Visual processing of motion

Image motion does not pose the same problem for the eye as it does for the camera. We are able to see objects with clarity when they move. We can also see motion on cinema or TV when what we are shown is a sequence of stills. As followers of fast ball-games like tennis and cricket know, we can see motion sequences as sharp when the actual individual stills on the cinema or TV screen, viewed singly or at slow speed, contain blurred images of moving actors or objects. Only recently has the idea emerged that visual abilities such as these may be explained by the specializations of visual neurones. Theoretical and experimental advances in neurophysiology are beginning to identify the tuning characteristics, in space and time, of mechanisms that make it possible to do what a camera cannot: resolve form and motion simultaneously.