Scene layout from ground contact, occlusion, and motion parallax

An important factor in determining perceived scene layout is optical contact between objects and the ground surface (‘‘ground contact’’). The relation between ground contact and occlusion was investigated in four experiments with stationary and motion parallax scenes containing a pole that occluded or was occluded by one or more cylinders. Some judgements were inconsistent with occlusion in stationary scenes, but judgements were consistent with occlusion in motion parallax scenes. When the range of object positions consistent with occlusion did not include the positions specified by ground contract or by motion parallax, the ground contact and motion parallax information still had a quantitative effect on the perceived position of the object within the range consistent with occlusion. These results demonstrate a cooperative interaction between ground contact, occlusion, and motion parallax in determining perceived layout in 3-D scenes.