A new approach to qualitative stereo

Nonmetric multidimensional scaling (MDS) is a family of algorithms that allow one to derive a quantitative representation of data from a set of qualitative measurements which must satisfy certain simple constraints. As a tool for vision, MDS combines the advantages of both qualitative and classical approaches, by relying, on the one hand, on an ordinal-scale input representation, and by supporting, on the other hand, the extraction of metric information. The present paper illustrates an application of MDS to the recovery of depth from the rank order of binocular disparity differences for a set of points. Our results indicate that multidimensional scaling constitutes a promising approach to the integration of biological and computational insights into the problem of depth perception.