Camera calibration using identical objects

This paper describes a method for camera calibration using identical products. In this paper, we postulate an imaginative rigid motion between any two identical products, and the imaginative rigid motion could offer a pair of circular points. As is known, three pairs of projections of the circular points are needed to result in the closed-form solution for calibration. In our method, we obtain three pairs of projections of the circular points from only two images of three identical products, or three images of two identical products. When only two identical products are utilized, our method is almost the dual of the stereo calibration from rigid motions. A direct approach is taken here instead of the two-step process in stereo calibration. Furthermore, a better projective reconstruction could be performed from the estimation of the camera parameters to avoid the dominant projective-to-affine error in the stereo calibration. Finally, we conduct a nonlinear refinement based on the maximum likelihood estimation. The experimental results from synthetic data and real data prove our method convenient and robust to noise.