Abstract
In binocular vision, a fundamental problem is how to match up image points in the left eye with the appropriate points in the right eye. We know that the visual system focuses the search range on a small set of binocular disparities. We asked how well that search range (and other properties of binocular vision) are tuned to natural scenes. We developed a mobile eye-and-scene tracker that measures gaze direction and 3D scene structure as people engage in everyday tasks. From the tracker we determined the statistics of binocular disparities. We found that the distribution of naturally occurring disparities is well matched to the search range the visual system uses in matching left- and right-eye image features. We also found that the natural distribution helps explain the perception of some ambiguous stereograms. And that the disparity preferences of cortical neurons in primates are consistent with the natural distribution. Finally, we examined whether vergence eye movements are biased toward naturally occurring disparities and found that they are.