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APPARATUS FOR CAPTURING A HIGH QUALITY IMAGE OF A MOIST FINGER

  • US 20080273771A1
  • Filed: 04/17/2008
  • Published: 11/06/2008
  • Est. Priority Date: 05/01/2007
  • Status: Active Grant
First Claim
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1. A fingerprint image capturing apparatus comprising:

  • a prism having an imaging plane on which a finger having valleys and ridges is place, a bottom plane parallel to the imaging plane and a reflective plane intercepting the imaging plane and intercepting the bottom plane at an angle α

    ;

    a light source for generating a light with an incident angle of approximately 0°

    with respect to a surface normal of the imaging plane;

    a lens for capturing light reflected from the reflective plane; and

    an image sensor for generating an image of the valleys and ridges of the finger, wherein the reflective plane is arranged in such a way to meet the following equation;


    α

    >

    45+(a sin(n1/n2))/2,where n1 is a refraction index of medium filled between the valleys of the finger and the imaging plane, and n2 is refraction index of the prism.

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