Patent ID: 7356200
Filing Date: 2008-04-08
Classification: G06K

Abstract:
1. A method of determining a skew angle of an image relative to a first axis, said image being generated by a plurality of pixels, wherein each of said pixels is represented by a pixel value, said method comprising: creating a first plurality of pixel groupings extending perpendicular to said first axis; sampling at least one pixel value of each of said first plurality of pixel groupings; creating a second plurality of pixel groupings extending perpendicular to said first axis; sampling at least one pixel value of each of said second plurality of pixel groupings; calculating differences between adjacent sampled pixel values in said first plurality of pixel groupings; calculating differences between adjacent sampled pixel values in said second plurality of pixel groupings; locating a first difference associated with said first plurality of pixel groupings, said first difference exceeding a first preselected value; locating a second difference associated with said second plurality of pixel groupings; fitting a second axis between said first difference and said second difference, said second axis having a slope relative to said first axis; and scaling said slope by the number of pixel values in each of said plurality of pixel groupings extending parallel and perpendicular to said first axis; said skew angle being the angle between said first axis and an axis generated by the scaled second axis.