Direct multi-resolution estimation of ego-motion and structure from motion

The paper describes an iterative algorithm that estimates the motion of a camera through an environment directly from brightness derivatives of an image pair. A global ego-motion constraint is combined with the local brightness constancy constraint to relate local surface models with the global ego-motion model and local brightness derivatives. In an iterative process, the author first refines the local surface models using the ego-motion as a constraint, and then refines the ego-motion model using the local surface models as constraints. He performs this analysis at multiple resolutions. He shows how information from local corner-like and edge-like image structures contribute to the refinement of the global ego-motion estimate, and how the ego-motion constraint can help resolve local motion ambiguities that arise from the aperture problem. Results of the algorithm are shown on uncalibrated outdoor image sequences, and also on a computer-rendered image sequence.>