Abstract: There is provided a new and useful system for judging boundary lines on a court in sporting games, for determining whether a ball in play bounces in or out of court. The system comprises at least one camera to capture as frames movement of the ball and a frame grabber associated with each of the cameras to process the frames. An image processing system is configured to receive the digitized frame from the frame grabbers and to process the digitized frame to determine whether the ball is in or out of court and to generate a signal if the ball is out of court. There is an output device coupled to the image processing system to receive the signal and alert the players.