ABSTRACT
The general problem addressed by this chapter is to understand how vision measures the geometric structure of environmental objects from stereoscopic and motion parallax. The chapter consists of two main sections: Section 21.2 introduces both the general problem of characterizing the optical information available to vision about the metric structure of environmental objects and the specific problem of explaining how the perceptual constancy of depth and shape can be obtained from optical patterns of stereoscopic and motion parallax. Questions are raised about the adequacy of traditional conceptions of space and geometrical structure in visual stimulation.
