stereo vision paper available

[Ning Qian]

Dear Connectionists,

The following paper on modeling disparity attraction and repulsion is
available at:

http://brahms.cpmc.columbia.edu/publications/attract-repul.ps.gz

It has 28 text pages and 11 figures.

Best regards,

Ning

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A Physiologically-Based Explanation of Disparity Attraction and
Repulsion

Samuel Mikaelian and Ning Qian, Vision Research (in press). 

Abstract

Westheimer and Levi found that when a few isolated features are viewed
foveally, the perceived depth of a feature depends not only on its own
disparity but also on those of its neighbors. The nature of this
interaction is a function of the lateral separation between the
features: When the distance is small the features appear to attract
each other in depth but the interaction becomes repulsive at larger
distances. Here we introduce a two-dimensional extension of our recent
stereo model based on the physiological studies of Ohzawa et al, and
demonstrate through analyses and simulations that these observations
can be naturally explained without introducing ad hoc assumptions
about the connectivity between disparity-tuned units. In particular,
our model can explain the distance-dependent attraction/repulsion
phenomena in both the vertical-line configuration used by Westheimer,
and the horizontal-line-and-point configuration used by Westheimer and
Levi. Thus, the psychophysically observed disparity interaction may be
viewed as a direct consequence of the known physiological organization
of the binocular receptive fields. We also find that the transition
distance at which the disparity interaction between features changes
from attraction to repulsion is largely determined by the preferred
spatial frequency and orientation distributions of the cells used in
the disparity computation. This result may explain the observed
variations of the transition distance among different subjects in the
psychophysical experiments.  Finally, our model can also reproduce the
observed effect on the perceived disparity when the disparity
magnitude of the neighboring features is changed.