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Image region dividing apparatus

  • US 5,867,593 A
  • Filed: 10/08/1996
  • Issued: 02/02/1999
  • Est. Priority Date: 10/20/1993
  • Status: Expired due to Fees
First Claim
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1. An image region dividing apparatus comprising:

  • image input means for inputting a mixed image in which character information and picture/graphics information are mixed as a digital image;

    same-kind image region extraction means for;

    selecting same kinds of the character information and the picture/graphics information in the input image by comparison,dividing the selected information into small region images of a size including the selected information,grouping the small region images into the same kinds of information,obtaining a position and size of each of the small region images, andspecifying a region in which it is discriminated whether the small region image is character information or picture/graphics information;

    local feature pattern detection means for detecting local feature patterns formed by mutually adjacent pixels of the small region images, for each of the small region images grouped in the image;

    means for calculating a frequency distribution of the local feature patterns;

    correction means for;

    obtaining a first classification vector based on each of differences obtained from horizontal and vertical pixel alignments of the small region images, andprojecting the first classification vector to the frequency distribution of the local feature patterns to correct the frequency distribution;

    frequency distribution normalization means for normalizing the frequency distribution corrected by the correction means using a random number;

    image kind identification means for;

    receiving the normalized frequency distribution andidentifying whether the information included in the small regions are character information or picture/graphics information; and

    image kind determination means for determining image kinds on the basis of the identification results from said image kind identification means; and

    said image kind identification means including;

    block image storage means for temporarily storing the small region images from said same-kind image region extraction means;

    histogram calculation means for calculating a gradient vector direction histogram and a corrected luminance vector histogram of the small region images read out from said block image storage means;

    supervising data storage means for pre-storing a plurality of classification vectors which are used as supervising data and predetermined in units of the kinds of images based on the character information and picture/graphics information;

    inner product calculation means for performing inner product calculations of the gradient vector direction histogram and the corrected luminance vector histogram, and the first classification vector, in units of images of the small regions output from the histogram calculation means; and

    buffer means for;

    temporarily storing calculation results of said inner product calculation means, andoutputting the calculation results to feature discrimination means comprising a neural network for discriminating the kinds of an image;

    FST means having a second classification vector to be used for classification between a handwritten character and a graphics image, andsaid image kind discrimination means calculates;

    inner products of the input small region images and the second classification vector, andinner products of the gradient vector direction histogram and the corrected luminance vector histogram, and the first classification vector calculated by the histogram calculation means; and

    said image kind discrimination means discriminates image kinds on the basis of results from the inner products.

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