Influence of display device and screen curvature on perceiving and controlling simulated ego-rotations from optic flow

This study investigated how display parameters influence humans’ ability to control simulated egorotations from optic flow. The literature on visual turn perception reports contradictory data, which might be partly due to the different display devices used in these studies. In this study, we aimed at disentangling the influence of display devices, screen curvature, and field of view (FOV) on the ability to control simulated ego-rotations solely from visual information. In Experiment 1, FOV and display device (projection screen vs. head-mounted display (HMD)) was manipulated. In Experiment 2, screen curvature and FOV were varied. Subjects’ task was to perform visually simulated self-rotations with target angles between 45 and 270◦. Stimuli consisted of limited lifetime dots on a dark background, and subjects used a joystick to control the turning angle of the visual stimulus. In Experiment 1, performance was tested in a within-subject design, using a curved projection screen (FOV 84◦×63◦), a HMD (40◦×30◦), and blinders (40◦×30◦) that restricted the FOV on the screen. Performance was best with the screen (gain factor 0.77) and worst with the HMD (gain 0.57). We found a significant difference between blinders (gain 0.73) and HMD, which indicates that different display devices can influence ego-motion perception differentially, even if the physical FOVs are equal. In Experiment 2, screen curvature was found to influence the perception of ego-rotations: At identical FOVs of 84◦, participants undershot target angles on the curved screen (gain 0.84), while they overshot target angles on the flat screen (gain 1.08). Perceptual mechanisms that may underlie these results will be discussed. We conclude the following: First, differences between display devices (HMD vs. curved projection screen) are more critical than the FOV for the perception of ego-rotations, with projection screens being better than HMDs. Second, screen curvature significantly influences performance for visually simulated egorotations: Compared to the flat screen, the curved screen enhanced the perception of ego-rotations. These findings have relevant implications for the design of motion simulators.