JP2008123168A - Biometric authentication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain a state so as to appropriately authenticate a person. <P>SOLUTION: For biometric authentication, a biometric authentication part 121 first obtains biometric information (step S101) and then a matching point I as an index showing the degree of matching between the biometric information obtained and biometric information previously registered in an authentication database is derived (step S103). Next, the relation between the matching point I derived and a threshold value TH 1 is specified, and based on the relation it is determined whether or not the authentication has been successful (step S104). That is, if the matching point I exceeds the threshold value TH 1, the authentication is successful; otherwise it is not. If the tendency of decreasing the matching point I is detected ("YES" in step S106), a screen prompting re-registration of biometric information is displayed on a liquid-crystal touch-panel display of an operating part 119 (step S107). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a biometric authentication device.

  In general, in biometric authentication such as fingerprint authentication, an index value indicating a degree of coincidence between biometric information acquired at the time of authentication and biometric information registered in advance is derived, and based on whether the index value exceeds a threshold value. The success or failure of authentication is often determined. In such biometric authentication, biometric information needs to be re-registered when the rejection of the person occurs due to changes in the biometric information due to aging or the like.

  Patent Document 1 is a prior art document related to the present invention, and paragraph 0154 and FIG. 43 show an index value indicating the degree of coincidence between biometric information acquired at the time of authentication and biometric information registered in advance in fingerprint authentication. A technique is disclosed that prompts the re-registration of a fingerprint when the “collation rate” in Patent Document 1 is below a threshold value.

JP-A-10-187987

  However, the technique disclosed in Patent Document 1 has a problem that it is not highly likely that re-registration of biometric information can be urged before the principal rejection occurs.

  The present invention was made to solve this problem. In biometric authentication, the possibility of prompting re-registration of biometric information before the rejection of the identity is increased, and appropriate authentication is possible. It aims to be able to maintain.

  In order to solve the above-mentioned problem, the invention of claim 1 derives an index value indicating the degree of coincidence between the acquisition means for acquiring the biological information and the biological information acquired by the acquisition means and the biological information registered in advance. Derivation means, determination means for determining success or failure of authentication based on whether or not the index value exceeds a first threshold, recording means for recording a history of the index value, and the index value based on the history A biometric authentication device comprising: a detecting unit that detects a decreasing tendency; and a re-registration promoting unit that prompts re-registration of biometric information when the detecting unit detects a decreasing tendency of the index value. .

  The invention according to claim 2 further includes a determination unit that determines whether or not the index value falls below a second threshold value that is greater than the first threshold value, and the re-registration promoting unit reduces the index value by the detection unit. 2. The biometric authentication device according to claim 1, wherein, when a tendency is detected and the determination unit determines that the index value is lower than the second threshold value, re-registration of biometric information is prompted. 3.

  The invention according to claim 3 is characterized in that, after the re-registration of biometric information is performed, the determination means performs a correction for increasing the index value on the index value. Device.

  According to a fourth aspect of the present invention, the determination means stops applying the correction to the index value when the total amount of correction reaches a reference after re-registration of biometric information. The biometric authentication device according to claim 3.

  The invention according to claim 5 is characterized in that the detecting means detects a decreasing tendency of the index value in consideration of an environment in which biological information is acquired. It is a biometric authentication device.

  According to the present invention, since re-registration of biometric information is urged when the index value tends to decrease, there is a high possibility that re-registration of biometric information can be promoted before the person's rejection occurs, and appropriate authentication is possible. Can be maintained.

  According to the invention of claim 2, since re-registration of biometric information is urged when the index value falls below a second threshold value that is larger than the first threshold value that determines the success or failure of authentication, re-registration of biometric information is performed before the rejection of the person occurs. The possibility of prompting is increased, and a state where appropriate authentication is possible can be more reliably maintained.

  According to the invention of claim 3, the biometric information is re-registered again immediately after the biometric information is re-registered because the index value is less than the second threshold value after the bio-information is re-registered. Can be suppressed.

  According to the fourth aspect of the present invention, after the biometric information is re-registered, if the authentication is repeated many times, the correction to the index value is stopped, so that the biometric information is re-registered appropriately. be able to.

  According to invention of Claim 5, the influence of the environment which acquired biometric information can be suppressed.

<1 Digital MFP configuration>
FIG. 1 is a block diagram showing a configuration of a digital multi-function peripheral 1 according to a preferred embodiment of the present invention. The digital multi-function peripheral 1 is also called MFP (Multi Function Peripherals) and has a facsimile function, a copy function, a scan function, a print function, and the like.

  As shown in FIG. 1, a computer 101 including a CPU 103, a ROM 105, and a RAM 107 is incorporated in the digital multifunction peripheral 1. The ROM 105 stores a program 1055, and the computer 101 executes the program 1055 to control the components 109 to 123 of the digital multi-function peripheral 1 to realize the functions of the digital multi-function peripheral 1.

  The digital multi-function peripheral 1 includes a print unit (print unit) 109 and a reading unit 111.

  The print unit 109 forms an image related to the image data on a recording medium such as recording paper by an electrophotographic method.

  The reading unit 111 reads a document with a CCD line sensor and generates image data relating to the document. The reading unit 111 reads an original by an ADF (Automatic Document Feeder) method or an FBS (Flat Bed Scanner) method.

  Further, the digital multifunction peripheral 1 includes a modem (MODEM) 113, a coupler 115, and a network interface board (Network I / F BD) 117 as communication means. The modem 113 and the coupler 115 are used for transmission / reception of facsimile image data via the public switched telephone network 901. The modem 113 is connected to the public switched telephone network 901 through the coupler 115 and is based on a facsimile transmission control procedure according to ITU (International Telecommunication Union) -T recommendation T.30. 17, V. 27ter, V.L. The facsimile image data is modulated / demodulated according to 29 or the like. Alternatively, the modem 113 can be connected to the V.V. The facsimile image data is modulated / demodulated in accordance with No. 34. The network interface board 117 connects the digital multifunction peripheral 1 to the Ethernet (registered trademark) (more generally, a local area network) 903.

  In addition, the digital multifunction peripheral 1 is provided with an operation unit 119 as a user interface. The operation unit 119 is configured by a liquid crystal touch panel display, and displays information as an operation target.

  The biometric authentication unit 121 acquires biometric information used for biometric authentication with a sensor or the like. As biometric authentication, for example, fingerprint authentication, face authentication, iris authentication, vein authentication, voice authentication, handwriting authentication, and palm-shaped authentication can be employed. Furthermore, the biometric authentication unit 121 acquires biometric information such as temperature, humidity, date and time when authentication is performed, verification time (time required for acquiring biometric information), verification points, and the number of times (number of authentications). Parameter information specifying the environment and the like is acquired by a sensor, a system clock, or the like.

  The authentication database 123 is configured by a nonvolatile auxiliary storage device such as a flash memory. In the authentication database 123, biometric information of an operator who is permitted to use is registered. Further, parameter information is recorded in the authentication database 123.

  The above-described components 103 to 123 of the digital multi-function peripheral 1 are connected by a bus 125 and can transmit and receive data between them.

  In the facsimile mode, the digital multi-function peripheral 1 reads the original using the reading unit 111, and uses the modem 113 and the coupler 115 to send the facsimile image data relating to the original to another facsimile machine via the public telephone exchange network 901. Then send. Further, the digital multifunction peripheral 1 receives facsimile image data transmitted from another facsimile machine via the public switched telephone network 901 using the modem 113 and the coupler 115, and uses the print unit 109 to An image related to the facsimile image data is formed on a recording medium.

  In the copy mode, the digital multi-function peripheral 1 reads an original using the reading unit 111 and forms an image related to the original on a recording medium using the printing unit 109.

  In the scan mode, the digital multi-function peripheral 1 reads an original using the reading unit 111 and generates image data relating to the original.

  In the print mode, the digital multifunction peripheral 1 receives image data transmitted from the computer 907 via the Ethernet (registered trademark) 903 using the network interface board 117, and uses the print unit 109 to receive the image. An image related to data is formed on a recording medium.

<2 Biometric authentication>
The digital multi-function peripheral 1 also functions as a biometric authentication device and is configured to be used only when authentication is successful. Of course, requesting success of authentication for all functions of the digital multifunction peripheral 1 is not essential, and success of authentication may be requested only for specific functions. Further, a part of the processing related to authentication may be performed by a computer (authentication server) 907 connected to the Ethernet (registered trademark) 903, and the processing related to authentication may be completed inside the biometric authentication unit 121. It may be.

  In the digital multi-function peripheral 1, the types and / or functions of jobs that can be used may be varied depending on the operator. For example, the first operator can use all the jobs of copy, scan, and fax transmission, but the second operator can use only copy and scan, and the third operator can It is possible that only scans are available. In a copy job, the first operator can use either monochrome copy or color copy, and the second operator can use only monochrome copy. Such a usage restriction is defined in the information registered in association with the specified operator when the type and / or function of an available job is registered in advance for each operator and the authentication is successful. Based on this, it is possible to limit the types and functions of jobs that are permitted to be used. In addition to assigning authority levels (administrators, internal users, other users) for each operator, register the types and functions of jobs that can be used in association with the authority levels, and identify the operators specified during authentication. It is also possible to refer to the authority level and execute the use restriction process according to the authority level.

  Next, the flow of biometric authentication realized by the computer 101 executing the program 1055 and performing overall control of each component 109 to 123 of the digital multifunction peripheral 1 will be described with reference to the flowchart of FIG.

  In biometric authentication, first, biometric information is acquired by the biometric authentication unit 121 (step S101), and parameter information stored in the authentication database 123 is acquired by the biometric authentication unit 121 (step S102). Then, the acquired biometric information and biometric information registered in the authentication database in advance are collated, and the number I of collation points serving as an index indicating the degree of coincidence between the acquired biometric information and the biometric information registered in the authentication database in advance. Is derived (step S103). Here, the “number of collation points” means the number of collation points that can be regarded as matching among the feature points of the biometric information.

  Subsequently, the magnitude relationship between the derived number of matching points I and the threshold value TH1 is specified, and success or failure of the authentication is determined based on the magnitude relationship (step S104). That is, when the number I of collation points exceeds the threshold value TH1, the authentication is successful, and otherwise, the authentication fails.

  Subsequently, based on the history of the verification point number I that can be known from the verification points included in the parameter information recorded in the authentication database 123, a decreasing tendency of the verification point number I is detected (step S105). Of course, the history of the number of verification points I should be a history of the same person. It should be noted that when detecting the tendency of the decrease in the number I of collation points, it is desirable to refer to the parameter information recorded in the authentication database 123 and consider the environment in which the biometric information is acquired. For example, it is desirable to make the comparison while keeping the conditions such as weather, date and time as the same as possible. This is because even if there is no change in the actual biometric information, the biometric information acquired by the biometric authentication unit 121 will be slightly different if conditions such as weather, date and time are different.

  If a downward tendency is detected (“YES” in step S106), a screen prompting re-registration of biometric information is displayed on the liquid crystal touch panel display of the operation unit 119 (step S107). On the other hand, when the operator desires to re-register biometric information (“YES” in step S108), a screen for guiding re-registration of biometric information is displayed on the liquid crystal touch panel display of the operation unit 119, and the biometric information is re-registered. Registration can be performed (step S109), and the process returns to step S101 after re-registration of biometric information.

  On the other hand, when the operator does not wish to re-register the biometric information, the parameter information in the current authentication is added to the authentication database 123 (step S110) and is processed as a successful authentication (step S111). In addition, even when a decrease tendency of the number I of collation points is not detected (“NO” in step S106), it is processed as authentication success (step S111).

  According to such a flow of biometric authentication, re-registration of biometric information is urged when the number I of collation points tends to decrease. Therefore, there is a high possibility that re-registration of biometric information can be urged before the person's rejection occurs. Thus, it is possible to maintain a state where appropriate authentication is possible.

<3 other>
In step S105, it is also determined whether or not the collation point number I is less than the threshold value TH2 (TH2> TH1). In step S106, in addition to detecting a decreasing tendency, the collation point number I is less than the threshold value TH2. It is also desirable to prompt re-registration of biometric information when it is determined. If the number I of collation points falls below a threshold value TH2 that is larger than the threshold value TH1 that determines the success or failure of authentication, re-registration of biometric information is prompted, and there is a possibility that re-registration of biometric information can be prompted before the rejection of the person occurs. It is because it becomes high and the state which can perform appropriate authentication can be maintained more reliably.

  Furthermore, in order to suppress prompting the re-registration of the biometric information again immediately after the bio-information is re-registered, the number of verification points after the re-registration of the bio-information is performed. It is also desirable to correct by multiplying I by a correction coefficient ξ (ξ> 1) to increase the number I of verification points. This is because the verification point number I is less likely to fall below the threshold value TH2, and it is possible to suppress prompting re-registration of biometric information.

  Of course, when the authentication is repeated many times after the re-registration of the biometric information, it is desirable to cancel the correction to the number of matching points I. For example, the history of the correction coefficient ξ representing the amount of correction may be managed, and the correction to the verification point number I may be stopped when the total reaches the reference. Thereby, it becomes possible to prompt the re-registration of the biometric information appropriately.

  In the above description, the case where the present invention is applied to user authentication of the digital multi-function peripheral 1 has been described. However, the present invention can also be applied to other uses.

1 is a block diagram illustrating a configuration of a digital multi-function peripheral 1 according to a preferred embodiment of the present invention. It is a flowchart which shows the flow of biometric authentication.

Explanation of symbols

1 Digital MFP 101 Computer 121 Biometric Authentication Unit 123 Authentication Database

Claims (5)

Obtaining means for obtaining biometric information;
Derivation means for deriving an index value indicating the degree of coincidence between the biological information acquired by the acquisition means and the biological information registered in advance;
Determining means for determining success or failure of authentication based on whether or not the index value exceeds a first threshold;
Recording means for recording a history of the index value;
Detecting means for detecting a downward tendency of the index value based on the history;
Re-registration facilitating means for encouraging re-registration of biometric information when a downward tendency of the index value is detected by the detecting means;
A biometric authentication device comprising: Determination means for determining whether or not the index value is below a second threshold value greater than the first threshold value;
Further comprising
The re-registration promoting means urges re-registration of biometric information when the detecting means detects a decreasing tendency of the index value and the determining means determines that the index value is below the second threshold value. The biometric authentication device according to claim 1.   The biometric authentication apparatus according to claim 2, wherein the determination unit performs correction for increasing the index value on the index value after re-registration of biometric information.   The determination means stops applying the correction to the index value when the total amount of correction reaches a reference after re-registration of biometric information. 3. The biometric authentication device according to 3.   The biometric authentication device according to any one of claims 1 to 4, wherein the detecting unit detects a tendency of the index value to decrease in consideration of an environment in which biometric information is acquired.

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