Patent ID: 6785416
Filing Date: 2004-08-31
Classification: G06K,H04N

Abstract:
A method of processing image data containing pixel values for pixels wherein said image data has a resolution of at least 600 dpi, said method comprising the steps of: positioning a pixel window over a subset of pixels in the image data, said pixel window surrounding a focus pixel; and performing calculations on pixel values of pixels in the pixel window to detect image type, said calculations distinguishing between a region containing large text image data and a region containing halftone image data, and wherein the performing of calculations further comprises the steps of:summing the pixel values of a first, second, third and fourth subset of pixels in said pixel window to form a respective first, second, third and fourth cumulative pixel value; subtracting said third cumulative pixel value from the first cumulative pixel value and the fourth cumulative pixel value from the second cumulative pixel value to produce respective results, the larger of the respective results being designated as an overall result, and comparing said overall result to previously obtained results for a region known to contain halftone image data and a region known to contain large text image data, to predict a likelihood of the pixel being examined belonging to a halftone image region or large text image region.