ACCURATE ALIGNMENT OF SETS OF IMAGES

Two modifications to the conventional procedure of crosscorrelation ar e described, widely used for establishing the relative alignment; of t he members of a set of images from which a higher resolution or more i nterpretable restoration is sought. Both achieve a high and sharp peak in circumstances where the conventional peak is too ill defined to be recognizable; neither involves significant additional computation tim e. The more general method requires rough knowledge of the imaging con ditions, but a variant applicable to images with axial resolution has no such requirement. In addition, a least-squares procedure is present ed for achieving an optimum compromise between many pair-wise displace ment measurements, preventing the accumulation of alignment errors acr oss a set of images.