JP5205190B2 - Biometric authentication device - Google Patents

Description

  The present invention relates to a biometric authentication apparatus used for personal authentication using biometric information, particularly a finger vein pattern.

  While information leakage countermeasures and internal control countermeasures are regarded as important, a technique capable of authenticating a person more reliably, for example, a person authentication technique using biometric information has attracted attention. Among them, the authentication method using the finger vein pattern has been increasingly introduced as a personal identification means in various applications including an automatic machine application of a financial institution. The reasons include less psychological resistance, higher authentication accuracy, faster authentication speed, and smaller devices compared to other biometric authentication technologies. In addition, since authentication is performed using information in the body, it has a feature of being excellent in anti-counterfeiting.

  However, if biological information cannot be obtained accurately, such advantages cannot be enjoyed. On the user side, it is difficult to capture correct biological information unless the finger is properly placed in the apparatus. 2. Description of the Related Art Conventionally, a technique for avoiding an inappropriate placement of a finger in a device is known (see, for example, Patent Document 1).

Patent Document 1 describes a technique in which a finger vein pattern template imaged under inappropriate conditions is stored in advance as an illegal template and used for finger placement determination. Here, the illegal template is composed of feature points of vein patterns, and one or more are stored in the storage means. Accordingly, for example, registration of a template similar to an unauthorized template can be excluded, and authentication using biometric information similar to the unauthorized template can be prohibited.
JP 2007-272501 A

  However, the conventional biometric authentication device has a problem that the convenience is not sufficient, for example, the user is confused because the reason why the biometric information is not properly captured is unknown or difficult to understand. In general, a biometric authentication device does not display a finger vein image to a user in order to maintain confidentiality.

  If the finger placement is different between registration and authentication, the biometric information obtained even with the same finger is not necessarily similar. Under such circumstances, the user was unable to confirm through visual observation, and the operability deteriorated.

  In view of the above situation, an object of the present invention is to provide a biometric authentication device that can be improved in operability or convenience as compared with the conventional art.

In order to solve the above problems, the present invention provides the following configurations.
The invention according to claim 1 is an authentication apparatus that performs personal authentication using finger vein information.
A finger placement unit for placing a finger;
A light source for irradiating light on a finger placed on the finger placement unit;
An imaging device that captures a transmission image of a finger through which light emitted from the light source has passed;
A plurality of determination means for determining whether or not the finger is appropriately arranged based on a transmission image of the finger imaged by the imaging device, and the determination that the finger is not properly arranged by any of the determination means An authentication processing unit having notification means for notifying one or more of the inappropriate placement state and part of the finger when
Equipped with a,
One of the determination means is a means for determining whether or not there is a bend in the joint portion of the finger based on whether or not there is a portion having a luminance of a predetermined value or more in the transparent image of the finger,
When it is determined by one of the determination means that the finger joint portion is bent, the notification means notifies a joint abnormality message;
It is characterized by that.

According to the present invention, it is possible to realize the biometric authentication apparatus can be improved in the operability or usability than traditional.

Hereinafter, embodiments of the present invention will be described with reference to the drawings showing examples.
FIG. 1 is a block diagram schematically showing an embodiment of a biometric authentication device according to the present invention. As shown in FIG. 1, the biometric authentication device 1 includes a biometric information imaging unit 11, a biometric authentication information database 12, an authentication processing unit 13, and a guidance display unit 14.

  The biometric information imaging unit 11 captures biometric information (hereinafter referred to as biometric authentication information) for authentication, and the biometric authentication information database 12 stores biometric information of a verification original. The authentication processing unit 13 compares the biometric authentication information with the verification original to perform personal authentication, and the guidance display unit 14 can display operation guidance. Here, the collation is performed on a predetermined feature portion or all patterns, for example, by pattern matching.

  FIG. 2 is a cross-sectional view (a) and a partial perspective view (b) showing the structure of the biological information imaging unit according to the present invention. As shown in FIG. 2, the biological information imaging unit 11 includes a near-infrared light source 111 that can emit imaging electromagnetic waves such as infrared rays, a camera 112 that can capture a transmission image of the finger F, a biological information imaging window 113, and It has finger rests 114 and 115. Here, the belly of the fingertip portion is placed on the finger placing table 114, and the base portion of the belly of the finger F is placed on the finger placing table 115, so that the finger F is stably placed.

  FIG. 3 is a diagram illustrating an example of a captured image of a finger placed correctly. The captured image is composed of a background image Ib partitioned by a finger outline Fc and a transparent image It of the finger, and the vein portion Fv of the finger appears dark and in shadow in the transparent image It. In addition, the finger joint portion Fj looks brighter because light passes more easily than other portions. When the finger is placed correctly, the center line Lc in the depth direction of the captured image substantially coincides with the center line of the finger, and the tip of the finger is on the finger rest outside the imaging range. Does not appear.

  The guidance display unit 14 includes, for example, a liquid crystal panel, a CRT display, and the like, and can display an operation, a procedure, and the like when performing authentication to provide guidance to the user. The user can receive provision of predetermined information for or in operation through the displayed message.

  FIG. 4 is a flowchart for explaining an example of processing performed by the biometric authentication device according to the present invention. Hereinafter, the operation of the biometric authentication device 1 and the user's response will be described separately. First, the authentication processing unit 13 controls the guidance display unit 14 in response to a user operation, displays a start message, and gives an operation start guidance (S101). As the start message, for example, “When the authentication start button is pressed, authentication starts.” Is displayed, and the user sees this message and presses the authentication start button displayed on the guidance display unit 14 (SU1). ).

  Next, the authentication processing unit 13 detects pressing of the authentication start button, and causes the biological information imaging unit 11 to turn on the infrared LED as the near-infrared light source 111 (S102). Next, the authentication processing unit 13 displays an arrangement request message via the guidance display unit 14 (S103). As the placement request message, for example, “Place your finger on the device's finger rest so that the nail is on the upper side” is displayed, and the user places the finger on the finger rest as seen in the placement request message. (SU2).

  Next, the authentication processing unit 13 causes the biometric information imaging unit 11 to adjust the amount of emitted light and to capture a finger vein image serving as biometric authentication information to be collated (S104), and to perform finger position estimation determination processing Is performed (S135). In the finger position estimation determination process, the position of the finger in the biological information imaging unit 11 is detected or estimated, and position determination information that can be used for determining whether or not the finger position is placed on the finger rest so as to be suitable for authentication is created. The

  Next, the authentication processing unit 13 determines whether or not the finger is properly placed on the finger rest based on the position determination information (S131), and if it is determined that the finger is not placed, the guidance display unit 14 The position adjustment request message is displayed via (S132). Examples of position adjustment request messages are “Your finger has not reached the end”, “Your finger is displaced to the side”, “A part of your finger is floating”, “The finger joint is bent. Is displayed. The user adjusts the arrangement of the finger by looking at each position adjustment request message (SU4). When the position adjustment request message is displayed in step S132, the process returns to step S104, and the subsequent processes are repeated.

  Next, when it is determined in step S131 that the finger is properly placed on the finger rest, the authentication processing unit 13 performs image processing on the obtained captured image and extracts a transmitted image of the finger. (S133). Next, the authentication processing unit 13 displays an imaging completion message via the guidance display unit 14 (S134). For example, “Thank you. Please put your finger out” is displayed as the imaging completion message, and the user sees the imaging completion message and extracts the finger from the biological information imaging unit 11 (SU5).

  Next, the authentication processing unit 13 extracts information on a specific part of the finger vein corresponding to the user from the transmitted image of the finger as biometric authentication information (S135). The specific part of the finger vein to be extracted is set in advance in the biometric authentication information database 12, for example, for each user, and for each finger. Next, the authentication processing unit 13 compares the original biometric information registered in the biometric authentication information database 12 and authenticates the user (S136).

  FIG. 5 is a flowchart illustrating the finger position estimation determination process in FIG. In the finger position estimation determination process, the authentication processing unit 13 detects the outline of the finger from the captured image and stores it in a predetermined memory (S111), and determines whether the fingertip is projected (S112).

  FIG. 6 is an explanatory diagram illustrating an example of a captured image on which a fingertip is projected. When the fingertip is placed on the biological information imaging window 113, the fingertip is displayed on the captured image. The biological information imaging window 113 is closer to the camera 113 than the finger rests 114 and 115. If the finger is placed on the biological information imaging window 113, the camera 113 may not be properly focused on the finger F. . As a result, finger veins, contours, and the like may not be properly displayed in the captured image.

  When it is determined in step S112 that the fingertip is being projected, the authentication processing unit 13 displays a back-to-back message as a position adjustment request message (S113), and the process proceeds to step S131. For example, “the finger has not reached the back” is displayed as the message for reaching the back.

  When it is determined in step S112 that the fingertip is not projected, the authentication processing unit 13 can use horizontal determination information that can be used to determine whether the contour of the finger is within a predetermined range in the horizontal direction. Is generated (S114). FIG. 7 is an explanatory diagram illustrating an example of a captured image when the finger is displaced in the horizontal direction. When the finger is displaced laterally, the finger is separated from the center line Lc in the depth direction of the image, and imaging electromagnetic waves such as near infrared rays are not evenly irradiated to the finger. As a result, the outline of the finger or the like is not properly displayed in the captured image.

  Next, the authentication processing unit 13 determines whether or not the contour of the finger is within a predetermined range in the horizontal direction based on the horizontal determination information (S115). When it is determined in step S115 that the contour of the finger is not within the predetermined range with respect to the horizontal direction, the authentication processing unit 13 displays a horizontal irregularity message as a position adjustment request message (S116), and the process proceeds to step S131. move on. As the horizontal irregularity message, for example, “a finger is shifted to the side” is displayed.

  When it is determined in step S116 that the contour of the finger is within a predetermined range with respect to the horizontal direction, the authentication processing unit 13 performs finger contour width abnormality detection processing (S117). In the finger contour width abnormality detection process, width variation information for detecting a variation variation in width related to the projected finger contour, for example, a maximum variation ratio is calculated.

  FIG. 8 is an explanatory diagram illustrating an example of a captured image when a variation abnormality is seen in the width of the projected finger outline. For example, when the abdomen is lifted and a finger is placed, a part where the camera is out of focus is generated. As a result, the width of the floating part may change abnormally.

  Next, the authentication processing unit 13 determines whether or not there is a variation abnormality in the width of the contour of the finger based on the width variation information (S118). Specifically, it is determined whether or not the maximum rate of variation is within a predetermined range. When it is determined in step S118 that there is an abnormality in the width of the contour of the finger, the authentication processing unit 13 displays an upper irregular message as a position adjustment request message (S119), and the process proceeds to step S131. As the upper irregular message, for example, “a part of the finger is floating” is displayed.

  When it is determined in step S118 that there is no fluctuation abnormality in the width of the finger outline, the authentication processing unit 13 performs joint luminance evaluation processing (S120). FIG. 9 is an explanatory diagram illustrating an example of a captured image obtained when a finger is bent and placed. When a finger is bent and placed, a lot of light passes through the joint part of the finger, and this part is projected white. In addition, the imaging range of the finger changes depending on the degree of bending of the joint, and there is a case where the user is not authenticated by mistake in authentication.

  In the joint portion luminance evaluation process, music determination information for determining the bending of the joint portion, for example, the luminance of this portion is calculated. Next, the authentication processing unit 13 determines whether or not the joint portion is bent based on the song determination information (S121). Specifically, it is determined whether or not there is a portion with a luminance equal to or higher than a predetermined value.

  When it is determined in step S121 that the joint portion is bent, the authentication processing unit 13 displays a joint abnormality message as a position adjustment request message (S122), and the process proceeds to step S131. As the joint abnormality message, for example, “a finger joint is bent” or the like is displayed. When it is determined in step S121 that the joint portion is not bent, “appropriate” is set in the position determination information (S123), and the process proceeds to step S131.

  The biometric authentication device according to the present invention is used as an authentication device for bank terminal access management, room entry management, etc., and can be used in the information terminal manufacturing industry, software manufacturing industry, electronic component manufacturing industry, etc. that manufacture this biometric authentication device. And enhance the usefulness of such products.

It is a block block diagram which shows typically one Example of the biometrics apparatus by this invention. It is sectional drawing (a) and a partial perspective view (b) which show the structure of the biometric information imaging part by this invention. It is a figure which shows an example of the picked-up image of the finger | toe correctly placed. It is a flowchart explaining an example of the process which the biometrics apparatus by this invention performs. It is a flowchart explaining the finger position estimation determination process in FIG. It is explanatory drawing which shows an example of the captured image in which the fingertip is projected. It is explanatory drawing which shows an example of the captured image when a finger | toe is shifted | deviated to the horizontal direction. It is explanatory drawing which shows an example of the captured image when a fluctuation | variation abnormality is seen in the width | variety of the projected finger | toe outline. It is explanatory drawing which shows an example of the captured image obtained when a finger | toe is bent and set | placed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Biometric authentication apparatus 11 Biometric information imaging part 12 Biometric authentication information database 13 Authentication processing part 14 Guidance display part 111 Near-infrared light source 112 Camera 113 Biometric information imaging window 114, 115 Finger rest F finger Fc Finger outline Fj Finger joint Part Fv Finger vein part Ib Background image It Transmission image Lc Center line in the depth direction

Claims (1)

In an authentication device that performs personal authentication using finger vein information,
A finger placement unit for placing a finger;
A light source for irradiating light on a finger placed on the finger placement unit;
An imaging device that captures a transmission image of a finger through which light emitted from the light source has passed;
A plurality of determination means for determining whether or not the finger is appropriately arranged based on a transmission image of the finger imaged by the imaging device, and the determination that the finger is not properly arranged by any of the determination means An authentication processing unit having notification means for notifying one or more of the inappropriate placement state and part of the finger when
Equipped with a,
One of the determination means is a means for determining whether or not there is a bend in the joint portion of the finger based on whether or not there is a portion having a luminance of a predetermined value or more in the transparent image of the finger,
When it is determined by one of the determination means that the finger joint portion is bent, the notification means notifies a joint abnormality message;
A biometric authentication device.

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