Patent ID: 8160393
Filing Date: 2012-04-17
Classification: G06K

Abstract:
1. A method for calculating a skew angle of an original image, the method executed at least in part on a computer system and comprising: storing image data for the original image in an electronic memory; forming an energy-normalized image according to the relative contrast amplitude of image features over each of a plurality of local image regions within the stored image data; forming a partitioned image by partitioning the energy-normalized image into a plurality of sub-regions; forming a summed region as a combination of image pixel data from the plurality of sub-regions; obtaining a Fourier magnitude spectrum by performing a Fourier transform on the summed region; calculating the skew angle according to a peak value of a radial line integration function that is formed by integrating the Fourier magnitude spectrum along each of a plurality of lines of constant radial angles; and providing an output signal that is indicative of the calculated skew angle.