Abstract

Gibson first showed that patterns of optical flow specify the direction of self-motion or heading. Recent experiments confirm this empirically: (1) During translation, observers perceive heading with 1° accuracy with as few as three dots, based on the radial structure of the flow pattern. Velocity field information is sufficient for such judgments and the visual system can tolerate large amounts of flow field noise. (2) During movement on a circular path, curvilinear heading is perceived with as few as two dots, based on the hyperbolic flow structure, although the velocity field is insufficient in this case. (3) Translational and rotational components of flow (e.g., during a pursuit eye movement) can be decomposed with as few as twelve dots—except in the special case of approach to a plane. Thus, observers rely on differential motion between elements separated in depth rather than a general solution.

© 1989 Optical Society of America