Most objects perceived visually are partly occluded by other objects; yet human observers accurately detect the unity and boundaries of objects under most circumstances. There are other phenomena in which boundaries are perceived in the the absence of local visual information, such as illusory contours and some perceived transparency phenomena. In all of these cases, perceived object boundaries are interpolated between physically- specified edges. This project will address the various cases of boundary interpolation, testing and refining a recently proposed unifying theory, and more generally attempting to specify the conditions under which interpolation occurs. Specific aims include tests of edge interpolation in both two and three- dimensional displays, development of methods for generation of random displays, and development of a variety of measures for assessing boundary perception, including both perceptual report and non-verbal measures. This work will have implications both for understanding human perception of objects and for object and boundary detection in computer vision systems.
