Catadioptric camera calibration based on RANSAC

In this paper, we propose a simple method for calibrating the effective focal length of central catadioptric cameras. This method uses the constraint that the projections of any three collinear space points on the viewing sphere should be on a great circle. We assume there are some inliers among the detected image points. If only three image points of a space line are well chosen, the constraint is effective. RANSAC is used for robust estimation. This approach needs no conic fitting, which is hard to accomplish and highly affects the accuracy of the calibration. Experiments on simulated and real data show the proposed method is robust and effective.