JP6206683B2 - Biological imaging apparatus and biological imaging method - Google Patents

Description

  The present invention relates to a biological imaging apparatus and a biological imaging method.

  A biometric authentication technique for authenticating an individual using a captured image of a finger is known as a method of collating an epidermis pattern such as a fingerprint or a blood vessel pattern with previously registered information.

  An example of such a biometric authentication technique is described in Patent Document 1.

  FIG. 10 is a block diagram of the invention of Patent Document 1. In FIG.

  In the invention of Patent Document 1, when performing personal authentication using a blood vessel pattern of a finger, the finger to be authenticated is placed between the infrared light sources 310 and 320 and the infrared transmission filter 340. When the microcomputer 370 drives the drive circuit 360 to turn on the infrared light source 310, the infrared light is absorbed by blood hemoglobin, so that a blood vessel pattern is formed on the image sensor 350 via the lens 340. Note that the infrared transmission filter 330 has a characteristic of cutting visible light that becomes noise to obtain a blood vessel pattern and transmitting only infrared light including the blood vessel pattern. On the other hand, when performing personal authentication using a fingerprint pattern, a finger to be authenticated is placed at the same position as personal authentication using a blood vessel pattern of the finger. When the infrared light source 310 is turned off, the surface of the finger is imaged on the image sensor 350 via the lens 340. The blood vessel pattern or fingerprint pattern imaged by the image sensor 350 is photoelectrically converted into an electric signal and is taken into the microcomputer 370. The infrared light source 320 is turned on for the purpose of obtaining sufficient brightness to obtain a fingerprint pattern.

  As described above, the invention of Patent Document 1 is a personal authentication device that switches a light source to irradiate and separately images a blood vessel and a fingerprint with a single imaging unit.

  Further, Patent Document 2 discloses a biological image input device having an imaging unit that inputs infrared light into a finger and captures a fingerprint image and a blood vessel image of the finger using the scattered light. This living body image input device has a window member formed by juxtaposing a fiber plate and a transparent plate thicker than the fiber plate on the light incident side of the imaging unit, and the fingerprint of the fingertip portion is in contact with the fiber plate side of the window member. Thus, the fingerprint image is taken through the fiber plate side of the window material, and the blood vessel image is taken through the transparent plate side of the window material.

JP 2004-234040 A JP 2009-69981 A

  However, the invention disclosed in the above-described patent document has the following problems.

  First, the invention of Patent Document 1 can obtain a blood vessel image having a better contrast than the reflected light method, but the light source must be arranged on the finger or on the side, and the apparatus becomes large. In addition, there is a problem in that it is difficult to place a finger due to a light source and the operability is deteriorated.

  Furthermore, the invention of Patent Document 1 must perform fingerprint image capture and blood vessel image capture separately by switching light sources, and can perform fingerprint image capture and blood vessel image capture at a time. Therefore, there is a problem that it takes time to obtain information for authentication.

  Further, the invention of Patent Document 2 has a structure in which a finger is brought into contact with a plate or a transparent plate to read the fingerprint and the blood vessel. By making the contact, the blood vessel is pressed and the blood escapes and it is difficult to obtain a blood vessel image. There was a problem.

  Therefore, the present invention has been invented in view of the above problems, and an object of the present invention is to provide a biological imaging apparatus and a biological imaging method capable of simultaneously capturing a blood vessel and a fingerprint image of a finger without switching light sources. It is to provide.

  The present invention that solves the above-described problems includes an irradiation unit that irradiates light to a first part of a living body, reflected light that is irradiated by the irradiation part and reflected by the first part, and a second part of the living body. An imaging unit that captures the biometric matching image of the first part and the second part with radiated light that is propagated and radiated inside, at least the second part being any member It is a living body imaging device which does not contact.

  The present invention that solves the above problem irradiates a first part of a living body with light, propagates the reflected light that is irradiated and reflected by the first part, and propagates inside the second part of the living body. In the biological imaging method, biometric verification images of the first part and the second part are captured with emitted radiation, and at least the second part is not in contact with any member.

  According to the present invention, it is possible to simultaneously capture a blood vessel and a fingerprint image of a finger without switching light sources.

FIG. 1 is a block diagram of a personal authentication apparatus in the present embodiment. FIG. 2 is an operation flowchart of fingerprint and blood vessel imaging and collation in the first embodiment. FIG. 3 is a perspective view of the living body imaging apparatus according to the first embodiment. FIG. 4 is a diagram for explaining the first embodiment. FIG. 5 is a longitudinal sectional view of the biological imaging apparatus. FIG. 6 is a diagram illustrating an example of a fingerprint image and a blood vessel image captured by the living body imaging apparatus according to the first embodiment. FIG. 7 is a diagram illustrating an example of image processing performed on a fingerprint image captured by the living body imaging apparatus according to the first embodiment. FIG. 8 is a diagram illustrating an example of image processing performed on a blood vessel image captured by the living body imaging apparatus according to the first embodiment. FIG. 9 is a block diagram of a personal authentication device according to another embodiment. FIG. 10 is a diagram for explaining a technique related to the present invention.

  An embodiment of the present invention will be described.

  The embodiment of the present invention shows an example in which the living body imaging apparatus of the present invention captures a living body, for example, a fingerprint of a human finger and blood vessels, and is applied to a personal authentication apparatus.

  FIG. 1 is a block diagram of a personal authentication device in the present embodiment. As shown in FIG. 1, the personal authentication device according to the first embodiment includes a spot light generation light source 1, an imaging unit 2, an imaging control unit 3, an image processing unit 4, a matching unit 5, and a display unit. 6.

  The spot light generation light source 1 is installed at a position where it does not come into contact with the finger FG, and the entire fingerprint part between the distal interphalangeal joint (first joint) of the finger FG and the finger tip has a substantially uniform brightness, and the fingerprint part. Irradiate parallel light spotwise. Here, the parallel light refers to light that uniformly strikes the fingerprint portion (the surface of the fingerprint portion) at substantially the same angle. In addition, the spot light generation light source 1 preferably irradiates from one direction because it is desirable to make a shadow due to the unevenness of the skin surface as much as possible in order to capture a fingerprint that is the unevenness of the skin surface of the finger FG.

  The spot light of the spot light generating light source 1 is preferably a wavelength component in the vicinity of a wavelength of 1000 to 600 nm, which is known to be easily transmitted through body tissues other than human bones. And a xenon lamp and a lens, or an LED having a light emission characteristic within a corresponding wavelength attached with the lens.

  The imaging unit 2 includes an image sensor such as a CCD or a CMOS and a control system, and a lens optical system that forms a fingerprint image and a blood vessel image on the image sensor. Here, the imaging unit 2 mainly uses the light reflected by the light emitted from the spot light generation light source 1 to the fingerprint part between the distal interphalangeal joint (first joint) of the finger FG and the finger tip, and the finger FG The fingerprint of the fingerprint part between the distal interphalangeal joint (first joint) and the finger tip is imaged, and the light irradiated to the fingerprint part from the spot light generating light source 1 is scattered and propagated inside the finger FG. A blood vessel image is captured by scattered light that escapes (emits) from the epidermis between the distal interphalangeal joint (first joint) and the proximal interphalangeal joint (second joint). Note that the fingerprint image and the blood vessel image are simultaneously captured by the imaging unit 2. In addition, the imaging part 2 is installed in the position which does not contact the finger FG similarly to the spot light generation light source 1.

  The imaging control unit 3 controls imaging of the imaging unit 2 and converts the signal of the imaging unit 2 into data, and sends a fingerprint image and a blood vessel image to the image processing unit 4.

  The image processing unit 4 extracts the fingerprint center from the fingerprint image data acquired from the imaging control unit 3, and measures the deviation of the finger center from the outer shape of the finger FG. Then, the amount of rotation of the finger is detected, and the correct position correction information of the finger is displayed on the display unit 6 based on the amount of rotation, thereby prompting the person to be authenticated to correct the position of the finger. Further, the image processing unit 4 extracts the image features of the fingerprint and the finger blood vessels from the image data captured by the imaging unit 2 after the finger FG is corrected to the correct position, and the extracted image feature data is sent to the matching unit 5. Output.

  The collation unit 5 stores the fingerprint of the person to be authenticated and the image features of the finger blood vessels. The stored fingerprint and finger image of the person to be authenticated and the image of the fingerprint and finger blood vessels from the image processing unit 4 are stored. Check against the features and perform authentication.

  The image processing unit 4 or the collation unit 5 records a plurality of reference data (image characteristics of fingerprints and finger blood vessels) registered by rotating the finger of the person to be authenticated in advance, and the image processing unit 4 It is also possible to select a rotation amount approximate to the image feature of the fingerprint and the finger blood vessel extracted in the above, and collate with the image feature of the fingerprint and the finger blood vessel.

  Next, fingerprint and blood vessel imaging and collation operations in the first embodiment will be described.

  FIG. 2 is an operation flowchart of fingerprint and blood vessel imaging and collation in the first embodiment.

  First, the spot light generating light source 1 irradiates the entire fingerprint region above the distal interphalangeal joint (first joint) of the finger FG with spot-like parallel light with uniform brightness (Step 100). .

  The imaging unit 2 uses the imaging control unit 3 to image a portion including the fingerprint and blood vessels from the proximal interphalangeal joint (second joint) of the finger FG to the fingertip (Step 101). Here, the fingerprint portion between the distal interphalangeal joint (first joint) of the finger FG and the finger tip is mainly imaged by the reflected light by the irradiated light. On the other hand, relatively thick blood vessels exist between the distal interphalangeal joint (first joint) and the proximal interphalangeal joint (second joint) of the finger FG and immediately below the skin near the joint. The light emitted to the fingerprint portion by the spot light generation light source 1 is scattered in the finger and propagated through the finger and emitted from the epidermis, and a blood vessel image is captured. Note that the fingerprint image and the blood vessel image are captured simultaneously.

  The imaging control unit 3 converts the signal of the imaging unit 2 into data, and outputs a fingerprint image and a blood vessel image to the image processing unit 4 (Step 102).

  The image processing unit 4 extracts the center of the fingerprint and determines whether or not the finger FG of the person to be authenticated is captured at a position suitable for collation based on the rotation amount of the finger (Step 103).

  When the finger FG of the person to be authenticated is not placed at a correct position suitable for collation, the image processing unit 4 prompts the person to be authenticated to correct the position of the finger on the display unit 6. For example, register multiple images of guidance such as “Do not tilt your finger”, “Tilt right”, “Tilt left”, etc. that are displayed to the user in advance. An appropriate guidance image is displayed according to the amount of rotation (Step 104).

  The image processing unit 4 extracts the image features of the fingerprint and the finger blood vessel from the image data captured by the imaging 2 with the finger FG corrected to the correct position, and outputs the extracted image feature data to the matching unit 5 (Step) 105).

  The collation unit 5 performs collation based on the fingerprint and finger blood vessel image features from the image processing unit 4 (Step 106).

  As described above, the first embodiment has the following effects.

  In the first embodiment, the fingerprint part of the finger is irradiated with parallel light in a spot manner, and scattered and propagated inside the finger from the fingerprint part, and the distal interphalangeal joint (first joint) and the proximal finger A blood vessel image by scattered light leaking (emitted) from the epidermis between the internode joint (second joint) and a fingerprint image by collimated light spotwise on the fingerprint part of the finger simultaneously by one imaging unit Since the image is taken, the verification process (personal authentication) can be performed in a short time with a simple structure.

  In addition, the parallel light irradiated spotwise on the fingerprint part is likely to cause a shadow due to the unevenness of the fingerprint, and a fingerprint image having a better contrast than the scattered light can be obtained.

  Furthermore, in the first embodiment, the fingerprint center is obtained from the simultaneously captured fingerprint image, thereby detecting the amount of finger tilt (rotation) and prompting the subject to correct the finger tilt. Since it is collated with reference data that has been rotated and registered in advance, personal authentication can be performed with higher accuracy.

  Next, a specific example 1 corresponding to the first embodiment will be described.

  FIG. 3 is a perspective view of the living body imaging apparatus according to the first embodiment.

  As shown in FIG. 3, the biological imaging apparatus according to the first embodiment includes an imaging unit 2 provided inside the biological imaging apparatus, and captures an imaging region of a finger fingerprint and a finger blood vessel pattern with respect to the imaging unit 2. The fingertip guide 102 that leads to a position suitable for the fingertip and the fingertip guide 103 are provided in the upper part of the imaging unit 2. Of the user's (authenticated person) fingers, at least the fingerprint region to be imaged and the epidermis between the distal interphalangeal joint (first joint) and the proximal interphalangeal joint (second joint) The portions corresponding to these portions are opened so that the portions are not pressed so as not to contact any member.

  Here, when photographing the finger, the tip of the finger of the user (authenticated person) is placed on the fingertip guide 102, and the root (finger part) of the finger is placed on the fingertip guide 103. The user's finger is guided to a position suitable for imaging by the imaging unit 2.

  As shown in FIG. 4, the fingertip guide 102 and the fingertip guide 103 are arranged such that when the fingerprint and blood vessel pattern of the user's finger are imaged by the imaging means 104, Is placed on the finger guide 103 so that the imaging region of the finger is guided to a position where it can be imaged.

  Here, a longitudinal sectional view including the imaging unit 2 of the biological imaging apparatus is shown in FIG. For convenience of explanation, an imaging control unit 3, an image processing unit 4, a collation unit 5, and a display unit 6 provided outside are also shown.

  As described above, the spot light generating light source 1 is installed in a non-contact manner with the finger FG, and the entire fingerprint portion between the distal interphalangeal joint (first joint) of the user's finger and the finger tip is substantially uniform. It is provided at a position where it is possible to irradiate parallel light in a spot from one direction with high brightness.

  In addition, since the blood vessel is compressed and blood does not escape, the living body imaging apparatus according to the first embodiment is a part to be imaged by the finger of the user (authenticated person), that is, a fingerprint part and a distal finger. The part between the internode joint (first joint) and the proximal interphalangeal joint (second joint) (part where the image of the finger blood vessel is imaged) is kept in a non-contact state. The part corresponding to the fingerprint part and the part between the distal interphalangeal joint (first joint) and the proximal interphalangeal joint (second joint) (the part that images the finger blood vessel image) is opened. Yes.

  FIG. 6 shows an example in which the fingerprint of the user (authenticated person) and the blood vessel pattern are imaged by the biological imaging apparatus of the first embodiment.

  As shown in FIG. 6, by irradiating the fingerprint portion of the finger with parallel light in a spot manner, the fingerprint image by reflected light reflected from the surface of the fingerprint portion of the finger and the irradiation light propagates inside the finger. It can be seen that the blood vessel image by the emitted light is simultaneously imaged by one imaging unit.

  7 and 8 show fingerprint images and blood vessel images obtained by performing image processing such as noise removal, image enhancement using a frequency filter, and image enhancement using gain adjustment on the biological image shown in FIG. It is.

  As shown in the fingerprint image after image processing shown in FIG. 7, the parallel light irradiated spotwise on the fingerprint portion is likely to cause shadows due to the unevenness of the fingerprint, and a fingerprint image having a better contrast than the scattered light can be obtained. I understand that. Further, as shown in the blood vessel image after image processing shown in FIG. 8, the blood leaks from the epidermis between the distal interphalangeal joint (first joint) and the proximal interphalangeal joint (second joint). It can be seen that an image with a clear blood vessel pattern can be obtained by scattered light (radiated).

  Next, another embodiment of the present invention will be described.

  As another embodiment of the present invention, the basic configuration is the same as that of the above-described embodiment, but the light source is further devised in order to capture a more stable blood vessel image. The configuration is shown in FIG.

  In another embodiment, an auxiliary light source 10 is provided in addition to the above-described embodiment. The auxiliary light source 10 is installed in the vicinity of the base side of the finger FG of the proximal interphalangeal joint (second joint) of the finger FG, and irradiates light inside the finger.

  Scattered light can be observed from between the first joint and the second joint only from the spot light generating light source 1 at the fingertip, but there is a problem that the base side of the finger becomes dark, and this auxiliary light source can be improved.

  A part or all of the above-described embodiment can be described as in the following supplementary notes, but is not limited thereto.

(Additional remark 1) The irradiation part which irradiates parallel light to the 1st site | part of a biological body,
A biological imaging apparatus including: an imaging unit configured to image the first part and a second part connected to the first part.

(Supplementary Note 2) The first site is a fingerprint site between the distal interphalangeal joint and the finger tip,
The biological imaging apparatus according to appendix 1, wherein the second part is a part between the proximal interphalangeal joint and the distal interphalangeal joint.

(Additional remark 3) The said irradiation part is a biological imaging device of Additional remark 1 or Additional remark 2 which irradiates the light containing the wavelength of 600 nm to 1000 nm.

(Supplementary note 4) The biological imaging apparatus according to any one of supplementary note 1 to supplementary note 3, wherein the first part and the second part are held at positions where they do not contact any member.

(Additional remark 5) The said imaging device is radiated | emitted by the reflected light which was irradiated by the said irradiation part and reflected on the surface of the said 1st site | part, and was irradiated by the said irradiation part and propagated inside the said 2nd site | part. The biological imaging apparatus according to any one of appendix 1 to appendix 4, wherein the first portion and the second portion are imaged with the emitted light.

(Supplementary note 6) The biological imaging according to any one of supplementary notes 1 to 5, further including a second irradiation unit that irradiates light to a third part that is continuous with the second part opposite to the first part. apparatus.

(Supplementary note 7) The first part of the living body is irradiated with parallel light,
A biological imaging method for simultaneously imaging the first part and the second part connected to the first part.

(Appendix 8) The first site is a fingerprint site between the distal interphalangeal joint and the finger tip,
The biological imaging method according to appendix 7, wherein the second part is a part between the proximal interphalangeal joint and the distal interphalangeal joint.

(Supplementary note 9) The biological imaging method according to supplementary note 7 or supplementary note 8, wherein the wavelength of the parallel light is a wavelength of 600 nm to 1000 nm.

(Supplementary note 10) The biological imaging method according to any one of supplementary note 7 to supplementary note 9, wherein the first part and the second part are imaged at positions that do not contact any member.

(Supplementary Note 11) The reflected light that is irradiated with parallel light and reflected from the surface of the first part, and the radiated light that is irradiated with parallel light and propagated inside the second part is emitted. The living body imaging method according to any one of appendix 7 to appendix 10, wherein the first part and the second part are imaged.

(Additional remark 12) Furthermore, the biological imaging method in any one of Additional remark 7 to Additional remark 11 which irradiates light to the 3rd site | part continuous with the said 2nd site | part opposite to the said 1st site | part.

(Supplementary Note 13) At least between a fingerprint region between a distal interphalangeal joint of a finger and the tip of the finger, and between a proximal interphalangeal joint of the finger and a distal interphalangeal joint of the finger Holding means for holding the finger in a state where the blood vessel part is not in contact with any member;
An irradiating unit that is installed below the finger to be held and irradiates the fingerprint part with parallel light;
A biological imaging apparatus that is installed under a finger to be held and includes an imaging unit that simultaneously images at least the fingerprint region and the blood vessel region with the irradiated light.

(Additional remark 14) The said imaging | photography part is a biological imaging device of Additional remark 13 which irradiates the light containing the wavelength of 600 nm to 1000 nm.

  Although the present invention has been described with reference to the preferred embodiments and examples, the present invention is not necessarily limited to the above-described embodiments and examples, and various modifications can be made within the scope of the technical idea. I can do it.

DESCRIPTION OF SYMBOLS 1 Spot light generation light source 2 Imaging part 3 Imaging control part 4 Image processing part 5 Collation part 6 Display part

Claims (9)

An irradiator that irradiates light to a first site between the distal interphalangeal joint of the finger and the finger tip ;
Radiation propagates with light reflected by the first portion is irradiated by said irradiation unit, to the inside of the second portion between the distal interphalangeal joint and the proximal inter-position phalangeal joints of the fingers An imaging unit that captures a fingerprint image of the first part and a blood vessel image of the second part with the emitted light,
At least the second part does not contact any member;
Biological imaging device. 2. The image capturing unit according to claim 1, wherein the imaging unit captures a blood vessel image of the second part with radiated light that is radiated and emitted from the irradiation unit to the inside of the second part of the finger . Biological imaging device. Biological imaging device according to claim 1 or claim 2 comprising a fingertip guide and Yubine guide for holding the finger. The living body imaging apparatus according to any one of claims 1 to 3 , wherein the irradiation unit irradiates light including a wavelength of 600 nm to 1000 nm. The living body imaging apparatus according to any one of claims 1 to 4 , further comprising: a second irradiation unit configured to irradiate light from a proximal interphalangeal joint of a finger to a third part on a finger base side . The irradiation unit does not irradiate the light emitted from the second portion of the second portion to which the radiation imaged by the imaging unit is emitted,
The living body imaging apparatus according to any one of claims 1 to 5 . Illuminating a first site between the distal interphalangeal joint of the finger and the finger tip ;
And light reflected by the first portion is the irradiation propagates inside the second region radiation emitted between the distal interphalangeal joint and the proximal interphalangeal joint of the finger Taking a fingerprint image of the first part and a blood vessel image of the second part with light,
At least the second part does not contact any member;
Living body imaging method. In radiation first the light irradiated light to the site of the finger is emitted propagates into the interior of the second portion of the finger, imaging a blood vessel image of the second region,
The biological imaging method according to claim 7 . The biological imaging method according to claim 7 or 8 , wherein the light does not irradiate a part of the second part from which radiation light to be imaged is emitted.