The following discusses computer based generation of stereo pairs as used to create a perception of depth. Such depth perception can be useful in many fields, for example, scientific visualisation, entertainment, games, appreciation of architectural spaces, etc. Depth cues There are a number of cues that the human visual system uses that result in a perception of depth.
Objects get smaller the further away they are.
Sizes of known objects. We expect certain object to be smaller than others. If an elephant and a tea cup appear the same size then we expect the elephant to be further away. An object that blocks another is assumed to be in the foreground. There a number of subtle cues implied by lighting, the way a curved surface reflects light suggests the rate of curvature, shadows are a form of occlusion.