The integration of disparity, shading and parallax cues for depth perception in humans and monkeys.

V. S. Weiner and P. H. Schiller, 2007
Soc Neurosci. Abstr., 716.14.

Abstract
This study examined how effectively the three depth cues of disparity (D), motion parallax (P) and shading (S) are processed and integrated in humans and monkeys by using a display system that enabled us to present them in concert, separately and in various combinations. The display, viewed through a stereoscope, consisted of a random dot array rocked back and forth along a central, vertical axis that mimicked the rocking of a solid, three dimensional object.
A discrimination task was used in which four truncated pyramids were shown that protruded from the background. Each pyramid consisted of five panels forming the upper, lower, left, right and center sections. The luminance of each panel could be set to create the impression of reflected light from a light source above the display or could be set to have the same luminance values throughout thereby providing no shading cues. The disparity of the random dots, their differential velocities, and their degree of shading could be systematically manipulated. These procedures allowed us to generate psychometric functions for percent correct performance as well as for response latencies. Human subjects pressed one of four buttons to indicate which of the four pyramids shown on each trial protruded the most; monkeys were trained to make saccadic eye movements to the target pyramid. Seven presentation conditions were used in which the depth cues were presented either singly or in various combinations as follows: (1) D, (2) P, (3) S, (4) D+P, (5) D+S, (6) P+S and (7) D+P+S.
The results show that in both humans and monkeys the information provided by each of the three depth cues could be effectively processed. Performance was the highest and latencies were the shortest when all three depth cues were provided. Performance was the lowest and had the longest latencies when only a single depth cue was provided. These findings suggest that in both humans and monkeys various depth cues are integrated thereby providing optimal performance and the most rapid processing times.

Support Contributed by: NIH Grant EY014884

Citation: V. S. Weiner and P. H. Schiller. The integration of disparity, shading and parallax cues for depth perception in humans and monkeys. Program No. 716.14. 2007 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2007. Online.



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