Optical Flow

The term optical flow refers to the apparent movement of edges, surfaces and objects in a scene that demonstrates the relative motion between an observer and a scene. This concept was first introduced in the 1940's by the American psychologist James J. Gibson. This concept measures the differences in the rotation rate of objects such as a round object where the central part of the ball appears to move at a slower rate than the ends, even though they are actually turning at the same rate.