The Perception and Content of Cast Shadows: An Interdisciplinary Review

Recently, psychologists have turned their attention to the study of castshadows and demonstrated that the human perceptual system values information fromshadows very highly in the perception of spatial qualities, sometimes to the detrimentof other cues. However with some notable and recent exceptions, computer visionsystems treat cast shadows not as signal but as noise. This paper provides a conciseyet comprehensive review of the literature on cast shadow perception from across thecognitive sciences, including the theoretical information available, the perception ofshadows in human and machine vision, and the ways in which shadows can be used.