The goal of vision is to recover physical properties of objects in a scene, such as the location of object boundaries and the structure, color, and texture of object surfaces, from the two-dimensional image that is projected onto the eye or camera. The first clues about the physical properties of the scene are provided by the changes of intensity in the image. The importance of intensity changes and edges in early visual processing has led to extensive research on their detection, description, and use, both in computer and biological vision systems. This article reviews some of the theory that underlies the detection of edges and the methods used to carry out this analysis.
