Patent ID: 8824735

Claim:
A method of determining a shift between a first image and a second image, the first image having first image projection characteristics and the second image having second image projection characteristics, said method comprising: determining a first correlation in a first direction, said first correlation being derived from the first image projection characteristics in the first direction and the second image projection characteristics in the first direction; determining a second correlation in a second direction, said second correlation being derived from the first image projection characteristics in the second direction and the second image projection characteristics in the second direction; identifying a first plurality of local maxima in the first correlation in the first direction; identifying a second plurality of local maxima in the second correlation in the second direction; determining a set of hypotheses, wherein each hypothesis in said set of hypotheses is a combination of one of the identified first plurality of local maxima and one of the identified second plurality of local maxima; and determining the shift between the first image and the second image based upon the set of hypotheses by: calculating a two-dimensional correlation score between the first image and the second image based on a shift indicated in at least one of the set of hypotheses; and selecting one of the set of hypotheses as the shift between the first image and the second image based on the calculated two-dimensional correlation score.