Distributions of Binocular Phase Disparities in Natural Stereopair Images

Abstract

Stereopsis is an ability to gauge depth from a pair of two-dimensional retinal images. Because the eyes are separated laterally, the two retinal images differ slightly from each other, with images of objects shifted mainly along the horizontal dimension. This shift is known as binocular disparity. Previous studies suggest that binocular disparity information may be encoded by simple cells with varying degrees of dissimilarity between left and right receptive field (RF) profiles [1]. Furthermore, there is an anisotropy in the distribution of RF dissimilarities (as quantified by RF phase difference) with respect to the neuron’s preferred orientation. Neurons that prefer near vertical orientation (which encode horizontal disparities) could have similar or dissimilar RF profiles. However, those that prefer near horizontal orientation (which encode vertical disparities) have highly similar RF profiles for the two eyes. Therefore, the visual system appears to employ a highly efficient encoding scheme tailored for statistical properties of the binocular visual environment.