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Image processing based on automatic image-type detection

  • US 9,055,251 B2
  • Filed: 09/24/2013
  • Issued: 06/09/2015
  • Est. Priority Date: 09/24/2013
  • Status: Active Grant
First Claim
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1. A method comprising:

  • receiving an image into a computerized device;

    automatically determining an image-type of said image; and

    automatically selecting an image processing mode based on said image-type of said image,said automatically determining said image-type comprising;

    automatically dividing said image into image blocks, using said computerized device;

    automatically determining a block average by determining an average pixel value for each of said image blocks, using said computerized device;

    automatically determining a squared error for each pixel within each of said image blocks by calculating a squared difference between a pixel value and said block average for each said pixel in each of said image blocks, using said computerized device;

    automatically determining a sum of squared errors value for each of said image blocks, using said computerized device;

    automatically removing ones of said image blocks determined to be a white background block to produce valid image blocks of said image, using said computerized device;

    automatically determining a number of high-variation blocks within said valid image blocks by counting ones of said valid image blocks that have said sum of squared errors value exceeding a block variation threshold, using said computerized device;

    automatically determining a page variance measure by dividing said number of high-variation blocks by a total number of said valid image blocks, using said computerized device;

    automatically classifying said image as comprising a halftone and text image based on said page variance measure exceeding a halftone threshold, using said computerized device;

    automatically determining a text index by counting a number of said valid image blocks that have said sum of squared errors value exceeding a text threshold, using said computerized device;

    automatically classifying said image as comprising a continuous tone image based on said page variance measure not exceeding said halftone threshold and said text index being below a text index threshold, using said computerized device; and

    automatically classifying said image as comprising a continuous tone and text image based on said page variance measure not exceeding said halftone threshold and said text index not being below said text index threshold, using said computerized device,said automatically selecting said image processing mode comprising automatically selecting said image processing mode based on said image being one of said halftone and text image, said continuous tone and text image, and said continuous tone image.

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