A review of image-warping methods

Image war ping is a transformation which maps all positions in one image plane to positions in a second plane. It arises in many image analysis problems, whether in order to remove optical distortions introduced by a camera or a particular viewing perspective, to register an image with a map or template, or to align two or more images. The choice of war p is a compromise between a smooth distortion and one which achieves a good match. Smoothness can be ensured by assuming a parametric for m for the warp or by constraining it using diOE erential equations. Matching can be speci ed by points to be brought into alignment, by local measures of correlation between images, or by the coincidence of edges. Parametric and non-parametric approaches to war ping, and matching criteria, are reviewed.