P1-23: The Difference between the Perceived Depth of Shapes with and without Head Movement

It is well known that depth can be perceived from motion parallax. To produce motion parallax, observers (with head movement) or objects (without head movement) need to move. In previous studies, the magnitude of perceived depth with head movement was compared with that without head movement using several corrugated surfaces. It was found that perceived depth with head movement was larger than that without head movement. The purpose of the present research was to investigate the influence of discontinuities on the perceived surface. We used stair-like (square-wave) stimuli, and investigated the magnitude of perceived depth with or without head movement. We found that: (1) the magnitude of perceived depth increased as the number of square-waves increased. (2) There was a tendency to perceive larger depth with head movement than without head movement, but the difference between magnitudes of depth with and without head movements decreased as the number of square-waves increased. (3) Observers tended to perceive 4- and 6-step square-wave stimuli as continuous. (4) For the 2-step square-wave stimulus, observers tended to grossly underestimate the magnitude of depth or could not perceive depth at all. These findings suggest the possibility that perception of increased depth is caused by the perception of surfaces as continuous