Computer vision based athlete tracking systems use different methods to segment players from the background and then track them automatically throughout the video. It is insufficient to know a player's position on the image plane if we want to extract performance analysis of the player. Furthermore, image plane coordinates need to be transformed to real world coordinates representing the position of the player on the field. Knowing that the soccer field is planar, the mapping between the world coordinate system and the image coordinate system can be described by a planar homography. In this paper, we provide a discussion on homography calculations between a three-camera player tracking system and the real world soccer field model. © 2012 IEEE.