JP2013033555A - Biometric authentication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a lower irradiation type finger vein authentication device which is compact and highly accurate, by providing structure for stabilizing fingers and preventing adverse effects by right and left fingers.SOLUTION: A finger vein authentication device comprises: a central finger stand 26 for placing an authentication target finger; light sources 3 for radiating infrared light onto the finger; an imaging unit 4 for taking a vein image of the finger by the light radiated from the light sources 3; an opening part 20 which opens in an imaging direction of the imaging unit 4; a storage device 14 for storing biological information of the finger; an authentication processing unit 10 for performing feature extraction from the image taken by the imaging unit 4 and feature collation of the extracted features and the biological information stored in the storage device 14; and right and left finger stands 27 and 28 for placing right and left fingers next to the authentication target finger. The right and left finger stands 27 and 28 are constructed at positions slightly higher than the central finger stand 26. Further, the right and left finger stands 27 and 28 are composed of a light shielding material, and the light sources 3 are installed under the right and left finger stands 27 and 28, respectively.

Description

  The present invention relates to a personal authentication device using a living body, and more particularly to a technique for authenticating using a blood vessel pattern obtained by imaging light transmitted through a living body.

  In recent years, security for personal information has been regarded as important. Biometric authentication is attracting attention as a personal authentication technology that protects security. Biometric authentication is a technology for authenticating using human biometric information, and is excellent in convenience and confidentiality.

  As a conventional biometrics authentication technique, authentication using a fingerprint, an iris, a voice, a face, a vein on the back of a hand, or a finger vein is known. Among these, biometric authentication using veins as described in Patent Document 1 is excellent in forgery resistance because it uses internal information of a living body.

  Hereinafter, a finger vein authentication device will be described in particular. The finger vein authentication device irradiates the finger with infrared light. Infrared light is scattered inside the finger and then transmitted to the outside. Then, the finger vein authentication device captures infrared light transmitted to the palm side of the finger. At this time, hemoglobin in the blood absorbs more infrared light than the surrounding tissue. Therefore, in the image captured by the finger vein authentication device, blood vessels (finger veins) distributed subcutaneously on the palm side of the finger are visualized as dark shadow patterns (finger vein patterns). The finger vein authentication device performs personal authentication by previously registering the characteristics of the finger vein pattern and obtaining the correlation between the user's finger vein pattern presented at the time of authentication and the characteristics registered in advance.

  As a conventional example of this type of finger vein authentication, for example, an authentication device described in Patent Document 1 is known. This captures a finger vein image by irradiating infrared light from the left and right sides of the finger. As a technique for reducing the size of the finger vein authentication device, Patent Document 2 discloses a device in which a photographing range is narrowed and a light source is installed below the finger.

JP 2004-265269 A JP 2008-181570 A

  In an apparatus with a narrow shooting range as shown in Patent Document 2, when the finger presentation position is deviated, even the person himself may be mistakenly determined to be another person. Further, when the fingertip side is strongly pressed, the blood vessel pattern may be crushed and a correct authentication result may not be obtained. In order to increase authentication accuracy with a device with a narrow imaging range, a device configuration that can present a finger more stably and a device configuration that prevents finger pressing are required. Further, in the method of irradiating light from the left and right sides of the finger as in Patent Document 1, a light source is blocked by a finger that is not subject to authentication, and a clear vein image cannot be captured by light reflected by a finger that is not subject to authentication. May be adversely affected.

  In the conventional small finger vein authentication device, no consideration is given to the device configuration for stably presenting the finger and the adverse effects of fingers that are not subject to authentication.

  Therefore, an object of the present invention is to realize a small and highly accurate finger vein authentication device by providing a configuration for stabilizing a finger in the finger vein authentication device and further preventing adverse effects of left and right fingers.

  Typical inventions disclosed in the present invention are as follows.

  A housing for placing a finger; a light source that irradiates the finger with infrared light; a light amount control unit that controls a light amount of the light source; an imaging unit that captures a vein image of the finger by light from the light source; An opening that opens in the imaging direction, a storage device that stores biometric information of a finger, an image calculation unit that performs feature extraction from an image captured by the imaging unit and feature matching between the biological information stored in the storage device, and The finger vein authentication device is provided with a finger rest on which the left and right fingers of the finger are placed. Further, the finger rests for the left and right fingers are made of a light shielding member.

  According to the present invention, the reproducibility of finger presentation is enhanced. Further, since it is possible to prevent deterioration in authentication accuracy due to the left and right fingers of the finger to be authenticated, a small and highly accurate finger vein authentication device can be realized.

1 is a schematic configuration diagram of a finger vein authentication system according to a first embodiment of the present invention. It is a figure which shows the finger vein data acquisition apparatus shape concerning a 1st Example. It is explanatory drawing of the image quality degradation factor by a right-and-left finger, and the solution of the image quality degradation by a 1st Example. It is a figure which shows an example of the finger rest of a right-and-left finger concerning a 1st Example. It is a figure for demonstrating the authentication process implemented by the authentication program concerning a 1st Example. It is a figure for demonstrating the speed-up method of the light quantity adjustment process concerning a 2nd Example. It is a figure which shows one specific example of the apparatus which determines how to put a finger concerning the 3rd Example. It is a figure which shows an example of the finger placement determination process based on a captured image according to the first embodiment. It is a figure which shows an example of the apparatus which determines how to put a finger | toe based on a touch sensor concerning a 1st Example. It is a figure which shows the specific example of the light source arrangement method concerning a 1st Example. It is a figure which shows the specific example of the locker incorporating the small finger vein authentication apparatus concerning a 4th Example. It is a figure which shows one specific example of the finger rest of a right and left finger concerning the 5th Example. It is a figure which shows an example of the finger vein data acquisition apparatus provided with the several light source of a different angle concerning the 6th Example. It is a figure for demonstrating the method to select the suitable light source for the finger | toe mounted from the several light source concerning the 6th Example. It is a figure which shows the other example of the locker incorporating the small finger vein authentication apparatus concerning a 4th Example. It is a figure which shows the other specific example of finger vein data acquisition apparatus shape concerning a 1st Example. It is a figure which shows one specific example of the finger vein data acquisition apparatus shape concerning a 5th Example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  Fig.1 (a) is a block diagram of the authentication system of a 1st Example. FIG. 1B is a diagram showing the inside of the memory 12 and the storage device 14 which are storage units in the authentication system in the first embodiment. The authentication system includes a finger vein data acquisition device 2, an image input unit 18, an authentication processing unit 10, a storage device 14, a display unit 17, an information input unit 19, an audio output unit 6, and a power supply unit 15.

  The finger vein data acquisition device 2 is a single housing and includes a light source 3, an imaging device 4, a central finger rest 26, a left finger rest 27, and a right finger rest 28. The light source 3 is, for example, an infrared emitting diode (LED), and irradiates the finger 200 presented on the central finger rest 26 with infrared light. The imaging device 4 images the presented finger 200.

  The image input unit 18 inputs an image captured by the imaging device 4 to the authentication processing unit 10 that functions as a processing unit.

  The authentication processing unit 10 includes a central processing unit (CPU) 11, a memory 12, and various interfaces (IF) 13. The CPU 11 performs various processes by executing the authentication program 100 stored in the memory 12. The memory 12 temporarily stores an authentication program 100 executed by the CPU 11. The memory 12 stores the image input from the image input unit 18. The interface 13 is connected to a device external to the authentication processing unit 10. Specifically, the interface 13 is connected to the finger vein data acquisition device 2, the storage device 14, the display unit 17, the information input unit 19, the audio output unit 6, the image input unit 18, and the like.

  The storage device 14 stores user registration data 220 and the authentication program 100 in advance. The registration data 120 in FIG. 1B is information for collating users, and is, for example, an image of a finger vein pattern. The finger vein pattern image is an image obtained by capturing blood vessels (finger veins) distributed under the skin on the palm side of the finger as dark shadow patterns.

  The display unit 17 is, for example, a liquid crystal display, and displays information received from the authentication processing unit 10. The information input unit 19 is, for example, a keyboard or the like, and transmits information input from the user to the authentication processing unit 10. The voice output unit 6 is a speaker or the like, and transmits information received from the authentication processing unit 10 by voice. The power supply unit 15 is a dry battery or an external power supply, and supplies power for driving the finger vein data acquisition device 2 and the authentication processing unit 10.

  In this authentication system, when the user presents the finger 200 to the finger vein data acquisition device 2, infrared light is emitted from the light source 3 to the finger 200. The light is scattered inside the finger 200, and the light transmitted through the finger 200 is incident on the imaging unit 4. The incident light is converted into an electrical signal by the imaging unit 4 and is taken into the authentication processing unit 10 as an image. The captured image is stored in the memory 12. Further, the registration data 220 and the authentication program 100 stored in the storage device 14 are stored in the memory 12 from the storage device 14 (FIG. 1B). In accordance with the authentication program 100 stored in the memory 12, the CPU 11 creates authentication data 240 from the input image and collates with the registration data 220. In the collation processing, a correlation between the two data to be compared is calculated, and it is determined whether or not it matches the registered data according to the value. An individual is authenticated using this determination result. The authentication result is displayed on the display unit 17 or notified by voice from the voice output unit 6.

  FIG. 2 is a diagram showing an appearance of the finger vein data acquisition apparatus 2 in the first embodiment. 2 (a) is a top view of the device 2, FIG. 2 (b) is a top view when a finger is presented to the device 2, FIG. 2 (c) is an AA cross-sectional view of FIG. (d) is BB sectional drawing of FIG.2 (b).

  On the upper surface of the apparatus 2, a central finger rest 26 is provided for the user to present an authentication target finger. The central finger rest 26 is provided with an opening 20. An infrared transmission filter 24 is installed in the opening 20 so as to cover the opening 20. The infrared transmission filter 24 prevents unnecessary light other than infrared light from entering the apparatus. It also prevents foreign objects such as dust and debris from entering the device. The filter 24 is installed at a position about several millimeters lower than the central finger rest 26 so that the finger 200 and the filter do not come into contact with each other. Thereby, it is possible to prevent the blood vessel pattern from disappearing or deforming due to the pressing of the finger. Further, it is possible to prevent dirt from adhering to the filter 24. The imaging unit 4 is installed immediately below the opening 20.

  When the finger 200 is placed, the light source 3 irradiates the finger 200 with infrared light from a plurality of light source elements. When the light reaches the inside of the finger, it is scattered in all directions. A part of the light scattered inside the finger reaches near the upper part of the opening 20, and a part of the light travels toward the outside of the finger. This light passes through the opening 20 and the filter 24 and is photographed by the imaging unit 4. Since this light is transmitted from the inside of the finger 200 to the palm side surface of the finger 200, the weak light attenuated because it has passed through the vein portion and the strong light that has not attenuated that has escaped from the portion without the vein. Has a contrast difference. Therefore, when this light is imaged, a finger vein pattern image of a partial region located directly above the opening 20 is displayed in the video. Thereby, the finger vein pattern in the partial region of the finger 200 is acquired.

  In order to capture a clear image of the partial region of the finger 200 located above the opening 20, that is, the finger vein pattern of the imaged portion, the following optical conditions must be satisfied. First, the reflected light of the light irradiated on the skin surface of the imaged part from the outside of the finger is not photographed, and the scattered light that does not reach the depth at which the finger vein exists is not photographed. When this condition is not satisfied, the light having no finger vein pattern information reduces the contrast between the finger vein portion and the other living tissue. Furthermore, unnecessary images such as wrinkles on the finger surface are reflected, making it difficult to see the finger vein pattern. Therefore, in this embodiment, the size of the opening 20 is made smaller than the width and length of the finger 200 so that the opening 20 is completely covered by the finger 200 when the user presents the finger 200. Thereby, it is possible to prevent light that does not pass through the finger from directly entering the apparatus.

  In the case of an apparatus having an opening size larger than the finger size as disclosed in Patent Document 1, the opening cannot be covered with a finger. Therefore, external light enters through the gap between the opening and the finger, and the image quality of the vein image is degraded. Therefore, it is necessary to provide a high light shielding wall around the finger 200 to prevent external light. Even when the light shielding wall can completely prevent external light, if the installation position of the light source 3 is low, the light output from the light source 3 enters the gap between the finger and the opening. Since the light that enters the gap is reflected on the finger surface, the image quality of the captured image is degraded. Therefore, in order to improve the image quality with an apparatus having a large opening size, it is necessary to increase the installation position of the light source 3. In the authentication apparatus according to the present embodiment, since the opening size is small, a clear vein image can be taken under the external light even without a high light shielding wall. Furthermore, the installation position of the light source 3 can be lowered. Therefore, the apparatus can be thinned. In addition, reducing the opening 20 has the effect of reducing the installation area of the apparatus.

  Further, in a conventional device having a large opening size, the finger is supported at two points, the fingertip side and the root side. For this reason, when the user presents his / her finger with great effort, the finger may warp and the vascular pattern to be photographed may be greatly distorted. On the other hand, when the opening size is smaller than the finger, the left and right ends of the palm of the finger come into contact with the finger rest 26 in addition to the fingertip and root side. That is, all the finger parts other than just above the opening 20 in a state where a hole is formed are in contact with the finger rest 26. As a result, since the contact area between the finger and the finger rest is increased, the presentation of the finger is stabilized and warping can be prevented. In the apparatus of this embodiment, the finger rest 26 is on a flat surface, so that the effect of preventing the finger from curling is high.

  The device 2 is provided with a protrusion 21 for positioning the finger 200. The user presents the finger with the fingertip aligned with the protrusion 21 (FIG. 2D). The protrusion 21 can prevent the finger 1 from being placed at a position shifted from the specified position.

The position of the opening 20 is a position at which the periphery of the first joint of the finger can be photographed when the user places the finger on the protrusion 21. This is because the finger joint part is thinner than the other parts and the veins are easy to photograph. In order to obtain the same effect, an apparatus that captures the vicinity of the second joint may be used. However, if the apparatus that performs positioning using the fingertip as a base point as in the present apparatus, the apparatus becomes large. Therefore, the area to be imaged in the present embodiment, that is, the position and size of the opening 20 is set near the first joint of the finger 200.

  Touch sensors 23 are provided on the fingertip side and the base side of the finger rest 26, respectively. Thereby, it can be detected that the user's finger is presented.

  The apparatus 2 is provided with an infrared light source 3 that is illumination for vein photography. The infrared light source 3 includes a plurality of light source elements such as LEDs. The installation position of the light source is on the left and right sides of the finger 200. The height to be installed is set to a position lower than half the height of the finger. Furthermore, the installation angle α of the light source is set to a range of 0 ° <α <90 °, and light is irradiated obliquely upward. As described above, the apparatus can be thinned by lowering the installation position of the light source. Moreover, since the light can be irradiated to a high position of the finger by installing it tilted obliquely upward on the left and right sides of the finger, a clear vein image can be taken. The light source is preferably installed outside the finger width of the finger 200. Thereby, light can be irradiated to the upper half surface of the finger 200, that is, the back side of the finger. If the light source is installed on the inner side than the finger width, light is irradiated on the lower surface of the finger 200, that is, on the palm side of the finger, so that the sharpness of the captured image decreases.

  As described above, in order to improve the image quality with this apparatus, it is important not to capture scattered light that has not reached the depth at which the finger vein exists. In order to realize this, it is effective to irradiate light as high as possible on the finger 200. Therefore, the installation angle α of the light source 3 is set to a large value. However, if the angle α is excessively increased, the light output from the light source 3 passes above the finger 200 and no light is applied to the finger 200 at all. Therefore, the angle α is set as large as possible within a range in which a sufficient amount of light can be irradiated even to a user with a thin finger. Thereby, it is possible to realize an authentication device that can handle users of fingers of various sizes and can capture clear images.

  When an LED is used as the light source 3, a wall 22 made of a light shielding member is installed between the finger 200 and the light source 3. Since the light emitted from the LED travels with a spread, the light emitted from the LED proceeds in a lower direction even if the LED itself is installed obliquely upward. Therefore, by concealing the lower side of the LED by the light shielding wall 22, light directed toward the lower direction of the finger is blocked and only light directed upward is allowed to pass. Thereby, since light is irradiated only on the high position of the finger, the sharpness of the vein image can be further increased.

  As described above, this apparatus performs authentication using finger vein data in a narrow area around the first joint of the finger. Therefore, if the finger presentation position greatly deviates between registration and authentication, a correct authentication result cannot be calculated even when the registrant authenticates. In order to perform more accurate authentication, it is necessary to stabilize the finger presentation. Below, the structure of the present Example for solving this subject is demonstrated.

  In this embodiment, left and right finger rests 27 and 28 are provided on both sides of the central finger rest 26 to place a finger that is not subject to authentication. The positions of the left and right finger rests 27 and 28 are above and outside the center finger rest 26. The upper surfaces of the left and right finger rests 27 and 28 have a shape such as a planar shape that allows easy finger placement. By providing the finger rests on the left and right sides of the authentication target finger, the finger is fixed by the authentication target finger and the three fingers on the left and right sides thereof, so that rotation of the authentication target finger can be prevented. Moreover, the positional deviation in the left-right direction can be restricted. Therefore, the reproducibility of finger presentation is improved, and a highly accurate authentication device can be realized. Also, the left and right finger rests are slightly higher than the central finger rest. Thereby, it can prevent that a user presses strongly the finger | toe 200 for authentication.

  The left and right finger rests 27 and 28 may be narrower than the finger width as long as the left and right fingers 201 and 202 can be placed thereon and the above-described purpose can be achieved. Thereby, a smaller apparatus can be realized. FIG. 2 shows an example in which the authentication target finger 200 is the middle finger, and the left and right fingers 201 and 202 are the ring finger and the index finger, but this apparatus can also authenticate with other fingers. For example, the index finger can be presented on the central finger rest 26, the middle finger can be presented on one finger rest, and the other finger rest can be placed without a finger. Since it is fixed by at least two fingers, rotation of the authentication target finger can be prevented.

  The left and right finger rests 27 and 28 also serve as a light shielding wall for preventing image quality deterioration due to the left and right fingers 201 and 202. Below, the problem of the authentication accuracy fall by the right and left fingers which is the subject of a downward irradiation system, and the apparatus structure which solves it are demonstrated using FIG.

As shown in FIG. 3 (a), the finger vein data acquisition device 2 of the present embodiment has a light source 3 installed at a low position on the left and right sides of the finger, and uses a downward irradiation method in which light is emitted obliquely upward. Of both low profile and high image quality. However, in a simple lower left / right irradiation type device, when the non-authenticated fingers 201 and 202 approach the center finger 200, the light source 3 is blocked by the fingers 201 and 202 (FIG. 3B). )). If the light source 3 is blocked, no light is irradiated on the finger 200 to be authenticated, so authentication cannot be performed. Even if the light source 3 is not completely blocked, the light 31 output from the light source 3 is reflected by the surfaces of the left and right fingers 201 and 202 as shown in FIG. It may change. Since the optical path is greatly deviated from the original irradiation direction, a clear vein image cannot be taken. Therefore, the authentication accuracy is reduced. In order to improve the image quality in the left and right lower illumination method, a structure that prevents the adverse effects of the left and right fingers is required. In order to prevent this, a method is conceivable in which a side wall is provided between the center finger 200 and the left and right fingers 201 and 202 so that the left and right fingers 201 and 202 cannot be placed near the center finger 200. However, in order to completely prevent the left and right fingers from moving to the center, it is necessary to make the height of the side wall the same or higher, and the device becomes large.

  Therefore, in the present embodiment, the above-described problem is solved by the following apparatus configuration (FIG. 3D). First, the left and right finger rests 27 and 28 are made of a light shielding member. Furthermore, the finger rests 27 and 28 are installed between the light source 3 and the non-authentication target finger. Thereby, the light 31 is not irradiated to the left and right fingers 201 and 202. That is, the left and right finger rests 27 and 28 are not only finger rests but also a light shielding wall. As a result, light traveling from directly above the light source out of the light output from the light source 3 is blocked by the finger rests 27 and 28. For this reason, light is not reflected on the surfaces of the left and right fingers, and image quality deterioration can be prevented.

  The left and right finger rests 27 and 28 are installed at a slightly higher position than the central finger rest 26 and a gap 32 is provided between the central finger rest 26 and the left and right finger rests 27 and 28. There is. Of the light emitted from the light source, the light traveling in the direction of the central finger passes through the gap 32 and is applied to the authentication target finger 200. Since only the central finger 200 to be authenticated can be placed on the central finger rest, the gap 32 is not blocked by the left and right fingers 201 and 202. For this reason, the light 31 is not blocked by the left and right fingers, and the light is reliably irradiated only to the central finger.

The gap 32 between the left and right finger rests 27 and 28 may be covered with a material that transmits infrared rays, such as an acrylic plate 98, as shown in FIG. This prevents foreign matter from entering the apparatus. Further, as shown in FIG. 16B, the light shielding wall 22 is installed inside the light shielding wall 22, that is, on the central finger rest 26 between the left and right finger rests 27 and 28 and the opening. Acrylic board 99 shaped
May be installed. As a result, the rounded shape of the finger 200 and the shape of the finger rests 27 and 28 formed of the slopes indicated by the dotted lines of the light shielding wall 22 and the inverted cross-shaped acrylic plate 99 are easily matched. It becomes possible to present a finger stably. Since the acrylic plate 99 has an inverted C shape, the installation position of the light source 3 can be brought closer to the inside while securing a space that can be presented even with a thick finger. Thereby, the installation area of an apparatus can be made small. In addition, since the light can be efficiently applied by bringing the light source close to the finger, power consumption can be suppressed.

  Here, the heights of the left and right finger rests 27 and 28 of this embodiment will be described with reference to FIG. FIG. 4B is an enlarged view of the right finger rest 28 and the light source 3 portion of the finger vein data acquisition apparatus 2 of FIG. In FIG. 4B, h1 indicates the height of the lower surface of the right finger rest 28 when the center finger rest 26 is used as a reference. Point a is the intersection of the irradiation axis 42 of the light source 3 and the left end of the finger rest 28, that is, the perpendicular 43 drawn from the end face on the center finger rest 26 side, and h2 is when the center finger rest 26 is used as a reference. Indicates the height of point a.

  As shown in FIG. 4B, the heights of the left and right finger rests 27 and 28 need to be high enough not to block the light toward the center finger 200. That is, the height of the finger rests 27 and 28 is set to a value satisfying h1> h2. Thereby, the light toward the left and right fingers can be blocked, and the light toward the center finger 200 can secure a sufficient amount of light. However, if the height h1 of the left and right finger rests 27, 28 is too high, the device becomes larger, the difference from the central finger rest is too large to place the fingers, and the left and right fingers are placed in the middle. Since adverse effects such as a finger floating occur, h1 is made as small as possible within a range in which the amount of light to the central finger can be secured. Specifically, it is desirable to suppress the step between the central finger rest 26 and the left and right finger rests 27 and 28 to about 10 mm or less.

  Hereinafter, an example of a processing procedure performed by the authentication program 100 executed by the CPU 11 will be described with reference to FIG. First, a finger presentation detection process (S101) for determining whether or not a finger is placed on the apparatus is performed, and a light quantity adjustment process (S103) for irradiating an appropriate light quantity from a light source when a finger is presented. carry out. In other words, the CPU 11 is a processing unit that functions not only as a feature extraction unit and a feature verification unit but also as a light amount control unit. After the light amount adjustment is completed, pattern extraction processing (S108) and feature data creation processing (S109) are performed. A collation process (S112) with previously registered feature data is performed to determine whether or not it is registered. Details of this flow will be described below.

  First, in order to know the timing for starting authentication, it is determined whether or not the finger is placed on the apparatus (S101). As this determination method, a method using the touch sensor 23 installed on the finger rest 26, a method using image processing, a method combining the touch sensor and image processing, or the like can be used. Here, an example of a method using image processing will be described. The method based on image processing has an advantage that a finger detection sensor is not required and the number of parts can be reduced and the cost can be reduced. First, the above-mentioned light source 3 used as illumination for finger vein pattern photography is blinked at a constant cycle. When nothing is placed on the apparatus, even if the light source 3 is turned on or off, the light emitted from the light source 3 is not reflected on the imaging unit 4 because there is no object that scatters light. Therefore, when the image of the imaging unit 4 is compared between the light source 3 turned on and the light source 3 turned off, the luminance value does not change greatly. On the other hand, when the finger 200 is placed on the apparatus, the light emitted from the light source 3 is scattered by the finger 200 and reflected on the imaging unit 4. Therefore, a large change occurs in the luminance value of the image when the light source 3 is turned on and when the light source 3 is turned off. This change amount is sent to the authentication processing unit 10 via the image input unit 18, calculated by the CPU 11, and held, thereby detecting the finger presentation.

  When the presentation of the finger is detected, the light amount for illumination is output from the light source 3. The amount of light required for vein photography varies depending on the thickness of the placed finger and the thickness of the skin. Therefore, the light amount of the light source 3 is adjusted so that the clearest image can be obtained (S103). In finger vein imaging, a clear vein image can be obtained when the average luminance value of the captured image is a value near the center of the luminance gradation. For example, when the average luminance of the image is too low, the contrast between the blood vessel and the other portions is poor, so that the image is not clear. On the other hand, when the average luminance is too high, a saturated portion occurs and blood vessels cannot be extracted. That is, in the light amount adjustment S103, the median value of the luminance gradation is set as the target luminance value, and the light amount is adjusted so that the average luminance value of the captured image approaches the target value. As this light amount adjustment method, in this embodiment, a method is used in which the average luminance value of the image is always monitored and the light amount is brought close to the target luminance value while feedback control is performed according to the value.

  FIG. 5B shows the flowchart. In this method, immediately after the finger presentation is detected, the light source 3 is turned on with a preset initial light amount value L0 (S1031). The initial light amount L0 is set in advance by measuring a light amount value at which a target luminance value image can be taken when a standard finger is placed. Next, an image is captured by the imaging unit 4 (S1032). The average luminance value V0 of this image is calculated (S1033). It is determined whether the calculated average luminance value V0 is a target luminance value (S1034). If the target luminance value has not been reached, the next light quantity value is reset (S1035). The next light quantity value is calculated using the feature that the light quantity value and the average luminance value of the captured image are in a proportional relationship. After resetting the light amount value, image capturing (S1032), average brightness value calculation (S1033), and average brightness value determination (S1034) are performed again. This flow is repeated to approach the target luminance value. When the target luminance value is reached in the determination of the average luminance value in S1034, the light amount adjustment is completed.

  Next, blood vessel pattern extraction processing is performed (S108). As this technique, a method using an edge emphasis filter or a matched filter for emphasizing a line segment, a method of extracting a line pattern by tracking a line component, and a method of extracting a local depression position of a luminance value in a cross-sectional profile of an image Etc. can be used.

  Thereafter, feature data is created from the extracted result (S109). As the feature data, a method using the image of the feature extraction processing result itself as a feature amount, a method of detecting a branch point or an end point, and the like can be used. When the image itself is used as a feature amount, a reduction process may be applied to the image after feature extraction in order to reduce the data size.

  Finally, the generated feature data and the feature data created and registered in advance by the same method are compared and collated. (S112). In the case where the image itself is used as the feature data, the images are overlapped and the pixel values are compared to calculate the coincidence rate. When branch points and end points are used as feature data, the coincidence rate is calculated by comparing information such as the position, number, branch line angle, and relative distance. Whether the patterns are the same pattern or different patterns is determined based on the matching rate obtained here. The threshold for determination can be statistically calculated in advance. If the coincidence rate is higher than the threshold, it is determined as a registrant, and if it is lower, it is considered that an unregistered finger has been presented and authentication is rejected.

  If it is determined that the user is a registrant, for example, unlocking is performed as a process after authentication (S114).

  FIG. 10 shows an arrangement example of the light source 3 composed of a plurality of light source elements for capturing an image with less luminance unevenness. 10A to 10C are views of the finger vein data acquisition device 2 as viewed from above.

  In the finger vein authentication pattern extraction process (S108), the luminance value of each pixel in the image is checked, and a pixel having a lower luminance than the surrounding pixels is determined to be a vein and extracted. Therefore, in order to perform highly accurate authentication, it is important to irradiate the entire finger with a uniform amount of light and capture an image with less luminance unevenness. If there is a bias in the light irradiation and only a part of the area is photographed dark, that area is erroneously extracted as a blood vessel when image processing is performed.

  Therefore, luminance unevenness is reduced by devising the light source arrangement. As long as the light source 3 can irradiate a finger with sufficient brightness, it may be installed one by one on the left and right, but in order to suppress luminance unevenness, a plurality of light sources 3 are provided as shown in FIGS. 10 (a) and 10 (b). It is desirable to arrange the light source elements along the longitudinal direction of the finger. In this case, the light source elements arranged on the left and right sides are arranged at equal intervals. Thereby, it can irradiate with uniform brightness from the fingertip side to the finger base side. In addition, since there is a case where sufficient light does not reach the fingertip and the base of the finger with only the light source on the left and right sides of the finger, a light source 3 is provided on the fingertip and the base of the finger as shown in FIG. Irradiation may be performed automatically. FIG. 10E is a side view along the straight line A of FIG. The light sources 3 on the fingertip side and the base side are installed facing upward as shown in FIG. At this time, if it is installed with a slight inclination in the direction away from the opening, it is possible to prevent light from directly entering the opening.

  In the light amount adjustment process (S103), it is effective to control the light amounts of these light sources independently. As described above, the optimum light quantity value varies depending on the thickness of the user's finger and the thickness of the skin. Similarly, even with the same finger, since the width and thickness are different between the fingertip side and the finger base side, appropriate light amount values are different. Therefore, the amount of light on the fingertip side and the fingertip side is controlled independently, or the finger width is adjusted in advance so that the amount of light on the fingertip side becomes stronger using the feature that the fingertip is narrower and thicker at the fingertip. The light amounts on the fingertip side and the finger base side may be controlled simultaneously. Alternatively, in the case where the same amount of light has to be irradiated, the position of the light source may be arranged closer to the fingertip and further away from the root side. Furthermore, it is desirable to control the left and right light quantity values independently, taking into account the left-right asymmetry of the finger shape and the left-right position shift when the finger is presented.

  In the case where a plurality of light sources 3 are arranged, not all the light sources 3 are installed at completely equal intervals, but the interval near the center may be slightly wider than the interval between the fingertip and the root side as shown in FIG. Good. In the present embodiment, as described above, photographing is performed with the first joint placed at the center of the opening 20. Since the first joint has thin skin, the vein can be photographed with a smaller amount of light than other parts. Therefore, the light source 3 is placed near the fingertip side and the root side as shown in FIG. Thereby, strong light hits parts other than the first joint, and weak light hits the first joint. Therefore, the light quantity of the entire image becomes uniform.

  As shown in FIG. 10B, when installing a total of six light sources, three on each side, the six LEDs are controlled independently. This device takes a picture of veins around the first joint with thin skin. Since the skin is thicker on the fingertip side than the first joint, a slightly stronger light intensity is required to capture a clear vein. In addition, when the first joint portion and the base side are compared, the base side needs stronger light. Therefore, when three light sources are installed on the left and right as shown in FIG. 10B, if the fingertip side, the root side, and the first joint part are controlled separately, the most appropriate amount of light can be irradiated to each part, and imaging is performed. The whole range can be clearly imaged.

  The second embodiment will be described with reference to processing for a case where authentication is limited to one registration data to be registered in one authentication device, that is, a device that performs 1: 1 authentication, for example, an authentication device incorporated in a locker or the like. In such a device, a plurality of people do not use the device at the same time. For example, a shared locker cannot be used by anyone other than the registrant until it is registered at the time of locking and then unlocked. That is, the authentication device stores only the registration data of the last registrant and performs authentication with only one registration data.

  In the second embodiment, the light amount adjustment processing S103 of the first embodiment is improved, and the processing time of S103 is shortened. Thereby, an inexpensive CPU with a slow processing speed can be used, and the price of the device itself can be reduced. Further, since power consumption can be suppressed, the device itself can be operated by battery drive.

  The light amount adjustment processing S103 of the first embodiment increases the processing time when the target average luminance value cannot be achieved and the light amount setting (S1035) and photographing (S1032) are repeated many times. In particular, when the photographed image is too bright and saturated, or too dark, the relationship between the light amount value and the average luminance value of the captured image becomes nonlinear, so the light amount value for the next photographing is calculated (S1035). ), It becomes difficult to predict a correct light amount value. In the second embodiment, the above problem is solved and the processing time of the light amount adjustment S103 is shortened.

  FIG. 6 is a flowchart of the second embodiment of the light amount adjustment processing S103. FIG. 6A shows a flow at the time of registration processing, and FIG. 6B shows a flow at the time of authentication processing.

  First, the light amount adjustment process at the time of registration will be described. Similar to the light amount adjustment of the first embodiment, the light amount adjustment at the time of registration is performed by performing the processing of S1031 to S1035, thereby monitoring the average luminance value of the image and bringing the light amount close to the target luminance value while performing feedback control according to the value. . However, before completing the light amount adjustment process, the light amount value L1 when the target average luminance value is reached is stored in the storage area 14 (S1036).

  Next, the light amount adjustment process at the time of authentication will be described. Simultaneously with the start of the authentication process, the light amount value L1 stored at the time of registration is read into the memory 12 from the storage area 14 in the previous period. The read light amount value L1 is turned on as the initial light amount (S1037). Next, in the same manner as in the first embodiment, by performing the processing of S1032 to S1035, the target average luminance value is brought close to. In this method, since the light amount value L1 that has reached the target average luminance value at the time of registration is used as the initial light amount value at the time of authentication, if the finger is the same at the time of registration and at the time of authentication, the first average luminance determination (S1034) Therefore, there is a high possibility that the target average luminance value will be reached. Therefore, the light amount adjustment can be completed immediately. In addition, even when the target average luminance value cannot be achieved with the light amount value L1 due to factors such as the finger position, the image is rarely saturated or extremely darkened. It is easy to estimate and light quantity adjustment can be completed immediately.

  Note that when storing the light amount value at the time of registration, the light amount value of each light source may be stored individually, or the average value of a plurality of light sources may be stored. In the method of irradiating from the lower left and right, when the finger 200 is presented biased to the left or right, the light amount value on the side closer to the finger tends to be small and the light amount value far from the finger tends to be large. If the light amount values of the left and right light sources are averaged and stored, the variation in the light amount value due to the left and right position shift of the finger 200 can be suppressed, so even if the finger is displaced during registration and authentication, it is short. The light amount adjustment can be completed in time. Moreover, the data amount to preserve | save can also be reduced by preserve | saving an average value.

  In the present embodiment, the 1: 1 authentication has been described, but this high-speed technique can also be applied to a 1: N authentication authentication system that registers registration data of N different fingers. In the case of 1: N authentication, in the registration process, the processes of S1031 to S1036 similar to the above-described 1: 1 authentication method are performed, and the optimum light amount value of each finger is stored. Next, an average value Ln of the N optimum light quantity values stored is calculated. In the initial light quantity value lighting process at the time of authentication (S1037), the average value Ln of the optimum light quantity is turned on as the initial light quantity. Thereby, the most suitable initial light quantity value can be turned on for N pieces of registered data. By customizing the initial light quantity value based on the data registered in the apparatus, the authentication processing time can be shortened. As the initial light amount value, an average value may be used as in the above example, or a mode value may be used.

  The third embodiment is an authentication system having a function of checking that a user can place a finger correctly. Hereinafter, this will be described with reference to FIG. FIG. 7A is a state in which the finger 200 is correctly placed, and FIG. 7B is a cross-sectional view of the straight line A in FIG. FIG. 7D and FIG. 7E show a state where the finger 200 is not correctly placed. FIG. 7C and FIG. 7F are examples of images taken by the imaging unit 4.

  The authentication device of the present embodiment has a protrusion 21 for determining the position of the fingertip. The user presents the finger with the fingertip aligned with the protrusion 21 as shown in FIG. Accordingly, since the finger can be presented at the same position at the time of registration and at the time of authentication, highly accurate authentication is possible. However, as shown in FIG. 7D, a user who is not familiar with how to use the device may mistakenly present his / her finger at a position deeper than the finger rest (finger climbing occurs). If an incorrect presentation is made as shown in FIG. 7 (d), since the fingertip side is not aligned, the finger presentation position is likely to deviate greatly during registration and authentication. You may not be properly authenticated as the person. Moreover, the light which should be irradiated to the high position of the side surface of a finger will be irradiated to the belly side of the finger. For this reason, an image containing a large amount of light reflected on the finger surface is taken, and a clear vein image cannot be obtained. As described above, if the vein pattern is registered in a state where the finger rest cannot be used correctly, the authentication accuracy is lowered.

  Therefore, in the third embodiment, the user's finger placement is determined at the time of registration, and if it is not placed correctly, a warning is issued to the user to prevent registration in the wrong placement. Except for the processing flow at the time of registration, the process is the same as in the first embodiment. FIG. 8 shows a processing flow at the time of registration according to the third embodiment. First, finger presentation detection (S101) is performed, and when a finger is presented, finger placement determination processing (S80) is performed. If the finger can be placed correctly, light amount adjustment (S103), pattern extraction (S108), and feature data creation (S109) are performed, and registration is completed. If the finger is not correctly placed, a warning is given to the user (S82), and the process returns to the finger presentation detection process (S101). The warning is transmitted to the user using the display unit 17 and the audio output unit 6. The finger presentation (S101), placement determination (S80), and warning (S81) are repeated until the user places the finger in the correct placement.

  The finger placement determination process (S80) is performed according to the following procedure. First, the aforementioned light source 3 is turned on with a constant light amount value. As described above, transmitted light is photographed in the correct placement, and reflected light is photographed in the wrong placement. When light passes through the finger, the light is scattered in the finger, and only a part of the light traveling downward is captured by the imaging unit 4. Accordingly, the luminance value of the image (FIG. 7C) taken by the imaging unit 4 is lowered. On the other hand, when light is reflected from the finger surface, most of the light output from the light source 3 is imaged by the imaging unit 4. Therefore, the luminance value of the image (FIG. 7 (f)) photographed by the imaging unit 4 is high. It is determined whether or not the finger can be correctly placed by using the difference in luminance value. When a plurality of light sources 3 are arranged as in the light source arrangement shown in FIG. 10, the light sources 3 that are turned on for the finger placement determination may be all the light sources of the device 2, but only the light sources on the fingertip side. May be lit. As shown in FIG. 7D, when a finger rides on the fingertip, the position on the fingertip side is higher than the finger base. For this reason, when only the light source on the fingertip side is turned on, the difference in the image due to the difference in the placement becomes remarkable.

  There is also a method of using the touch sensor 23 as a detection method of the finger ride. As shown in FIG. 9, touch sensors 23-(1) and 23-(2) are respectively installed on the upper surface of the protrusion 21 and the finger rest 26. When the finger is correctly presented, the touch sensor 23- (1) of the finger rest 26 is turned on and the touch sensor 23- (2) of the protrusion 21 is turned off. On the other hand, when the finger has been picked up, the touch sensor 23- (1) is turned off and the touch sensor 23- (2) is turned on. Thus, it is possible to detect whether or not the finger is correctly placed by determining the state of the touch sensor.

  FIG. 11 shows a fourth embodiment in the case where the small finger vein authentication device described above is used by being incorporated in a locker.

  As a method of incorporating an authentication device into the locker 90, there are a central management type in which a plurality of doors are controlled by one authentication device and an individual management type in which an authentication device is incorporated in each door. Among these, the individual management type is more convenient than the central management type in which locking and unlocking is performed at a position away from the door to be used because the locker locking and unlocking procedures can be performed in front of each door. In addition, since an authentication device is attached to each door, there is an advantage that no waiting time occurs when a plurality of users use lockers. Since the authentication device of the present invention is sufficiently small relative to the locker door, it can also be used for an individual management type. In the fourth embodiment, a case of using as an individual management type will be described.

  In this embodiment, the apparatus 2 is installed on the surface of the locker door 92 as shown in FIG. When installing on the higher door 92- (a), install the device so that the fingertip of the device 2 faces upward, and when installing the authentication device on the lower door 92- (b) Set up the device so that it faces. Thereby, even when a finger is presented to any height of the locker, the finger can be presented naturally. If the fingertip is placed upward even at a low door, the user is authenticated with a low posture, which reduces convenience. As described above, changing the direction of the finger presentation between the upper door and the lower door also has an effect of making it difficult to forget which door the user has put in the luggage. Further, when the upper stage door is assembled with the apparatus below the door and the lower stage door is assembled with the apparatus above the door, the convenience is further enhanced.

  In addition, when installing in a locker, you may install in the direction which becomes substantially horizontal as shown in FIG. FIG. 15A shows an individually managed locker. 15 (b), FIG. 15 (c), and FIG. 15 (d) show the door 92- (a) at the high position from the direction A in FIG. 15 (a), the door 92- (b) at the middle stage, and the low position. It is the figure which looked at door 92- (c). In the case where the device 2 is installed on a door having a height similar to the height of the user's shoulder, the device 2 is installed horizontally as shown in FIG. When installing on a high door, as shown in FIG. 15B, the position where the fingertip is presented is tilted so as to be slightly higher. Conversely, when installing on a lower door, place the fingertips downward. This makes it easier for the user to present a finger. Moreover, although the example in which the apparatus 2 is incorporated in the locker door has been described above, the locker is not limited to the door but may be mounted in, for example, the space 94 between the locker box and the like.

  When the user puts a package in the locker 90 and closes the door, the authentication device is activated and the registration process is started. The user presents a finger according to the procedure of the first embodiment and performs registration processing. When registration is complete, the locker is locked. When opening the locker, an authentication process is performed. If it is determined that the finger is the same as the pattern at the time of registration, the locker is unlocked.

  When performing registration and authentication processing, a guide is given to the user through the display unit 17 or a speaker installed on the locker door 90. When the display unit 17 such as a liquid crystal monitor is used as a guide method, the authentication device and the display unit 17 are installed as close as possible. If the display unit 17 and the device 2 are installed at positions separated from each other, the user needs to see the display unit 17 and the device 2 alternately at the time of authentication, which reduces convenience. In addition, depending on the user, there is a case in which only the display unit 17 is watched and a finger is presented by relying solely on the sense of touch without visually confirming the position of the protrusion 21 of the device 2. If the finger presentation position is determined only by tactile sense, the reproducibility of the finger presentation position decreases. Therefore, the display unit 17 and the device 2 are installed close enough to allow the user to see at the same time.

  As disclosed in Patent Document 2, when using the finger vein data acquisition device 2 with a narrow imaging range, the authentication accuracy is improved by capturing a plurality of vein images at the time of registration and holding a plurality of registered patterns. Can do. In the present embodiment as well, a technique for increasing the authentication accuracy by holding a plurality of registered patterns is used. However, it is burdensome for the user to take multiple shots at the time of registration.

  Therefore, in this embodiment, the burden on the user is reduced while photographing a plurality of registered patterns using two methods.

  First, a method for reducing the mental burden on the user by devising guidance to the user will be described. Specifically, out of N registered image captures, a display “register” is displayed except for the last registered image capture, and the registered image is captured and stored. Next, at the time of the last registration data shooting, a guide “Check that authentication is correct” is displayed. After that, an image is taken and feature data is created, and collation processing is performed to confirm whether authentication can be performed correctly. At this time, the feature data created for the verification test is also used as the feature data for registration. As a result, the user feels that the registration work has been completed one less than the number of shots. Therefore, the experience time at the time of user registration can be reduced, and the mental burden can be reduced. In particular, when shooting two registration patterns, the user feels that the registration has been completed with a single registration, so the mental burden on the user can be particularly effectively reduced.

  Next, a method for reducing the burden on the user by reusing the registered pattern will be described.

  Since ordinary lockers are used by an unspecified number of people, it is not possible to store registration data for all users. Further, only one user uses one door 90 at the same time. Therefore, as a processing flow performed in the authentication system, a method of registering when the locker is locked and repeating the process of discarding the registration pattern when the locker is unlocked can be considered.

  However, in this method, even when the same person uses the same locker continuously, a registration procedure is required every time the locker is locked. In particular, when using the N-time registration method described above, it is necessary to take N times of registered images every time the locker is used. This places a heavy burden on the user. Therefore, while the same person is continuously using the registration data 220, the burden on the user is reduced.

  A processing procedure for reusing the registration data 220 will be described. In this method, the registration data is not discarded even after the authentication is successful, and a transition is made to the next user registration waiting state while retaining the registration data. When the next user performs the registration procedure, it is determined whether this user is the same person as the previous registrant. Specifically, first, the user takes the first registered image. Next, the registration data 220 of the previous registrant stored in the storage device 14 is compared with the registration pattern created from the first captured image of the current user. Based on this result, it is determined whether or not the current user is the previous user. As a result of the collation, when it is determined that the same user is continuously used, the previous registration data is reused as the current registration data, and the registration process is terminated. If the user is another user, the previous registration data is deleted from the storage area 14. After that, the registered images are taken until the required number of images is reached, such as the second image, the third image, and the registration data is created and stored after the completion of N times of image capturing, and the registration process is completed.

  In this way, by reusing registered images, a plurality of registered images can be acquired only by taking the first registered image. For this reason, when the same person is used continuously twice or more, in the second and subsequent registration processes, the registration process can be completed at the stage where one registered image is taken.

  It may be a security problem if the registered pattern is stored in the storage device 14 for a long time even after the user uses it. Therefore, when a certain time has passed after the last user has used, it is determined that the locker is not continuously used, and the registration data 220 is deleted from the storage area 14. Thereby, the safety | security of this apparatus is securable.

  In this embodiment, in the method of reducing the burden on the user by reusing the registration pattern, the registration data for the past one person is retained, and the registration process for the corresponding person is shortened. However, for example, by storing registration data for the past three people and holding the registration data as long as the storage area 14 is not restricted, such as shortening the registration processing for the three people concerned, The number of people and opportunities that can reduce the burden on the person can be increased.

  FIG. 12 is an embodiment showing another shape of the left and right finger rests 27 and 28. 12A and 12B are top views of the vein data acquisition apparatus 2, and FIGS. 12C, 12D, and 12E are cross sections taken along the straight lines A, B, and C in FIG. The figure is shown.

  When a light source such as a light guide that has high directivity and can accurately control the irradiation direction is used as the light source 3, the shapes of the left and right finger rests 27 and 28 can be simplified. For example, the device 2 of FIG. 12 is provided with finger rests 27 and 28 for supporting only the fingertips and the root side of the left and right fingers. Since the left and right fingers 201 and 202 are supported at two points, the fingertip and the base, they can be maintained at a higher position than the central finger 200. For this reason, the light source is not blocked by the left and right fingers 201 and 202. In addition, when the directivity of the light source 3 is high, there is no light that travels directly above the light source 3, so even if the light is not shielded between the left and right fingers 27 and 28 and the light source 3, Is not illuminated. Therefore, a smaller apparatus can be realized while having the same image quality as the apparatus of the first embodiment. When the device is large in the longitudinal direction of the finger, the finger may bend back and support the light source 3 by supporting only the two points of the fingertip and the base. Therefore, as shown in FIG. 12 (f), the finger rests 27 and 28 may be arranged at the left and right positions of the opening to support the left and right fingers 201 and 202 at three points. This further stabilizes the left and right fingers.

  When a light source with high directivity is used, the installation position of the light source 3 can be increased to the same height as the left and right finger rests 27 and 28 as shown in FIG.

  The light source 3 shown in the example of FIG. 17A is a light guide that is designed so that light is emitted only in the inner direction of the apparatus and no light is output in the direction directly above or outside the light source 3. For this reason, the left and right fingers 201 and 202 are not irradiated with light even if the light shielding member is not installed directly above the light source 3. In addition, the light source 3 is installed close to the inside so that the left and right fingers 201 and 202 are not blocked by the left and right fingers even when they approach the center finger 200. Therefore, the light source is not blocked when the left and right fingers approach, and the image quality of the vein image does not deteriorate.

  In the example of FIG. 17A, a step is provided between the central finger rest and the left and right finger rests. Thereby, even when the left and right fingers approach the center finger, a space is created under the left and right fingers. Therefore, the light output from the light source 3 can be reliably irradiated to the central finger 200 without being blocked. If a device such as that shown in FIG. 17B is not provided with a step and irradiates light at the same position as the device shown in FIG. to degrade.

  FIG. 13 shows an example of a finger vein data acquisition apparatus 2 in which light source elements 3- (a) and 3- (b) having two types of angles are arranged as the light source 3 and are switched on and turned on for each finger. 13 (a) and 13 (b) show top views of the apparatus. 13C and 13D are cross-sectional views taken along lines A and B in FIG. 13A.

  The installation angle α of the light source element 3- (a) is a small value that can reliably irradiate light even on a thin finger. On the other hand, the light source element 3- (b) has a larger installation angle α than the light source element 3- (a), and can irradiate light toward a higher position. When a thin finger is presented, a vein is photographed using only the light source element 3- (a), and when a thick finger is presented, only the light source element 3- (b) is photographed. Thereby, since light can be irradiated to the highest position of each finger | toe, a clear vein image can be image | photographed.

  The processing flow of the apparatus shown in FIG. 13 will be described with reference to FIG. When the presentation of the finger 200 is detected (S101), an optimal light source for the finger is selected (S102). The processing flow for light source selection is as shown in FIG. First, the light source element 3- (b) aimed at the upper side is selected as a candidate (S1020), and is lit at the maximum light quantity value (S1021). Next, the image at that time is taken (S1022), and the average luminance of the image is calculated (S1023). Thereafter, it is determined whether the calculated value is equal to or greater than the target luminance value. If it is equal to or higher than the target luminance value, it can be determined that a sufficient amount of light has been applied to the presented finger 200. Therefore, the light source element 3- (b) is selected, and the light source selection process is completed. Conversely, when the average luminance is lower than the target value, it is determined that the finger is not sufficiently irradiated with light, that is, the light is passing over the finger. Therefore, the light source is selected again. The light source element 3- (a) is selected as the next candidate, and the processing from the light source lighting (S1021) to the average brightness determination (S1024) is performed. . As described above, it is possible to select a light source aiming at a position as high as possible for the finger by lighting in order from the light source facing in the high direction. After the light source selection is completed, the light amount adjustment (S103) is performed using the selected light source 3, and pattern extraction processing (S108) and feature data creation processing (S109) are performed. Similar to the speed-up method of the light amount adjustment (S103) described in the second embodiment, the light amount value after the light amount adjustment is completed and the selected light source may be stored in the storage device 14. Thereby, the light quantity selection process at the time of authentication becomes unnecessary, and high-speed and highly accurate authentication can be performed.

  Note that the order of arrangement of the light sources 3 is light source element 3- (a), light source element 3- (b), light source element 3- (a), and light source element 3- (b) in order from the fingertip side. . Since the finger is narrower on the fingertip side than on the root side, the light source element 3- (a) having a small α is disposed on the fingertip side, so that it is possible to deal with a thinner finger.

  In the present embodiment, the light source elements with two types of angles have been described. Similarly, when the installation angle of the light source elements is set to three or more types, similarly, the image quality can be enhanced most by sequentially lighting the light source elements from the higher angle. A light source element can be selected.

  In the various embodiments described above, a locker is cited as an object to which the finger vein authentication device is applied. However, the authentication device of the present invention can be a mobile phone terminal, a personal digital assistant (PDA), a personal computer (PC). It can also be applied to mobile devices such as automobiles, entry / exit management devices, and the like. Moreover, the described examples are merely examples, and it goes without saying that the present invention is not limited to the above-described embodiments.

DESCRIPTION OF SYMBOLS 2 ... Vein data acquisition apparatus, 3 ... Light source, 4 ... Imaging part, 6 ... Audio | voice output part, 10 ... Authentication process part, 11 ... CPU, 12 ... Memory, 13 ... Interface (IF), 14 ... Memory | storage device, 15 ... Power supply unit, 17 ... display unit, 18 ... image input unit, 19 ... information input unit, 20 ... opening, 21 ... positioning projection, 22 ... light shielding wall, 23 ... touch sensor, 24 ... infrared transmission filter, 26 ... Central finger rest, 27 ... Left finger rest, 28 ... Right finger rest, 31 ... Light (optical path), 32 ... Gap, 42 ... Irradiation axis of light source 3, 43 ... Left end of finger rest 28, 200 ... Authentication Target finger 201: Left finger of authentication target finger 202: Right finger of authentication target finger 100: Authentication program 220 ... Registration data 240 ... Authentication data 98, 99 ... Acrylic board.

Claims (15)

A first finger rest on which a finger to be authenticated is placed;
A light source for irradiating the finger to be authenticated with light;
An imaging unit that images a blood vessel image of the authentication target finger based on light transmitted through the palm side of the authentication target finger;
A processing unit that performs authentication using blood vessel feature information in the blood vessel image;
A second finger rest that is installed at a position higher than the first finger rest and places a finger other than the authentication target finger; and
The height from the first finger rest is lower than the height of the second finger rest in the direction from the first finger rest to the second finger rest. A light-shielding wall installed between the first finger rest and the second finger rest;
With
The light source is
The lower part of the finger placing table and a part of the light source are arranged to be lower than the first finger placing table,
The second finger rest is
A light shielding member that blocks light from the light source irradiated to a finger other than the placed authentication target finger;
The light shielding wall is
Blocking light from the light source toward the palm side of the finger to be authenticated;
A biological body characterized in that light from the light source directed from the palm side to the back side of the finger to be authenticated is allowed to pass from a light transmitting portion formed between the second finger rest and the light shielding wall. Authentication device. The biometric authentication device according to claim 1, wherein the light source is arranged obliquely upward from below the first finger rest. The biometric authentication device has a housing,
The biometric authentication device according to claim 1, wherein the first finger rest, the second finger rest, and the light shielding wall are integrally formed. The biometric authentication device according to any one of claims 1 to 3, wherein the processing unit performs authentication by using blood vessel feature information in the blood vessel image and pre-stored feature information. . 5. The biometric authentication device according to claim 1, wherein the light transmitting unit is formed so as to direct light from the light source toward an imaging axis of the imaging unit. . The biometric authentication device according to any one of claims 1 to 5, wherein an opening is formed at a position lower than the first finger rest. A finger presentation unit for presenting a finger to be authenticated;
A light source for irradiating the finger to be authenticated with light;
An imaging unit for imaging a blood vessel image of the finger to be authenticated;
A finger placement table that is placed at a position higher than the finger presentation unit and can place a finger other than the authentication target finger; and
A light shielding wall installed in the finger presentation unit;
Have
The ground plane of the light source is formed below the finger placement table and at least a part of the light source is lower than the finger presentation unit,
The finger placement table is:
A light shielding member that blocks light from the light source irradiated to a finger other than the placed authentication target finger;
A biometric authentication device that allows light from the light source to pass through a window formed between the finger placing table and the light shielding wall. The biometric authentication apparatus according to claim 7, further comprising a processing unit that performs authentication using blood vessel characteristic information in the blood vessel image. The biometric authentication device according to claim 7 or 8, wherein the light source is arranged from below the finger presentation unit to obliquely above. The biometric authentication device has a housing,
The biometric authentication device according to claim 7 or 8, wherein the finger presentation unit, the finger placement table, and the light shielding wall are integrally formed. The biometric authentication apparatus according to claim 8, wherein the processing unit performs authentication by using blood vessel feature information in the blood vessel image and feature information stored in advance. The biometric authentication device according to claim 7, wherein the window portion is formed so as to direct light from the light source toward an imaging axis of the imaging unit. The biometric authentication device according to claim 7 or 8, wherein an opening is formed at a position lower than the finger presentation unit. The body,
A finger presenting unit formed on the housing and presenting a finger to be authenticated;
A light source for irradiating the finger to be authenticated with light;
An imaging unit for imaging a blood vessel image of the finger to be authenticated;
Have
A part of the casing is a convex shape formed on the side of the finger presentation unit so as to be higher than the finger presentation unit,
The grounding surface of the light source is formed so that at least a part of the light source is lower than the finger presentation unit inside the convex portion of the housing.
The convex portion of the housing is
Formed by a light-transmitting member disposed at a position higher than the finger presenting unit on the side surface on the finger presenting unit side and a light shielding member that blocks light from the light source,
A biometric authentication apparatus, wherein light from the light source is transmitted through the light transmitting member. The biometric authentication device according to claim 14, wherein the light source is disposed obliquely upward from below the finger presentation unit.

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