A Method of Calibration and Measuring Foeal Length for Pan-Tilt-Zoom Camera*

摘要

In view of the installed Pan-Tilt-Zoom (PTZ) camera, a calibration method is proposed in this paper. Unlike other calibration methods, we consider that simple distortion models cannot describe the distortion of non-axisymmetric lenses. To solve this problem, we use a distortion matrix to describe the distortions of different parts of the lens under non-axisymmetric conditions. The camera intrinsic parameters and distortion matrix are then determined at discrete steps in a monotonically increasing zoom sequence that spans the full zoom range of the camera. Finally, we briefly discuss how this can be used to estimate intrinsic parameters and distortion matrix of the image captured within the camera's full range of pan tilt and zoom configurations.