An efficient zoom tracking method for pan-tilt-zoom camera

Zoom tracking plays an important role in camera tracking. It is always a challenge for camera calibration when the focal length becomes long, for the principal plane would move and rotate inevitably in the process of zoom. To deal with this problem, a new method is presented in this paper, in which we does not lay emphasis on the camera calibration itself, but focuses on the compensation to the extrinsic parameters of camera. A compensation matrix which consists of the bias of principal plane is applied to verify the extrinsic parameters of camera in zoom process. Experimental results indicate that this method can provide higher tracking accuracy than traditional methods.