ABSTRACT
Photographs of scenes typically contain a very large number of pixels. It is not uncommon for modern cameras to have in excess of 15 megapixels, and high-end cameras can have 80 megapixels or more. The pixels in an image can be seen as observations of a set of processes that gave rise to this image. Light sources emit light, all objects in the scene reflect, absorp or transmit light, and the medium through which light travels may participate by scattering light. Some light will eventually pass through the optical system of the camera and will be recorded as pixels.
