JP5047773B2 - Finger vein imaging device and personal authentication device - Google Patents

Description

  The present invention relates to a device that captures a finger vein image and a personal authentication device that authenticates an individual using the captured vein image data.

  Recently, a valuable locker (Patent Document 1) that can be authenticated using a bar code, a non-contact IC card or the like together with a personal identification number has become widespread. Recently, it has been proposed to improve convenience and security at the same time by authenticating individuals using biometric information such as fingerprints and finger veins. Among them, finger vein authentication technology has begun to be recognized by general users through ATMs of financial institutions, and has attracted attention as an authentication means for valuable lockers.

Regarding finger vein authentication technology, a device (see Patent Document 2) for improving the reproducibility of vein data by providing various guide portions for a finger to regulate the position of the finger to improve authentication accuracy, A device (see Patent Document 3) of a personal authentication device having a function of reading palm vein data is known.
JP 2002-129795 A JP 2006-331441 A JP 2006-331239 A

  Generally, the finger vein authentication device includes a user interface for photographing a finger vein arranged above an acrylic imaging surface. However, the user interface of the finger vein authentication device has a portion similar to that of the fingerprint authentication device, and a user who is not familiar with the finger vein authentication device may mistake this as a fingerprint authentication device. In particular, when a finger vein authentication device is used as an authentication unit for valuable lockers used by an unspecified number of users, it is expected that the rate of occurrence of such misidentification will increase.

  If the finger vein authentication device is mistakenly recognized as a fingerprint authentication device, the user starts photographing of the finger vein with the tip of the abdomen of the finger in contact with the acrylic imaging surface. The finger vein image data captured in this manner cannot perform correct biometric authentication, resulting in a decrease in authentication accuracy.

  Therefore, a control algorithm for shooting after detecting that a finger is placed on each guide part by incorporating a sensor for detecting the approach of the finger in each guide part on which the tip and base of the finger pad are placed. There is something to prepare. However, even when the tip of the finger belly is in contact with the acrylic imaging surface, if the tip of the finger approaches the guide part, the sensor detects that the tip of the finger has approached and starts shooting. . Thus, the present situation is that the control algorithm cannot be sufficiently functioned.

  The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a finger vein imaging device capable of imaging a finger vein image with a finger placed in a correct position, and An object of the present invention is to provide a personal authentication device for performing personal authentication using finger vein video data photographed by this finger vein imaging device.

  According to a first aspect of the present invention, there is provided a tip placement portion including a tip placement surface on which a tip of the belly of a finger is placed and a first finger sensor that detects the approach of the finger from a change in capacitance, and a finger belly. A base mounting portion having a base mounting surface on which the base of the head is mounted, a photographing surface that forms a recess between the tip mounting surface and the base mounting surface, and a tip of the finger on the tip mounting surface and the base mounting surface. Take a picture of the finger vein through the imaging surface and a light source that emits light with a higher light absorption rate to the finger vein than other parts of the finger toward the finger with the tip and root in contact with each other. An imaging unit, an imaging control unit that instructs the imaging unit to perform imaging when at least the first finger sensor detects the approach of a finger, and a side surface of a recess that connects the tip placement surface and the imaging surface. The gist of the present invention is to provide a finger vein imaging device having an insulating member.

  According to the first feature of the present invention, by disposing the insulating member along the side surface of the recess that connects the tip mounting surface and the imaging surface, the user can use the side surface of the recess that connects the tip mounting surface and the imaging surface. The tip of the finger can no longer be approached. Therefore, the first finger sensor is prevented from detecting the approach of the finger while the tip of the finger belly is in contact with the imaging surface, so that the imaging unit is in a state where the tip of the finger belly is in contact with the imaging surface. Taking pictures of finger veins is also suppressed.

  A second feature of the present invention is that a tip placement portion including a tip placement surface on which a tip of the belly of the finger is placed and a first finger sensor that detects the approach of the finger from a change in capacitance, A base mounting portion having a base mounting surface on which the base of the belly is placed; a photographing surface that forms a recess between the tip mounting surface and the base mounting surface; and a finger pad on the tip mounting surface and the base mounting surface. Take a picture of the finger vein through the imaging surface and a light source unit that emits light with a higher light absorption rate to the finger vein than the other parts of the finger toward the finger in contact with the tip and root of the finger An imaging unit, an imaging control unit that instructs the imaging unit to perform imaging when at least the first finger sensor detects the approach of a finger, and a side surface of a recess that connects the tip contact surface and the imaging surface. Insulating member and vein image data for registering finger vein image data captured by the imaging unit A registration unit, and summarized in that the photographing unit is a personal authentication apparatus and a data matching unit for matching the image data registered in the image data and the vein image data registration unit of the vein of the finger taken.

  According to the second feature of the present invention, by disposing the insulating member along the side surface of the recess that connects the tip mounting surface and the imaging surface, the user can use the side surface of the recess that connects the tip mounting surface and the imaging surface. The tip of the finger can no longer be approached. Therefore, the first finger sensor is prevented from detecting the approach of the finger while the tip of the finger belly is in contact with the imaging surface, so that the imaging unit is in a state where the tip of the finger belly is in contact with the imaging surface. Taking pictures of finger veins is also suppressed. Therefore, it is possible to register the image data of the finger vein arranged at the correct position, and also to check the image data of the finger vein arranged at the correct position with the registered image data. Authentication accuracy is improved.

  In the first and second features, the exposed portion of the insulating member may be formed of a material that does not cause irregular reflection of light rays emitted from the light source unit. Thereby, irregular reflection of light by the insulating member is suppressed, and the imaging unit can capture a clear finger vein image.

  Alternatively, the exposed surface of the insulating member may be subjected to a surface treatment that does not cause irregular reflection of light emitted from the light source unit. Thereby, irregular reflection of light by the insulating member is suppressed, and the imaging unit can capture a clear finger vein image.

  In the first and second features, the base placement unit further includes a second finger sensor that detects the approach of a finger from a change in capacitance, and the imaging control unit includes the first finger sensor that approaches the finger. And when the second finger sensor detects the approach of the finger, the photographing unit may be instructed to perform photographing. Thereby, when the first and second finger sensors detect the approach of the finger, the image of the finger vein is captured, so the imaging unit captures the image of the finger vein with the finger placed at the correct position. be able to.

  In the second feature, the vein image data registration unit registers and registers the finger vein image data captured by the imaging unit and the order in which the first and second finger sensors detect the approach of the finger, The collation unit may collate the finger vein image data captured by the image capturing unit and the order in which the finger approach is detected with the image data and order registered in the vein image data registration unit.

  As the order of placing the finger, there are two ways to place the finger: placing the finger base after placing the finger tip; and placing the finger placing the finger tip after placing the finger base. is there. By registering the finger vein image data and the finger placement method, that is, the order in which the finger sensor detects the approach of the finger connected and registered, and collating the finger vein image data and the finger placement order, Since finger vein authentication can be performed in consideration of finger position shifts due to differences in finger placement and individual differences (癖) in finger placement, authentication accuracy is improved.

  According to the present invention, a finger vein imaging device capable of capturing a finger vein image with a finger placed in a correct position, and personal authentication using finger vein image data captured by the finger vein imaging device A personal authentication device can be provided.

Embodiments of the present invention will be described below with reference to the drawings. In the description of the drawings, the same parts are denoted by the same reference numerals.
(First embodiment)
With reference to FIG. 1, the overall configuration of the finger vein imaging apparatus according to the first embodiment of the present invention will be described. The finger vein imaging apparatus according to the first embodiment is an apparatus that images a vein image inside a finger of a user's hand 1, for example, an individual using a captured finger vein image. It can be used as a part of a personal authentication device (biometric authentication device) for authenticating. The finger of the hand 1 to be photographed may be any finger (mother finger, index finger, middle finger, ring finger, little finger), but here, an example of photographing the vein of the middle finger (hereinafter simply referred to as “finger”) To explain.

  Specifically, as shown in FIG. 1, the finger vein imaging device places a base portion 2 that supports the entire user's hand 1, a tip placement portion 11 for placing the tip of the finger belly, and a base of the finger belly. The root placement portion 12, the transparent plate 13 arranged on the line connecting the tip placement portion 11 and the root placement portion 12, and the tip and root of the finger pad are respectively the tip placement portion 11 and the root placement portion 12. A light source unit 14 a that emits a light beam toward the finger placed on the head, and an insulating member 15 disposed between the tip mounting unit 11 and the transparent plate 13.

  The user places the palm of his / her hand 1 on the surface of the base portion 2. At this time, the user places the tip of the abdomen of one finger (middle finger) on the surface (tip placement surface) of the tip placement unit 11 and places the base of the belly of one finger (middle finger) on the root placement unit 12. Place on the surface (base mounting surface). The light source unit 14 a is disposed between the tip mounting unit 11 and the root mounting unit 12. The light beam emitted from the light source unit 14 a is mainly emitted in a direction substantially perpendicular to the line connecting the tip mounting unit 11 and the root mounting unit 12. Thereby, the light beam emitted from the light source unit 14a is applied to the finger of the hand 1 placed in the state shown in FIG.

  In the example of FIG. 1, two side walls are formed on both sides of the tip placement portion 11, the transparent plate 13 and the root placement portion 12 along a line connecting the tip placement portion 11 and the root placement portion 12. The light source part 14a is arrange | positioned inside one side wall. An elongated window is formed on the inner side surface of the side wall along a line connecting the tip mounting portion 11 and the root mounting portion 12, and the light emitted from the light source unit 14a is placed in the state shown in FIG. 1 through this window. 1 finger is irradiated. Although not shown in FIG. 1, similarly, a light source part is also arranged inside the other side wall, an elongated window is formed on the inner side surface, and light rays emitted from the light source part are passed through this window as shown in FIG. The finger of the hand 1 placed in the state shown in FIG. Each of the two side walls is inserted between the index finger and the middle finger and between the middle finger and the ring finger, so that the left and right direction of the middle finger to be imaged (a line connecting the tip placement portion 11 and the root placement portion 12) The function of regulating the positional deviation in the direction perpendicular to ().

  Although not shown in FIG. 1, the finger vein imaging apparatus further includes an imaging unit that captures an image of the finger vein through the transparent plate 13 and an imaging control unit that controls the operation of the imaging unit. The imaging unit will be described later with reference to FIG. 3, and the imaging control unit will be described later with reference to FIGS. 4, 7, and 8. Moreover, although the surface of the base part 2 is a plane, it may have a shape that can be easily adapted to the palm of the user's hand 1.

  With reference to FIG. 3, the structure of the imaging | photography part 17, the imaging | photography control part 18, etc. which are arrange | positioned inside the base part 2 of FIG. 1 is demonstrated. FIG. 3 is a cross-sectional view taken along the line BB in FIG. Side walls are arranged between the ring finger 1b and the middle finger 1a and between the middle finger 1a and the index finger 1c, and light source portions 14a and 14b are arranged inside each side wall. Each of the light source units 14a and 14b is obtained by arranging a plurality of LEDs on one circuit board along the longitudinal direction of the window of FIG. The light beams emitted from the plurality of LEDs are irradiated to the middle finger 1a from the window formed on the inner surface of the side wall.

  Inside the base unit 2, an imaging unit 17 including a solid-state imaging device such as a CCD (charge coupled device) image sensor or a CMOS image sensor, and a mirror 19 that reflects light transmitted through the transparent plate 13 toward the imaging unit 17. A photographing control unit 18 that controls the photographing operation of the photographing unit 17 is disposed. The photographing unit 17 photographs an image composed of light that is transmitted through the transparent plate 13 and reflected by the mirror 19. As part of the image captured by the imaging unit 17, an image of the vein of the finger 1a is captured.

With reference to FIG. 2, the detailed structure of other members excluding the base portion 2 in FIG. 1 will be described. 2 is a cross-sectional view taken along the line AA in FIG. The tip placement section 11 includes a tip placement surface TF _{F on} which the tip of the belly of the finger is placed, a first finger sensor 21 that detects the approach of the finger from a change in capacitance, and a place on which the tip of the finger is placed. And an induction lamp 23 disposed on the surface. The tip placement surface TF _F is a surface with which the tip of the belly of the finger contacts, and has a concave curved shape that fits the tip of the finger belly. The first finger sensor 21 is disposed inside the tip placement unit 11 and detects that a finger approaches the tip placement unit 11. The guide lamp 23 functions to teach the user the position where the tip of the finger is to be placed by turning on and blinking. Further, the induction lamp 23 forms a convex portion relative to the distal mounting surface TF _F, by inducing to a position in contact with the tip of a finger on the convex portion, the mounting longitudinal direction (the tip of the middle finger portion 11 and The positional deviation in the direction parallel to the line connecting the root placement portions 12 can be regulated.

Base mounting portion 12 includes a base mounting surface TF _B Place the base of the ball of the finger and a second finger sensor 22 for detecting the approach of the finger from the change in capacitance. The base mounting surface TF _B is a surface with which the base of the belly of the finger contacts, and has a concave curved surface shape that fits into the base of the base of the finger. The second finger sensor 22 is disposed inside the root placement unit 12 and detects that a finger approaches the root placement unit 12.

  The imaging control unit 18 in FIG. 3 captures the finger vein with respect to the imaging unit 17 when the first finger sensor 21 detects the approach of the finger and the second finger sensor 22 detects the approach of the finger. Instruct to do. The imaging control unit 18 is not limited to this. When the first finger sensor 21 detects the approach of the finger, the imaging control unit 18 opens the finger vein to the imaging unit 17 regardless of the result of the second finger sensor 22. You may instruct to shoot.

The transparent plate 13 includes an imaging surface BF that forms a recess between the tip mounting surface TF _F and the root mounting surface TF _B. Since the imaging surface BF forms a recess, the finger is placed above the imaging surface BF of the transparent plate 13 when the tip and base of the belly of the finger are placed on the tip placement surface TF _F and the base placement surface TF _B , respectively. It can float and be held stably. Examples of the transparent plate 13 include an acrylic plate or a glass plate.

  The light source unit 14a irradiates a finger placed above the imaging surface BF of the transparent plate 13 with light rays. The imaging unit 17 captures an image of a finger vein within a range irradiated with light rays. In the range of the finger irradiated with light, the first joint (distal interphalangeal joint) counted from the fingertip in the case of the second to fifth fingers (indicator, middle finger, ring finger, little finger) excluding the thumb : DIP joint; distal interphalangeal joint) to the second joint (proximal interphalangeal joint: PIP joint). Of course, further, light may be irradiated in the range from the distal interphalangeal joint to the fingertip or in the range from the proximal interphalangeal joint to the base of the finger (MP joint; metacarpophalangeal joint). Absent. The same applies to the image range of the finger vein imaged by the imaging unit 17.

  The wavelength band of the light beam emitted from the light source unit 14a is preferably higher in the light absorption rate with respect to the finger vein than other parts of the finger. Since the vein absorbs more light rays than other parts, the imaging unit can capture the image of the finger vein more clearly. However, the present invention is not limited to this, and the wavelength band of the light emitted from the light source unit 14a may have a lower light absorption rate with respect to the finger vein than other parts of the finger. That is, it is only necessary to irradiate light having a wavelength band that is different from that of other parts of the finger with respect to the finger vein.

The insulating member 15 is disposed along the side surface of the recess that connects the tip placement surface TF _F and the imaging surface BF. The surface of the insulating member 15 is a surface which contacts the tip of the ball of the finger, as with the tip mounting surface TF _F, has the shape of a concave surface, as familiar to the tip of the ball of the finger. Furthermore, the surface of the insulating member 15 preferably has a shape which is continuous with the tip mounting surface TF _F.

  The material of the insulating member 15 is preferably made of a material that does not cause irregular reflection of light rays emitted from the light source unit. It is desirable that at least the exposed portion of the material of the entire insulating member 15 is made of a material that does not cause irregular reflection of light rays emitted from the light source portions 14a and 14b. By suppressing the irregular reflection of light by the insulating member, the imaging unit 17 can capture a clear finger vein image. Alternatively, the exposed surface of the insulating member may be subjected to a surface treatment that does not cause irregular reflection of light emitted from the light source units 14a and 14b.

  The thickness of the insulating member 15 in the direction perpendicular to the side surface of the recess is set in advance depending on the degree of finger approach that can be detected by the first finger sensor 21.

Specifically, the first finger sensor 21 measures a change in capacitance due to the approach of a finger, which is a conductor, and detects that the finger has approached the tip placement unit 11 from the amount of change in capacitance. Therefore, as shown in FIG. 4 (a), by placing the tip top tip mounting surface TF _F of the ball of the finger 1a, first finger sensor 21, the finger has approached the tip mount 11 Detect that.

However, the approach of the finger is possible not only from the tip placement surface TF _F but also from the side surface of the recess that connects the tip placement surface TF _F and the imaging surface BF. Therefore, as shown in FIG. 4B, the first finger sensor 21 is brought into contact with the tip placement portion 11 when the tip of the finger contacts or approaches the side surface SF _F of the recess. Will be detected.

  As shown in FIGS. 1 and 2, the user interface of the finger vein authentication device that images the finger vein placed above the imaging surface BF of the transparent plate 13 is similar to that of the fingerprint authentication device. There is a risk that a user unfamiliar with the finger vein authentication device may mistake this as a fingerprint authentication device. If the finger vein authentication device is mistakenly recognized as a fingerprint authentication device, the user may cause the tip of the finger pad to contact the imaging surface BF of the transparent plate 13 as shown in FIG.

It is contacted with the tip portion of the ball of the finger to the imaging surface BF of the transparent plate 13, if the tip of the finger if approaching or whether contact with the side surface SF _F of the recess, the first finger sensor 21 is approaching the finger Will be detected. Therefore, on the condition that the second finger sensor 22 also detects the approach of the finger, the imaging control unit 18 in FIG. 3 instructs the imaging unit 17 to image the finger vein, The finger vein imaging is started. Correct biometric authentication cannot be performed on video data of finger veins taken with the tip of the abdomen of the finger in contact with the imaging surface BF of the transparent plate 13, and authentication accuracy is reduced.

Therefore, as shown in FIG. 4C, by disposing the insulating member 15 along the side surface SF _F of the concave portion that connects the tip placement surface TF _F and the imaging surface BF, the user can place the side surface SF _F of the concave portion. The tip of the finger 1a cannot be approached. Accordingly, since the first finger sensor 21 is prevented from detecting the approach of the finger 1a in a state where the tip of the finger belly is in contact with the imaging surface BF, the tip of the belly of the finger 1a is in contact with the imaging surface BF. In this state, the photographing unit 17 is also prevented from photographing the vein image of the finger 1a.

Therefore, the insulating member 15 is only required to be disposed at least in the sensitivity region of the first finger sensor 21 extending in the direction perpendicular to the side surface SF _F from the side surface SF _F of the recess, and in the direction perpendicular to the side surface SF _F of the recess. The thickness of the insulating member 15 may be a thickness that does not detect the finger 1a approaching the side surface SF _F of the recess.

  The detection principle of the first finger sensor 21 and the second finger sensor 22 will be described with reference to FIG. Here, the first finger sensor 21 and the second finger sensor 22 are simply referred to as “finger sensors”. As shown in FIG. 7A, in the circuit configuration of the finger sensor, a predetermined power supply voltage is applied between the resistor R and the switch connected in series, and the capacitor Ca and the sensor unit are connected in parallel to the switch. Has been. FIG. 7A shows a case where the finger is not in contact with the sensor unit, and FIG. 7B shows a circuit configuration when the finger is in contact with the sensor unit. When the finger comes into contact with the sensor unit, a capacitor Cx formed by the sensor unit and the finger is newly connected in parallel to the switch. The graph of FIG. 7C shows the time change of the voltage Vc applied to both ends of the switch after the switch is turned off. (A) shows the time when the finger is not in contact, and (b) shows the time when the finger is in contact. The time required for the voltage Vc to reach the predetermined threshold voltage Vth after the switch is turned off is different between when the finger is not in contact (Tca) and when the finger is in contact (Tcx). The finger sensor detects the approach of the finger.

  As described above, according to the first embodiment of the present invention, the following operational effects can be obtained.

By disposing the insulating member 15 along the side surface SF _F of the recess that connects the tip placement surface TF _F and the imaging surface BF, the user can use the side surface SF _{F of the} recess that connects the tip placement surface TF _F and the imaging surface BF. The tip of the finger can no longer be approached. Accordingly, since the first finger sensor 21 is prevented from detecting the approach of the finger in a state where the tip of the finger belly is in contact with the imaging surface BF, the tip of the finger belly is in contact with the imaging surface BF. It is also suppressed that the imaging unit 17 captures a finger vein image.

  By forming the exposed portion of the insulating member 15 with a material that does not cause irregular reflection of the light rays emitted from the light source portions 14a and 14b, the irregular reflection of light by the insulating member 15 can be suppressed, and the photographing unit 17 has a clear finger. A vein image can be taken. Similarly, by subjecting the exposed surface of the insulating member 15 to surface treatment that does not cause irregular reflection of light emitted from the light source parts 14a and 14b, irregular reflection of light by the insulating member 15 can be suppressed, and the photographing unit 17 can capture a clear finger vein image.

When the first finger sensor 21 detects the approach of the finger and the second finger sensor 22 detects the approach of the finger, the image capturing control unit 18 instructs the image capturing unit 17 to perform the image capturing. Since the image of the finger vein is captured when the first and second finger sensors 21 and 22 detect the approach of the finger, the imaging unit 17 captures the image of the finger vein with the finger placed at the correct position. be able to.
(Second Embodiment)
With reference to FIG. 5, the overall configuration of a personal authentication apparatus according to the second embodiment of the present invention will be described. The personal authentication device according to the second embodiment is an example of a biometric authentication device that authenticates an individual using a finger vein image captured using the finger vein imaging device 42 of FIG.

  Specifically, the personal authentication device is a finger vein imaging device 42 in FIG. 1 and a vein data verification device that registers finger vein video data and compares the captured finger vein video data with registered data. 43, and a data cable 32 for connecting the finger vein imaging device 42 and the vein data collating device 43 to mutually transmit and receive data. Since the finger vein imaging device 42 has the same configuration as shown in FIGS. 1 to 3, detailed description of the configuration and illustration of a detailed cross-sectional view are omitted.

  With reference to FIG. 6, a functional configuration of the personal authentication apparatus of FIG. 5 will be described. The personal authentication device 41 includes a finger vein imaging device 42 and a vein data collating device 43. The vein data collation device 43 includes a vein image data registration unit 51 for registering finger vein image data captured by the finger vein imaging device 42, video data registered in the vein image data registration unit 51, and the finger of the imaged finger A data collation unit 52 that collates with vein video data and a memory 53 that stores video data registered by the vein video data registration unit 51 are provided.

  For example, the vein image data registration unit 51 determines whether image data of the user's finger vein is registered in the memory 53. If not registered, the vein image data registration unit 51 controls the finger vein imaging device 42 to image the finger vein image data of the user, and registers the imaged image data in the memory 53. On the other hand, if registered, the data collation unit 52 controls the finger vein imaging device 42 to capture the image data of the user's finger vein, and the captured image data and the image data registered in the memory 53. Are compared to determine whether or not they match. Thereby, the personal authentication device can authenticate the individual using the finger vein (biological information).

  The vein data collating device 43 is, for example, a microprocessor such as a CPU that performs data calculation processing, a storage device such as a RAM or ROM that stores data, and an input / output that controls data input / output via the data cable 32. This can be realized using a normal computer system including an output control unit. Of the functional blocks constituting the vein data collation device 43, the vein image data registration unit 51 and the data collation unit 52 can be implemented as a computer program that specifies the function performed by the microprocessor in the computer system. The computer program can be stored in a computer-readable recording medium. The above-described vein data collating device 43 can be realized by reading this recording medium by a computer system and executing the computer program to control the computer. Here, the recording medium includes a memory device, a magnetic disk device, an optical disk device, and other devices capable of recording a program.

  With reference to the flowchart of FIG. 8, an example of an operation procedure until the personal authentication device shown in FIGS. 5 and 6 detects the approach of the finger and starts photographing the finger vein will be described.

  (A) First, in step S01, the imaging control unit 18 sets the first finger sensor 21 and the first finger sensor 21 in a state where the tip and base of the finger belly are not placed on the tip placement unit 11 and the root placement unit 12, respectively. The stray capacitance of the second finger sensor 22 is initialized.

  (B) Proceeding to step S03, the imaging control unit 18 activates the imaging unit 17. Thereby, the photographing unit 17 starts photographing.

  (C) The process proceeds to step S05 and waits for a change to occur in the image captured by the imaging unit 17. Specifically, a change in the image is detected when the imaging unit 17 captures an image of the finger due to the finger appearing on the imaging surface BF.

  (D) When a change in image is detected (YES in step S03), the process proceeds to step S05, and the imaging control unit 18 starts an integration process of the voltage Vc of the first finger sensor 21 and the second finger sensor 22. Thus, the time change of the voltage Vc of the first finger sensor 21 and the second finger sensor 22 is measured.

  (E) Proceed to step S09, and when the first finger sensor 21 detects the approach of the finger as a result of measuring the time change of the voltage Vc of the first finger sensor 21 (YES in step S09), proceed to step S11. Then, it is determined whether or not the second finger sensor 22 detects the approach of the finger. Then, when the second finger sensor 22 detects the approach of the finger (YES in step S11), the process proceeds to step S15, and the vein image data registration unit 51 in FIG. → "Finger root" is registered in the memory 53. Thereafter, the flow of FIG. 8 ends, and shooting of the finger vein image is started.

  (F) When the second finger sensor 22 does not detect the approach of the finger (NO in step S11), the process proceeds to step S13, and steps S11 and 13 are repeatedly performed until a predetermined time has elapsed (YES in step S13). Then, it waits for the second finger sensor 22 to detect the approach of the finger. If the predetermined time has elapsed (YES in step S13), the process returns to step S09.

  (G) On the other hand, when the first finger sensor 21 does not detect the approach of the finger in step S09 (NO in step S09), the process proceeds to step S17, and has the second finger sensor 22 detected the approach of the finger? Judge whether or not. When the second finger sensor 22 detects the approach of a finger (YES in step S17), the process proceeds to step S19. When the second finger sensor 22 does not detect the approach of the finger (NO in step S17), the process returns to step S09.

  (H) In step S19, it is determined whether or not the first finger sensor 21 detects the approach of the finger. When the first finger sensor 21 detects the approach of the finger (YES in step S19), the process proceeds to step S23, and the vein image data registration unit 51 in FIG. → "Finger tip" is registered in the memory 53. Thereafter, the flow of FIG. 8 ends, and shooting of the finger vein image is started.

  (L) On the other hand, when the first finger sensor 21 does not detect the approach of the finger in step S19 (NO in step S19), the process proceeds to step S21, and until a predetermined time has elapsed (YES in step S21), step S19 And 21 are repeatedly performed to wait for the first finger sensor 21 to detect the approach of the finger. If the predetermined time has elapsed (YES in step S21), the process returns to step S09.

  The vein image data registration unit 51 registers the finger placement data, that is, the data in the order in which each finger sensor detects the approach of the finger, with the finger vein image data in the memory 53. Then, the data collation unit 52 collates the data by connecting the finger vein image data and the finger placement order.

  As described above, according to the second embodiment of the present invention, the following operational effects can be obtained in addition to the first embodiment.

By disposing the insulating member 15 along the side surface SF _F of the recess that connects the tip placement surface TF _F and the imaging surface BF, the user can use the side surface SF _{F of the} recess that connects the tip placement surface TF _F and the imaging surface BF. The tip of the finger can no longer be approached. Accordingly, since the first finger sensor 21 is prevented from detecting the approach of the finger in a state where the tip of the finger belly is in contact with the imaging surface BF, the tip of the finger belly is in contact with the imaging surface BF. It is also suppressed that the imaging unit 17 captures a finger vein image. Therefore, the vein image data registration unit 51 can register the image data of the finger vein arranged at the correct position, and the data collation unit 52 can store the image data of the finger vein arranged at the correct position. Since it is possible to collate with the registered video data, the authentication accuracy is improved.

  As the order of placing the finger, there are two ways to place the finger: placing the finger base after placing the finger tip; and placing the finger placing the finger tip after placing the finger base. is there. The vein image data registration unit 51 registers and registers the finger vein image data and the finger placement, that is, the order in which the finger sensor detects the approach of the finger, and the data matching unit 52 registers the finger vein image. Finger vein authentication that takes into account differences in finger position due to differences in finger placement and individual differences (癖) due to differences in finger placement is performed by concatenating and collating data and the order of finger placement. Authentication accuracy is improved.

  As described above, the present invention has been described according to the first and second embodiments. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. That is, it should be understood that the present invention includes various embodiments not described herein. Therefore, the present invention is limited only by the invention specifying matters according to the scope of claims reasonable from this disclosure.

1 is a perspective view showing an overall configuration of a finger vein imaging apparatus according to a first embodiment of the present invention. It is sectional drawing along the AA cut surface of FIG. 1 which shows the detailed structure of the other member except the base part 2. FIG. It is sectional drawing along the BB cut surface of FIG. FIG. 4A is a cross-sectional view showing an example of “correct finger position” in which the tip of the finger pad is placed on the tip placement surface TF _F , and FIG. 4B shows the tip of the finger pad. is a cross-sectional view showing an example of placed on the imaging surface BF of the transparent plate 13 "position of the wrong finger", FIG. 4 (c) side surface of the recess connects the imaging plane BF and distal mounting surface TF _F along the SF _F is a sectional view showing an example of the "position of the wrong finger" in the case of disposing an insulating member 15. It is a perspective view which shows the whole structure of the personal authentication apparatus concerning the 2nd Embodiment of this invention. It is a block diagram which shows the functional structure of the personal authentication apparatus shown in FIG. 5, especially the vein data collation apparatus 43. FIG. It is a figure for demonstrating the detection principle of the 1st finger sensor 21 and the 2nd finger sensor 22, FIG.7 (a) shows a circuit structure when a finger | toe is not contacting, FIG.7 (b) FIG. 7C is a graph showing a time change of the voltage Vc when the finger is not in contact and when the finger is in contact. It is a flowchart which shows the operation | movement procedure of the personal authentication apparatus shown in FIG.5 and FIG.6.

Explanation of symbols

1 ... hand 1a ... middle finger (finger)
DESCRIPTION OF SYMBOLS 1b ... Ring finger 1c ... Index finger 2 ... Base part 11 ... Tip placement part 12 ... Root placement part 13 ... Transparent plate 14a, 14b ... Light source part 15 ... Insulating member 17 ... Imaging part 18 ... Imaging control part 19 ... Mirror 21 ... 1st finger sensor 22 ... 2nd finger sensor 23 ... Guide lamp 32 ... Data cable 41 ... Personal authentication device 42 ... Finger vein imaging device 43 ... Vein data collation device 51 ... Vein image data registration unit 52 ... Data collation unit 53 ... Memory BF ... Shooting surface SF _F ... Side surface TF _B ... Base mounting surface TF _F ... Tip mounting surface

Claims (9)

A tip placement portion comprising a tip placement surface on which the tip of the belly of the finger is placed and a first finger sensor that detects the approach of the finger from a change in capacitance;
A root placement portion having a root placement surface on which the base of the belly of the finger is placed;
An imaging surface that forms a recess between the tip mounting surface and the root mounting surface;
The absorption rate of light with respect to the finger vein is higher than that of other parts of the finger toward the finger in a state where the tip of the finger and the base of the finger are in contact with the tip placement surface and the root placement surface, respectively. A light source unit that emits light rays;
An imaging unit that captures an image of the finger vein through the imaging surface;
An imaging control unit that instructs the imaging unit to perform imaging when at least the first finger sensor detects the approach of a finger;
A finger vein imaging apparatus, comprising: an insulating member disposed along a side surface of the recess that connects the tip placement surface and the imaging surface.   The finger vein imaging apparatus according to claim 1, wherein the exposed portion of the insulating member is made of a material that does not cause irregular reflection of light emitted from the light source unit.   The finger vein imaging apparatus according to claim 1, wherein the exposed surface of the insulating member is subjected to a surface treatment that does not cause irregular reflection of light emitted from the light source unit. The base mounting portion further includes a second finger sensor that detects the approach of the finger from a change in capacitance,
The imaging control unit instructs the imaging unit to perform the imaging when the first finger sensor detects a finger approach and the second finger sensor detects a finger approach. The finger vein imaging device according to any one of claims 1 to 3. A tip placement portion comprising a tip placement surface on which the tip of the belly of the finger is placed and a first finger sensor that detects the approach of the finger from a change in capacitance;
A root placement portion having a root placement surface on which the base of the belly of the finger is placed;
An imaging surface that forms a recess between the tip mounting surface and the root mounting surface;
The absorption rate of light with respect to the finger vein is higher than that of other parts of the finger toward the finger in a state where the tip of the finger and the base of the finger are in contact with the tip placement surface and the root placement surface, respectively. A light source unit that emits light rays;
An imaging unit that captures an image of the finger vein through the imaging surface;
An imaging control unit that instructs the imaging unit to perform imaging when at least the first finger sensor detects the approach of a finger;
An insulating member disposed along a side surface of the recess that connects the tip contact surface and the imaging surface;
A vein image data registration unit for registering finger vein image data captured by the imaging unit;
A personal authentication device, comprising: a data collating unit that collates image data of a finger vein imaged by the imaging unit and image data registered in the vein image data registration unit.   The personal authentication device according to claim 5, wherein the exposed portion of the insulating member is made of a material that does not cause irregular reflection of light emitted from the light source unit.   The personal authentication apparatus according to claim 5, wherein the exposed surface of the insulating member is subjected to a surface treatment that does not cause irregular reflection of light emitted from the light source unit. The base mounting portion further includes a second finger sensor that detects the approach of the finger from a change in capacitance,
The imaging control unit instructs the imaging unit to perform the imaging when the first finger sensor detects a finger approach and the second finger sensor detects a finger approach. The personal authentication device according to any one of claims 5 to 7. The vein image data registration unit registers and registers the finger vein image data captured by the imaging unit and the order in which the first and second finger sensors detect the approach of the finger,
The data collating unit collates the finger vein image data photographed by the photographing unit and the order in which the finger approach is detected with the image data and order registered in the vein image data registering unit. 9. The personal authentication device according to claim 8, wherein

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