JP2018077741A - Blood vessel image capturing apparatus and personal identification system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in which there is the possibility that with the technology disclosed in the patent literature 1, when a hand as an image capture target is moving upon capturing a blood vessel image, a proper image capture timing cannot be determined, thereby a quality of a captured blood vessel image lowers and further authentification accuracy lowers.SOLUTION: A blood vessel image capturing apparatus has a plurality of light sources disposed in a matrix fashion, a sensor for obtaining hand position information, a light amount control unit for selecting a radiation light source for applying a radiation to a hand from the plurality of light sources to control a light amount of the radiation light source, and an image capturing unit for capturing an image of blood vessels included in a finger of the hand irradiated with light from the radiation light source disposed at a position opposing to the radiation light source. The image capturing unit captures an image at an image capturing timing determined by an image capturing timing determining unit based on history information of a hand position.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an apparatus and a method for identifying an individual using human biological information, in particular, a finger blood vessel pattern.

One biometric authentication device that can perform high-precision personal authentication uses a blood vessel pattern. This uses the fact that blood vessel patterns differ from person to person. For example, when using a finger blood vessel pattern, the blood vessel pattern that emerges when light is applied to the finger is compared with the finger blood vessel pattern information registered in advance. This is a device that performs personal authentication. Patent Document 1 describes a personal authentication device that performs personal authentication using a finger blood vessel pattern while walking.
Patent Document 2 discloses a biometric authentication apparatus capable of capturing a clear image of a living body with a small halation area by installing the extension line of the optical axis of irradiation light so as not to intersect with an imaging apparatus for capturing a finger vein image. Etc. are described. Patent Document 3 describes a biometric authentication device that can perform personal authentication using a finger blood vessel while moving a hand.

WO2016 / 084214

  In the technique disclosed in Patent Literature 1, when the imaging target hand is moving at the time of imaging a blood vessel image, an appropriate imaging timing cannot be determined, and thus the quality of the captured blood vessel image may be deteriorated. Yes, as a result, the authentication accuracy may be reduced.

Based on a plurality of light sources arranged in a grid, a sensor for acquiring hand position information, and a light source for irradiating the hand based on the position information acquired from the position sensor, the light source for irradiation is selected from the plurality of light sources. A light amount control unit that controls the light amount of the light source for imaging, and an imaging unit that captures an image of a blood vessel included in the finger part of the hand irradiated with light from the irradiation light source arranged at a position facing the irradiation light source. Prepared,
The imaging unit performs imaging at the imaging timing determined by the imaging timing determination unit based on the history information of the hand position.

  Even when the imaging target hand is moving at the time of imaging a blood vessel image, an appropriate imaging timing can be determined, and the quality of the imaged blood vessel image is improved, and as a result, improvement in authentication accuracy can be expected.

Figure showing the authentication device from diagonally above View of the authentication device from the side System configuration example of authentication device The figure which shows the flowchart of personal authentication processing The figure which shows the history of the position of the hand at the time of personal authentication The figure which shows the flowchart at the time of estimating the imaging | photography position in a personal authentication. The figure which shows the modification of an authentication apparatus The figure which shows the modification of an authentication apparatus The figure which shows the modification of an authentication apparatus The figure which shows the modification of an authentication apparatus The figure which shows the modification of an authentication apparatus The figure which shows the modification of an authentication apparatus The figure which shows the modification of an authentication apparatus The figure which shows the modification of an authentication apparatus The figure which shows the modification of an authentication apparatus

  In the present embodiment, an apparatus for authenticating a person with high accuracy when authenticating while moving a hand during walking will be described. Note that this example assumes that the biometric authentication device performs personal authentication processing within the main unit. However, in the main unit, processing is performed up to blood vessel image capturing, and authentication processing is performed by a server installed outside the main unit. May be.

  FIG. 1 is a view of the authentication device as viewed obliquely from above. The authentication device 101 is disposed so as to face the upper side from the front of the position sensor 104 and the imaging unit 105, the position sensor 104 that acquires the position information of the hand, the imaging unit 105 that is installed in the vicinity and facing the same direction. A light source array 102 composed of a plurality of point light sources 103 and an arrow mark 107 indicating a direction in which the hand 106 passes are provided.

  At the time of personal authentication, the user opens his / her finger with his fingertip facing downward and extends the position sensor 104 and the imaging unit 105 between the light source array 102 and the palm toward the position sensor 104 and the imaging unit 105. Pass in the direction of the arrow mark 107. The process flow of personal authentication will be described later with reference to FIG.

  The point light source 103 is disposed from the back of the hand so that the finger can be irradiated from an oblique direction at an angle of 1 to 89 degrees with respect to the extended finger (for example, at an angle of 45 degrees downward from the horizontal direction). .

  FIG. 2 is a side view of the authentication device. When taking a blood vessel image of a moving hand, it is generally necessary to shorten the exposure time in order to take a clear blood vessel image while preventing image blurring. When the exposure time is shortened, the image generally becomes dark. Therefore, it is necessary to apply strong illumination to obtain a clear image. In order to increase the degree of freedom of the hand presentation position and direction and the movement path to the presentation position, light is applied from above the fingertip direction when a blood vessel image is taken from a position 10 cm to 50 cm away from the hand. Luminance saturation (halation) occurs at the fingertips, the sides of the fingers, and the crotch between the fingers. The halation is generated when the imaging unit directly receives the light irradiated and reflected on the finger side surface. When strong illumination is applied, the area where halation occurs increases and authentication accuracy decreases. However, when light is emitted from the wrist side of the hand at an angle of 1 to 89 degrees with respect to the extended finger, the distance of passing light in the living body becomes longer and halation can be reduced. Illumination is arranged to irradiate light.

  FIG. 3 is a system configuration diagram of the authentication apparatus. The position sensor 104 of the authentication apparatus 101 converts the position information of the hand 106 into an electrical signal and takes it into the computer 311 via the position information input unit 309 and the interface 312. The computer 311 calculates the posture of the hand 106, the position of the finger, the posture of the finger, and the like by the CPU 317 using the program stored in the memory 316 from the captured position information, and records the hand position history information 319 in the memory 316. To do. Details of the history information 319 will be described later with reference to FIG. The computer 311 stores the hand position history information 319 recorded in the history information 319, the posture of the hand 106, the finger position, the finger posture, and the hand posture, finger position, and finger posture calculated immediately before. Then, the CPU 317 calculates the predicted time when the hand reaches a position suitable for angiography. As a result of the calculation, when the current time has reached the predicted time, the predicted position of the finger among the plurality of point light sources 103 arranged in the light source array 102 is illuminated from the computer 311 via the interface 312 and the light source control unit 310. An object is selected and turned on, irradiated light is applied to the finger, and the light reaching the imaging unit 105 disposed on the opposite side is received. The received light is converted into an electrical signal by the imaging unit 105, and is taken into the computer 311 as an image via the image input unit 308 and the interface 312 and recorded in the memory 316. The recorded image is collated with one or more images recorded in advance in the external storage device 318 by a program recorded in the memory 316 to perform personal authentication. By applying irradiation light from a point light source to a plurality of fingers, images of a plurality of fingers can be taken simultaneously and used for personal authentication. The authentication result can be notified to the person through the speaker 313 or the display device 315.

  FIG. 4 is a flowchart of the personal authentication process. First, in step 401, the authenticator presents a hand. Next, in step 402, the CPU 317 acquires position information from the position sensor. Next, in step 403, the CPU 317 detects a hand in the vicinity of the sensor from the position information acquired in step 402. Next, in step 404, the CPU 317 determines whether or not a hand has been detected in step 402. If no hand is detected, the process returns to step 402. If a hand is detected, the process proceeds to step 405 where the CPU 317 calculates information such as the fingertip position, finger orientation, and finger tilt of each finger from the hand position information acquired from the position sensor, and stores the hand on the memory. Is written in the history information 319 at the position of. Next, in step 407, the CPU 317 reads the previously written information such as the fingertip position, finger orientation, and finger tilt from the hand position history information 319, and the time at which the hand reaches an appropriate position for angiography. Make predictions. Details of step 407 will be described later with reference to FIG. Next, in step 408, the CPU 317 determines whether or not the predicted arrival time at the shooting position of the hand performed in step 407 is the current time. If the current time has not yet reached the expected arrival time, step 408 is performed. Return to 402. If the current time has reached the predicted arrival time at the shooting position of the hand performed in step 407, the process proceeds to step 409, where the CPU 317 is arranged in the light source array 102 via the interface 312 and the light source control unit 310. The point light source 103 that illuminates the predicted position of the finger is selected and lit. Next, in step 410, the CPU 317 captures a finger blood vessel image by the imaging unit 105 and captures the image into the computer 311. In step 411, the CPU 317 detects a plurality of finger regions from the finger blood vessel image. Next, in step 412, the CPU 317 corrects the finger orientation and the distortion due to posture fluctuation. Next, in step 413, the CPU 317 extracts finger blood vessel feature information from each finger blood vessel image. Next, in step 414, the CPU 317 collates the finger blood vessel feature information extracted in step 413 with the finger blood vessel feature information recorded in the external storage device 318 in advance, and calculates a collation score. Next, in step 415, the CPU 317 compares whether or not the collation score calculated in step 414 exceeds the threshold value TH1. If the verification score exceeds the threshold value TH1, the process proceeds to step 416, and after the processing after successful authentication is performed, the process proceeds to step 418 and the authentication process is terminated. If the verification score does not exceed the threshold value TH1, the process proceeds from step 414 to step 417, the CPU 317 performs post-authentication processing, and proceeds to step 418 to end the authentication process.

  FIG. 5 is an example of a detailed view of the hand position history information 319. Each column of the hand position history information includes a time 501 when the position sensor information is acquired, and an x coordinate 503 that is a three-dimensional coordinate acquired from the position sensor 502 of the position information 502 of the fingertip of the first finger of the identified hand. , Y coordinate 504, z coordinate 505, fingertip information 506 of the second finger, fingertip information 507 of the third finger, fingertip information 508 of the fourth finger, fingertip information 509 of the fifth finger, Is composed of.

  A pointer variable top 510 indicates the position of the history information written last. In the example of FIG. 5, the pointer variable top 510 is history information that records the position information of the fingertip for five times. In other words, when writing new information, the oldest information is overwritten, and the indication destination of the pointer variable top 510 is changed to the written history information entry. The destination of the pointer variable top 510 moves to line 511 and line 512 every time new history information is written. After the line 515 is designated, the line 511 is designated again.

  FIG. 6 is a flowchart for predicting the photographing position in the personal authentication, and is a diagram illustrating the processing in step 407 performed by the CPU 317. In step 601, prediction of the time when the hand comes to the shooting position is started. In step 602, the history information recorded in the hand position history information 319 is read. Next, in step 603, the approximate function x = fx (t) indicating the correlation between the time and the x-space coordinate of the hand by the least square method, the approximate function y = fy (t) indicating the correlation between the time and the y-space coordinate of the hand, and the time An approximate function z = fz (t) indicating the correlation between the hand and the z-space coordinates of the hand is calculated. Next, in step 604, the approximate function calculated in step 603 described above is used to calculate the time at which the fingertip reaches the coordinates at which the hand is appropriate for angiography. To do. At this time, the coordinates at which the hand is at an appropriate position for angiography are not deviated from the angle of view of the camera, and the values have such a width that the focus shift is within a predetermined range, so that the expected arrival time can be calculated. The possibility of disappearing can be reduced. The parameter indicating the range may be set as a fixed value in advance, but may be designed so that it can be changed according to the installation location of the authentication device. Finally, in step 605, the prediction of the time when the hand comes to the shooting position is ended.

  FIG. 7 shows a modified example of the authentication device, and is a diagram showing a blood vessel image photographing device in which a light source and an imaging unit are stored in two columnar protrusions each having a columnar part in a columnar shape. . By arranging so that the distance between the two protrusions is the narrowest in front of the camera, when presenting the finger, keep the posture of opening the hand, extending the finger, and pointing the palm toward the camera, It can be urged to pass in front of the camera. In addition, by causing the light emitting unit 701 in the form of opening the open hand, which is arranged in the projecting part where the light source is arranged, to emit light at predetermined intervals in order from the approach side of the hand, triggered by the sensor detecting the hand, It is possible to urge the user to open the hand, extend the finger, pass the palm in front of the camera toward the camera side, and move the hand in accordance with the hand locus and the speed of the light emitting unit. The trigger may be a method other than hand detection. For example, the light emission may be started when it is detected that a person approaches by another sensor (not shown).

  In the present embodiment, if the hand does not pass through a position suitable for angiography, a warning sound may be emitted from the speaker 313 to notify the authenticator and prompt the user to present the hand again.

  In the present embodiment, an apparatus will be described in which an opening is installed on the top surface of the housing, and an imaging unit installed upward in the housing captures a finger vein image through the opening.

  FIG. 8 is a view of a modification example of the authentication device viewed obliquely from above. In this example, an opening 801 is provided on the upper surface of the housing 101, and a blood vessel image is captured through the opening 801. The light source 102 is installed on the top of the housing so as to emit light toward the imaging unit 105. Further, the light source 102 is installed at an angle with an angle so that it is difficult to contact the user during authentication.

  FIG. 9 is a view of a modification example of the authentication device viewed from the side. Since the description of each configuration overlaps with the description of FIG.

  FIG. 10 is a view of a modified example of the authentication device viewed obliquely from above. A dent disposed along the trajectory for moving the hand on the upper surface of the authentication device housing illustrated in FIG. 8 and FIG. It is a figure which shows the authentication apparatus which installed the light emission part in the shape of several palms. By providing the depression along the locus for moving the hand, it is possible to encourage the locus of the hand when presenting the hand to be along the depression. In addition, the light emitting unit 701 in the shape of the open hand, which is installed in the hollow, emits light at a predetermined interval in order from the approach side of the hand, so that the hand is opened, the finger is extended and passed in front of the camera, and It is possible to prompt the user to move the hand according to the light emission interval of the light emitting unit.

  FIG. 11 is a diagram of a modification example of the authentication device viewed from above. This figure shows an authentication device having a function of avoiding contact by moving the light source 102 when the hand passes. In order for the light source 102 to irradiate light at an angle of 1 to 89 degrees on the finger extended from the wrist side of the hand presented at the shooting position, the light source 102 is positioned closer to the authenticator than directly above the hand. is set up. For this reason, since there is a possibility of contact with the authenticator who is walking, it is possible to contact the authenticator by moving the light source 102 as indicated by the arrow and moving it away from the authenticator after completing the finger vein image capturing. Can be reduced.

  In this embodiment, an authentication device that performs authentication by presenting a hand with a fingertip facing upward will be described.

  FIG. 12 shows a modified example of the authentication device, which has a hand-shaped cutout, and is 1 to 89 degrees from the horizontal direction so that the fingertip direction of the hand-shaped cutout is upward. It is a figure which shows the apparatus which is equipped with the guide plate 1201 installed at an angle, and image | photographs and authenticates a blood vessel image, when moving a hand in parallel with respect to the guide plate 1201. The light source 102 is disposed on the front side of the guide plate 1201 with respect to the traveling direction of the authenticator, and the position sensor 104 and the imaging unit 105 are disposed on the back side of the guide plate with respect to the traveling direction.

  FIG. 13 is a side view of a modified example of the authentication device. In order to reduce the possibility that the authenticator contacts the light source 102 and improve the operability, the point light source 103 is disposed obliquely on the light source 102. The light irradiation direction is the same as that described in FIG.

  FIG. 14 is a view of a modification example of the authentication device viewed from above. Since the description of each configuration overlaps with the description of FIG.

  FIG. 15 is a view of a modification example of the authentication device viewed from above. In this example, the light source 102 is moved to reach the irradiation position when the hand passes, so that a feeling of openness at the time of authentication by the authenticator is ensured. With this configuration, when the hand approaches the guide plate 1201, the light source 102 moves to the irradiation position as indicated by the arrow, and the finger vein image is captured and authenticated when the hand passes through the notch of the guide plate. .

DESCRIPTION OF SYMBOLS 101: Authentication apparatus 102: Light source array 103: Point light source 104: Position sensor 105: Imaging part 106: Hand 107: Arrow mark 308: Image input part 309: Position information input part 310: Light source control part 311: Computer 312: Interface 313 : Speaker 314: Keyboard 315: Display device 316: Memory 317: CPU 318: External storage device 319: Hand position history information 701: Light-emitting unit with open hand 801: Opening on top of housing 1201 Induction plate

Claims (8)

A plurality of light sources arranged in a grid, a sensor for acquiring hand position information, and an irradiation light source for irradiating the hand are selected from the plurality of light sources based on the position information acquired from the position sensor. Photographing a blood vessel image included in a finger portion of the hand irradiated with light from the irradiation light source disposed at a position facing the irradiation light source; A photographing unit;
The blood vessel image photographing device, wherein the photographing unit performs photographing at a photographing timing determined by a photographing timing determining unit based on history information of a hand position. In the blood vessel imaging device according to claim 1,
The history information is information indicating coordinates on the three-dimensional space regarding the position of the hand for each time,
The blood vessel image photographing device, wherein the photographing timing determining unit determines a photographing timing based on a predetermined approximate function. In the blood vessel imaging device according to claim 2,
A first protrusion that stores a light source in a horizontal direction and a part of a column surface is cylindrical;
A second projecting portion facing the light source and having a columnar part in a columnar shape,
The imaging unit is disposed on the second protrusion,
The blood vessel image photographing apparatus, wherein the first projecting portion and the second projecting portion are arranged so that a distance between them is the smallest in front of the photographing section. In the blood vessel imaging device according to claim 3,
The second protrusion includes a plurality of light emitting portions arranged in a hand shape,
The plurality of light emitting units emit light at a predetermined order and at predetermined time intervals when the sensor detects a hand. In the blood vessel imaging device according to claim 2,
An opening that is installed on the top surface of the housing and allows light to reach the imaging unit;
A depression placed on the top surface of the housing and arranged along a trajectory through which the hand passes;
A plurality of light emitting units arranged in a shape with open hands in the depression,
The light source is installed on the upper part of the opening so as to face the imaging unit,
The plurality of light emitting units emit light at a predetermined order and at predetermined time intervals when the sensor detects a hand. In the blood vessel imaging device according to claim 5,
The blood vessel imaging apparatus according to claim 1, wherein the light source is provided in a movable part that moves when the sensor detects a hand and avoids contact with the authenticator. In the blood vessel imaging device according to claim 2,
A guide plate installed on the side of the housing, having a hand-shaped cutout and installed at an angle of 1 to 89 degrees from the horizontal direction so that the fingertip direction of the cutout is upward; An angiography apparatus characterized by the above. In the blood vessel image capturing device according to claim 7,
The blood vessel image photographing apparatus according to claim 1, wherein the light source is provided in a movable part that moves to an irradiation position when a hand is detected.

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