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Authentication Device And Authentication Method

  • US 20100278397A1
  • Filed: 08/27/2008
  • Published: 11/04/2010
  • Est. Priority Date: 08/31/2007
  • Status: Active Grant
First Claim
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1. An authentication apparatus comprising:

  • a light source that emits an infrared light beam onto a finger;

    image pick-up means that picks up an image of the finger by using a transmitted light beam, and thus outputs an image signal;

    low-frequency brightness component extracting means that extracts a low-frequency brightness component signal from the image signal by using a low-pass filter;

    middle-frequency brightness component extracting means that extracts a middle-frequency brightness component signal from the image signal by using a middle-pass filter;

    correction means that corrects the middle-frequency brightness component signal by using the low-frequency brightness component signal;

    quaternary-value converting means that converts the corrected middle-frequency brightness component signal into quaternary values such that the quaternary values are distributed at a predetermined ratio;

    storage means that stores a quaternary-valued image obtained from the quaternary-value conversion by the quaternary-value converting means;

    correlation coefficient calculating means that calculates a correlation coefficient between a quaternary-valued evaluation image as an object of evaluation and a quaternary-valued registered image by using a pattern matching method based on a normalized correlation method, the quaternary-valued evaluation image obtained from the quaternary-value conversion by the quaternary-value converting means, the quaternary-valued registered image being beforehand stored in the storage means; and

    judgment means that judges whether or not the quaternary-valued evaluation image and the quaternary-valued registered image are images picked up from the same finger on a basis of the correlation coefficient which is calculated by the correlation coefficient calculating means.

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