RELATIVE SIZE DISPARITIES AND THE PERCEPTION OF SURFACE SLANT

Perceived slant produced by size disparities in random-dot displays wa s measured by tactile matching. For a 60 deg surface, slant produced b y vertical-size disparity (the induced effect) was opposite to that pr oduced by horizontal-size disparity. Overall-size disparity produced a little slant. With small displays, effects of horizontal and vertical disparities were reduced but not those of overall disparity, A zero-d isparity surround increased effects of horizontal and overall disparit ies but reduced the induced effect. A mixture of horizontally disparat e and zero-disparity dots produced two slanted surfaces. Vertically di sparate and zero-disparity dots produced one slanted surface, Abutting opposite horizontal disparities produced surfaces with a sharp bounda ry, Abutting vertical disparities produced surfaces with a gradual bou ndary, Perceived slant depends on the difference between horizontal-si ze disparity detected locally and mean vertical-size disparity over a relatively large area. Copyright (C) 1996 Elsevier Science Ltd.