Determining Three-Dimensional Shape from Orientation and Spatial Frequency Disparities

Binocular differences in orientation and foreshortening are systematically related to surface slant and tilt and could potentially be exploited by biological and machine vision systems. Indeed, human stereopsis may possess a mechanism that specifically makes use of these orientation and spatial frequency disparities, in addition to the usual cue of horizontal disparity. In machine vision algorithms, orientation and spatial frequency disparities are a source of error in finding stereo correspondence because one seeks to find features or areas which are similar in the two views when, in fact, they are systematically different. In other words, it is common to treat as noise what is useful signal.