Abstract
It has been shown that motion parallax is an effective depth cue for humans, however most of previous studies examined motion parallax accompanied by observer's head movement only in the right and left direction. In the present study, we quantified apparent depth specified by motion parallax when the observer moved horizontally, vertically or in both directions to examine the effects of head-movement direction. The results showed that perceived depth depended neither on the head-movement direction nor the surface orientation but on the spatial frequency of depth corrugation, i.e. larger depth was perceived for lower spatial frequency. Moreover, five of ten observers perceived opposite depth to the geometrical prediction for convex surfaces with more than 1.25 of peak gradient.
