Spatial limitation of vertical-size disparity processing.
We investigated the upper limit of horizontal spatial modulation of vertical-size disparity in a textured surface for the perception of depth. In Experiment 1 subjects matched the appearance of a surface with modulated horizontal-size disparity to that of a surface with modulated vertical-size disparity. In Experiment 2 we determined the threshold amplitude of modulation of vertical-size disparity required for the perception of depth as a function of the spatial frequency of disparity modulation. The results indicate that sensations of depth are not elicited by modulations of vertical-size disparity of any amplitude at spatial frequencies higher than about 0.04 c/deg. We conclude that vertical disparities are averaged within about 20 deg-wide areas and suggest that this global measurement is used to scale local horizontal disparities for the perception of surface slant.
Kaneko
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ATR Human Information Processing Research Laboratories, Kyoto, Japan. kaneko@hip.atr.co.jp
Howard
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IP
D003867:Depth Perception; D006801:Humans; D010775:Photic Stimulation / Q000379:methods; D011601:Psychophysics; D012684:Sensory Thresholds; D015357:Vision Disparity / Q000502:physiology*