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Visible authentication patterns for printed document

  • US 7,809,152 B2
  • Filed: 05/14/2003
  • Issued: 10/05/2010
  • Est. Priority Date: 05/14/2002
  • Status: Active Grant
First Claim
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1. A method for use with an authenticator, the method comprising:

  • creating an original digital pattern containing an authentication pattern;

    producing at least one original analog form from the original digital pattern causing a first loss of information in the at least one original analog form;

    making a digital recording from at least a portion of the at least one original analog form or from at least a portion of another analog form derived from the at least one original analog form causing a second loss of information in the recorded portion;

    comparing using a computer the digital recording with a corresponding portion of the original digital pattern using the sum of the first and second loss of information to determine a degree of dissimilarity between the digital recording made from the portion and the corresponding portion of the original digital pattern; and

    using the degree of dissimilarity to determine at said authenticator whether the recording was made from the at least one original analog form or from the other analog form.

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