Tracking Soccer Players

Pascual Figueroa


In this talk I'm going to present the problem of tracking soccer players during a game, which consist in finding the position of each player in the field at each instance of time. This is a challenging problem because of different factors, such as, quality of image sequence, occlusion of the players, the need to use many cameras in order to cover the whole field, change of illumination, problem with shadows, camera movement, etc. Tracking soccer players is of the great interest, because the information obtained maybe used for tactical variation that a team can assume during a game, it can contribute for improving the training of players of different positions, the measurement variables such as total distance and velocity may be associated to the physiological variables and to technical and tactical information. The information may also be useful for annotation and for computer animation, giving the possibility to generate virtual cameras.

We attack this problems using at least four cameras in order to cover the whole field and to have a reasonable size of players in the image sequence. The problem we divide in two parts: The first is the segmentation, which consist in extracting the players from the image. The segmentation gives as result a set of blobs in each image. In the second part we use this information for constructing a graph, where the node are the blobs and the edges are the distance between the blobs of two consecutives frames. Each node contains all the information such as the color, area, size, position, etc. For tracking players we use this graph and search the minimal path to find the trajectory. The edges are weighted using the color similarity and the direction of the trajectory. I'm going to present some results that we get using this approach.

Maintained by Philippos Mordohai