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Method and apparatus for checking print products, a computer program and a computer program product

  • US 8,611,613 B2
  • Filed: 05/27/2009
  • Issued: 12/17/2013
  • Est. Priority Date: 05/28/2008
  • Status: Expired due to Fees
First Claim
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1. A method for checking print products of the same kind which are transported by a conveying device, comprising:

  • recording test images in a teach-in phase at a plurality of points on the print product using a digital camera;

    defining an evaluation region within each test image, which evaluation region is smaller than, or equal to, a size of the test image;

    analyzing characteristic information of each evaluation region;

    selecting the test image, in which the evaluation region with a most distinctive characteristic information is located, as a reference image; and

    checking subsequent print products of the same kind by recording at least one check image at a position corresponding to the reference image and by image-data comparison of at least one subregion of the check image with the evaluation region of the reference image;

    wherein, for ascertaining the reference image, the evaluation region is divided into a plurality of subregions, which are evaluated in terms of their characteristic information;

    wherein, for checking subsequent print products, a comparison of characteristic information of the subregions of the evaluation region of the reference image with corresponding subregions of the check image is carried out; and

    wherein the comparison is carried out for a number of subregions by correlation methods and for a number of subregions by comparing gray-scale mean values.

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