Finding the epipole from uncalibrated optical flow

This article presents a novel method for determining the location of the instantaneous epipole in a sequence of images acquired by an uncalibrated camera and containing a single, rigid motion (e.g. the camera moves in a static environment). The method uses the full perspective camera model and requires the estimation of the optical flow at a minimum of six image locations. The key observation is that the optical flow equations can be written in terms of the epipole in a strikingly simple form if the translational and rotational flow components are not separated as performed usually. The epipole location can then be obtained as the minimum of a least-square residual function associated to the computed optical flow. We report and discuss initial experiments on both synthetic and real data and illustrate possible developments of this method towards the use of uncalibrated optical flow for 3-D motion and structure reconstruction.