Identity verification apparatus and fingerprint image pickup method

• US 20040179723A1
• Filed: 03/08/2004
• Published: 09/16/2004
• Est. Priority Date: 03/13/2003
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Nakajima, Hajime, Shikai, Masahiro, Shiratsuki, Akihide, Sano, Emiko
• Granted Patent: US 7,577,279 B2
• Time in Patent Office: Days
• US Class Current: 382/124
• CPC Class Codes: G06V 40/1312 direct reading, e.g. contactless acquisition
• CPC Class Codes: G06V 40/1341 Sensing with light passing through the finger
• CPC Class Codes: G06V 40/14 Vascular patterns

Abstract

An identity verification apparatus includes a light source for applying light that can pass through an object to be detected having a fingerprint to the object to be detected, an image pickup unit for picking up both light emitted out of the light source and passing through projections of the fingerprint and light emitted out of the light source and passing through depressions of the fingerprint, and for generating a fingerprint image including dark portions corresponding to the projections and bright portions corresponding to the depressions, and a signal processing unit for performing image processing on the fingerprint image generated by the image pickup unit so as to generate fingerprint information, and for verifying an identity based on the fingerprint information.

Claims

1. An identity verification apparatus comprising:

a light source for applying light that can pass through an object to be detected having a fingerprint to said object to be detected;

an image pickup means for picking up both light emitted out of said light source and passing through projections of said fingerprint and light emitted out of said light source and passing through depressions of said fingerprint, and for generating a fingerprint image including dark portions corresponding to said projections and bright portions corresponding to said depressions; and

a signal processing unit for performing image processing on said fingerprint image generated by said image pickup means so as to generate fingerprint information, and for verifying an identity based on the fingerprint information.

2. The identity verification apparatus according to claim 1, further comprising a transparent object-to-be-detected holding member for holding said object to be detected with a fingerprint side surface of said object to be detected, which is an object to be detected, being in contact therewith.

3. The identity verification apparatus according to claim 1, further comprising an object-to-be-detected holding member for holding said object to be detected with a fingerprint side surface of said object to be detected, which is an object to be detected, being in noncontact therewith.

4. The identity verification apparatus according to claim 3, wherein said image pickup means detects light that is incident upon a fingerprint contact surface of said object-to-be-detected holding member, said fingerprint contact surface being in contact with the fingerprint of said object to be detected, at an angle equal to or less than a critical angle of total reflection determined by both an index of refraction of a gas between said depressions of said fingerprint and said object-to-be-detected holding member, and an index of refraction of said object-to-be-detected holding member.

5. The identity verification apparatus according to claim 1, wherein said image pickup means picks up a distribution of intensity of light passing through at least a part of internal tissues of said object to be detected, which is at only a predetermined distance from a fingerprint side surface of said object to be detected toward an inner side of said object to be detected.

6. The identity verification apparatus according to claim 5, wherein said image pickup means is provided with an image formation means whose focal point is in a plane located between said fingerprint side surface of said object to be detected and said internal tissues.

7. The identity verification apparatus according to claim 5, wherein said predetermined distance ranges from 0.1 mm to 11.0 mm.

8. The identity verification apparatus according to claim 2, wherein said transparent object-to-be-detected holding member has a reflective prevention means.

9. The identity verification apparatus according to claim 1, wherein the light applied to said object to be detected has dominant wavelengths in a red or near-infrared region, and said image pickup means has sensibility to light having wavelengths in the red or near-infrared region.

10. The identity verification apparatus according to claim 9, wherein the light applied to said object to be detected has dominant wavelengths ranging from 630 nm to 780 nm, and said image pickup means has sensibility to light having wavelengths ranging from 630 nm to 780 nm.

11. The identity verification apparatus according to claim 1, wherein said apparatus further comprises a means for adjusting the intensity of the light applied to said object to be detected so that the fingerprint image outputted from said image pickup means has lightness that falls within a predetermined range.

12. An identity verification apparatus comprising:

a light source for applying light that can pass through an object to be detected having a fingerprint to said object to be detected, a fingerprint side surface of said object to be detected, which is an object to be detected, being in noncontact with any structure;

an image pickup means for picking up both light emitted out of said light source and passing through projections of said fingerprint and light emitted out of said light source and passing through depressions of said fingerprint, and for generating a fingerprint image including dark portions corresponding to said projections and bright portions corresponding to said depressions; and

a signal processing unit for performing image processing on said fingerprint image generated by said image pickup means so as to generate fingerprint information, and for verifying an identity based on the fingerprint information.

13. The identity verification apparatus according to claim 12, further comprising an object-to-be-detected holding member for holding said object to be detected with the fingerprint side surface of said object to be detected, which is an object to be detected, being in noncontact therewith.

14. The identity verification apparatus according to claim 12, further comprising a means for detecting a position of the fingerprint side surface of said object to be detected without being in contact with the fingerprint side surface.

15. A fingerprint image pickup method comprising the steps of:

applying light that can pass through an object to be detected having a fingerprint to said object to be detected; and

generating a fingerprint image corresponding to light transmittance of internal tissues that are close to a fingerprint side surface of said object to be detected.