Automatic extrinsic camera self-calibration based on homography and epipolar geometry

In this paper we present a method to calibrate the extrinsic parameters of a monocular camera on a moving vehicle. The method is based on a homography between two camera shots. Therefore, only the road surface has to be visible in the pair of images. A reasonable definition of the vehicle coordinate system in combination with the use of epipolar geometry reduces the complexity to parameterize the underlying homography matrix. The extrinsic parameters are determined analytically by two correctly matched feature points located on the road surface. The final parameter set is determined by a recursive filter which considers various estimates over time. Results with a real-world video sequence indicate that the method is comparable to classical offline calibration techniques using objects of known geometry.