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.