Perception of image motion during head movement

Abstract

Previous studies have shown that self-motion has an inhibiting effect on concurrent 3D motion perception. To investigate whether self-motion similarly impairs concurrent image motion perception, we examined human perception of head-referenced horizontal image motion during head movement. The displayed stimulus was composed of a checkerboard image in a head mounted display oscillating from side to side at four frequencies (0.25, 0.5, 1 and 2 Hz) with half peak-to-peak amplitudes ranging from 0° to 5.64. Eight observers rated the magnitude of the checkerboard motion while either rotating their head about a vertical axis (yaw), about a horizontal axis (pitch), or holding it still. For all image oscillation frequencies, perceptual sensitivity to image motion amplitude was reduced during both horizontal and vertical head movements (mean reduction: 0.44 and 0.17, respectively). In contrast, perceptual bias was affected only at 2 Hz (mean shift: −9.9% and −12.2% of the full image motion amplitude for horizontal and vertical head movements, respectively). The results indicate that head movement causes gain reductions in motion magnitude estimation at image oscillation frequencies ≤1 Hz. At an oscillation frequency of 2 Hz, head movement produces both a gain reduction and a bias shift. Virtual environment developers could take advantage of such effects by relaxing requirements for image stability as well as motion fidelity during head movement.