Perception of 3-D Transparent Illusory Surface in Binocular Fusion

A new discovery is the illusion of 3-D transparent surface perception in the binocular fusion. When adequate visual stimuli are suitably arranged partially along the surface boundary or are given beyond the occluding illusory surface, a transparent or translucent illusory surface can be seen. These phenomena are unique to binocular fusion and have been classified into three categories: glassy (crystal) transparency, semi-transparency and translucent. Optogeometrical arrangements for the perception of these transparent illusory surfaces were clarified. The transparency of these surface has been investigated by using illusory probe stimuli. These newly found illusory phenomena have a close relationship to the visual perception of the 3-D structure of space in binocular viewing and can offer a clue by which to reveal the mechanism underlying the 3-D space perceiving ability of the human visual system.