CROSS-MODAL SLANT AND CURVATURE MATCHING OF STEREO-INDUCED AND MOTION-INDUCED SURFACES

In many laboratory setups and in many day-to-day situations, a unique solution of the structure-from-two-views problem is unobtainable. Yet, when the visual system is presented with two projections in a sequenc e, it nevertheless appears to generate a reasonably stable percept of structure. In the research reported here, we examined whether the same surface would be perceived when subjects were presented with a pair o f views that alternated in time monocularly (two-frame motion) or were shown simultaneously to both eyes (stereo). In Experiment 1, we studi ed slant perception: human observers were asked to match the slant of st motion-induced planar surface with its stereo-induced counterpart. In Experiment 2, the perceived curvature of parabolic surfaces was mat ched in a similar way. The results show that motion-induced slant is m atched with a higher value of the stereo-induced slant. However, the c urvature experiment showed that motion-induced curvature is matched wi th a lower stereo-induced curvature. One possible explanation may be t hat the slant and curvature are internally inconsistent in at least on e of the modalities.