Video Orbits of the Projective Group: A New Perspective on Image Mosaicing

We present a new technique for estimating the projective (homographic) coordinate transformation between pairs of images, taken with a camera that is free to pan, tilt, rotate about its optical axis, and zoom. The technique solves the problem for two cases of static scenes: images taken from the same location of an arbitrary 3-D scene, or images taken from arbitrary locations of a at scene. A new algorithm is presented for the parameter estimation and applied to the task of constructing high resolution still images from video. This approach generalizes inter-frame camera motion estimation methods which have previously used an aane model and/or which have relied upon nding points of correspondence between the image frames. The new projective algorithm which operates directly on the image pixels is shown to be superior in accuracy and ability to enhance resolution. The proposed method works well on image data collected from both good-quality and poor-quality video under a wide variety of conditions (sunny, cloudy, day, night). This new fully-automatic technique is also shown to be robust to deviations from the assumptions of static scene and no parallax.