Image analysis – Applications – Personnel identification
Reexamination Certificate
2000-02-29
2001-09-18
Mehta, Bhavesh (Department: 2621)
Image analysis
Applications
Personnel identification
C356S071000, C340S005830
Reexamination Certificate
active
06292576
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to a fingerprint scanning system, and more particularly to a method and apparatus for distinguishing a human finger from a reproduction of a fingerprint.
BACKGROUND OF THE INVENTION
Automatic fingerprint scanners are commonly used to obtain an analog or digital image for security, access, verification, or record-keeping applications. In most conventional scanners, a two-dimensional (2D) image of the fingerprint is captured by an imaging device having a matrix of picture elements or pixels arranged as multiple rows and columns. A 2D light-sensitive electronic sensor, such as a charge-coupled device (CCD), is typically used to capture a fingerprint image.
Fingerprint imaging systems must determine if the image presented is a real finger or an optical or mechanical reproduction of a fingerprint, to deny access when a reproduction is presented. Such reproductions may be in the form of a fingerprint printed on paper, a fingerprint printed on clear or reflective plastic, or may be in the form of a three-dimensional (3D) model of a fingerprint, such as a rubber stamp. In the extreme case, a finger may be removed from its rightful owner and used with the imaging system without the rightful owner being present.
SUMMARY OF THE INVENTION
The present invention provides a method and apparatus for distinguishing a human finger from a reproduction. A finger is placed on a transparent platen having a prism or microprism array attached. A first light source directs light to the platen, the first light positioned to show illumination in the areas where the skin is in contact with the platen. A first image of the fingerprint is captured by an imaging device when the finger is illuminated by the first light source. A second light source directs light at the platen, the second light positioned to show illumination in the areas where there is no skin contact. A second image of the fingerprint is captured by the imaging device when the finger is illuminated by the second light source. A determination that the fingerprint is from a human finger is made if a mathematical comparison of the two images meets a predetermined criteria.
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Blakely , Sokoloff, Taylor & Zafman LLP
Digital Persona, Inc.
Mehta Bhavesh
LandOfFree
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