V.S. Weiner, Y. Zhang and P.H. Schiller,
2004
Soc Neurosci. Abstr., 865.12
Abstract
Human psychophysical studies have established that both motion parallax and
stereopsis are routinely used as cues for the perception of depth. Recently,
it has been shown that rhesus monkeys also process both depth cues. To investigate
further how motion parallax and stereopsis are processed in the visual system
of the monkey, we assessed how the two cues interact when they are presented
either together in harmony or in conflict with each other.
We used a unique display to show images in depth. Two images were presented, one to each eye, through a stereoscope. A random-dot computer display was used. The two images were put in motion by rocking them back and forth along a central axis. Depth was created by presenting selected regions of the display with disparity and/or differential motion velocity. The procedure allowed us to provide depth with both cues or with only one of them. When presented together, the stereo and motion parallax cues could be arranged to signal either identical or conflicting depths.
Two behavioral tasks were used. In the first one, "detection," to be rewarded the monkey had to make a saccadic eye movement to a single patch that appeared in depth at one of four locations. In the second task, "discrimination," the monkey had to make a saccade to one of four patches appearing in depth that was shown at a greater depth than the other three (the distractors). Saccadic accuracy and latency data were collected.
When stereopsis and motion parallax were presented together, providing cues
for the same depth, saccadic latencies were significantly shorter and performance
was more accurate than when either cue was presented singly. This was true for
both the detection and discrimination tasks. When the stereo and parallax cues
were presented in conflict, the extent of depth perceived was a product of the
weighted average of the two cues. These data suggest that motion parallax and
stereopsis are processed interactively at higher levels in the visual system.
Support Contributed By: NIH grant EY08502
Citation: V.S. Weiner, Y. Zhang, P.H. Schiller. INTERACTIVE VISUAL PROCESSING OF STEREOPSIS AND MOTION PARALLAX Program No. 865.12. 2004 Abstract Viewer/Itinerary Planner. Washington, DC: Society for Neuroscience, 2004. Online.