Calibration of panoramic catadioptric sensors made easier

We present a new method to calibrate panoramic catadioptric sensors. While many methods exist for planar cameras, it is not the case for panoramic catadioptric sensors. The aim of the proposed calibration is not to estimate the mirror surface parameters which can be known very accurately, but to estimate the intrinsic parameters of the CCD camera and the pose parameters of the CCD camera with respect to the mirror Unless a telecentric lens is used, this pose must be estimated, particularly for sensors that have a unique effective view point. The developed method is based on the original and simple idea that the mirror external and internal boundaries can be used as a 3D calibration pattern. The improvement introduced by our approach is demonstrated on synthetic experiments with incorrectly aligned sensors and validation tests on real images are described. The proposed technique opens new ways for better designed catadioptric sensors where self-calibration can be easily performed in real-time in a completely autonomous way. In particular this should allow to avoid errors due to vibrations one can notice when using catadioptric sensors in practical situations.