9602080 BANKS We use our eyes to determine the layout of the scene before us and to assess the desirability of our path of motion with respect to stationary and moving obstacles in the scene. The ease with which we perceive 3-D layout and carry out visually-guided navigation belies the underlying complexity of these tasks. The primary stimulus information for determining scene layout is binocular disparity (the differences in the two eyes' images which creates the sensation of depth seen in, for example, the Magic Eye Stereograms) and motion parallax (differences in the speeds at which images stream across the retina when a person moves the head). Binocular disparity and motion parallax are provided in retinal coordinates, but the positions and orientations of surfaces must generally be determined in body- centered coordinates in order to guide appropriate actions of the limbs and torso. Similarly, the information needed to judge the direction of an object's motion (or one's own motion) is contained in the changing pattern of light falling on the retinas, but motion direction must generally be estimated relative to the body in order to be useful in guiding motor responses to objects in the scene. This research will examine how comparisons of the two eyes' images are used to determine surface orientation and curvature and to determine the direction of an object's motion. This research will be important to our understanding of human space perception, but it may well also have practical consequences. First, biological systems have evolved robust mechanisms for estimating surface orientation, shape, and position and for estimating object velocity. A better understanding of how biological systems perform may lead to better algorithms for mobile robotic systems. Second, the perception of an object's motion relative to the self is crucial for action, including the control of a motor vehicle. Thus, a better understanding could lead to improved procedures fo r assessing driving and flying capability. Third, a better understanding of the retinal and extra-retinal information used in the perception of 3D layout and motion may well aid construction of virtual reality displays. ***
