Optical flow
Optical flow or optic flow is the pattern of apparent motion of objects, surfaces, and edges in a visual scene caused by the relative motion between an observer and a scene. Optical flow can also be defined as the distribution of apparent velocities of movement of brightness pattern in an image.
The concept of optic flow has roots as far back as Euclid's Optics, but its modern formulation arose from Second World War research into pilot vision during landing. Several researchers arrived at the idea independently; James J. Gibson gave it its most influential treatment, publishing his theory in 1947 and created the term "optic flow" in 1950.
The term optical flow is also used by roboticists, encompassing related techniques from image processing and control of navigation including motion detection, object segmentation, time-to-contact information, focus of expansion calculations, luminance, motion compensated encoding, and stereo disparity measurement.