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

Claim 20:
21. A method of image cross correlation, comprising:
a) correlating a first window in a first image to a second larger window in a second image to produce a correlation surface;
b) first extracting at least one first pair of correlation offsets X and Y from at least one peak in the correlation surface, said correlation offsets X and Y being real numbers including at least 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 only the fractional portions of the correlation offsets X and Y;
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 resampled correlation surface;
e) iterating steps b, c and d with the resampled correlation surface at least once to improve the accuracy of the at least one first pair of correlation offsets X and Y by driving the fractional portions to zero to sharpen the peaks in the resampled correlation surface until convergence or oscillation is reached;
f) extracting at least a final pair of correlation offsets X and Y from the resampled correlation surface, said at least final pair of correlation offsets X and Y including both non-zero integer and non-zero fractional portions;
g) computing an offset uncertainty for the at least one final pair of correlation offsets X and Y from range and variation of the plurality of the fractional offsets from the preceding iterations, and
h) outputting at least one of,
the offset uncertainty;
the at least one final pair of correlation offsets X and Y as tie points that define the registration between the original first and second images; and
at least one pair of integer-valued correlation offsets X and Y from the at least one final pair of correlation offsets as tie points do define the registration between the resampled pixels values within the first window of the first image or the second larger window of the second image.