Method and apparatus for determination and visualization of player field

Abstract

A method and apparatus for deriving an occupancy map reflecting an athlete's coverage of a playing area based on real time tracking of a sporting event. The method according to the present invention includes a step of obtaining a spatio-temporal trajectory corresponding to the motion of an athlete and based on real time tracking of the athlete. The trajectory is then mapped over the geometry of the playing area to determine a playing area occupancy map indicating the frequency with which the athlete occupies certain areas of the playing area, or the time spent by the athlete in certain areas of the playing area. The occupancy map is preferably color coded to indicate different levels of occupancy in different areas of the playing area, and the color coded map is then overlaid onto an image (such as a video image) of the playing area. The apparatus according to the present invention includes a device for obtaining the trajectory of an athlete, a computational device for obtaining the occupancy map based on the obtained trajectory and the geometry of the playing area, and devices for transforming the map the a camera view, generating a color (or other visually differentiable) coded version of the occupancy map, and overlaying the color coded map on a video image of the playing area. In particular, the spatio-temporal trajectory may be obtained by an operation on a video image of the sporting event, in which motion regions in the image are identified, and feature points on the regions are tracked as they move, thereby defining feature paths. The feature paths, in turn, are associated in clusters, which clusters generally correspond to the motion of some portion of the athlete (e.g., arms, legs, etc.). The collective plurality of clusters (i.e., the trajectory) corresponds with the motion of the athlete as a whole.