Dynamic Structural Change of 3-D Illusory Surface Observed with Binocular Viewing

Abstract

When adequate visual stimuli are suitably arranged, for example, partially along the surface boundary or beyond the covering illusory surface, an opaque or transparent illusory surface can be seen (Idesawa, 1991 Japanese Journal of Applied Physics 30-4B L751 – 754; 30-7B L1289). By moving the visual stimuli of the occluding objects which were not physically depicted, several interesting phenomena have been observed.

Dynamic fusion and separation of illusory surfaces have been observed when the visual stimuli were changed continuously between two different conditions; only one illusory surface was perceived in the first condition and two separate illusory surfaces were perceived in the second condition. Hysteresis was recognised in the geometrical positions between fusion and separation of the surfaces.

In addition, elastically distorting illusory surfaces have been observed when the positions of two occluding objects, placed on opposite sides, were moved continuously in a sinusoidal way in opposite phase between two positions where the two illusory surfaces could not be bridged together when they were stationary. The phenomena have been observed both for opaque and for transparent illusory surfaces. They could be interpreted as reflections of the surface-perceiving process in our visual system. Probably our visual system tends to contain the previously perceived structure; then the transition from one structure to another is delayed until the geometrical conditions change sufficiently to break the previously perceived structure.