A Novel Camera Calibration Method of Variable Focal Length Based on Single-View

The key of camera calibration is to calculated the initial value of extrinsic and intrinsic camera parameters. Since the calculation of initial value is not a purely linear problem, 3D measurement products are often using a fixed focal length camera calibration method, but the measuring exists the problem of inconvenience of usage and a limited measurement-range. We have derived a novel camera calibration method which focal length of camera can be variable. By means of using the orthogonal rotation matrix and constraints among camera parameters in the single-view vision, a new algorithm to linearly and exactly calibrate the camera from single-view at least six known feature points is developed. The theoretical analysis and the experiments have demonstrated that the suggested algorithm is fast, exact, efficient and rather robust against noise, and it can be applied to the area of 3D measurement of variable focal length.