A New Method of Camera Calibration for Large Field Videometrics

Abstract

A new method of camera calibration is proposed for high-precise videometrics in large field. The camera to be calibrated and the control points used in the new method are both close to the ground. In the condition that the control points and the optical center of the camera are approximately coplanar, the principle point position, focal length, lens distortion coefficients and the camera's position and attitude parameters are calibrated precisely by the method. Two calibration images are taken by the camera to be calibrated in measurement state and vertical rotation state respectively. If the vertical tangent lens distortion can be neglected or the movement field of the targets to be measured are close to the ground, only the measurement state calibration image is needed to calibrate the camera's parameters except the vertical tangent lens distortion coefficients. By the new method, to cali- brate the camera's intrinsic parameters in laboratory in advance is not needed. The new method breaks the localization for the traditional camera calibration methods in large field videometrics which require the control points must be distributed in space rationally.