A Simple Method for Recovering a Relative Depth Map in the Case of a Translating Sensor

When an optical sensor translates along a known direction In a stationary world the relative depth map of object points on the surface can be easily obtained when some simplifying assumptions are made. Under these assumptions the angular speeds of projecting rays can be obtained from (approximations to) temporal and spatial derivatives of Image brightness. The relative depth of any two image points is then directly computable as a simple ratio of linear functions of their angular velocities because the directions of angular velocities are known in this special situation.