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Optical fingerprint correlator

  • US 5,050,220 A
  • Filed: 07/24/1990
  • Issued: 09/17/1991
  • Est. Priority Date: 07/24/1990
  • Status: Expired due to Fees
First Claim
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1. An apparatus for correlating fingerprints and producing correlation indicia, said apparatus comprising:

  • a means for introducing a known fingerprint image to said apparatus;

    a means for introducing an unknown fingerprint image to said apparatus;

    a switching means for connecting the outputs of said means for introducing a known fingerprint and said means for introducing an unknown fingerprint, said switching means having a first side connected to said means for introducing an unknown fingerprint and a second side connected to said means for introducing a known fingerprint;

    a first means for producing spatial light modulation;

    a second means for producing spatial light modulation disposed coaxially in optical alignment with said first means for producing spatial modulation;

    a first spatial light modulator drive connected between the second side of said switching means and said first means for producing spatial light modulation;

    a means for producing a matched filter from said unknown fingerprint image, said means for producing a matching filter having an input and an output, said input being connected to the first side of said switching means;

    a second spatial light modulator drive connected between the output of said means for producing a matched filter and said second means for producing spatial light modulation;

    a first Fourier transform lens coaxially disposed in optical alignment with and between said first and second means for producing spatial light modulation;

    a second Fourier transform lens coaxially disposed in optical alignment with and on the side of said second means for producing spatial light modulation opposite the side facing first Fourier transform lens;

    a means for detecting correlation indicia, said means for detecting correlation indicia being disposed coaxially in optical alignment with said second Fourier transfer lens and on the opposite side of said lens from said second means for producing spatial light modulation;

    a means for displaying said indicia of correlation, said means for displaying said indicia connected to said means for detecting correlation indicia; and

    a means for providing collimated coherent light to and disposed coaxially in optical alignment with said first means for producing spatial modulation.

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