ABSTRACT
Digital images consist of an array of pixels, each representing the average incoming illumination from a small part of the scene. Effectively, each pixel of a digital camera sensor integrates light over a small area, storing it as a single number. If we were to use a very low resolution sensor consisting of a single pixel, our digital image would simply be a single number representing the average light in the scene-this is, after all, what a photometer does. This is illustrated in Figure 4.1.
