The measuring and display system for a merathon TV program employing a realtime image processor and a fast graphic processor has been developed. The system consists of two parts, the step frequency subsystem and the Computer Graphic display subsystem. In the first subsystem, the step frequency for a marathon runner is detected from the image signal by tracking the motion of the runner's face. In the second subsystem, the data for the position of each joint in the runner's leg are prepared beforehand. By applying the step frequency to those prepared data, the runner's motion is drawn out as an animation.