Variable Homography Compensation of Parallax Alone Mosaic Seams

摘要

A variable homography is presented which can improve mo-saicing across image seams where parallax (I.e., depth variations) occur. Homographies are commonly used in image mosaicing, and are ideal when the acquiring camera has been rotated around its optical center, or when the scene being mosaiced is a plane. In most cases, however, objects in the overlapping areas of adjacent images have different depths and exhibit parallax, and so a single homography will not result in a good merge.To compensate for this, an algorithm is presented which can adjust the scale of the homography relating two views, based upon scene content. The images are first rectified so that their retinal planes are parallel. The scale of the homography is then estimated for each vertical position of a sliding window over the area of overlap, and the scaled homography is applied to this region. The scale is blended so that there are no abrupt changes across the homography field, and the images are finally stitched together. The algorithm has been implemented and tested, and has been found to be effective, fast, and robust.