High Precision Camera Calibration Method Based on Full Camera Model

In existing camera calibration methods, the principal point coordinates are commonly treated as the distortion center. However, in reality, the principal point coordinates and the distortion center are not strictly identical. Failing to distinguish between them can lead to a reduction in the accuracy of camera parameter calibration. Based on this, a high-precision camera calibration method based on full camera model is proposed. This method comprises the following steps: Firstly, the initial camera parameters are obtained using the Zhang Zhengyou calibration method. Secondly, based on the camera's internal and external parameters, the centers of circles in the image and in the world coordinate system are projected onto the normalized plane to obtain the actual and ideal points of the circle's center on the normalized plane. The actual point on the normalized plane is then corrected using the full camera model. Next, the distortion center and distortion parameters are calculated from the positional relationship between the actual point and the ideal point on the normalized plane. Subsequently, the corrected actual points on the normalized plane are projected back onto the image plane, and camera calibration is performed again. Finally, high precision camera calibration is achieved after several iterations of projection and calibration. Experimental results demonstrate that this method significantly enhances the accuracy of camera calibration.