Pictorial depiction, as used in this entry, refers to two-dimensional representations of environmental objects or scenes. Imagine an artist standing in front of a canvas and observing a scene that contains many different objects and variations in illumination. To produce a realistic depiction of this scene, the artist must solve the following problems: (a) The scene is three-dimensional, extending into space and with objects located at various distances, whereas the canvas is a flat, two-dimensional surface; (b) The scene has a large range of illuminations, created by sunlight and shadows, whereas the picture's range of illumination is limited by the amount of light reflected by light and dark paints; (c) The scene contains a myriad of details, far too many to depict in a small ...