide glass fibres for mid-infrared laser applications

Journal article Optics Express · 1997 Gallium lanthanum sulphide based glasses are proposed as high quality hosts for rare-earth doped, mid-infrared fibre lasers, that would offer compact and rugged sources for gas sensing, atmospheric transmission, and medical applications. The infrared emiss ... Cite

Adaptive decentralized multiuser receiver for deep-water acoustic telemetry

Journal article Journal of the Acoustical Society of America · 1997 Full text Link to item Cite

Parallel lithographic fabrication of micro-optical lenslets by photoexpansion in chalcogenide glasses

Journal article Conference Proceedings Lasers and Electro Optics Society Annual Meeting LEOS · December 1, 1996 The non-locality of the photoexpansion effect as well as large volume changes observed in the fabrication of micro-lenses on the surface of As2S3 (chalcogenide) glass was investigated experimentally. The parallel photolithographic pro ... Cite

Rapid DNA sequencing of more than 1000 bases per run by capillary electrophoresis using replaceable linear polyacrylamide solutions.

Journal article Analytical chemistry · October 1996 The read length for DNA sequencing using capillary electrophoresis and replaceable linear polyacrylamide (LPA) solutions has been extended to more than 1000 bases with a run time of 80 min. This result was successfully achieved through the combined use of ... Full text Cite

Fabrication of holographic gratings in As2S3 glass by photoexpansion and photodarkening

Journal article IEEE Photonics Technology Letters · August 1, 1996 The spatial dynamics of the photo-induced surface relief and phase gratings in As2S3 glass are described. Excursion amplitudes up to 150 nm and grating efficiencies up to 27% are observed. Depth and resolution limits for the effect ar ... Full text Cite

Dynamic grating formation in As2S3

Journal article Conference Proceedings Lasers and Electro Optics Society Annual Meeting LEOS · January 1, 1996 This work focuses on using the photoexpansion effect to fabricate surface-grating structures and studying the applicability in photonic circuitry. Surface gratings with periods ranging from 2.95 μm to 0.377 μm were written holographically using 514.5-nm li ... Cite

Characterization of complex space-time optical fields

Journal article Proceedings of SPIE the International Society for Optical Engineering · January 1, 1996 We consider interferometric techniques for capturing ultra-fast pulsed images. We analyze the signal-to-noise performance and information capacity of pulsed image detection systems and we briefly discuss the possibility of improving detection systems using ... Cite

Adaptive detection for shallow-water acoustic telemetry with cochannel interference

Journal article IEEE Journal of Oceanic Engineering · January 1, 1996 Adaptive decision feedback equalization (DFE) has recently been used to enable high-rate data transmission through shallow-water acoustic channels. This adaptive receiver successfully tracks and suppresses intersymbol interference due to a dispersive multi ... Full text Cite

Dynamic grating formation in As₂S₃

Journal article Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS · 1996 This work focuses on using the photoexpansion effect to fabricate surface-grating structures and studying the applicability in photonic circuitry. Surface gratings with periods ranging from 2.95 μm to 0.377 μm were written holographically using 514.5-nm li ... Cite

Integrated optical pulse shapers for high-bandwidth data packet encoding

Journal article Proceedings of SPIE the International Society for Optical Engineering · December 1, 1995 We describe distributed Bragg pulse shapers for the ultra-fast communication system wavepacket encoding. We discuss Bragg pulse shaper design and fabrication and we present experimental results from first and second generation devices. ... Cite

Pulsed-image generation and detection

Journal article Optics Letters · May 15, 1995 We describe an experimental system that programs three-dimensional optical fields to 200-fs resolution over a 10-ps window by using photorefractive volume reflection holograms in lithium niobate. These pulsed images are detected with an imaging interferome ... Full text Cite

Suboptimal Multiuser Detector for Frequency-Selective Rayleigh Fading Synchronous CDMA Channels

Journal article IEEE Transactions on Communications · January 1, 1995 We propose a suboptimal low-complexity multiuser receiver for synchronous CDMA frequency-selective Rayleigh fading channels. In contrast to the conventional RAKE receiver, which suffers from near-far effects due to channel fading, the proposed multiuser re ... Full text Cite

Differentially Coherent Multiuser Detection in Asynchronous CDMA Flat Rayleigh Fading Channels

Journal article IEEE Transactions on Communications · January 1, 1995 We present the performance analysis of decorrelating detector for differentially coherent transmission over a CDMA frequency-nonselective Rayleigh fading channel. While the correlation-type receiver is near-far limited in this channel, it is shown that the ... Full text Cite

Multiuser Detection in Mismatched Multiple-Access Channels

Journal article IEEE Transactions on Communications · January 1, 1995 In this paper we consider an additive white Gaussian noise multiple-access channel and investigate the performance degradation of several multiuser detectors due to imperfect knowledge of channel parameters, induced by either estimation errors or sampling/ ... Full text Cite

Degrees of freedom of polychromatic images

Journal article Journal of the Optical Society of America A Optics and Image Science and Vision · January 1, 1995 Detection and evaluation of time- and space-domain fields scattered by one-dimensional objects is considered for applications in superresolved microscopy. Modal decomposition of scattered fields is used to estimate the information passed by band-limited di ... Full text Cite

Space-time processing with photorefractive volume holography

Journal article Proc. SPIE - Int. Soc. Opt. Eng. (USA) · 1995 Photorefractive volume holography for processing ultrashort optical pulses carrying spatial, temporal and spatio-temporal optical information is introduced. These new holographic methods can process 4-dimensional information that in addition to the 3 spati ... Cite

Pulsed-image generation and detection

Journal article Optics Letters · 1995 A volume holographic pulse shaper that programs the three-dimensional space-time structure of optical fields is described. This system produces images in which each pixel contains an independent and programmable pulse shape. The pulsed images were recorded ... Cite

Control of spatial excitation patterns in two-level systems by use of time-domain fields

Journal article Optics Letters · December 1, 1994 Spatial structures created by pulsed field interactions with surface-bound two-level systems are considered. Superresolved pattern formation is possible by the use of extra degrees of freedom programmed in the time-domain field. © 1994 Optical Society of A ... Full text Cite

Dispersion compensation in coherence domain multiplexed communications systems

Journal article IEEE LEOS Annual Meeting Proceedings · December 1, 1994 We demonstrate dispersion compensation in coherence domain multiplexed (CDM) systems by transmitting three 100 fs signal pulses and a reference pulse in a packet through an optical fiber. In CDM systems, detection of bits is independent of dispersion, but ... Cite

Holographic storage in a near-ir sensitive photochromic dye

Journal article Optics Communications · June 15, 1994 Application of a near infra-red sensitive spirothiopyran/merocyanine system to dynamic volume holographic data storage is considered. © 1994. ... Full text Cite

Multiuser Detection in Single-Path Fading Channels

Journal article IEEE Transactions on Communications · January 1, 1994 In this paper the performance analysis of maximum likelihood sequence and decorrelating multiuser detectors is developed for the single-path Rayleigh fading channel. The received signal in this multipoint-to-point channel is additively composed of white Ga ... Full text Cite

Adaptive Multiuser Detection for Underwater Acoustical Channels

Journal article IEEE Journal of Oceanic Engineering · January 1, 1994 An underwater acoustic local area network (ALAN) provides multipoint-to-point telemetry between many high-rate, ocean-bottom sensors and a central, surface-deployed receiver in the 10–30 kHz vertical acoustical channel. Ocean-bottom modems initiate the tra ... Full text Cite

Dispersion compensation in coherence-domain multiplexed systems

Journal article Optics Letters · January 1, 1994 An ultrahigh-bandwidth point-to-point communications system based on white-light sources, pulse shapers, and interferometric receivers is proposed. Dispersion compensation by interferometric receivers is described and demonstrated. Linear dispersion-limite ... Full text Cite

Electrically controlled multiple hologram storage

Journal article Opt. Mem. Neural Netw. (USA) · 1994 Gated techniques for selectively addressing limited regions in volume storage systems are considered. An experimental system which selectively addresses layers in a volume using polarization sensitive holograms and liquid crystal modulator is described ... Cite

Finite-difference time-domain modeling of dispersive nonlinear Fabry-Perot cavities

Journal article Journal of the Optical Society of America B: Optical Physics · 1994 This paper proves that finite-difference time-domain (FD-TD) algorithms can be applied for the analysis of time-domain response of nonlinear Fabry-Perot cavities, and time-domain pulse selectivity obtained. The energy absorbed from various pulse shapes by ... Cite

Characterization of waveguide and grating formation in As₂S₃

Journal article IEEE LEOS Annual Meeting - Proceedings · 1994 Photodarkening in the chalcogenide glass As2S3 makes it attractive for applications in integrated optics and data storage Various optical devices can be fabricated using the laser-induced change of refractive index in this material. Waveguides, directional ... Cite

Two-wavelength reversible holograms in azo-dye doped nematic liquid crystals

Journal article Applied Physics Letters · December 1, 1993 We describe reversible holographic effects in azo-dye doped liquid crystals. Surface-stabilized holograms are recorded at 514 nm using beams polarized parallel to the molecular director of the liquid crystals. While these holograms persist for several hour ... Full text Cite

Holographic pulse shaping in organic media

Journal article Conference Proceedings Lasers and Electro Optics Society Annual Meeting · December 1, 1993 In our system the index modulation is formed by cis-trans isomerization of an azo-dye in an organic matrix. The index modulation is recorded by 514 nm light. Data is encoded on the reflection grating by spatially modulating one of the recording beams. The ... Cite

Information capacity of 3-D holographic data storage

Journal article Optical and Quantum Electronics · September 1, 1993 Capacities for angular and wavelength multiplexed holographic data storage systems are considered. Limitations due to the spatial resolution of the recording and reconstructing fields and to the holographic recording process are derived. © 1993 Chapman & H ... Full text Cite

Impulse responses of strong reflection holograms

Journal article Applied Optics · August 10, 1993 Strong scattering in broad spatial bandwidth reflection holograms is analyzed by using numerical techniques. Transfer functions and impulse responses for various index modulations are found, and techniques for constructing holograms for optical pulse shapi ... Full text Cite

Spherical distributed dielectric resonators

Journal article Journal of the Optical Society of America B Optical Physics · January 1, 1993 Spherical radially periodic dielectric structures inhibit electromagnetic propagation over a complete solid angle and a finite frequency range. The range of inhibited frequencies is linear in the amplitude of the radial modulation. Depending on the phase, ... Full text Cite

Pulse shaping in volume reflection holograms

Journal article Opt. Lett. (USA) · 1993 Ultrashort pulses are shaped by reflection from dynamic volume holograms recorded in azo-dye-doped epoxies. The spectral resolution and controllability of the reflection geometry are optimal for this application ... Cite

Time-of-flight cross correlation on a detector array for ultrafast packet detection

Journal article Opt. Lett. (USA) · 1993 We describe and demonstrate an interferometric technique for measuring the first-order cross correlation of ultrafast optical pulses. This technique may permit single-shot pulse detection and is applicable to receivers for time-domain optical communication ... Cite

Spherical distributed dielectric resonators

Journal article Journal of the Optical Society of America B: Optical Physics · 1993 This paper discusses the classical theory of electromagnetism for spherical distributed dielectric resonators. It is postulated that for complete solid angles, these structures inhibit propagation for a finite frequency range, whose range is linear in ampl ... Cite

Multiple-wavelength operation of a laser-diode array coupled to an external cavity

Journal article Optics Letters · January 1, 1993 We report a novel geometry for coupling a laser-diode array to an external cavity that produces a diffractively stabilized lasing wavelength separation between elements of the array. The geometry allows for control of the wavelengths and wavelength spacing ... Full text Cite

Volume holographic pulse shaping

Journal article Optics Letters · April 15, 1992 Volume holograms for subpicosecond pulse shaping are described. Experimental results with a camphorquinone-doped plastic hologram probed by a colliding-pulse mode-locked laser are presented. We observe a 2-THz beat frequency in the diffracted pulse. © 1992 ... Full text Cite

Control of volume holograms

Journal article Journal of the Optical Society of America A Optics and Image Science and Vision · January 1, 1992 The mismatch in the number of degrees of freedom supported by volume holograms and the boundary fields that control them limits the dynamic range of recorded holograms. For holograms controlled by using fractal sampling grids, the maximum dynamic range fal ... Full text Cite

Real-time holography in azo-dye-doped liquid crystals

Journal article Opt. Lett. (USA) · 1992 When exposed to an Ar laser at 514 nm, azo-dye molecules in a nematic liquid-crystal host undergo photoisomerization from trans-isomers to cis-isomers. The conformation change of the azo-dye molecules reorients liquid-crystal molecules. Reversible polariza ... Cite

Liquid-crystal-doped polymers as volume holographic elements

Journal article Proceedings of SPIE the International Society for Optical Engineering · December 1, 1991 Nematic liquid crystal molecules doped into polymer matrices are investigated for holographic information storage. Holographic effects due to thermal and optically driven anisotropies are observed. ... Cite

A semiclassical analysis of optical code division multiple access

Journal article IEEE Transactions on Communications · 1991 A model noncoherent, optical, asynchronous, code-division multiple-access (CDMA) system is described. The error rate for a single-user matched-filter receiver that is valid for arbitrary photomultipliers and signature sequence sets, adheres to the semiclas ... Full text Link to item Cite

Holographic interconnections in photorefractive waveguides

Journal article Appl. Opt. (USA) · 1991 An architecture for implementing large scale holographic interconnections in photorefractive waveguides is described. Methods for controlling the hologram using unguided light are considered and experimentally demonstrated ... Cite

Periodically refreshed multiply exposed photorefractive holograms

Journal article Optics Letters · July 15, 1990 We describe a method for increasing the diffraction efficiency of multiply exposed photorefractive holograms by periodic copying. The method is experimentally demonstrated with photorefractive and thermoplastic recording media. © 1990 Optical Society of Am ... Full text Cite

Diffraction efficiency of strong volume holograms

Journal article Optics Letters · March 15, 1990 We investigate the diffraction efficiency of strong volume holograms in which the coupling parameter is several times that needed for maximum diffraction efficiency. We discuss the implications of our findings on photorefractive implementations of various ... Full text Cite

Switching arrays make light work in a simple processor

Journal article Nature · January 1, 1990 Full text Cite

Holography in artificial neural networks.

Journal article Nature · January 1990 The dense interconnections that characterize neural networks are most readily implemented using optical signal processing. Optoelectronic 'neurons' fabricated from semiconducting materials can be connected by holographic images recorded in photorefractive ... Full text Cite

Limitations of opto-electronic neural networks

Journal article Proceedings of SPIE the International Society for Optical Engineering · June 29, 1989 Neural networks are composed of three components: Neurons, weights, and connections. Limitation on implementing these components in electronics and optics are discussed. We show that using electronically fabricated neurons and a combination of optics and e ... Full text Cite

Fractal sampling grids for holographic interconnections

Journal article Proceedings of SPIE the International Society for Optical Engineering · February 8, 1989 The optical implementation of weighted interconnections is investigated and basic relationships are derived between the number of neurons, the number of connections and the size of the optical system that is used to perform the connections. Specific method ... Full text Cite

Performance Analysis Of An Asymptotically Quantum-Limited Optical Dpsk Receiver

Journal article IEEE Transactions on Communications · January 1, 1989 In this paper, we analyze an optical, direct-detection DPSK receiver whose error probability is quantum-limited as the transmitting laser linewidth vanishes. The receiver design is based on a binary equiprobable hypothesis test with doubly stochastic point ... Full text Cite

Optoelectronic Implementations of Neural Networks

Journal article IEEE Communications Magazine · January 1, 1989 Full text Cite

Photorefractive crystals in optical neural computers

Journal article Proceedings of SPIE the International Society for Optical Engineering · May 3, 1988 The storage capacity for neural interconnections in photorefractive crystals and the use of the dynamic nature of the photorefractive effect to train these interconnections are discussed. We describe an optical neural architecture which uses the characteri ... Full text Cite

A photorefractive integrated optical vector matrix multiplier

Journal article Proceedings of SPIE the International Society for Optical Engineering · February 19, 1988 A method for implementing general linear transformations on one dimensional optical field distributions in integrated optics is described. This method uses the Bragg selectivity of volume holograms to replace one dimension of the bulk optical vector matrix ... Full text Cite

Adaptive optical networks using photorefractive crystals

Journal article Applied Optics · January 1, 1988 The capabilities of photorefractive crystals as media for holographic interconnections in neural networks are examined. Limitations on the density of interconnections and the number of holographic associations which can be stored in photorefractive crystal ... Full text Cite

Dynamic holographic interconnections for optical neural computers

Journal article Neural Networks · January 1, 1988 A neural system comprised of p neurons with c interconnections per neuron requires cp degrees of freedom in its interconnections. If these interconnections are formed by interactions between narrow-band signals emitted by the p active elements, only p degr ... Full text Cite

LEARNING IN OPTICAL NEURAL COMPUTERS.

Journal article undefined · December 1, 1987 The authors consider the optical implementation of learning networks using volume holographic interconnections in photorefractive crystals. The use of volume holograms permits the storage of a very large number of interconnections per unit volume, and the ... Cite

Experimental implementation of coded aperture coherent scatter spectral imaging of cancerous and healthy breast tissue samples

Journal article Proc. SPIE 9412, Medical Imaging 2015: Physics of Medical Imaging Full text Cite

Multimodal multiplex spectroscopy using photonic crystals

Journal article Opt. Express (USA) Spatio-spectral transmission patterns induced on low coherence fields by disordered photonic crystals can be used to construct optical spectrometers. Experimental results suggest that 1 to 10 nm resolution multimodal spectrometers for diffuse source analys ... Cite