Practical pure pan and pure tilt camera calibration

Often the deployed pan-tilt-zoom (PTZ) cameras undergo a pure pan or pure tilt rotation. This is a degenerate case for most of the PTZ camera calibration methods. That is, under this motion, the estimated camera parameters are not unique. In this regard, we present a novel camera calibration method to estimate five camera parameters from these pure pan/tilt cameras by using only two images. Our solution is based on using the infinite homography and performing its eigendecomposition. Our solutions and analyses are thoroughly validated and tested on both synthetic and real data, whereby the proposed method is shown to be accurate and noise resilient.