A Physiologically-Based Explanation of Disparity Attraction and
Repulsion
Samuel Mikaelian and Ning Qian, Vision Research,
2000, 40:2999-3016.
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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.
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