IRCS Technical Reports Series

Document Type

Technical Report

Date of this Version

March 2004

Comments

University of Pennsylvania Institute for Research in Cognitive Science Technical Report No. IRCS-04-01.

Abstract

From a modern Bayesian point of view, the classic Julesz random-dot stereogram is a cue-conflict stimulus: texture cues specify an unbroken, unslanted surface, in conflict with any variation in depth specified by binocular disparity. We introduce a new visual stimulus based on a novel texture, the Starry Night Texture (SNT), that is incapable of conveying slant, depth edges, or texture boundaries, in a single view. Changing density and changing intensity are equivalent for SNT, so an instance of the texture is characterized (up to the random locations of the texture elements) by its densintensity. We describe the SNT in its ideal form, consider deviations from the ideal that are needed to realize the texture in practice, and describe a physical device that approximates SNT using backlit metal foil. In three experiments with computer-generated stimuli we examined human perception of SNT, to show that (1) the deviations from ideal that were needed to realize SNT do not affect the invariance of its appearance, across changes in distance of several orders of magnitude; (2) as predicted, observers match SNT better than other textures across changes in distance; and (3) the use of SNT in a slant perception experiment did not significantly increase observers' reliance on stereoscopic slant cues, as compared to the sparse random dot displays that have been commonly employed to study human perception of shape from binocular disparity and motion.

Keywords

Texture, stereoscopic vision, cue combination

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Date Posted: 14 October 2004