NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Stereo transparency and the disparity gradient limitSeveral studies (Vision Research 15 (1975) 583; Perception 9 (1980) 671) have shown that binocular fusion is limited by the disparity gradient (disparity/distance) separating image points, rather than by their absolute disparity values. Points separated by a gradient >1 appear diplopic. These results are sometimes interpreted as a constraint on human stereo matching, rather than a constraint on fusion. Here we have used psychophysical measurements on stereo transparency to show that human stereo matching is not constrained by a gradient of 1. We created transparent surfaces composed of many pairs of dots, in which each member of a pair was assigned a disparity equal and opposite to the disparity of the other member. For example, each pair could be composed of one dot with a crossed disparity of 6' and the other with uncrossed disparity of 6', vertically separated by a parametrically varied distance. When the vertical separation between the paired dots was small, the disparity gradient for each pair was very steep. Nevertheless, these opponent-disparity dot pairs produced a striking appearance of two transparent surfaces for disparity gradients ranging between 0.5 and 3. The apparent depth separating the two transparent planes was correctly matched to an equivalent disparity defined by two opaque surfaces. A test target presented between the two transparent planes was easily detected, indicating robust segregation of the disparities associated with the paired dots into two transparent surfaces with few mismatches in the target plane. Our simulations using the Tsai-Victor model show that the response profiles produced by scaled disparity-energy mechanisms can account for many of our results on the transparency generated by steep gradients.
Document ID
20040088194
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
McKee, Suzanne P.
(Smith-Kettlewell Eye Research Institute San Francisco, CA 94115, United States)
Verghese, Preeti
Date Acquired
August 21, 2013
Publication Date
July 1, 2002
Publication Information
Publication: Vision research
Volume: 42
Issue: 16
ISSN: 0042-6989
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: EY 06644
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Space Human Factors
Non-NASA Center

Available Downloads

There are no available downloads for this record.
No Preview Available