Recovery of Ego Motion by Region Registration

A robust method is introduced for computing the camera motion the ego motion in a static scene The method is based on detecting a single image region and com puting its D motion in the image plane directly from image intensities The detected D motion of this image region is used to register the images so that the detected image region appears stationary The resulting residual displacement eld for the entire scene in such registered frames is a ected only by the D translation of the camera Canceling the e ects of the D rotation of the camera by using such D image registration simpli es the computation of the translation The D translation of the camera is computed by nding the focus of expansion in the translation only set of registered frames This step is followed by computing the D rotation to complete the computation of the ego motion The presented method avoids many of the inherent problems in the computation of optical ow and of feature matching and does not assume prior feature detection or feature correspondence This research has been sponsored by ARPA through the U S O ce of Naval Research under Grant N R T Project Code and by the Israeli Ministry of Science and Technology M Irani is now with David Sarno Research Center Princeton NJ U S A