VIDEO ORBITS OF THE PROJECTIVE GROUP - A SIMPLE APPROACH TO FEATURELESS ESTIMATION OF PARAMETERS

We present direct featureless methods for estimating the eight paramet ers of an ''exact'' projective (homographic) coordinate transformation to register pairs of images, together with the application of seamles sly combining a plurality of images of the same scene, resulting in a single image (or new image sequence) of greater resolution or spatial extent, The approach is ''exact'' for two cases of static scenes: 1) i mages taken from the same location of an arbitrary three-dimensional ( 3-D) scene, with a camera that is free to pan, tilt, rotate about its optical axis, and zoom, or 2) images of a flat scene taken from arbitr ary locations, The featureless projective approach generalizes interfr ame camera motion estimation methods that have previously used an affi ne model (which lacks the degrees of freedom to ''exactly'' characteri ze such phenomena as camera pan and tilt) and/or which have relied upo n finding points of correspondence between the image frames, The featu reless projective approach, which operates directly on the image pixel s, is shown to be superior in accuracy and ability to enhance resoluti on, The proposed methods work well on image data collected from both g ood-quality and poor-quality video under a wide variety of conditions (sunny, cloudy, day, night), These new fully automatic methods are als o shown to be robust to deviations from the assumptions of static scen e and no parallax.