JP2003208603A - Fingerprint reading and collating system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fingerprint reading and collating system capable of preventing fingerprint information of an individual from leaking as its shape is and preventing its forgery. <P>SOLUTION: The field of view 23a of a rod lens at left end is restricted by a slit 6 to form Fourier transform image in the lateral direction in an optical electric transducing element and obtain Fourier transform data d1 in the lateral direction. In the same way, Fourier transform data d2, d3 in the lateral direction corresponding to the fields of view 23b, 23c are obtained. Furthermore, Fourier transform data restricting a field of view by scanning a finger is obtained as time series data. Since these Fourier transform data d1, d2, d3 in the lateral direction do not include phase information, it is impossible to reproduce original fingerprint from the data transformed by the optical electric transducing element. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a collation system for optically reading a fingerprint to determine who the fingerprint is.

[0002]

2. Description of the Related Art As a security system for access to information equipment such as computers and communication equipment, a system for recognizing an individual by reading and collating fingerprints is becoming widespread. An apparatus disclosed in Japanese Patent Laid-Open No. 11-318863 is known as an optical fingerprint reading / verifying system. This device optically forms an image of fingerprint information directly on a photoelectric conversion element such as a CCD and converts it into an electrical signal to extract the characteristics of the image and determine who the fingerprint belongs to. I am trying to judge.

[0003]

In the above-mentioned prior art, a real image of a fingerprint is formed on a photoelectric conversion element and the fingerprint information is directly converted into an electric signal by the photoelectric conversion element. Since this electric signal is the fingerprint itself, there is a possibility that the computer forges the fingerprint based on this signal or the fingerprint information of the individual leaks in its original form.

[0004]

In order to solve the above-mentioned problems, a fingerprint reading and collating system according to the present invention comprises an optical system which cannot reproduce a real image of a fingerprint and creates optical information including a fingerprint feature. , A photoelectric conversion element that receives the optical information from the optical system and converts it into an electrical signal, and a feature is extracted by performing a numerical operation on the electrical signal, and the fingerprint of whom the feature is collated with a database. It is composed of a numerical operation unit for determining whether or not.

In order to create optical information in which the real image of the fingerprint cannot be reproduced and which includes the features of the fingerprint, for example, Fourier transform may be performed. Specifically, when the optical system includes a rod lens array as an imaging lens, the pitch of the rod lens array, the distance between the rod lens array and the top plate on which the finger is placed, and the rod lens array and the photoelectric conversion element. By adjusting the distance between and, the Fourier transform image can be input to the photoelectric conversion element. As the optical system for creating the optical information, a means for illuminating a fingerprint, a means for limiting a part of light reflected from the fingerprint (for example, a slit), and a photoelectric conversion element for converting the limited fingerprint image. And a means for forming an image on (for example, a lens array).

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram showing an internal structure of a fingerprint reading / verifying system according to the present invention, FIG. 2 is a view as seen from the direction of arrow A in FIG. 1, and FIG. 3 is a diagram for explaining Fourier transform.

In the fingerprint reading and collating system, an optical system 2 and a photoelectric conversion element array 3 are arranged in a box 1, and a numerical operation section 4 is provided outside the box 1. The numerical operation unit 4 may be provided in the box 1.

The upper surface of the box 1 is covered with a plate 5,
A slit 6 is formed in the plate 5, and a transparent top plate 7 is further provided so as to overlap the plate 5. This transparent top plate 7 is for preventing dust from entering through the slit 6 and for allowing light to strike the finger 8 through the slit 6.

The optical system 2 includes an LED array 21 for illumination,
It is composed of an illumination lens 22, an imaging rod lens array 23, and a slit 6. The arrays 21 and 23 are one-dimensional, the illumination LED array 21 has a plurality of illumination LEDs arranged in a direction perpendicular to the paper surface in FIG. 1, and the imaging rod lens array 23 has a plurality of imaging rods perpendicular to the paper surface. A series of lenses. Incidentally, the photoelectric conversion element array 3
Also has a plurality of photoelectric conversion elements arranged in a direction perpendicular to the plane of the drawing.

Further, in the present invention, the characteristics of the lens elements constituting the rod lens array 23, particularly the meandering period (pitch), the distance between the rod lens array 23 and the transparent top plate 7, the rod lens array 23 and the light The Fourier transform image of the fingerprint image is input to the photoelectric conversion element by adjusting the distance from the electric conversion element array 3.

In the above, when a finger is placed on the transparent top plate 7 and illuminated through the LED array for illumination 21 and the illumination lens 22, the fingerprint has fine irregularities,
Since the convex portion of the fingerprint is in contact with the transparent top plate 7, the reflectance of the convex portion of the fingerprint is different from that of other portions, and a bright and dark fingerprint image is formed.

In the illustrated example, the rod lens array 23 is composed of three rod lenses. In this case, as shown in FIG. 3, the visual field 23a of the rod lens at the left end is limited by the slit 6, so that a lateral Fourier transform image is formed on the photoelectric conversion element, and lateral Fourier transform data d1 is obtained. To be Similarly, the field of view 23
horizontal Fourier transform data d corresponding to b and 23c
2, d3 is obtained. Further, by scanning the finger, Fourier transform data with a limited field of view is obtained as time series data.

These lateral Fourier transform data d1 and d
Since 2 and d3 do not include phase information, the original fingerprint cannot be reproduced from the data converted by the photoelectric conversion element.

A feature can be extracted by performing a numerical operation on the Fourier transform data obtained as described above, and the fingerprint can be judged by comparing the feature with a database in which personal information is registered in advance. .

In the illustrated example, the imaging rod lens array 23 has a one-dimensional shape. However, by making it into a two-dimensional shape, it is possible to make a determination by simply placing the finger without scanning. Good.

The image forming lens array is not limited to the rod lens array. It may be a lens array in which a plurality of convex lenses are stacked. In this case, a flat lens array in which a plurality of lenses are formed on a flat plate is easy to assemble the optical system,
Especially preferred. Generation of optical information that cannot reproduce a fingerprint image and includes fingerprint features is not necessarily limited to the method using the lateral Fourier transform. Various optical image conversions are possible by changing the shape of the slit, which is a means for limiting the fingerprint image, or by inserting an optical element for image conversion before entering the photoelectric conversion element. You may use it.

[0017]

As described above, according to the present invention, Fourier-transformed data that does not include phase information is input to the photoelectric conversion element without directly forming the fingerprint image on the photoelectric conversion element. Therefore, the fingerprint cannot be reproduced from the data. Since the data includes the fingerprint feature, it is possible to determine who the fingerprint is. Therefore, according to the present invention, personal fingerprint information is not leaked or forged as it is.

[Brief description of drawings]

FIG. 1 is a diagram showing an internal structure of a fingerprint reading / matching system according to the present invention.

FIG. 2 is a view in the direction of arrow A in FIG.

FIG. 3 is a diagram illustrating a Fourier transform.

[Explanation of symbols]

1 ... Box, 2 ... Optical system, 3 ... Electric conversion element array,
4 ... Numerical value calculation part, 5 ... Plate, 6 ... Slit, 7 ... Transparent top plate, 8 ... Finger, 21 ... Illumination LED array, 22 ... Illumination lens array, 23 ... Imaging rod lens array,
23a, 23b, 23c ... The field of view of the rod lens, d1,
d2, d3 ... Horizontal Fourier transform data.

Continued front page    F term (reference) 2F065 AA49 CC16 FF44 GG07 GG14                       HH05 JJ02 JJ25 LL10                 5B047 AA25                 5B085 AA08 AE26                 5L096 BA15 CA01 FA23 HA07 JA11

Claims (4)

[Claims] 1. An optical system that creates optical information that cannot reproduce a real image of a fingerprint and that includes characteristics of the fingerprint, and light that receives the optical information from the optical system and converts it into an electrical signal. A fingerprint reading / collating system comprising an electrical conversion element and a numerical computation unit for extracting a feature by numerically computing the electrical signal and collating the feature with a database to determine the fingerprint of the fingerprint. 2. The fingerprint reading and matching system according to claim 1, wherein the optical information created by the optical system is Fourier transform data. 3. The fingerprint reading and collating system according to claim 1, wherein the optical system for creating the optical information includes means for illuminating the fingerprint, means for limiting a part of light reflected from the fingerprint, and A fingerprint reading and collating system comprising: a means for forming a limited fingerprint image on a photoelectric conversion element. 4. The fingerprint reading and matching system according to claim 3, wherein the means for limiting a part of the light reflected from the fingerprint is a slit, and the limited fingerprint image is formed on the photoelectric conversion element. A fingerprint reading and collating system, wherein the means for performing is a lens array.