Range image statistics can explain the anomalous perception of length.


Journal Article

A long-standing puzzle in visual perception is that the apparent extent of a spatial interval (e.g., the distance between two points or the length of a line) does not simply accord with the length of the stimulus but varies as a function of orientation in the retinal image. Here, we show that this anomaly can be explained by the statistical relationship between the length of retinal projections and the length of their real-world sources. Using a laser range scanner, we acquired a database of natural images that included the three-dimensional location of every point in the scenes. An analysis of these range images showed that the average length of a physical interval in three-dimensional space changes systematically as a function of the orientation of the corresponding interval in the projected image, the variation being in good agreement with perceived length. This evidence implies that the perception of visual space is determined by the probability distribution of the possible real-world sources of retinal images.

Full Text

Duke Authors

Cited Authors

  • Howe, CQ; Purves, D

Published Date

  • October 2002

Published In

Volume / Issue

  • 99 / 20

Start / End Page

  • 13184 - 13188

PubMed ID

  • 12237401

Pubmed Central ID

  • 12237401

Electronic International Standard Serial Number (EISSN)

  • 1091-6490

International Standard Serial Number (ISSN)

  • 0027-8424

Digital Object Identifier (DOI)

  • 10.1073/pnas.162474299


  • eng