Abstract

The variation in the perception of three-dimensional structures due to different types of motion was investigated. The depth perception of points on surfaces of a rigid object was best when it was in vertical rotation. When the object was in translation (ie. sidewise or approaching motion), the effect was not as clear. Hence, an assumption could be derived that this difference in effects due to motion types resulted from the nature of display patterns, of which translation only reveals limited parts of an object while vertical rotation provides dimensions of the object viewed from diverse angles. In order to further investigate the effect of rotation in the perception of three-dimensional structures, the objects were rotated around the vertical, horizontal and depth axes, and their combinations. The perception of three-dimensional structure was poorest when the object was rotated around the axis of depth in which case only limited parts of the object could be seen. The structure was more easily perceived when the object was rotated around the combinations of axes rather than the vertical or the horizontal axis alone. However, even when the object was rotated around an axis which provided information from various angles, the subjects had difficulty in distinguishing its three-dimensional structure unless the outline was provided. These results imply that different motion types and outline information of a moving object affect the perception of three-dimensional structures.