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Counterfeit Deterrent Features for the Next-Generation Currency Design (1993) / Chapter Skim
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Appendix D: Induced Moire Pattern Background
Pages 115-116

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From page 115...
... A simple illustration of induced moire can be seen using the concentric-circle pattern shown in Figure D-~. To observe an induced moire pattern, place a pocket comb one to two inches above the concentric-circle pattern.
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From page 116...
... The presence of a sampling function leads to the generation of aliased frequencies, which, when reconstructed, represent the moire pattern. The same calculation can be performed in the spatial domain using discrete sampling.
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Key Terms

  • comb serves
  • ratio relationship
  • digital imaging
  • sampling ratio
  • domain using

  • spatial domain
  • function leads
  • aliased frequencies
  • false data
  • discrete sampling

  • using discrete
  • pattern shown
  • moire pattern
  • pocket comb
  • seen using

  • simple illustration
  • induced moire


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