2 TYPES OF OCCLUSION CUES FOR THE PERCEPTION OF 3-D ILLUSORY OBJECTS IN BINOCULAR FUSION

In three-dimensional (3-D) space perceptual functioning of the human visual system, occlusion cues play an important role. Two types of occlusion cues in binocular fusion were postulated and investigated using the newly discovered 3-D illusion. One type is called the contour occlusion cue, in which the visibility of occluded objects changes at the border where they pass beyond the occluding object contour. The second type is newly postulated and is named the bulky occlusion cue, which applies to volumetric occlusion, in which the visibility of occluded objects changes at the boundary where they pass through the object surface from the outside space to the inside space of the occluding object. These newly postulated and clarified occlusion cues are closely related to the visual perception of 3-D-space in binocular viewing, and they are expected to provide clues to revealing the mechanism underlying the 3-D-space perceptual ability of the human visual system.