JPH0981728A - Individual authenticating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the individual authenticating device which can obtain high collation precision even for a person which is small in sweating amount of a finger surface by effectively removing spike noise included in a signal for authentication. SOLUTION: This device has feature extraction parts 11-13 which extracts features of a finger from a distribution of resistance values between adjacent electrodes of a linear electrode array obtained when the finger is brought into contact along the array direction of the linear electrode array and outputs feature pattern data, a spike noise removal part 14 which removes spike noise from the feature pattern data, and a collation part 15 which compares and collates the feature pattern data outputted through the spike noise removal part with previously registered feature pattern data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a personal authentication device for performing personal authentication using the physical characteristics of a person to be authenticated.

[0002]

2. Description of the Related Art In recent years, there has been an increasing interest in personal authentication devices that identify whether a person to be authenticated is a preregistered individual for authentication in order to manage entrance and exit of important facilities. Generally, in these personal authentication devices, fingerprints are often used to identify individuals.

In the fingerprint input device used in such a personal identification device, various methods have been conventionally proposed for detecting a fingerprint. The most common of these is a method of optically detecting a fingerprint as a two-dimensional image signal.
Furthermore, some methods have been proposed in which the pressing force corresponding to the unevenness of the fingerprint is detected as a two-dimensional image signal.

A method has also been proposed in which an image signal of the entire finger is used to form a one-dimensional multi-valued projection signal in the longitudinal direction of the finger, and this signal is used as an authentication signal as a characteristic amount of the finger.
("Personal authentication method using finger characteristics" Takeda, Uchida, Hiramatsu, Matsunami, IEICE Technical Report: PRU89
-50). According to this method, since the authentication signal is one-dimensionally configured, it is possible to reduce the data amount as compared with the fingerprint image which is a two-dimensional signal, and it is possible to simplify the processing algorithm. For this reason, the signal processing speed is improved, and the time required for authentication verification can be reduced.

Further, a plurality of linear electrodes that are long in a direction orthogonal to the lengthwise direction of the finger are arranged in the lengthwise direction of the finger to form a linear electrode array, and the finger is pressed against the linear electrode array. There is also proposed an individual authentication device that uses a signal obtained by sequentially reading and combining resistance values between adjacent electrodes in the finger length direction as an authentication signal. According to this device, an optical system is not required, and the device can be downsized and the cost can be reduced.

However, in the personal identification device for detecting the physical characteristics of the person to be authenticated such as the fingerprint or the characteristics of the finger as described above, the signal strength of the obtained authentication signal largely depends on the amount of perspiration from the finger surface. are doing. Further, there is an individual difference in the amount of sweat on the finger surface. Therefore, when a person to be authenticated with extremely small amount of sweat on the finger surface is measured, the frequency of spike noise in the authentication signal due to the perspiration that occurs locally on a part of a dry finger. Becomes higher. FIG.
Is an example of the authentication signal in which such spike noise is generated. In addition, in FIG. 4, the horizontal axis represents the position of two adjacent electrodes, and the vertical axis represents the output Vi of the authentication signal that varies according to the change in the resistance value between the two adjacent electrodes.

As described above, such spike-like noise is considered to be caused by local sweating on a part of a dry finger, but the sweating state on the finger surface is measured every time even in the same individual. Therefore, there is a problem that the reproducibility of spike-like noise is low and the signal strength of the spike-like noise also varies greatly with each measurement. Therefore, there is a problem that such noise is erroneously recognized as feature information at the time of matching and the matching accuracy is lowered.

[0008]

As described above, instead of using an image signal, a plurality of linear electrodes that are long in the direction orthogonal to the length direction of the finger are arranged in the length direction of the finger to form a linear shape. In the personal authentication device that constitutes an electrode array and sequentially reads and combines the resistance value between adjacent electrodes when the finger is pressed against the linear electrode array in the length direction of the finger as the authentication signal, There is a problem that spike-like noise is likely to occur when a person to be authenticated with a small amount of sweat on the surface is measured, and collation accuracy decreases.

The present invention has been made in consideration of the above circumstances, and effectively removes spike-like noise included in an authentication signal, so that even a person to be authenticated who has a small amount of sweat on the finger surface can authenticate it. An object of the present invention is to provide a personal identification device that can obtain high matching accuracy.

[0010]

According to the present invention, a feature of a finger is extracted from a distribution of resistance values between adjacent electrodes of the linear electrode array due to contact of the finger along the array direction of the linear electrode array. Characteristic extraction means for outputting characteristic pattern data, spike-shaped noise removing means for removing spike-shaped noise of the characteristic pattern data, and characteristic pattern data output via the spike-shaped noise removal means are registered in advance. It is characterized in that it is provided with a collating means for comparing and collating the existing characteristic pattern data.

As described above, according to the present invention, the finger feature is extracted from the distribution of the resistance value between the adjacent electrodes of the linear electrode array, is output as the feature pattern data, and is then included in the feature pattern data. Spike noise is removed. Then, the characteristic pattern data output via the spike-shaped noise removing means and the previously registered characteristic pattern data are compared and collated. At this time, spike noise is removed from both feature pattern data, so only the feature pattern of the finger is compared and collated without considering the effect of perspiration on the finger surface of the authenticated person when measuring the feature pattern data. can do. That is, high matching accuracy can be obtained regardless of individual differences in sweating of the finger of the person to be authenticated or the state of sweating of the finger during measurement.

The personal identification device according to one aspect of the present invention determines the characteristics of a finger from the distribution of the resistance value between the adjacent electrodes of the linear electrode array due to the contact of the finger along the array direction of the linear electrode array. Feature extracting means for extracting and sequentially outputting feature pattern data that changes along the array direction of the linear electrode array, feature pattern data sequentially output from the feature extracting means, and the array direction of the linear electrode array. If two differences between the preceding and following characteristic pattern data are obtained, and if any of these two differences is larger than a predetermined threshold value, then one of the preceding and following characteristic pattern data is output, and if not, the characteristic pattern data is output. Spike noise removing means for removing spike noise by outputting as it is, and a characteristic pattern output through the spike noise removing means Characterized by comprising a verification means for comparing compares the feature pattern data is data registered in advance.

In the personal authentication device configured as described above,
The finger feature is extracted from the distribution of the resistance value between the adjacent electrodes of the linear electrode array, and the feature pattern data that changes along the array direction of the linear electrode array is sequentially output. And
These characteristic pattern data are compared with the characteristic pattern data before and after the characteristic pattern data, and based on the characteristic pattern data, processing for removing spike noise is performed. That is, if a certain characteristic pattern data is spike noise, it is considered that the value of the characteristic pattern data is sufficiently larger than the values of the characteristic pattern data before and after the characteristic pattern data. By comparing the difference with the characteristic pattern data before and after that with a predetermined threshold value, it is detected whether or not the characteristic pattern data is spike noise, and if it is spike noise, it is removed.

At this time, by setting the threshold appropriately,
The characteristic pattern that actually changes from the characteristic of the person to be authenticated can be left as it is, and only the spike-shaped noise contained in it can be detected. Then, when certain characteristic pattern data is detected as spike noise, the characteristic pattern data is not output, and one of the characteristic pattern data before and after that is output instead to remove the spike noise. Since the three adjacent feature pattern data obtained along the array direction of the linear electrode array are data in a range close to each other in the array direction, instead of the feature pattern data in which spike noise is detected, It can be considered that even if one of the preceding and following characteristic pattern data is output, it is substantially the same as the original characteristic pattern.

A personal identification device according to another aspect of the present invention includes a linear electrode array in which a plurality of linear electrodes are arranged,
Detecting means for detecting a distribution of resistance values between adjacent electrodes of the linear electrode array due to contact of a finger along the array direction of the linear electrode array, and logarithmic amplification for logarithmically amplifying an output signal of the detecting means. Means, signal processing means for performing signal processing on the output signal of the logarithmic amplification means, and sequentially outputting characteristic pattern data of the finger, and the characteristic pattern output signal output from the signal processing means and the characteristic pattern registered in advance. It is characterized by comprising a collating means for comparing and collating with data. The signal processing means performs filtering processing, analog-digital conversion, and the like on the output signal logarithmically amplified by the logarithmic amplification means, and outputs it as a characteristic data pattern.

In the personal authentication device configured as described above,
By uniformly logarithmically amplifying the output signal that indicates the characteristics of the finger of the person to be authenticated, a component with an extremely large amplitude, such as spike-like noise, is compressed compared to the signal that depends on the original characteristic pattern. Therefore, the intensity ratio of spike noise can be reduced.

According to still another aspect of the present invention, there is provided a personal identification device, which is characterized by a distribution of resistance values between adjacent electrodes of the linear electrode array due to contact of the finger along the array direction of the linear electrode array. Characteristic extracting means for extracting the characteristic pattern data and outputting the characteristic pattern data, a heating resistor provided under the linear electrode array, the characteristic pattern data output from the characteristic extracting means, and the characteristic pattern registered in advance. It is characterized by comprising a collating means for comparing and collating with data.

In the personal authentication device configured as described above,
A heating resistor is provided below the linear electrode array that is brought into contact with the finger of the person to be authenticated, for example, located in a gap on the electrode surface of the linear electrode array. When the heating resistor is energized and heated when extracting the characteristics of the finger of the person to be authenticated, the heat is transferred to the finger of the person to be authenticated who is in contact with the linear electrode array, which promotes perspiration on the entire finger surface of the person to be authenticated. Be done. As described above, the cause of the spike noise is the perspiration that locally occurs on a part of a dry finger. Therefore, sweating the entire finger surface eliminates the local perspiration, and the spike noise is generated. Can be prevented.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 is a view showing the schematic arrangement of a personal authentication apparatus according to the first embodiment of the present invention. As shown in FIG. 1, the personal identification device according to the embodiment has a feature input unit 11 for inputting a feature of a finger, and a feature information calculation for obtaining feature information of the finger as an electric signal via the feature input unit 11. Section 12, a signal processing section 13 that outputs finger characteristic pattern data by performing filtering processing and analog-digital conversion on the output of this characteristic information calculation section 12, and if spike-like noise occurs in this output The spike-shaped noise removal processing unit 14 for removing this
And the feature pattern data output from the spike noise removal processing unit 14 and the feature pattern data registered in advance are compared and registered, and the new feature pattern data from which the spike noise is removed is registered and collated. And the unit 15.

2A and 2B are diagrams showing a schematic structure of the feature input section 11, where FIG. 2A is a side view and FIG. 2B is a plan view. The linear electrode array 22 is formed on the surface of the insulating substrate 21. The linear electrode array 22 has a plurality of linear electrodes arranged in a one-dimensional array. As the material of the substrate 21, for example, glass epoxy or other printed circuit board material, ceramic, or a thin metal plate with an insulating coating is used. Examples of the electrode material of the linear electrode array 22 include Cu thin film, Au thin film, Ni plating film, P
A conductive material such as a t-thin film or a Pd-thin film that is not easily attacked by body fluid such as sweat from the human body is used.

The linear electrode array 22 is to be touched by the finger of the person to be authenticated, and the electrode interval is set to about 0.1 mm in consideration of the pitch of the irregularities forming the fingerprint. The length of the linear electrode array 22 in the array direction (array length) is set so as to completely include the second joint from the tip of the finger. Since the electrode interval is constant, the array length can be adjusted by the number of electrodes. Further, the feature input unit 11 is arranged with the surface of the linear electrode array 22 exposed so that the user can bring his / her finger into contact with the linear electrode array 22. At the time of feature input, the finger 23 is pressed along the array direction of the linear electrode array 22, that is, substantially orthogonal to the individual longitudinal directions of the electrodes.

FIG. 3 is a diagram showing a circuit configuration of the feature input unit 11 and the feature information calculation unit 12 in FIG. As shown in FIG. 3, the resistance value between adjacent electrodes when a finger is pressed onto the linear electrode array 22 (shown as n + 1 electrodes 21-1 to 22-n + 1 in FIG. 3) is shown in FIG. By sequentially reading in the length direction, a signal output representing the characteristics of the finger is obtained. That is, when the person to be authenticated presses his / her finger on the linear electrode array 22, two adjacent electrodes 22i, 22i +
The convex portion forming the fingerprint enters the space between 1 (i = 1, 2, ..., N). In this case, the resistance value Ri between the two adjacent electrodes 22i and 22i + 1 changes according to the amount of the convex portion of the finger that enters the inter-electrode space. That is, the greater the amount of the protrusions that enter the inter-electrode space, the lower the value of Ri.

One end of the analog switch group 2a is connected to one end of each of the electrodes 22-1 to 22-n.
The other ends of −2 to 22-n + 1 are connected to one end of the analog switch group 2b, respectively. Electrodes 22-1 to 22
-N + 1 number of analog switch groups 2a, 2b
Since it has multiple channels, the circuit can be downsized by configuring these with an analog multiplexer IC. The analog switch groups 2a and 2b receive the timing control signal St output from the timing control circuit 3 to change the combination of two electrodes to 22.
-1 and 22-2, 22-2 and 22-3, ... 22-n and 2
2-n + 1 is sequentially switched.

The other end of the analog switch group 2b is commonly connected, and the reference resistor Rref is connected to this common connection point. The other end of the analog switch group 2a is commonly connected, and two adjacent electrodes 22i, 2 are connected to this common connection point.
A voltage source Vo for applying a voltage is connected to a series circuit between 2i + 1 and a reference resistor Rref. At this time, the reference resistance R
The potential difference Vi across ref is given by the following equation.

Vi = Rref.Vo / (Rref + Ri) Further, a sample hold circuit 4 is further connected to the common connection point at the other end of the analog switch group 2b. The sample and hold circuit 4 is the timing control circuit 3
The timing control signal St output from the reference resistor Rref is supplied to the timing control signal St, and the potential difference Vi across the reference resistor Rref is sequentially read in synchronization with the switching operation of the analog switch groups 2a and 2b. The analog switch groups 2a and 2b, the timing control circuit 3, the sample and hold circuit 4, the reference resistance Rref, and the voltage source Vo constitute a characteristic information calculation unit 12.

That is, in the characteristic information calculation unit 12,
The analog switch groups 2a and 2b have two adjacent electrode combinations 22-1 and 22-2 whose resistance values are to be detected,
22-2 and 22-3, ... 22-n and 22-n + 1 are sequentially switched to apply a voltage to the series circuit of the resistance Ri and the reference resistance Rref between two adjacent electrodes, and the sample and hold circuit 4 The potential difference Vi across the reference resistor Rref is sequentially read in the finger length direction to obtain a signal output. FIG. 4 is a diagram in which the potential difference Vi thus read is plotted in a time series, and a part thereof is enlarged and shown. In FIG. 4, the horizontal axis represents the positions of two adjacent electrodes, and the vertical axis represents the potential difference Vi. As shown in FIG. 4, a pattern equivalent to the multivalued projection signal in the longitudinal direction of the finger is obtained. Further, as shown in the enlarged portion, spike-like noise occurs at i = k.
This indicates that spike noise was generated when reading the resistance value between the electrodes 22k and 22k + 1.

Next, the spike noise removing operation in this embodiment will be described with reference to the flow chart shown in FIG. First, the feature pattern data A () obtained by inputting the feature of a finger in the feature input unit 11, obtaining feature information in the feature information calculation unit 12, and performing filtering processing and analog-digital conversion in the signal processing unit 13. i) = (V1, V2
, ..., Vn) are input to the noise removal calculation processing unit 14 (step S1). Now, this characteristic pattern data A
It is assumed that (i) contains spike noise.

Next, with respect to the variable i of the characteristic pattern data A (i), the removal of spike noise is started with an initial value of 2 (step S2). As will be described later, this is due to three characteristic pattern data V that are adjacent to each other in this embodiment.
Since i-1, Vi, and Vi + 1 are compared with each other, at least one characteristic pattern data Vi-1 is required in advance to judge whether or not a certain characteristic pattern data Vi is spike noise. Because there is.

Here, the determination as to whether or not the certain characteristic pattern data Vi is spike noise is performed as follows. First, the value of Vi-Vi-1 is compared with a predetermined threshold value Vth1 (step S3). If the value of Vi-Vi-1 is smaller than the predetermined threshold value Vth1, the characteristic pattern data Vi is regarded as not spike noise and the data is left as it is (step S4).

When the value of Vi-Vi-1 is larger than the predetermined threshold value Vth1, the characteristic pattern data Vi is largely changed as compared with the preceding characteristic pattern data Vi, and it is a spike noise. Since there is a possibility, the value of Vi-Vi + 1 is further compared with a predetermined threshold value Vth2 (step S5).

If the value of Vi-Vi + 1 is smaller than the threshold value Vth2, the characteristic pattern data Vi is regarded as not spike noise and the data is left as it is (step S4).

When the value of Vi-Vi + 1 is larger than the threshold value Vth2, the characteristic pattern data Vi is sufficiently larger than the preceding and succeeding characteristic pattern data Vi-1, Vi + 1.
It is determined that the noise is spike-like noise, and the characteristic pattern data Vi is replaced with the value of Vi-1 or Vi + 1 (step S6). This is the three characteristic pattern data Vi-1, which are adjacent in the array direction of the linear electrode array 22.
Since Vi and Vi + 1 are data in a range close to each other in the array direction, instead of the characteristic pattern data Vi in which spike-like noise is detected, one of the preceding and following characteristic pattern data Vi-1 and Vi + 1 is replaced. This is because it can be considered that even if it is output, it is substantially the same as the original characteristic pattern Vi.

Since it is possible that the value of the characteristic pattern data may greatly change even in a range close to the array direction of the linear electrode array 22, the value of the characteristic pattern data to be replaced is, for example, the characteristic pattern data before and after the value. You may perform the process which takes the average of the value of Vi-1 and Vi + 1.

Further, regarding the operations of steps S3 to S7, the value of i in the characteristic pattern data Vi is increased until i = n-1, that is, the characteristic pattern data Vn-.
It is determined whether the noise is spike noise up to 1 (step S7). This is because, as described above, in the present embodiment, three adjacent characteristic pattern data items Vi-1 and Vi-1.
, Vi + 1 for comparison, and for determining whether or not a certain characteristic pattern data Vi is spike noise, at least one characteristic pattern data Vi + 1 is required thereafter.

From the above, the characteristic pattern data A (i)
The spike-like noise included in is completely removed, and the feature pattern data A (i) that correctly represents the features of the finger of the person to be authenticated.
Is obtained (step S8). At this time, the threshold value Vth1,
By properly adjusting the value of Vth2, it is possible to accurately reflect the characteristics of the finger of the person to be authenticated and remove only spike noise. The threshold values Vth1 and Vth2 have the same value (Vth
1 = Vth2) or may be appropriately changed with respect to the value of the characteristic pattern data.

Here, the characteristic pattern data (hereinafter referred to as authentication data A (i)) extracted in this embodiment, and the characteristic pattern data registered in advance and read from a file system or the like (hereinafter referred to as registered data). Ad
It is written as (i). ) Will be described below.

First, the registration process of the authentication data and the registration data is performed. That is, although the registration data Ad (i) is obtained when the finger is placed on the linear electrode array 22 in a certain state in the feature input unit 11, when the authentication data A (i) is obtained. The state in which the user puts his / her finger on the characteristic input unit 11 is not necessarily the same as when the registration data Ad (i) is obtained. Therefore, the authentication data A (i)
The registration processing is performed in order to create a state similar to that obtained in the same position state as when the registration data Ad (i) was obtained. First, the squared error between Ad (i) and A (i + m) obtained by shifting A (i) by m is added over a certain range. If this added value is S (m), this is m
Either of the following expressions (1) and (2) depends on the range of the value of. Note that m ≧ 0 corresponds to a state where the finger is moved in the fingertip direction, and m <0 corresponds to a state where the finger is moved in the opposite direction, that is, the root direction.

[0038]

[Equation 1]

This added value S (m) is calculated by A (i + m) and A (i + m)
This is a parameter indicating the degree of coincidence with d (i), and this S
It is indicated that the smaller the value of (m) is, the closer the agreement is. By changing m within a certain range, m when the value of S (m) becomes the minimum is set as the position shift amount M, and it is determined that the position of M is aligned. Next, the difference E between the registered authentication data A (i + M) and the registered data Ad (i) is calculated by the following equations (3) and (4).

[0040]

[Equation 2]

This dissimilarity E is obtained by aligning A (i
+ M) and the square error of Ad (i) are summed over a certain range and then normalized by the sum of squares of Ad (i) in the same range. That is, the difference E is obtained by comparing the registered authentication data A (i + M) with the registration data Ad (i).
The greater the value of E, the greater the difference between the two signals, and the smaller the value, the more similar the two signals. In this process, if spike-like noise is present, the value of the squared error becomes large and the matching accuracy is lowered.

Next, the dissimilarity E and a predetermined threshold TH
Are compared, and if E ≦ TH, both signals match and it is judged that the person to be authenticated is the person himself and the collation processing is ended. Also, E>
If it is TH, it is determined that the two signals do not match, it is determined that the person to be authenticated is another person, and the matching process is ended.

Next, another embodiment of the present invention will be described with reference to FIGS. In the following embodiments, parts corresponding to those in FIGS.
The following description focuses on the differences from the first embodiment.

(Second Embodiment) FIG. 6 shows a second embodiment of the present invention.
It is a figure which shows schematic structure of the personal identification device which concerns on embodiment of this. As shown in FIG. 6, it comprises a feature input unit 11, a feature information calculation unit 12, a logarithmic amplification unit 16 as spike noise removal means, a signal processing unit 13, and a registration / collation unit 15. The logarithmic amplification section 16 logarithmically amplifies the output of the characteristic information calculation section 12 and sends it to the signal processing section 13.

FIG. 7 is a diagram showing a circuit configuration of the feature input unit 11, the feature information calculation unit 12, and the logarithmic amplification unit 16 in FIG. As shown in FIG. 7, a logarithmic amplifier 5 is connected to the output side of the sample and hold circuit 4 in the first embodiment, and the spike amplifier noise is reduced by the logarithmic amplifier 5. Here, the logarithmic amplifier 5 inputs the input signal from the sample and hold circuit 4 to Vin.
Then, logarithmic amplification represented by the following equation is performed to obtain an output signal Vout.

Vout = Alog (Vin / E) where E is an input normalization constant and A is an output normalization constant. At this time, in a region where the value of the input signal Vin is small, the amplification factor of the output signal Vout increases as the input signal Vin increases, but when the value of the input signal Vin exceeds a certain value, the amplification factor saturates. Go. The value of the input signal Vin at which the amplification factor begins to saturate is determined by the input normalization constant E. That is, by appropriately setting the normalization constant E of the input, it is possible to suppress the amplification degree for a component having a sufficiently large value as compared with the signal of the original characteristic pattern such as spike-shaped noise. It is possible to relatively reduce the intensity ratio of spike noise from the output signal while maintaining the overall shape.

FIG. 8 is a diagram in which the effect of reducing spike noise by the logarithmic amplifier 5 is actually measured. FIG. 8A is a diagram showing a characteristic pattern without logarithmic amplification, and FIG. 8B is a characteristic with logarithmic amplification. It is a figure which shows a pattern. As shown in FIG. 8, it can be confirmed that the spike noise included in the characteristic pattern is removed.

(Third Embodiment) FIG. 9 shows a third embodiment of the present invention.
Feature input unit 12 in the personal authentication device according to the embodiment
Is a diagram showing a schematic configuration of, (a) is a side view,
(B) is a plan view. As shown in FIG. 9, in the first embodiment shown in FIG. 3, the heating resistor 24 meanders near the surface of the substrate 21 and the linear electrode array 22 so as to pass through the voids of the linear electrode array 22. Are arranged. The resistor wire 24 is adapted to promote the perspiration of the finger of the person to be authenticated, which comes into contact with the linear electrode array 22, by causing an electric current to flow through the resistor wire 24 to generate heat. Ni-C that can generate a large amount of heat just by flowing it
r and the like are preferable. Further, the resistor wiring 24 is provided so as to pass through the void of the linear electrode array 22, but it may be arranged so as to cover the entire lower surface of the linear electrode array 22, and in some cases, the linear wiring may be provided. The electrode array 22 itself may generate heat.

According to this embodiment, if the person to be authenticated presses his or her finger against the linear electrode array 22 to start the measurement,
The heat generated by the heating resistor 24 is transmitted to the finger of the authenticated person,
The subject's fingers are encouraged to sweat. As mentioned above, the cause of spike noise is the perspiration that occurs locally on a dry finger, so sweating the entire finger surface eliminates local perspiration and prevents the occurrence of spike noise. it can.

As described above, the spike noise is
It mainly occurs when measuring the amount of sweating.
Therefore, since the signal intensity measured by the linear electrode array 22 is generally low for a person with a small amount of sweating, the sum of the outputs from the linear electrode array 22 is calculated and the sum of the outputs is equal to or less than a predetermined threshold value. In such a case, a configuration may be adopted in which a current is passed through the heating resistor 24 to generate heat. As a result, sweating is promoted even in a person with a small amount of sweating, and spike-like noise caused by local sweating is reduced.

[0051]

According to the present invention, the characteristics of a finger are extracted from the distribution of the resistance value between the adjacent electrodes of the linear electrode array due to the contact of the finger along the array direction of the linear electrode array. Spike noise included in the authentication signal is effective by removing spike noise from the feature pattern data and comparing and collating the feature pattern data after the spike noise removal with the previously registered feature pattern data. The high verification accuracy is obtained even for a person to be authenticated who has a small amount of sweat on the finger surface.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a personal authentication device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a feature input unit in FIG.

FIG. 3 is a diagram showing a circuit configuration of a feature input unit and a feature information calculation unit in FIG.

FIG. 4 is a diagram showing a characteristic pattern of a finger in the same embodiment.

FIG. 5 is a flowchart showing an operation of removing spike noise in the same embodiment.

FIG. 6 is a diagram showing a schematic configuration of a personal authentication device according to a second embodiment of the present invention.

7 is a diagram showing a circuit configuration of a feature input unit, a feature information calculation unit, and a logarithmic amplification unit in FIG.

FIG. 8 is a diagram showing experimental results of the same embodiment.

FIG. 9 is a diagram showing a schematic configuration of a feature input unit in a personal identification device according to a third embodiment of the present invention.

[Explanation of symbols]

 11 ... Feature input unit 12 ... Feature information calculation unit 13 ... Signal processing unit 14 ... Noise removal calculation processing unit 15 ... Registration / collation unit 21 ... Substrate 22 ... Linear electrode array 22-1 to 22-n + 1 ... Linear electrode 23 ... finger 24 ... heating resistors 2a, 2b ... analog switch group 3 ... sample and hold circuit 4 ... timing control circuit 5 ... logarithmic amplifier circuit Rref ... reference resistance Vo ... voltage source St ... timing control signal

Claims (4)

[Claims] 1. A personal authentication device for performing personal authentication using the physical characteristics of a person to be authenticated, wherein a finger is contacted along the array direction of the linear electrode array between adjacent electrodes of the linear electrode array. Feature extracting means for extracting the feature of the finger from the distribution of resistance values and outputting feature pattern data, spike noise removing means for removing spike noise of the feature pattern data, and through this spike noise removing means An individual authentication apparatus comprising: a collating unit that compares and collates the output characteristic pattern data with previously registered characteristic pattern data. 2. A personal authentication device for performing personal authentication using a physical characteristic of a person to be authenticated, wherein a finger comes into contact with the adjacent electrodes of the linear electrode array along the array direction of the linear electrode array. Feature extraction means for extracting a feature of a finger from the distribution of resistance values and sequentially outputting feature pattern data that changes along the array direction of the linear electrode array; and feature pattern data sequentially output from the feature extraction means. If two differences with the characteristic pattern data before and after the linear electrode array in the array direction are obtained, and if any of these two differences is larger than a predetermined threshold value, one of the characteristic pattern data before and after is output, If not, the spike-like noise removing means for removing the spike-like noise by directly outputting the characteristic pattern data and the spike-like noise removing means are provided. Personal authentication apparatus according to claim a wherein the pattern data outputted by the feature pattern data registered in advance that a verifying means for comparing collation. 3. A personal authentication device for performing personal authentication using the physical characteristics of a person to be authenticated, and a linear electrode array in which a plurality of linear electrodes are arranged, and an array direction of the linear electrode array. Detecting means for detecting the distribution of the resistance value between the adjacent electrodes of the linear electrode array due to the contact of the finger with the finger, a logarithmic amplifying means for logarithmically amplifying the output signal of this detecting means, and an output signal of this logarithmic amplifying means Signal processing means for sequentially processing the characteristic pattern data of the finger and the collating means for comparing and collating the characteristic pattern data output from the signal processing means with the previously registered characteristic pattern data. Personal authentication device characterized by the fact. 4. A personal authentication device for performing personal authentication using the physical characteristics of a person to be authenticated, wherein a finger is contacted along the array direction of the linear electrode array between adjacent electrodes of the linear electrode array. Feature extraction means for extracting the feature of the finger from the distribution of resistance values and outputting feature pattern data, a heating resistor provided under the linear electrode array, and feature pattern data output from the feature extraction means And a collating means for comparing and collating with the previously registered characteristic pattern data.