The Role of Contours in Stereopsis

JULESZ 1 showed that the presence of monocular patterns or familiar shapes is not necessary for stereopsis and that correlated noise matrices presented binocularly can yield vivid depth effects. Random dot stereograms “demonstrated that stereopsis not only can occur without monocularly recognizable shapes but actually does occur. That is, if monocular shapes exist then stereopsis precedes their recognition … 2 ”. Julesz also suggested that stereopsis may result from simple point to point matching 3 of the left and right eye fields. Experiments with random letter stereograms 4 and gratings 5 emphasized the importance of brightness gradients in stereopsis and Kaufman concluded that “subjective contours” are not sufficient to produce stereopsis.