<title>Stereo depth and the control of locomotive heading</title>

Abstract

Does the addition of stereoscopic depth aid steering--the perceptual control of locomotor heading--around an environment? This is a critical question when designing a tele-operation or Virtual Environment system, with implications for computational resources and visual comfort. We examined the role of stereoscopic depth in the perceptual control of heading by employing an active steering task. Three conditions were tested: stereoscopic depth; incorrect stereoscopic depth and no stereoscopic depth. Results suggest that stereoscopic depth does not improve performance in a visual control task. A further set of experiments examined the importance of a ground plane. As a ground plane is a common feature of all natural environments and provides a pictorial depth cue, it has been suggested that the visual system may be especially attuned to exploit its presence. Thus it would be predicted that a ground plane would aid judgments of locomotor heading. Results suggest that the presence of rich motion information in the lower visual field produces significant performance advantages and that provision of such information may prove a better target for system resources than stereoscopic depth. These findings have practical consequences for a system designer and also challenge previous theoretical and psychophysical perceptual research.