5Perception of Image Motion During Head Movement

We examined human perception of head-referenced image motion during concurrent head movement. The visual stimulus was a checkerboard image in a head mounted display that moved from side-to-side. 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. In Experiment 1, we tested four image oscillation frequencies (0.25, 0.5, 1, and 2 Hz) while holding the head motion frequency constant at 0.5 Hz. In Experiment 2, we tested three head motion frequencies (0.25, 0.5, and 1 Hz) while holding the image oscillation frequency constant at 1 Hz. Across all image and head motion frequencies, perceptual sensitivity to image motion was reduced by about 45% during horizontal head movement. During vertical head movement, perceptual sensitivity was reduced by about 25 % when head and image motion were of the same frequency. Compared with when the head was still, horizontal and vertical head movements produced a downward shift of about 10 % in overall motion magnitude estimation response. Findings from this study provide virtual environment developers with a quantitative description of the influence of concurrent head movement on the perception of frontoparallel image motion