Abstract
Two experiments examined the effects of relative movements of the head with respect to a stimulus display on the magnitude and direction of the perceived depth from motion parallax. In Experiment 1, a velocity gradient of random-dots moving in opposite directions was presented in three viewing conditions: (a) stationary head-and-display, (b) display-movement, and (c) head-movement. The observer's task was to report the direction and magnitude of the perceived depth. The results with 10 observers showed that the magnitude of the perceived depth in condition (b) was lower than those in conditions (a) and (c), while the direction was unambiguous in (b) and (c), but ambiguous in (a). In Experiment 2, the direction of the perceived depth was examined in six conditions including the three of Experiment 1; in the other three conditions both head and display were moving in the same direction but with different ratios of the display velocity to the head one: (d) 0.5, (e) 1.0, and (f) 2.0. The results with 11 observers showed that unambiguous depth perception was obtained in conditions (b), (c), and (f) but not in conditions (a), (d), and (e).Furthermore, the depth order perceptions in (b) and (a) were identical to those in (f), and (e), respectively. The experimental results suggest that relative movement of the head with respect to the display irrespective of either movement is processed to determine the perceived depth order and that the velocity gradient within the display is processed to determine the magnitude of the perceived depth.
