Real time tracking for enhanced tennis broadcasts

This paper develops real time tracking technology for sports broadcast applications. The specific sport chosen here is the game of tennis. The outputs of the tennis tracking system are spatio-temporal trajectories of motion of the players and the ball which can in turn provide a number of statistics about the game. For instance, the distance travelled by a player, the speed and the acceleration at any instant, as well as court coverage patterns can be obtained from the trajectories. The statistics so obtained can be visualized in compelling ways to enhance the appreciation of the athleticism and strategy involved in the sport. We present techniques for tracking the players and the ball in video obtained from stationary cameras. The problem is challenging as the tracking needs to be performed outdoors, players are fast-moving non-rigid objects, and the ball is a small object that can move at speeds in the range of 150 miles an hour. Player trajectories are obtained by dynamically clustering tracks of local features. Ball segmentation and tracking is based on shape and color features of the ball. Real time tracking results are presented on video recorded live by the authors in an international tennis tournament