Abstract: Considering that the intrinsic and extrinsic parameters of road side pan/tilt/zoom (PTZ) camera are variable, the absolute distance of object to camera is difficult to solve. An automatic calibration method for PTZ camera based on analyzing traffic video is presented. A model of traffic camera is given. By using the relative distances of points on road, a method is established to solving all the unknown parameters in the model. An automatic calibration implementation procedure is given. Experiment shows the calibration errors. During the procedure, only images of the traffic scene are needed without any manual intervention and configuration. This method has advantage of simple calculation and good flexibility, the demand of intelligent transportation surveillance system can be satisfied.

Key words: video surveillance, pan/tilt/zoom camera, camera calibration, corner detection