Vertical-disparity gradients are processed independently in different depth planes.
We examined the effects of vertical-disparity gradients on apparent depth curvature of textured surfaces. In Experiment 1, vertical disparities induced expected curvatures when the surface had a horizontal disparity of < +/-40.34'. A central row of elements, lacking vertical disparities, ceased to have the same apparent curvature as the surface when the horizontal disparity between row and surface exceeded +/-5'. In Experiment 2, vertical disparities were not pooled between superimposed surfaces separated by horizontal disparities > +/-10'. Thus, vertical-disparity gradients are not pooled over depth for curvature perception. Our results suggest that vertical disparities are used to determine distances to surfaces directly, rather than to estimate vergence.
Duke
Philip A
PA
Centre for Vision Research, York University, 4700 Keele St., Toronto, Ont., M3J 1P3, Canada. pduke@yorku.ca
Howard
Ian P
IP
D000328:Adult; D000368:Aged; D003463:Cues; D004215:Distance Perception / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D010364:Pattern Recognition, Visual / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods; D011601:Psychophysics; D015357:Vision Disparity / Q000502:physiology*; D015348:Vision, Binocular / Q000502:physiology