An Automatic Calibration Method for PTZ Camera in Expressway Monitoring System

Camera vision calibration is the key technology of Video-based Traffic Monitoring System (VTMS). PTZ camera is used more and more widely in the VTMS for its high flexibility and mobility which also bring great difficulties in its calibration. This paper presented an automatic method of calibration for PTZ camera used in Expressway Monitoring System so that the system can implement calibration without any manual intervention as soon as the operator changes the situation of the camera. A novel model of traffic monitoring camera is given in the beginning, a theoretical framework is established, aimed at computing all the unknown parameters in the model. Test results using real data are described. Both accuracy and speed are reported. Implementation ways and steps of practical application in the project are given.