RECOVERY OF EGO-MOTION USING REGION ALIGNMENT

A method for computing the 3D camera motion (the ego-motion) in a stat ic scene is described, where initially a detected 2D motion between tw o frames is used to align corresponding image regions. We prove that s uch a 2D registration removes all effects of camera rotation, even for those image regions that remain misaligned. The resulting residual pa rallax displacement field between the two region-aligned images is an epipolar field centered at the FOE (Focus-of-Expansion). The 3D camera translation is recovered from the epipolar field. The 3D camera rotat ion is recovered from the computed 3D translation and the detected 2D motion. The decomposition of image motion into a 2D parametric motion and residual epipolar parallax displacements avoids many of the inhere nt ambiguities and instabilities associated with decomposing the image motion into its rotational and translational components, and hence ma kes the computation of ego-motion or 3D structure estimation more robu st.