9511198 BRAUNSTEIN The ability of human observers to perceive and recognize objects in a three-dimensional scene involves several different levels of analysis, including the perception of the overall depth of the scene, the perception of the relative positions of objects or layout of the scene, and the perception of the shapes of objects within the scene. At each level of analysis the observer may gain information from a number of different sources, some informative about distances from the observer to parts of the scene or to parts of objects (viewer-centered) and others informative about depth relationships within the scene or within objects, independent of the position of the observer (object- centered). Three series of experiments will be conducted to determine how information at each level, scene, layout, and object, and information of each type, viewer-centered and object- centered, combine to provide an integrated perception of the three-dimensional environment. The first series of experiments will examine the relationship between simulated layout and perceived layout as information for scene depth is manipulated. The second series of experiments will assess the effect of layout information on the perception of object properties (relative depth, surface orientation, and overall shape). The third series of experiments will use selected conditions from the first two series to examine the combined effects of scene depth and layout on the perception of object properties. Within each of these series, the type of information (viewer-centered or object-centered) for each level under consideration will be manipulated. Several different cues for the specification of viewer-centered and object-centered information will be examined including accommodation, linear perspective, motion parallax, disparity, relative size, texture, structure from motion, and shading. The majority of the experiments will involve computer-generated displays. Some experiments in volving real scenes will also be conducted. This will be the first comprehensive study of the integration of visual information at multiple levels for the perception of the three-dimensional environment. An understanding of the perception of objects in three-dimensional scenes is important in any situation in which an observer moves through a scene or must recognize or manipulate objects in a scene. For this reason there is a close relationship between basic research on human visual perception in dynamic scenes and technological developments involving both human and artificial visual systems, ranging from improving visual displays for the training of pilots in flight simulators to developing more effective robotic visual systems. ***
