JP2002083290A - Fingerprint collating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin fingerprint collating device. SOLUTION: In this fingerprinting collating device, an operation changeover part 103 calculates black ratio from shading gradation data detected by detection cells 101a in a small area 110, makes a fingerprint sensor 101 execute full-area measurement, when the calculated black ratio exceeds a value A, and makes a fingerprint collation part 104 certify the fingerprint image read.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a fingerprint matching device for matching a fingerprint of a finger.

[0002]

2. Description of the Related Art In the progress of the information society and the environment of the modern society, interest in security technology is increasing. For example, in the information-oriented society, personal authentication technology for system construction such as electronic cashing is an important key. Research and development of authentication technology to prevent theft and unauthorized use of cards are also being actively conducted (for example, Yoshimasa Shimizu et al. Technical report of IE
ICE, OFS92-32, p25-30 (1992)).

[0003] There are various authentication methods using fingerprints and voice prints as such authentication methods for preventing unauthorized use. Among them, many fingerprint authentication technologies have been developed. . In fingerprint authentication, a fingerprint measurement device capable of inputting a fingerprint image and a collation device for collating a fingerprint image read by the fingerprint measurement device with registered feature information are required.

As shown in FIGS. 6 (a) and 6 (b), the fingerprint measuring device has a structure in which a fingerprint sensor 601 for reading a fingerprint image is arranged in a groove 603 corresponding to the shape of a finger on an upper plate 602. ing. A mechanical switch 605 is arranged below the fingerprint sensor 601, and the fingerprint sensor 601 is mounted on the mechanical switch 605. Therefore, when the fingerprint sensor 601 is pressed, the fingerprint sensor 601 is pressed.
At the same time, the mechanical switch 605 is also pressed. When the mechanical switch 605 is pressed, the measurement (image reading) operation of the fingerprint sensor 601 starts, and fingerprint authentication is performed. That is, when the mechanical switch 605 is pressed,
The fingerprint measurement device starts a fingerprint authentication operation.

[0005]

However, the fingerprint measuring device shown in FIG. 6 has a problem that the fingerprint measuring device cannot be formed thin because the mechanical switch 605 is used. Since a mechanical switch cannot be made too thin, a fingerprint measurement device using the mechanical switch cannot be mounted on an IC card or the like, and its application range is limited.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to make a fingerprint collating apparatus thinner.

[0007]

According to the present invention, there is provided a fingerprint collating apparatus comprising: a fingerprint sensor for reading a fingerprint pattern as image data composed of a plurality of pixels consisting of data indicating shading between white and black; A fingerprint dictionary in which the pattern data of the fingerprint are stored, a comparison and collation unit that compares and compares the pattern data of the fingerprint stored in the fingerprint dictionary with the image data read by the fingerprint sensor, and a standby state in which the fingerprint sensor reads the image. An operation switching unit that switches between a state and an authentication operation state in which comparison and comparison by the comparison and comparison unit using the image data read by the fingerprint sensor is performed according to the state of the image data read by the fingerprint sensor in the standby state. is there. According to the present invention, when a finger is placed on the fingerprint sensor, the fingerprint authentication operation starts even if the fingerprint sensor does not move in the vertical direction or the like.

In the above invention, the image data read by the fingerprint sensor in the standby state only needs to be read in a partial area of the fingerprint sensor. Further, the operation switching unit performs the authentication operation when the number of pixels in a state other than white among the pixels constituting the image data read by the fingerprint sensor in the standby state is equal to or greater than a preset threshold. Switch to

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram (a) showing a configuration of a fingerprint matching device according to an embodiment of the present invention, and a plan view partially showing the configuration. FIG.
As shown in (a), a fingerprint sensor 101 for reading a fingerprint pattern as image data, and a fingerprint image processing unit 102 for performing image processing such as binarization processing on the read image data.
And In addition, the fingerprint collation apparatus includes a fingerprint image processed by the fingerprint image processing unit 102 and the fingerprint dictionary 1.
And a fingerprint collation unit 104 for comparing and collating with the registered fingerprint image stored in the storage unit 05. In addition, the fingerprint matching device of the present embodiment includes an operation switching unit 103 that switches operations according to the state of image data read by the fingerprint line 101.

First, the fingerprint sensor 101 will be described. In the fingerprint sensor 101, detection cells 101a for detecting a distance to an object disposed above are arranged in a matrix. The detection cell 101a detects, for example, capacitance. The detection cell 101a is, for example, “0” when the upper object is in contact with the object, “255” when the upper object is at a distance where the upper object cannot be detected, Correspondingly, a multi-level signal of 256 gradations is output.

When the fingerprint portion of the finger is placed (contacted) on the fingerprint sensor 101, the detection cells 101a
Then, the convex portion outputs a value closer to “0”, and the concave portion outputs a value closer to “255”, corresponding to the unevenness of the upper fingerprint. By reflecting the matrix arrangement state of the detection cells 101a and combining the output values of the above-described detection cells 101a with shading, the image data corresponding to the fingerprint pattern as shown in FIG. 2 can be obtained. In addition, when a fingerprint is detected by the fingerprint sensor 101, the number of detection cells 101a (pixels) for each gray level to be detected is as shown in the histogram of FIG. In FIG. 3, gradation 0 indicates black, and gradation 255 indicates white.

In this embodiment, the operation switching unit 103
Determines that the fingerprint detection target finger has been placed on the fingerprint sensor 101 based on the grayscale data detected by each of the detection cells 101a in the small area 110 of the fingerprint sensor 101. Is switched. Hereinafter, the operation of the fingerprint matching device including the operation switching unit 103 will be described with reference to the flowchart of FIG. First, in step S1, the operation switching unit 103 sets the small area 1 shown in FIG.
The image is read only in the area of No. 10. When the finger to be subjected to fingerprint collation is not placed on the fingerprint sensor 101, the gray scale of the image data read by the detection cell 101a in the small area 110 is all 255 representing white.

Next, in step S2, the operation switching unit 103 determines “black ratio = (grayscale 0 to 254) based on the grayscale data detected by the detection cell 101a in the small area 110.
Is calculated as an index indicating the state of the image data read by the fingerprint sensor 10. Next, step S
In 3, the operation switching unit 103 determines whether the calculated black ratio is larger than a preset value A. The value A is, for example, 0.3. When the finger is placed, small area 1
Some of the detection cells 101a in FIG.
Since data other than 55 is output, the black ratio exceeds the value A.

If it is determined in step S3 that the calculated black ratio exceeds the value A, the operation switching unit 103 first causes the fingerprint sensor 101 to perform the whole area measurement (step S4). When the fingerprint sensor 101 measures the entire area and reads the fingerprint image to be authenticated, in step S5, the operation switching unit 103 causes the fingerprint collation unit 104 to authenticate the read fingerprint image. This authentication determines whether the read fingerprint image matches the registered fingerprint image in the fingerprint dictionary 105,
This is performed by making a determination within a predetermined allowable error. on the other hand,
If it is determined in step S3 that the calculated black ratio is equal to or smaller than the value A, the process returns to step S1, and the operation switching unit 10
No. 3 causes the detection operation to be performed only in the area of the small area 110.
That is, as long as the calculated black ratio is equal to or less than the value A, the operation is not switched.

As described above, in the present embodiment,
The small area 110 of the fingerprint sensor 101 is always in the detection state,
When the detection result in the small area 110 is in a predetermined state, it is determined that the finger is placed on the fingerprint sensor 101. Further, when it is determined that the finger is placed, the fingerprint authentication operation of the finger placed on the fingerprint sensor 101 is started. As a result, according to the present embodiment, it is possible to switch between the standby state and the fingerprint authentication operation state without using a mechanical switch.

In the above description, whether or not a finger is placed in a small area at the center of the fingerprint sensor 101 is detected. However, the present invention is not limited to this. The detection of the placement of the finger may be performed in a rectangular area passing through the center of the fingerprint sensor 101. Further, the detection that the finger is placed may be performed in the entire area of the fingerprint sensor 101. As described above, in the case of a fingerprint sensor in which a plurality of detection cells for detecting capacitance are arranged in a matrix, detection in a small area is faster than detection in the entire area. Becomes possible. In addition, the charge transfer element (CC
When an image sensor such as D) is used as a fingerprint sensor,
Whether the detection is performed in the entire area or in the small area, there is no large difference in the time required for the detection.

In the above embodiment, when the operation switching unit switches between the standby state and the authentication state,
Although the black ratio was used as an index indicating the state of the image data read by the fingerprint sensor in the standby state,
It is not limited to this. As an index, for example, gradation 0 to 0
The standby state and the authentication state may be switched by using a numerical value obtained by dividing the number of detection cells included in 100 by all the detection cells. FIG. 5A shows a histogram indicating the number of detected cells for each gradation of light and shade to be detected.
5 (b) is multiplied by the set weight (b) to derive a distribution as shown in FIG. 5 (c). And the authentication state may be switched. FIG.
In (b), a weight that changes linearly from gradation 0 to 255 is used, but a weight function other than a temporary straight line, such as a weight that changes like a quadratic curve, may be used.

[0018]

As described above, according to the present invention,
Even without using a mechanical switch, since the fingerprint authentication operation is started by detecting the state where the finger is placed, an excellent effect that the fingerprint collation device can be formed thinner can be obtained.

[Brief description of the drawings]

FIG. 1A is a configuration diagram illustrating a configuration of a fingerprint matching device according to an embodiment of the present invention, and FIG. 1B is a plan view partially illustrating a fingerprint sensor 101;

FIG. 2 is a diagram illustrating an example of read fingerprint image data.

FIG. 3 is a histogram showing the number of detection cells 101a (pixels) for each shade of gray in read image data.

FIG. 4 is a flowchart showing an operation of the fingerprint matching device according to the embodiment of the present invention.

FIG. 5 is an explanatory diagram for describing switching between a standby state and an authentication state.

FIG. 6 is a plan view (a) and a cross-sectional view (b) showing a partial configuration of a conventional fingerprint matching device.

[Explanation of symbols]

101: fingerprint sensor, 102: fingerprint image processing unit, 103
... An operation switching unit; 104; a fingerprint collation unit;

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinnori Konaka 2-3-1 Otemachi, Chiyoda-ku, Tokyo Inside Nippon Telegraph and Telephone Corporation (72) Inventor Yukio Okazaki 2-chome Otemachi, Chiyoda-ku, Tokyo No. 3-1 Nippon Telegraph and Telephone Corporation (72) Inventor Riki Yamaguchi 2-3-1 Otemachi, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Hiroki Shuto Otemachi, Chiyoda-ku, Tokyo 2-3-1, Nippon Telegraph and Telephone Corporation F term (reference) 4C038 FF01 FF05 FG00 5B043 BA02 CA05 DA04 EA05 GA01 5B047 AA25 AB02 BA02 BB10 CB17 CB21 DC07

Claims (3)

[Claims] 1. A fingerprint sensor for reading a fingerprint pattern as image data composed of a plurality of pixels consisting of data indicating shading between white and black; a fingerprint dictionary storing fingerprint pattern data; A comparison / matching unit that compares and matches the fingerprint pattern data stored in the fingerprint dictionary with the image data read by the fingerprint sensor; and a standby state in which the fingerprint sensor reads an image.
An operation switching unit that switches between an authentication operation state in which the comparison and collation unit performs comparison and collation using the image data read by the fingerprint sensor according to a state of the image data read by the fingerprint sensor in the standby state. A fingerprint matching device characterized by the above-mentioned. 2. The fingerprint matching device according to claim 1, wherein the image data read by the fingerprint sensor in the standby state is data read in a partial area of the fingerprint sensor. Collation device. 3. The fingerprint matching device according to claim 1, wherein the operation switching unit is in a state other than white among the pixels constituting the image data read by the fingerprint sensor in the standby state. A fingerprint collation device that switches to the authentication operation when the number of pixels is equal to or greater than a preset threshold value.