Abstract
Constraints of the binocular matching solution are described by several rules, one of which is the minimum-relative-disparity (MRD) rule (smoothness constraint), which minimizes the relative depth between nearby features. Occlusion has been shown to affect surface interpolation (especially 3-D) of nearby partially occluded features in 2-D images. Does partial occlusion of nearby surfaces facilitate their MRD matching solution?
Our stimulus configuration was two vertically separated 1-D Gabors, with a 1.2 cpd carrier, presented with a fixed relative disparity (360° phase disparity) over a range of absolute pedestal disparities (70°–150°). The envelope disparity matched the carrier disparity. The Gabors were presented with a 2° high blank gap between them (blank gap), or with a RDS presented inside the gap (partial gap), or with a RDS that covered the gap (no gap). The RDS had zero disparity. We measured the probability of MRD solutions as a function of the absolute disparity of the pedestal. The results were compared for the three conditions in order to investigate the influence of partial occlusion on the matching solution.
The matching solution could be influenced by several factors, including MRD of the Gabor carrier, and the absolute disparity of the Gabor envelope (second order information). We put these two factors into conflict for the matching solution and we tested if the RDS occlusion cue could change the balance between the two solutions. We found that the likelihood of an MRD matching solution was highest in the no-gap (partial occlusion) condition and lowest in the blank gap condition. These results indicated that high-level processing such as depth ordering, cued by partial occlusion of nearby surfaces, could influence the binocular matching solution.