I wanted to implement kalman filters for each soccer player in the sequence. Along with this i used the hungarian algorithm to do data association. For this sequence i had truth data (on how many soccer players there were in each frame, as well as their locations). I used this truth data as the observation in the kalman filter.
Since the observations were nearly perfect the tracker works very well.
You can see that when a player leaves his tracking box is removed. When a player enters the scene a new tracking box is present.