Vehicle guidance from one dimensional optical flow

This paper is based on the observation that if a viewing camera is appropriately mounted on a vehicle which moves on a planar surface, i.e., the image plane of the camera is orthogonal to the planar surface and the optical axis parallel to the instantaneous direction of translation, then the optical flow obtained from the moving camera depends on two parameters only, the angular velocity around an axis orthogonal to the planar surface and the ration between the the viewed depth and the translational speed, or generalized time-to-collision.