Patent ID: 7574050

Claim:
A method of automatically identifying a pattern on a page, comprising: a computer performing the following: synthetically generating textual patterns as signal templates; generating a compensated image, compensating, if necessary, for visual differences between the synthetically generated textual patterns and images being compared against the synthetically generated patterns; and comparing compensated images against images in a database; and identifying a pattern on a page based upon the comparison; wherein compensating an image includes reducing resolution, inverting and mirroring a page image in the database; and wherein comparing compensated images against images in a database includes: performing a Fast Fourier Transform (FFT) on the compensated image, moving the compensated image from the spatial to frequency domain; performing an FFT on a search target image; multiplying the FFT on the image to be searched by the FFT of the search target image to produce a correlation plane; performing an inverse FFT of the correlation plane, converting the correlation plane from the frequency domain to a spatial specification to produce a similarity matrix for search pattern locations within the target image; and applying a threshold to the similarity matrix to extract location of matches above the threshold.