The role of the information channel in visual computing

Around seventy years ago, Claude Shannon, who was working at Bell Laboratories, introduced information theory with the main purpose of dealing with the communication channel between source and receiver. The communication channel, or information channel as it later became known, establishes the shared information between the source or input and the receiver or output, both of which are represented by random variables, that is, by probability distributions over their possible states. The generality and flexibility of the information channel concept can be robustly applied to numerous, different areas of science and technology, even the social sciences. In this chapter, we will present examples of its application to select the best viewpoints of an object, to segment an image, and to compute the global illumination of a three-dimensional virtual scene. We hope that our examples will illustrate how the practitioners of different disciplines can use it for the purpose of organizing and understanding the interplay of information between the corresponding source and receiver.