JPH1049675A - Individual body confirmation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an individual body authenticating device which is applicable to even the security device of a small-sized information processor such as a personal computer by providing linear electrodes with switching means alternately. SOLUTION: A finger input part has a substrate 11, a finger rest part composed of linear contact electrodes 12 which are provided in linear array on the surface of the substrate 11 and an analog switch circuit which has alternate switches 13 connected to those linear contact electrodes 12. Then, this analog switch circuit detects the resistance of the surface of a finger 14 between those linear contact electrodes 12 in order along the length of the finger 14. Consequently, the switched need not be connected electrically to all of couples of adjacent linear contact electrodes 12, so the number of the switches 13 can be decreased and wiring area is reducible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an individual authentication apparatus for performing individual authentication using an uneven pattern on the surface of an individual such as a human or an animal.

[0002]

2. Description of the Related Art As the information-oriented society becomes more sophisticated, the amount of information to be handled continues to increase. Much of this information should be kept confidential externally. For this reason, in recent years, there has been an increasing interest in personal authentication devices that perform authentication by identifying whether or not a person to be authenticated is an individual registered in advance for the purpose of entry / exit management of important facilities. Among them, fingerprint authentication is often used for personal authentication.

Conventionally, personal authentication devices using various types of fingerprints have been proposed. The most common type is a fingerprint input unit of the personal authentication device, which is a type that optically detects a fingerprint as a two-dimensional image signal. belongs to. In addition to this, several types have been proposed which detect a pressing force corresponding to the unevenness of a fingerprint as a two-dimensional image signal.

Further, a one-dimensional multi-valued projection signal (fingerprint information) in the longitudinal direction of the finger is formed from the image signal of the entire finger, and the one-dimensional multi-valued projection signal is extracted as a characteristic amount of the finger. A method of using as a signal for personal authentication has been proposed ("Personal authentication method using finger characteristics" Takeda, Uchida, Hiramatsu, Matsunami, IEICE Technical Report: PRU89-5
0).

According to this method, since a one-dimensional multi-valued projection signal is used, the data amount can be reduced and the processing algorithm can be simplified as compared with the case where a two-dimensional fingerprint image signal is used. For this reason, the signal processing speed is improved, and the time required for authentication verification can be reduced.

However, even in the case of a fingerprint input unit using this method, a two-dimensional image signal of the entire finger is once detected by the above-mentioned optical or pressure array sensor, and a one-dimensional fingerprint is obtained from the two-dimensional image signal. Is obtained.

In this case, a large amount of information is required to form an image signal of the entire finger, and a complicated algorithm is also required for signal processing for forming a multilevel projection signal. There is a problem that the time spent on the computer increases.

Further, when an optical type image input device is used, since the entire finger is input as an image signal by one operation, there is a problem that the whole device is expensive and large.

On the other hand, the present inventor has determined the resistance value between adjacent linear electrodes when the finger is pressed against a plurality of linear electrodes that are long in a direction perpendicular to the length direction of the finger. There has been proposed a personal authentication apparatus that uses a signal sequentially read and synthesized in the length direction as an authentication signal (Japanese Patent Application No. Hei 5-3234).
8).

According to this personal authentication device, no optical system is required, and the size and cost of the device can be reduced. As a result, application to security devices in small information processing devices such as personal computers and portable terminals, which are expected to be demanded as a new market in the future, in addition to entry / exit management, can be considered.

[0011] However, in this personal authentication device, since all two adjacent linear electrodes are connected to an external circuit, the number of switches for connection is large, and the area occupied by the wiring connected to each switch is large. Also increases.

For this reason, although it is advantageous in terms of miniaturization and cost reduction as compared with an optical personal authentication device, it is small in size and price.
With respect to application to security devices in small information processing devices such as personal computers, which are advantageous in that they are inexpensive, there has been a problem that miniaturization and cost reduction are insufficient.

[0013]

As described above, the conventional individual authentication device is advantageous in terms of miniaturization and cost reduction as compared with an optical personal authentication device, but is small and low in price. As for the application to a security device in a small information processing device such as a personal computer, which has an advantage, there is a problem that downsizing and cost reduction are insufficient.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an individual authentication device which is effective even when applied to a security device in a small information processing device such as a personal computer. It is in.

[0015]

[Means for Solving the Problems]

[Configuration] In order to achieve the above object, an individual authentication device according to the present invention (claim 1) provides an authentication that forms a one-dimensional electric signal distribution in response to a change in electric characteristics caused by contact with the surface of an individual. An individual authentication device comprising a pattern input unit and an individual authentication unit for performing individual authentication based on an output signal of the authentication pattern input unit, wherein the authentication pattern input unit is one-dimensionally arranged in a direction intersecting a longitudinal direction thereof. And three or more linear electrodes arranged in a line, and switching means for selectively connecting an electrode selected from the plurality of linear electrodes to an external circuit. A portion is provided at least every other one of the plurality of linear electrodes.

Further, another individual authentication device according to the present invention (claim 2) is the above-mentioned individual authentication device (claim 1).
The same number of linear electrodes exist between the linear electrodes provided with the switching means.

[Operation] In the present invention, since all of the two adjacent linear electrodes are not electrically connected, the number of switches can be reduced and the wiring area can be reduced.

Here, according to the research of the present inventor, even if all adjacent two linear electrodes are not connected to form a one-dimensional electric signal distribution, for example, one linear electrode can be formed. It has been found that sufficient collation accuracy can be obtained even if two linear electrodes sandwiching are connected to form a one-dimensional electric signal distribution.

Therefore, according to the present invention, downsizing and cost reduction can be achieved while maintaining high collation accuracy, so that an individual authentication device that is effective as a security device in a small information processing device such as a personal computer can be realized. Become like

[0020]

Embodiments of the present invention (hereinafter, referred to as embodiments) will be described below with reference to the drawings. FIG.
FIG. 1 is a block diagram illustrating a configuration of an individual authentication device according to an embodiment of the present invention.

The individual authentication device according to the present embodiment is roughly divided into a finger input unit 1 for inputting a finger pattern and finger irregularities.
(Authentication pattern input unit), a finger information calculation unit 2 that obtains finger information based on the output of the finger input unit 1, and a signal processing unit 3 that performs collation calculation and the like based on the output of the finger information calculation unit 2. It is composed of

Here, the finger information calculation unit 2 and the signal processing unit 3 serve as an individual authentication unit. These may be different in function but the same as a hard wafer. For example, when the individual authentication device of the present embodiment is applied to a personal computer, the finger information calculation unit 2 and the signal processing unit 3 are realized by, for example, a CPU or a memory of the personal computer and become a common hardware.

FIG. 2 is a schematic diagram showing a schematic configuration of the finger input unit. The finger input unit includes a substrate 11, a finger placement unit including a plurality of linear contact electrodes 12 (linear electrodes) provided in a one-dimensional array on the surface of the substrate 11, An analog switch circuit in which a switch 13 is connected to every other electrode 12 is provided, and a finger between these linear contact electrode electrodes 12 is formed by the three consecutive linear contact electrode electrodes 12 as a unit. The surface resistance can be sequentially detected in the longitudinal direction of the finger 14.

Here, it is usually preferable that the number of the linear contact electrodes 12, that is, the length in the longitudinal direction of the electrode array, completely includes the second joint from the tip of the finger 14. When the person to be authenticated presses the finger 14 against the finger rest, the convex portion forming the fingerprint enters the gap between the adjacent linear contact electrodes 12. As a result, the resistance between the adjacent odd-numbered (for example, the first and third) linear contact electrodes 12, that is, the resistance of the index surface between the continuous three linear contact electrodes 12 is:
It changes according to the amount of the convex portion of the finger that enters between the linear contact electrodes 12. The greater the amount of protrusions forming the fingerprint, the lower the resistance.

FIG. 3 is a diagram showing a specific circuit configuration of the finger input unit. The finger rest part has n linear contactor electrodes 12.
(12 ₁ ,..., 12 _n ). here,
A case where n is an odd number will be described, but the same applies to an even number.

The analog switch circuit includes two analog switch groups 10a and 10b. One end of the switch 13 of the analog switch group 10a is connected to one end of each of the odd-numbered linear contactor electrodes 12 excluding the _nth (last) linear contactor electrode 12n, and the other end is connected to the voltage source 15. Commonly connected.

On the other hand, one end of the switch 13 of the analog switch group 10b is connected to the odd-numbered end of the linear contact electrode 12 excluding the linear contact electrode 12 ₁ of 1 No. plane (first), other The end is connected to a reference resistor 17 via an analog switch group 16 and also to a sample / hold circuit 18.

The reference resistor 17 is composed of m resistors 19. One end of these resistors 19 is grounded, and the other end can be selectively connected to each switch of the analog switch group 16 by a reference resistance switching signal Sr. That is, the resistance value of the reference resistor 17 is variable.

When the finger 14 is placed on the finger rest, the analog switch groups 10a and 10b activate the timing control circuit 20.
, The first switch 13 of the analog switch group 10a, the first switch 13 of the analog switch group 10b, the second switch of the analog switch group 10a, and the second switch of the analog switch group 10b 13, the switch 13 is sequentially switched.

At this time, the potential difference V at both ends of the reference resistor 17 is obtained.
i is given by the following equation. Vi = Rr · V ₀ / (Rr + Ri) where Rr is the resistance value of the reference resistor 17 and V ₀ is the voltage source 1
The voltage value Ri of 5 indicates a resistance value between the i-th (i is an odd number) linear contact electrode 12 and an odd-numbered (i + 2) -th linear contact electrode 12 adjacent thereto. For example,
The resistance value between the first and third linear contactor electrodes 12 is shown.

In this embodiment, the resistance value R of the reference resistor 17 is
Since r is variable, the resistance value Rr can be selected so as to facilitate identification and detection of each potential difference Vi. The threshold may also be variable. By changing the resistance value Rr and the threshold value in this manner, it becomes possible to flexibly cope with the resistance Ri different for each person to be authenticated.

The sample / hold circuit 18 is supplied with a timing control signal St output from the timing control circuit 20 in the same manner as the analog switch groups 10a and 10b, and operates in synchronization with the analog switch groups 10a and 10b.

That is, the sample and hold circuit 18
Sequentially reads the potential difference Vi between both ends of the reference resistor Rr in the length direction of the finger, and sends the result to the finger information calculation unit 2. The finger information calculator 2 calculates the sum of the potential differences Vi as finger information.

Here, when the potential differences Vi are plotted in time series, a one-dimensional potential distribution as shown in FIG. 4 is formed. Unlike the conventional one-dimensional potential distribution, this one-dimensional potential distribution is not obtained by sequentially connecting all adjacent linear contactor electrodes 12, but is equivalent to a multilevel projection signal in the longitudinal direction of the finger. I found it.

Therefore, according to the present embodiment, accurate finger information (sum of each potential difference Vi) can be obtained even with a small number of switches and a small wiring area. It is possible to realize a personal authentication device that is effective for application.

In FIG. 4, the horizontal axis represents the positions of the linear contact electrodes 12 _i and 12 _2i-1 , and the vertical axis represents the potential difference Vi. The finger information calculation unit 2 sends the finger information to the signal processing unit 3. The signal processing unit 3 collates the finger information (measurement data) with pre-registered finger information (registration data) to determine whether or not the user is the person. That is, if the difference between the measurement data and the registered data is smaller than a predetermined value (threshold), it is determined that the user is the subject, and if the difference is the same or larger, the user is determined to be another person.

Registration of registration data is performed by placing a finger on a finger rest and collecting finger information as in the case of collation. At this time, signal processing such as filtering processing for removing noise or the like superimposed on the potential difference Vi may be performed.

FIG. 5 is an equivalent circuit showing a state where a finger is placed on the finger rest of the present embodiment (the present invention) and a comparative example. FIG. 5A shows the present invention, and FIG. (C) shows Comparative Examples 1 and 2, respectively.

In the figure, the resistance caused by the protrusion forming the fingerprint entering between the linear contact electrodes 12 is represented by R1 to R3.
Indicated by When the arrangement pitch of the linear contact electrodes 12 is d, the resistors R1 and R2 exist over a length of 2d, and the resistor R3 exists over a length of d.

In the case of the present invention, as shown in FIG.
Switch 13 connected line shaped contact shoe in _first electrode 12 ₁ and the switch 13 between the linear contact electrode 12 ₃ connected to _3, one linear contacts of which are not connected to the switch electrode 12 ₂ there exist, resistance between the switch 13 ₁ and the switch 13 _3, R1 // R2 + R1 // R2 // R3 , and the resistor R3 is reflected values.

Here, the symbol // represents a parallel resistance and R1
// R2 = 1 / (1 / R1 + 1 / R2). For Comparative Example 1, the line between the 5 (b), the switch 13 linear contact electrodes 12 ₁ connected to ₁ and the switch 13 linear contact electrode 12 ₃ connected to the ₃ since Jo contacts electrode is not present, the resistance between the switch 13 ₁ and the switch 13 ₃ is a 2R1 // 2R2. Therefore, the resistance R3 that actually exists is not reflected in the finger information, and the accuracy of the finger information is reduced as compared with the present invention.
Matching accuracy will be reduced.

Further, in Comparative Example 2, as shown in FIG. 5 (c), the linear contact electrodes 12 _1, 12 _2, 12 ₃ to the switch 13, respectively _1, 13 _2, 13 ₃ provided, that is,
Since a switch for all linear contact electrodes, the resistance between the switch 13 ₁ and the switch 13 _3, R1 /
/ R2 // R3, and the finger information reflecting the resistance R3 is obtained as in the present invention.

However, since the number of switches and the number of wirings are larger than in the case of the present invention, there is a problem that mounting on a personal computer, a portable terminal or a card is hindered, and the cost is also increased. .

The inventor of the present invention has proposed a personal authentication device using the finger rest shown in FIG. 5A (the present invention), a personal authentication device using the finger rest shown in FIG. 5B (Comparative Example 1), and FIG. In order to evaluate the personal authentication device (Comparative Example 2) using the finger placement of c), the personal recognition rate of each personal authentication device was measured.

Specifically, the arrangement pitch d is 0.2 mm,
The number of linear contactor electrodes was set to 255 (therefore, the length was 51 mm), and data of 10 testers were taken for each of 50 testers. It was measured. Further, the measurement conditions, that is, the threshold value, the reference resistance, and the surrounding environment (temperature, humidity, etc.) were set to be substantially the same.

As an analog switch, 16 channels
Of the present invention, the number of which is
In the case of Comparative Example 2, the number is 16
Individual. As a result, the cost of the comparative example 2 was about twice as large as that of the other examples because the printed circuit board for mounting the analog switch and the processing circuit became large and the number of wirings increased.

The results of the collation characteristic evaluation are as follows.
That is, in the case of the present invention, the personal identification rate is 90%,
A value almost equivalent to that of a commercially available optical system was obtained. On the other hand, in the case of Comparative Example 1, the identity recognition rate was 78%, which was about 1
It decreased by 2%. On the other hand, in the case of Comparative Example 2, the personal identification rate was 91%, which was only slightly higher than that of the present invention.

The present invention is not limited to the above embodiment. For example, in the above-described embodiment, every other switch 13 is provided, but every other switch 13 may be provided as shown in FIG.

Further, switches 13 are provided on all the linear contactor electrodes 12 where the first and second joints of the finger, which greatly affect the accuracy of the finger information, are provided. The switch 13 may be provided every two or more.

Further, as shown in FIG. 7, a mark 21 indicating the outline of the finger may be printed in the area where the linear contact electrode 12 is formed. By placing a finger with the mark 21 as a guide during finger input, finger information with high reproducibility can be obtained.

Further, the longitudinal direction of the linear contact electrode 12 and the arrangement direction do not necessarily have to be orthogonal to each other, and may intersect obliquely. Further, in the above embodiment, the finger is used, but an uneven pattern of the skin of another part may be used.

In the above embodiment, the case of human authentication has been described. However, the present invention can also be applied to an individual authentication device for authenticating animals such as livestock. In addition, various modifications can be made without departing from the technical scope of the present invention.

[0053]

As described above, according to the present invention, it is possible to reduce the size and cost of the apparatus while maintaining high matching accuracy. Therefore, it is possible to realize an individual authentication device that is also effective as a security device in a small information processing device such as a personal computer.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an individual authentication device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a schematic configuration of a finger input unit of the individual authentication device according to one embodiment of the present invention;

FIG. 3 is a diagram showing a specific circuit configuration of a finger input unit of the individual authentication device according to the embodiment of the present invention;

FIG. 4 is a diagram showing a potential difference distribution obtained by a finger input unit of the individual authentication device according to one embodiment of the present invention.

FIG. 5 is an equivalent circuit diagram showing a state where a finger is placed on a finger rest of the present invention and a comparative example.

FIG. 6 is a diagram showing a modification of the finger input unit in FIG. 2;

FIG. 7 is a diagram showing still another modification of the finger input unit of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Finger input part (authentication pattern input part) 2 ... Finger information calculation part (individual authentication part) 3 ... Signal processing part (individual authentication part) 10a, 10b ... Analog switch group 11 ... Substrate 12 ... Linear contact electrode ( 13 ... switch 14 ... finger 15 ... voltage source 16 ... analog switch group 17 ... reference resistor 18 ... sample and hold circuit 19 ... resistor 20 ... timing control circuit 21 ... mark

Claims (2)

[Claims] 1. An authentication pattern input unit for forming a one-dimensional electric signal distribution in response to a change in electrical characteristics caused by contact with the surface of an individual, and individual authentication for performing individual authentication from an output signal of the authentication pattern input unit. And an authentication pattern input unit, wherein the authentication pattern input unit comprises three or more linear electrodes one-dimensionally arranged in a direction intersecting the longitudinal direction thereof, and Switching means for selectively connecting an electrode selected from among the linear electrodes to an external circuit, at least a part of the switching means being provided at least every other one of the plurality of linear electrodes. An individual authentication device characterized by the above-mentioned. 2. The individual authentication device according to claim 1, wherein the same number of linear electrodes exist between the linear electrodes provided with the switching means.