The present invention is directed to a system for finding a transformation
of a gray level pattern in an image. The system recursively searches a
transformation space in a multi-resolution manner. At each resolution, the
transformation space is divided into groups of translations. For each
group, a set of difference values are computed and compared against a
previously known best difference value. If any of the computed difference
values are greater than the previously known best difference value, the
corresponding group of translations is removed from further consideration.