Automatic Camera Calibration for Image Sequences of a Football Match

In the broadcast of sports events one can commonly see adds or logos that are not actually there - instead, they are inserted into the image, with the appropriate perspective representation, by means of specialized computer graphics hardware. Such techniques involve camera calibration and the tracking of objects in the scene. This article introduces an automatic camera calibration algorithm for a smooth sequence of images of a football (soccer) match taken in the penalty area near one of the goals. The algorithm takes special steps for the first scene in the sequence and then uses coherence to efficiently update camera parameters for the remaining images. The algorithm is capable of treating in real-time a sequence of images obtained from a TV broadcast, without requiring any specialized hardware.