A statistical model of binocular disparity

Binocular disparity provides important information about the three-dimensional structure of the environment. The current study sought to complement our geometrical understanding of binocular vision by considering the distributions of horizontal and vertical disparities that might be expected in images of the natural environment, using a simple environmental model. It was observed that the distribution of disparities depends critically on fixation, and varies greatly from one image location to another. The results were considered in relation to computational models of binocular stereopsis, and compared to two known properties of the visual system—the small disparity preference in disparity matching, and the influence of eccentricity on Panum's fusional limit. Overall, the study characterizes the binocular disparities that are likely to be encountered in the real world scenes, and discusses the implications of these for our understanding of binocular visual systems.