Representations for low-level vision

Representations play a central role in the study of any visual processing system (Marr 1982). The representations and algorithms that describe a visual process are a particular instantiation of a general computational theory, and are constrained by the hardware that is available for their implementation. Representations make certain types of information explicit, while requiring that other information be computed when needed. For example, a depth map and an orientation map may represent the same visible surface, but complex computations may be required to convert from one representation to the other. The choice of representation becomes crucial when the information being represented is uncertain (McDermott 1980).