The Magnitude of Stereoscopic Depth as a Function of Convergence and Retinal Disparity

Abstract

Two experiments examined the magnitude of stereoscopic depth as a function of convergence and retinal disparity in holding the viewing distance and accommodation constant. Stimuli were random-dot stereograms (30 mm wide X 35 mm long) and were presented with a haploscope. In Experiment 1, eight observers estimated the magnitude of the perceived depth for seven convergence angles (-2, 0, 4, 8, 12, 16, and 20 degrees) and three retinal disparities (8’, 16’, and 32’). The perceived depth increased nonlinearly with a decrease of the convergence angle and linearly with an increase of the disparity. In Experiment 2, eleven observers estimated the perceived depth, distance, and size for the seven convergence angles with and without an artificial pupil. The perceived depth, distance, and size increased with a decrease of the convergence angle. The accommodation had almost no effect on the perceived depth, distance, and size. The results of the two experiments suggest that the visual system calibrates retinal disparity by means of convergence in processing depth.