The Accommodation Cue in Vision
Any imaging system, such as the human eye, a video-camera, a CT scanner or a telescope, entails a map of the three-dimensional environment onto the two-dimensional surface of an imaging sensor. Images of any such map are characterized by a loss of information along one spatial dimension. The visual system of primates has evolved to exploit two-dimensional images to retrieve a representation of the environment that can be used to perform spatial control tasks crucial to survival.