Patent ID: 11915435
Assignee: RAYTHEON COMPANY
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 8:
9. A method of image cross correlation, comprising:
a) correlating a plurality of first windows in a first image to a plurality of second larger windows in a second image to produce a plurality of correlation surfaces;
b) extracting a plurality of pairs of correlation offsets X and Y from the correlation surface, said correlation offsets X and Y being real numbers including fractional portions capable of representing fractional offsets;
c) resampling the pixel values within the first window of the first image or the second larger window of the second image using the fractional portions of the plurality of pairs of correlation offsets X and Y; and
d) using the resampled pixel values to correlate the first window in the first image to the second larger window in the second image to produce a plurality of resampled correlation surfaces;
e) computing a figure of merit (FOM) for a peak in the plurality of resampled correlation surfaces;
f) extracting at least one final pair of correlation offsets X and Y from the resampled correlation surface;
g) accepting or rejecting each final pair of correlation offsets X and Y based on the FOM;
h) for the accepted final pairs of correlation offsets X and Y, extracting pairs of integer-valued correlation offsets X and Y from the resampled correlation surfaces, and
i) using the pairs of integer-valued correlation offsets X and Y as tie-points to register the resampled first image to the second image without resampling.