Robust pan, tilt and zoom estimation

In this paper we propose a method for estimating the motion parameters for a rotating camera with a possibly changing focal length. This method is suitable for analysing sport event videos. The estimation process consists of three stages: (1) robust estimation of the 2-D translational components, (2) 2-D block-based motion estimation and (3) robust estimation of a parametric motion model. For more reliability con dence measures for 2-D motion vectors are introduced. The reliability of the method is illustrated on some di cult real image sequences.