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Group average filter algorithm for digital image processing

  • US 7,242,816 B2
  • Filed: 04/27/2004
  • Issued: 07/10/2007
  • Est. Priority Date: 08/11/2003
  • Status: Expired due to Fees
First Claim
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1. A method of enhancing an image comprising the steps of:

  • converting the image to a two-dimensional array;

    converting said image to grayscale;

    selecting a row of pixels from said image for processing;

    computing the mean intensity of said pixels in said row;

    dividing said image into sections;

    computing the mean intensity of the pixels of each section;

    processing the pixels in each of said sections according to a first method if said mean intensity of said section is greater than said mean intensity of said row;

    processing the pixels in each of said sections according to a second method if said mean intensity of said section is less than said mean intensity of said row; and

    disregarding the pixels in sections where said mean intensity of said section is equal to said mean intensity of said row; and

    wherein said first method of processing pixels in a section consists of the steps of;

    computing the value of the intensity of each pixel in said section plus a percentage threshold multiplied by the intensity of each pixel in said section; and

    assigning to each pixel in said section an intensity corresponding to white if the computed value is greater than the mean intensity of said row; and

    assigning to each pixel in said section an intensity corresponding to black if the computed value is less than the mean intensity of said row; and

    wherein said second method of processing pixels in a section consists of the steps of;

    computing the value of the intensity of each pixel in said section minus a percentage threshold multiplied by the intensity of each pixel in said section; and

    assigning to each pixel in said section an intensity corresponding to white if the computed value is greater than the mean intensity of said row; and

    assigning to each pixel in said section an intensity corresponding to black if the computed value is less than the mean intensity of said row; and

    wherein said percentage threshold is greater than or equal to one and less than or equal to twenty.

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