Abstract

It is possible to create a perception of transparency by combining patterns having different motions. Two particular combination rules have specific interpretations in terms of physical phenomena: additive (specular reflection) and multiplicative (shadow illumination). Arbitrary combination rules applied to random patterns generate percepts in which the motions of the two patterns are visible but with superimposed noise. It is also possible to combine the patterns (using an exclusive-OR rule) so that only noise is visible. Within a 1-D family of combination rules, which include addition and multiplication, there is a range where smooth motions are seen with no superimposed noise; this range is centered about the additive combination. This result strengthens the finding of Anstis and Mather¹ that the motion system deals with a linear representation of luminance and is consistent with the analysis of motion by linear sensors.

© 1988 Optical Society of America