Rotoscope

A device that enables animators to trace the movement of live actors, frame by frame, into an animation sequence. The rotoscope is decried by some animation purists, but has often been used to good effect. The device was invented by Max Fleischer, who used it in his series "Out of the Inkwell" before World War I.

In computer graphics, to rotoscope is to create an animated matte indicating the shape of an object or actor at each frame of a sequence, as would be used to composite a CGI element into the background of a live-action shot.