Simple mechanisms in stereoscopic depth perception

This paper reviews a number of psychophysical experiments designed to test popular theories on stereopsis which have been developed in machine vision. The results indicate that stereoscopic depth perception can be based on differences in image intensities which do not correspond to localized image features. In addition to this intensity-based stereo vision, image intensities can also modulate feature-based stereo, e.g., in the solution of the correspondence problem or in the quantification of perceived depth. Further results indicate that the underlying mechanism is based on squared contrast differences between the two halfimages. A similar mechanism has been proposed by Julesz (1971) for global stereopsis.