Rotation and translation effects on stereoscopic acuity

Abstract

This study examined the effects of rotation or translation on the detectability of a dotted target plane embedded in a dotted masking cube. Julesz-type stereograms were generated in real time, using a small laboratory computer. Subjects displayed an excellent ability to compensate for x-y projected density variations produced by changes in the angle of rotation of the target plane so that performance was equal at all rotations. This finding indicates that dot density is being processed in a three- rather than a two-dimensional manner. Translation of a frontoparallel plane from the back of the stereoscopically defined cube to its front produced systematic changes in performance. Performance was best at the central fixation distance and decreased as either crossed or uncrossed disparity increased. Thus, it appears that stereo acuity decreases symmetrically with increases in disparity in either direction.