Perspective based on stereopsis and occlusion

Perspective is usually considered a monocular pictorial cite, distinct from other cues such as occlusion and stereopsis. We cut across these distincti ons by asking whether purely binocular (cyclopean) contours, created by ste reoscopically shifting a region of homogeneous texture nearer or further th an its surround, can act as a linear perspective cite and whether the conto urs' ability to do this is influenced by their surface belongingness. We fo und that the left/right orientation of cyclopean trapezoids nearer than a s urround strongly influenced perceived slant, showing that perspective const raints are applied to stereoscopically derived contours. Further regions, h owever; appeared as surfaces seen through a trapezoidal aperture. Because t he aperture "owned" the trapezoidal contours, their orientation had little effect on perceived slant. We conclude that the application of perspective constraints depends critically on how contours are classified by stereo-spe cified occlusion relationships among surfaces and that perspective, stereop sis, and occlusion are not distinct processing systems.