JP2022051149A - Blood vessel image capturing device and personal authentication system - Google Patents

Abstract

To provide a finger vein authentication device which is compact and capable of performing accurate personal authentication, and to provide a personal authentication device.SOLUTION: A blood vessel image capturing device comprises: light sources disposed at opposing positions and configured to irradiate a finger from right and left; an imaging unit for imaging a vein pattern of the finger from below; and light shield plates, each having a cut-out portion, disposed below the light sources in such a way that the light sources are not imaged in an imaged image. The imaging unit images an image including a background and an outline of a finger imaged through the cut-out portions as well as the finger.SELECTED DRAWING: Figure 1

Description

The present invention utilizes human biological information, particularly an imaging device that irradiates a finger with near infrared rays to capture an image of a venous blood vessel, and a blood vessel that identifies an individual by utilizing the fact that the blood vessel pattern of the venous blood vessel image differs from person to person. Regarding the image imaging device and the personal authentication system.

One of the biometric authentication devices capable of highly accurate personal authentication is one that uses a blood vessel pattern. This is a device that utilizes the fact that the blood vessel pattern is different for each individual, for example, the blood vessel pattern that emerges by shining light on the finger is compared with the information of the finger blood vessel pattern registered in advance to authenticate the person. .. Patent Document 1 describes a personal authentication device that authenticates a person using a finger blood vessel pattern by irradiating light from the left and right sides of the finger with an open type without a cover on the part to which the finger touches. An example of the device is described.

Japanese Patent Application Laid-Open No. 2009-093385 Japanese Unexamined Patent Publication No. 2017-175244

By reducing the size of the personal authentication device that authenticates the person using an open finger blood vessel pattern without a structure on the part where the hand is held, as described in Patent Document 1, and making it an embedded type. It can be built in a limited space. In addition, because it is an open type, the protrusion of the device housing at the part where the finger is presented can be suppressed, and it can be incorporated not only in large buildings but also in the entrances of small buildings, entrance doors of general houses, guest room doors of hotels, etc. , The range of use can be expanded.

However, when the authentication device is miniaturized, the size of the entire device may be reduced, so that the components may not be placed in a desired position. For example, it is desirable to place the light source in an appropriate position so that the light source does not appear as a bright spot in the image of the finger to be authenticated, but it may not be possible to place it in such a position due to device size restrictions. .. In such a case, a bright spot is reflected in the image, and it is not possible to distinguish whether the finger is shining or the bright spot is shining, which may hinder accurate finger contour acquisition. Accurate finger contour information is obtained by finding the finger width and performing normalization to enlarge or reduce the image so that the finger width is constant. It is possible to improve the accuracy of personal authentication by aligning the variations. The bright spot of the light source can be hidden so that the light source is not reflected in the image by arranging the light-shielding plate described in Patent Document 1. However, since the device is small, it is easy for the finger to touch the light-shielding plate, and when the finger touches it, the light radiated to the finger is transmitted inside the finger due to internal scattering and turns to the surface opposite to the light source of the light-shielding plate. The light that comes out of the finger again may cause the light-shielding plate itself to shine with the same brightness as the vicinity of the contour of the finger due to reflection, and the finger contour position may not be accurately obtained.

In addition to the light source itself, the peripheral part of the light source reflects light and is reflected in the captured image as a bright spot, and it is not possible to distinguish whether the finger is shining or the bright spot is shining, so the accurate finger contour It may interfere with the acquisition.

Due to the small size of the device, the distance between the fingertip side and the finger rest on the finger base side, which encourages the finger to be held along the device, is short, which makes it easier to hold the finger diagonally, which is one of the finger contours in the captured image. If the part is not shown, the authentication accuracy may decrease.

In order to make the device smaller, the finger and the image pickup device are close to each other for shooting, which inevitably results in wide-angle shooting. It can be obtained in a wide range in the length direction of the finger. In order to improve the authentication accuracy, it is desirable to use the widest possible range of the acquired finger as information, but when the blood vessel pattern is extracted from such an image, the pattern becomes elongated in the length direction of the finger and narrow in the width direction. At the time of collation, the processing time may become longer because the search range for investigating the deviation width of the position where the finger is held is widened.

An optical path length of a certain length is required to capture a wide range of images up to the contour of the finger. In the miniaturized device configuration, in order to secure the required length of the optical path, it is devised so that the housing does not become large in only one direction by bending the optical path using a mirror. As the miniaturization progresses further, the distance between each device component becomes closer. Bright spots may appear at overlapping positions, which may interfere with clear angiography. If there is a margin between the components, it is possible to arrange the layout so as to suppress the reflection of bright spots, but it is difficult to achieve both if miniaturization is prioritized. In particular, in order to both include the part where the finger contour is reflected in the imaging range and to fit the optical path length in a small housing, it is conceivable to use a curved mirror, but in that case, it is a component for the imaging range. The degree of proximity between them becomes stronger, and the influence of the bright spots becomes remarkable.

When a user authenticates himself / herself using an authentication device, he / she may want to authenticate without touching the device. In the case of a blood vessel image imaging device in which a finger is held over the device, it is necessary to hold the finger stationary on the device when authenticating without touching it, but when trying to make it stationary, it moves left and right due to the shaking of the finger. The image will be blurred. It is easier to keep your finger moving slowly, rather than letting it rest, in order to reduce blurring and take an image, but if you keep your finger down, you will eventually touch the device. Of course, it is also conceivable not to place the components of the device at the point where the finger is kept down so that the finger does not touch the device. However, in order to clearly photograph the veins of the finger, it is desirable that the imaging unit is arranged in the direction of travel of the finger in this case, and if there is nothing, the optimum position for authentication cannot be known, and the accuracy is improved. There is a risk of adverse effects.

Patent Document 2 describes a description in which the biometric information is encrypted, the person is authenticated while the biometric information is kept secret, and the biometric information is safely used against information leakage. However, some users may not be able to recognize that the biometric information is encrypted and registered, and may have a psychological resistance to registering the biometric information.

INDUSTRIAL APPLICABILITY The present invention is a blood vessel image imaging device capable of increasing authentication accuracy, performing personal authentication without contact, or reducing psychological resistance to registration of biometric information in a small personal authentication device. And the purpose is to provide a personal authentication system.

The blood vessel image imaging device according to one aspect of the present invention is arranged at a position facing each other, and is imaged by a light source that irradiates light from the left and right sides of the finger, an imaging unit for photographing a vein pattern of the finger from below, and the light source. A light-shielding plate arranged below the light source so as not to be reflected in an image, the light-shielding plate having a notch is provided, and the image pickup unit includes the background and the outline of the notch together with the finger. It is configured as a blood vessel image imaging device characterized by taking a picture of a light source.

According to one aspect of the present invention, in an authentication device for identifying a small individual, there is an effect of increasing the authentication accuracy, performing personal authentication without contact, or reducing psychological resistance to registration of biometric information. ..

An example of a blood vessel image imaging apparatus provided with a light-shielding plate having a notch for carrying out the present invention, as viewed from diagonally above. A view from above an example of a blood vessel image imaging apparatus provided with a light-shielding plate having a notch for carrying out the present invention. The figure of the example which installed the antireflection plate on the light source protection cover on the notch in the blood vessel image image pickup apparatus provided with the light-shielding plate with a notch which carries out this invention. The figure when the reflection is generated from the peripheral part of the light source of the light source storage part. The figure of the light source storage part which suppressed the reflection from the peripheral part of the light source which carries out this invention. A view of an example of a blood vessel image imaging device provided with a guide so as to present a finger carrying the present invention along the device, as viewed from diagonally above. Top view of an example of a blood vessel image imaging device that is not provided with a guide to present the finger along the device. A view from above an example of a blood vessel image imaging apparatus provided with a guide for presenting a finger carrying the present invention along the apparatus. The figure which shows the imaging range in the width direction of a finger when the image is taken close to a finger and when it is not close to the finger. The figure which shows the search range for adjusting the misalignment at the time of collation by the long blood vessel pattern in the length direction of a finger. A diagram in which the search range for alignment at the time of collation is reduced by the vein pattern reduced in the length direction of the finger according to the present invention. A cross-sectional view of a blood vessel image imaging device for suppressing a bright spot due to reflection from a curved mirror according to the present invention as viewed from the finger base. An example of a blood vessel pattern for which the present invention is carried out, excluding a portion affected by a bright spot due to reflection from a curved mirror. A view of a blood vessel image imaging apparatus for carrying out the present invention, which is provided with an openable lower part and performs non-contact imaging, as viewed from diagonally above. Cross-sectional view of a blood vessel image imaging device for performing non-contact imaging with an openable lower part for carrying out the present invention as viewed from the finger base side (state in which the lower part of the device is closed). Cross-sectional view (state in which the lower part of the device is open) of a blood vessel image imaging device for performing non-contact imaging with an openable lower part for carrying out the present invention as viewed from the base of the finger. A view of a blood vessel image imaging device provided with a display device for showing encrypted biological information to a user, which carries out the present invention, viewed from diagonally above. An example of a system configuration diagram of a personal authentication device using a blood vessel image imaging device for carrying out the present invention. An example of a flowchart for performing personal authentication by the personal authentication device of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description and drawings are examples for explaining the present invention, and are appropriately omitted and simplified for the sake of clarification of the description. The present invention can also be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

The positions, sizes, shapes, ranges, etc. of each component shown in the drawings may not represent the actual positions, sizes, shapes, ranges, etc., in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the position, size, shape, range and the like disclosed in the drawings.

In the following description, various information may be described by expressions such as "table" and "list", but various information may be expressed by a data structure other than these. The "XX table", "XX list", etc. may be referred to as "XX information" to indicate that they do not depend on the data structure. When expressions such as "identification information", "identifier", "name", "ID", and "number" are used in explaining the identification information, these can be replaced with each other.

When there are a plurality of components having the same or similar functions, they may be described by adding different subscripts to the same reference numerals. However, if it is not necessary to distinguish between these multiple components, the subscripts may be omitted for explanation.

Further, in the following description, a process performed by executing a program may be described, but the program is determined by being executed by a processor (for example, a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit)). In order to perform the processed processing while appropriately using storage resources (for example, memory) and / or interface devices (for example, communication port), the main body of the processing may be a processor. Similarly, the main body of the process of executing the program may be a controller, an apparatus, a system, a computer, or a node having a processor. The main body of the processing performed by executing the program may be any arithmetic unit, and may include a dedicated circuit (for example, FPGA (Field-Programmable Gate Array) or ASIC (Application Specific Integrated Circuit)) for performing specific processing. ..

The program may be installed from a program source into a device such as a calculator. The program source may be, for example, a program distribution server or a computer-readable storage medium. When the program source is a program distribution server, the program distribution server includes a processor and a storage resource for storing the program to be distributed, and the processor of the program distribution server may distribute the program to be distributed to other computers. Further, in the following description, two or more programs may be realized as one program, or one program may be realized as two or more programs.

Further, in the following, a case where the personal authentication device is configured by using the blood vessel image imaging device is illustrated, but each part constituting the personal authentication device such as a CPU, a memory, and an optical filter is held in the blood vessel image imaging device. However, it may be configured as one system. Further, in the examples shown below, processing such as control of the light source, generation of blood vessel patterns, opening / closing of the lower part of the device, encryption and visualization of biological information, and control of each part are performed by the blood vessel image imaging device and personal authentication. This can be achieved by executing the CPU of the device.

In this embodiment, in a small blood vessel image imaging device provided with a light-shielding plate for preventing the light source from being reflected in the captured image, the light-shielding plate is provided with a notch for accurately acquiring the contour position of the finger. This is an example.

FIG. 1 is a view from diagonally above. The blood vessel image imaging device 101 includes a plurality of light sources 104, 105, 106, 107 that irradiate a finger with near infrared rays, transparent protective covers 102, 103 for protecting the light sources, a finger rest 108 on the fingertip side, and a finger. A finger rest 109 on the base side and light-shielding plates 110 and 111 for hiding the light source so as not to be reflected in the captured image are provided. The shading plates 110 and 111 include notches 112 and 113 for obtaining an accurate finger contour position. It is desirable that the notch is provided at a position that does not impair the function of preventing the light-shielding plate from being reflected in the captured image. In the case of FIG. 1, since there are light sources on the left and right sides of the fingertip side and on the left and right sides of the finger base side, it is preferable to provide them at the center of the fingertip side and the finger base side of the light-shielding plate, which are located away from any of the light sources. In addition, in order to reduce the possibility that the edge of the notch is mistaken for the contour line of the finger, the edge portion should be provided at a right angle to the length direction of the finger or at an angle close to a right angle so as to be distinguishable from the contour line of the finger. Is good.

FIG. 2 is a view of the blood vessel image capturing apparatus of FIG. 1 as viewed from above. By providing the notches 112 and 113 in the light-shielding plates 110 and 111, a portion where the finger does not touch the light-shielding plate is formed, so that accurate finger contour information can be obtained from this portion. Specifically, since the background is always shown in the notch, not the finger, the finger is shown in the image when the luminance scan of each pixel is performed from the notch in the image to the vicinity of the center of the image. In this case, the contour line of the finger always exists closer to the center of the image than the notched part, and there is a difference in brightness from the background near the contour line, so it is possible to obtain the contour accurately by detecting this difference. can. If there is no notch, there is no part that can be determined as the background, so it is difficult to distinguish between the contour line of the finger and the boundary line of the light-shielding plate, especially when the finger is in close contact with the light-shielding plate. There is a possibility that the part with a relatively large difference in brightness is mistaken for a contour line. Further, it is also possible to acquire the intensity of the external light of the background from the brightness of the notched portion and adjust the exposure of the image pickup apparatus.

FIG. 3 is an example in which the antireflection plates 301 and 302 are provided on the portion of the protective covers 102 and 103 of the light source above the notch of the light shielding plate in the blood vessel image imaging apparatus of FIG. When the blood vessel image imaging device is used in an environment where there is external light that is light from a source other than the light source of the device due to the presence of the notches 112 and 113, the external light is reflected by the protective covers 102 and 103 from the notches. It may enter the device and appear as a bright spot in the captured image. The antireflection plates 301 and 302 can prevent such light reflection. Instead of providing an anti-reflection plate, the protective cover is divided into the fingertip side and the finger base side to make the upper part of the notch opaque to suppress reflection, or on the notch of the protective cover. The surface of the portion may be subjected to surface treatment such as grain processing to suppress reflection.

As described above, in the first embodiment, a light source (for example, light sources 104 to 106) that is arranged at a facing position and irradiates light from the left and right of the finger and an imaging unit for photographing the vein pattern of the finger from below (for example, for example). A light-shielding plate arranged at the bottom of the light source so that the light source is not reflected in the captured image, and has a notch. A light-shielding plate (for example, light-shielding plates 110 and 111) is provided, and the image pickup unit captures an image including a background and a finger contour with the notch together with the finger. Therefore, for example, even if the light-shielding plate shines and an accurate finger contour cannot be obtained, by providing a notch in the light-shielding plate, a portion where the finger contour and the background can be reflected without always touching the finger on the light-shielding plate can be created. An accurate finger contour can be obtained as a clue.

In this embodiment, in order to prevent the peripheral portion of the light source from reflecting light and being reflected in the captured image as a bright spot, the transparent protective covers 102 and 103 are curved and extended to the portion where the light is reflected. This is a configuration example of a blood vessel image imaging device that transmits light and suppresses bright spots due to reflection.

FIG. 4 is a cross-sectional view of the light source storage portion of the blood vessel image imaging device as viewed from the finger base side. The light of the light source 107 enters the vascular image imaging device by reflection by the ceiling portion of the light source storage portion such as the light traveling path 401 or by the interface of the upper part of the protective cover of the light source such as the light traveling path 402. , May be reflected in the captured image as a bright spot.

FIG. 5 is an example of a blood vessel image imaging device that reduces the reflection of bright spots on the captured image due to the reflection shown in FIG. The curved protective cover 501 extends the transparent protective cover to the ceiling portion of the light source storage portion. As a result, the position of the interface of the protective cover near the ceiling of the light source storage part is shifted, and the light in the direction of the ceiling is transmitted without being reflected to reduce the intrusion of the reflected light into the blood vessel image imaging device. The occurrence is suppressed.

As described above, in the second embodiment, the transparent cover for transmitting the light of the light source while protecting the light source (for example, the light source 107), and the transparent cover covered with a curved surface up to the upper part of the light source (for example, the protective cover). 501) is provided. Therefore, for example, even when the peripheral part of the light source reflects light and is reflected in the captured image as a bright spot, the light is transmitted by making the part that reflects the light transparent to suppress the bright spot due to the reflection. can do.

In this embodiment, in order to prevent the authentication accuracy from being deteriorated because a part of the finger contour is not reflected in the captured image when the finger is held diagonally, a guide is provided so that the finger is held along the device on the finger base side. This is a configuration example of a blood vessel image imaging device that prompts the user to hold a finger along the device.

FIG. 6 is provided with guides 601 and 602 on the finger base side. The guide is the center height in the thickness direction of the finger, that is, the height at which the finger protrudes most in the finger width direction, and is long in the direction along the finger so that the finger can be held along the device. The effect of encouraging things is high. Although it is possible to extend the entire finger rest on the finger base side, the size of the entire device becomes large, so by providing a guide as a protrusion, the influence on the size of the entire device is minimized. Although the shape of the guide is triangular in FIG. 6, it does not have to be triangular as long as the height at the center in the thickness direction of the finger is long in the direction of the base of the finger.

FIG. 7A is an example in which the finger 701 is obliquely presented to the blood vessel image capturing apparatus without a guide. Due to the small size of the entire device, the distance between the finger rest on the fingertip side and the finger rest on the base of the finger is short, and when the finger is presented at an angle, part of the vicinity of the finger contour deviates from the angle of view and is out of the imaging range. It may become. FIG. 7B is an example of an captured image in which a part of the vicinity of the finger contour is deviated from the angle of view by holding a finger diagonally over a blood vessel image imaging device without a guide. The upper right part of the image is out of the angle of view. As a result, the contour of the finger cannot be correctly identified, and the finger may be mistaken for a thin finger at the base of the finger.

FIG. 8A is an example in which the finger 801 is obliquely presented to the guided blood vessel image imaging device. By providing a guide, the range in which the finger can be presented at an angle is limited, and it is possible to encourage the finger to be presented along the device. FIG. 8B is an example of an image taken by holding a finger over a guided finger blood vessel image imaging device. By being prompted by the guide 602 to hold the finger along the device, it is possible to take a picture without a part of the finger deviating from the angle of view.

As described above, in the third embodiment, the finger rest (for example, the finger stand 109 on the finger base side) is provided at least at the base of the finger, and the finger stand is the left and right portions of the finger stand, which are presented. It has a guide (eg, guides 601 and 602) extending in the direction of the base of the finger at the central height of the finger thickness. Therefore, for example, in order to prevent the authentication accuracy from being lowered due to the fact that a part of the finger contour is not reflected in the captured image by holding the finger diagonally, a guide is provided on the base side of the finger so that the finger is held along the device. Can encourage you to hold your finger along the device.

In this embodiment, an image is taken with a device configuration in which the finger and the image pickup device are close to each other. This is an example for preventing the lengthening of. Specifically, this is an example in which the captured image is reduced in the length direction of the finger before the blood vessel pattern is generated, and then the blood vessel pattern is generated to prevent the processing time from becoming long. The blood vessel pattern information is lost due to the reduction in the length direction of the finger in the image, but since most of the blood vessels of the finger run in the length direction of the finger, the mesh pattern may be missing due to the reduction in the length direction. Although it depends on the shooting size of the image, if the image size in the finger length direction is reduced by 20 to 30%, there is almost no effect on the authentication accuracy.

9 (a) is an example in which the finger 901 and the image pickup device 902 are brought closer to each other by a predetermined reference value or more by downsizing the device, and FIG. 9 (b) is the finger 905 and the image pickup means 906. This is an example of shooting at a distance from a predetermined reference value. The finger has a columnar shape, and when the image pickup means 902 is brought close to the finger by a certain distance or more, the line 903 indicating the image pickup range of the finger becomes a tangent line from the image pickup means to the left and right of the finger. The imaging range 904 is a range surrounded by a line indicating the imaging range. When the finger 901 and the imaging means 902 are close to each other as shown in FIG. 9A, the contact point between the line 903 indicating the imaging range and the finger 901 is located near the lowest point of the finger. On the other hand, when the finger 905 and the image pickup means 906 are separated from each other as shown in FIG. 9B, the contact point between the line 907 indicating the imaging range and the finger 905 is that of the finger as compared with FIG. 9A. Since the position is far from the lowest point, the imaging range 908 is wider than the imaging range 904.

FIG. 10 is an example of a blood vessel pattern generated as it is from an image taken with a finger and an image pickup device brought close to each other by a certain distance or more as shown in FIG. 9A. FIG. 10 (a) is an example of the registered blood vessel pattern 1001, and FIG. 10 (b) is an example of the input blood vessel pattern 1002. For matching between blood vessel patterns, for example, template matching is performed to check whether a pattern of one image exists in another image, and the number of matching pixels is checked by slightly shifting the position of the image pattern to be checked from front to back and left and right. , The score is calculated by counting the number of non-matching pixels at the place where the number of matching pixels is the largest, and the smallest score is obtained. FIG. 10 (c) is an example of a range in which the registered blood vessel pattern 1001 and the input blood vessel pattern 1002 are superposed while being slightly shifted back and forth and left and right to search for the position having the smallest mismatch rate. The search range 1003 is a range surrounded by a dotted line.

FIG. 11 is an example of a blood vessel pattern generated by reducing an image taken by bringing a finger and an image pickup device closer to each other by a certain distance or more in advance in the length direction of the finger as shown in FIG. 9A. 11 (a) is an example of the registered blood vessel pattern 1101, and FIG. 11 (b) is an example of the input blood vessel pattern 1102. FIG. 11C is an example of a range in which the registered blood vessel pattern 1101 and the input blood vessel pattern 1102 are superposed while being slightly shifted back and forth and left and right to search for the position having the smallest mismatch rate. The search range 1103 is a range surrounded by a dotted line. In the blood vessel pattern generated by reducing in the length direction of the finger, the search range 1103 is smaller than the search range 1003 in FIG. 10, so that the processing time can be shortened.

In addition, by combining with a curved mirror, it is possible to take an elongated image in the length direction of the finger, but on the other hand, this also means that a magnified high-definition image can be obtained, so a visible light imaging means is also used. There is also an advantage that a high-definition image for the epidermis can be used for highly accurate collation by taking a picture when combined with other biological information such as an epidermis pattern.

As described above, in the fourth embodiment, the image of the finger taken by the image pickup unit (for example, the image pickup means 902) in close proximity to a certain degree or more is shrunk in the length direction of the finger to obtain a search range for alignment. A control unit (for example, a CPU similar to the CPU 1810) for making the size smaller is provided. Specifically, an elongated blood vessel pattern is generated in the length direction of the finger by taking a picture with a device configuration in which the finger and the image pickup device are close to each other. By reducing the size to, it is possible to prevent the search range for investigating the deviation width of the position where the finger is held from becoming wide and the processing time from becoming long.

In this embodiment, when a mirror, especially a curved mirror, is used to reduce the size of the device, the light reflected by the curved mirror is reflected by the optical filter installed between the image pickup unit and the finger, and the bright spot is the captured image. This is a configuration example of a blood vessel image imaging device that reduces a decrease in authentication accuracy due to reflection on the image.

FIG. 12 is a configuration example of a blood vessel image imaging device that reduces the generation of bright spots by applying an antireflection coating to an optical filter. The near-infrared rays emitted from the light sources 105 and 107 are scattered inside the finger 1206, then escape from below the finger, pass through the optical filter 1205 as shown by the light traveling path 1203, and then reach the curved mirror 1202. It is reflected and directed to the image pickup means 1207, but a part of the reflection may be reflected in the direction returning to the optical filter and further reflected by the optical filter. When the position of reflection here is within the range of the imaging range 1201, it may be reflected in the captured image as a bright spot 1204. Therefore, by applying an antireflection coating to the optical filter, it is possible to reduce the occurrence of bright spots and prevent a decrease in authentication accuracy. The optical filter 1205 is installed for the purpose of capturing a clear blood vessel image with less noise by transmitting only near infrared rays in the frequency band transmitted through the living body and for the purpose of preventing dust from entering the inside of the device. ..

FIG. 13 is a configuration example of a blood vessel image imaging device that reduces a decrease in authentication accuracy due to the bright spots shown in FIG. 12 being reflected in the captured image from the blood vessel pattern. In the blood vessel pattern 1301 of FIG. 13A, there is a line 1302 of a pseudo blood vessel generated when the outer edge of the bright spot is relatively darker than the finger portion other than the blood vessel. Since the pseudovascular line 1302 appears at the same position for all fingers regardless of how it is placed, similar parts appear even though the blood vessel patterns are originally different, and the authentication accuracy is lowered. Leads to. As shown in FIG. 13B, by setting the portion of the blood vessel pattern 1303 excluding the line 1304 of the pseudo blood vessel as the authentication target area 1305, it is possible to prevent a decrease in authentication accuracy.

As described above, in the fifth embodiment, the imaging unit (for example, the imaging means 1207) is arranged between the curved mirror (for example, the curved mirror 1202) for widely photographing the finger and the finger and the curved mirror. The optical filter is provided with an optical filter (for example, an optical filter 1205) for passing light in a predetermined wavelength range emitted from a light source (for example, light sources 105 and 107) and preventing dust from entering the inside of the apparatus. An antireflection coating is applied to suppress the bright spots of the light transmitted through the optical filter and reflected on the curved mirror by the optical filter. Further, the image pickup unit (for example, the image pickup means 1207) is arranged between the curved surface mirror (for example, the curved surface mirror 1202) for taking a wide image of the finger and the finger and the curved surface mirror, and the light source (for example, the light source 105) is arranged. , 107) is provided with an optical filter (for example, an optical filter 1205) for passing light in a predetermined wavelength range and preventing dust from entering the inside of the apparatus, and the image pickup unit (for example, an image pickup means 1207) is provided. A control unit (for example, with the CPU 1810) whose authentication target area is a portion of the photographed finger image excluding the portion of the image of the finger reflected by the curved mirror excluding the bright spot reflected by the optical filter on the curved mirror. It has a similar CPU). Therefore, when a mirror, especially a curved mirror, is used to reduce the size of the device, the reflected light from the mirror is reflected by the optical filter installed between the image pickup unit and the finger, and the bright spot is reflected in the captured image. In order to prevent this, it is possible to prevent deterioration of the authentication accuracy by applying an antireflection coating to the optical filter or excluding the portion where the bright spots are reflected from the target of the blood vessel pattern generation.

In this embodiment, the lower part of the device is opened and closed so that the user can authenticate the person without touching the device, the lower part of the device is opened when the person authentication is completed, and the blood vessel image is taken without touching the device by passing a finger. This is a configuration example of a device capable of performing the above.

FIG. 14 is an example of a blood vessel image imaging device in which the lower part of the device is openable and closable. Before the start of authentication, the lower part 1401 of the device, which is a flat plate-shaped portion as shown in FIG. 14A, is closed. When the finger is slowly lowered from above and presented, the lower portion 1401 of the device opens as shown in FIG. 14 (b) by detecting the finger with a proximity sensor or the like immediately before touching the device. Therefore, the presented finger can be pulled out downward, and the blood vessel image can be taken without touching the device by shaking the finger.

FIG. 15 is a cross-sectional view of the blood vessel image capturing apparatus of FIG. 14 as viewed from the finger base side. The arrangement of the light sources 105 and 107, the shading plates 110 and 111, and the protective covers 501 and 502 is the same as in FIG. The lower part 1401 of the device has a hollow inside and has a built-in curved mirror. There is an optical filter 1502 on the upper part facing the finger, and a shooting window 1503 on the side surface. The image of the finger 1509 is reflected by the curved mirror 1501 through the optical filter 1502, and is photographed by the imaging means 1505 through the photographing window 1503 and the photographing device side photographing window 1504. Further, the lower portion 1401 of the apparatus is connected to the plunger 1507 of the solenoid actuator 1506 via the stay 1508. The proximity sensor 1510 senses the approach of the finger and opens the lower part of the device by the solenoid actuator 1506 at the timing when the finger approaches a predetermined distance sufficient for photographing.

FIG. 16 shows a state in which the lower portion 1401 of the device is opened by energizing the solenoid actuator 1506, pulling up the plunger 1507, and pulling the connected stay 1508. When the energization of the solenoid actuator 1506 is stopped, the plunger 1507 is lowered to the original position again, and the lower portion 1401 of the apparatus returns to the closed state shown in FIG.

As described above, in the sixth embodiment, the image pickup unit (for example, the image pickup means 1505) for photographing the vein pattern of the finger from below and the lower part of the device (for example, the lower part 1401 of the device) are openable and closable, and the finger is used by the image pickup unit. A control unit (for example, a CPU similar to the CPU 1810) that opens the lower portion of the device when the vein pattern of the above device is photographed is provided. Specifically, the lower part of the device is openable so that the user can authenticate the person without touching the device, the finger presentation position suitable for authentication is clearly indicated, and the blood vessel image is taken until just before the finger touches the device. By doing so, the lower part of the device can be opened just before the finger swings, and the blood vessel image can be taken without touching the device while suppressing the blurring of the finger by passing the finger.

In this embodiment, some users cannot recognize that the biometric information is encrypted and registered, and the encrypted biometric information is displayed in order to reduce the psychological resistance to registering the biometric information. This is an example of a blood vessel image imaging device provided with a display device for the purpose. FIG. 17 is an example of a blood vessel image imaging device provided with a display device for displaying encrypted biological information. By visualizing and displaying the encrypted biometric information 1702 on the display device 1701, it is possible to show the user that the biometric information is encrypted and safely used instead of using the biometric information as it is. Instead of visualizing and displaying the encrypted biometric information, a symbol or pattern indicating that the biometric information is encrypted may be displayed.

As described above, the seventh embodiment includes a display unit (for example, a display device 1701) for displaying an encrypted registered blood vessel pattern or an encrypted matching blood vessel pattern. Therefore, some users cannot recognize that the biometric information is encrypted and registered, and it is possible to reduce the psychological resistance to registering the biometric information. Further, it is possible to display the encrypted biological information by installing a display device on the blood vessel image imaging device to indicate that the biological information is safely used.

This embodiment is an example of a system in which a personal authentication device is configured by using any of the blood vessel image imaging devices of Examples 1, 2, 3, 4, 5, and 6.

FIG. 18 is a system configuration diagram of the personal authentication device. When the finger 1801 is presented to the authentication device 101, the image of the finger within the range of the angle of view 1812 irradiated with near infrared rays from the light sources 104, 105, 106, and 107 is passed through the optical filter 1105 and is electrified by the image pickup means 1802. It is converted into a signal, taken into the CPU 1810 as an image via the near-infrared image input unit 1803 and the interface 1804, and recorded in the memory 1809. The near-infrared light source control unit 1805 controls the amount of near-infrared light emitted from the light sources 104, 105, 106 and the like. The image recorded in the memory 1809 is collated with one or more biometric information previously recorded in the external storage device 1811 by the program recorded in the memory 1809, and the person is authenticated. The result of the authentication can be displayed on the display device 1808 by an instruction from the speaker 1806 or the keyboard 1807 and notified to the person himself / herself. The authentication device 101 may be used as a blood vessel image imaging device for transmitting information on the photographed blood vessel to the authentication unit, and the process shown in FIG. 19 may be executed by an external computer.

FIG. 19 is an example of a flowchart of a program for authenticating a person with a person authentication device. First, in step 1901, the user presents a finger. Next, the process proceeds to step 1902, and the CPU 1810 controls the near-infrared light source control unit 1805 to irradiate the near-infrared rays from the right side of the finger. Next, the process proceeds to the means 1903, and the CPU 1810 controls the near-infrared image input unit 1803, the image pickup means 1802, and the like to acquire the near-infrared image of the finger.

Next, the process proceeds to step 1904, and the CPU 1810 controls the near-infrared light source control unit 1805 to irradiate the near-infrared rays from the left side of the finger. Next, the process proceeds to the means 1905, and the CPU 1810 controls the near-infrared image input unit 1803, the image pickup means 1802, and the like to acquire the near-infrared image of the finger. Next, the process proceeds to step 1906, and the CPU 1810 detects the finger from the near-infrared image of the finger acquired by the near-infrared image input unit 1803, the image pickup means 1802, or the like. Next, the process proceeds to step 1907, and the CPU 1810 determines whether or not a finger has been detected in the previous step 1906.

If the CPU 1810 determines that the finger has not been detected (step 1907; NO), the process returns to step 1902. On the other hand, if the CPU 1810 determines that the finger has been detected (step 1907; YES), the process proceeds to step 1908 to detect the finger contour and clarify the finger region of the near-infrared image of the finger. Next, the process proceeds to step 1909, and the CPU 1810 calculates the average length of the finger width from the finger contour obtained in the previous step 1908, and the finger width of the near-infrared image of the finger becomes a preset standard length. The image is enlarged or reduced as described above, and the near-infrared image of the finger is normalized. Next, the process proceeds to step 1910, and the CPU 1810 calculates the average brightness of the finger from the normalized near-infrared image of the finger.

Next, the process proceeds to step 1911, and the CPU 1810 checks whether or not the average brightness of the finger calculated in step 1910 is between the upper limit and the lower limit of the target brightness. If the CPU 1810 determines that the average brightness is not between the upper and lower limits of the target value (step 1911; NO), the process proceeds to step 1912, and if the average brightness is below the lower limit of the target value, the light intensity value is increased and the average. If the brightness exceeds the upper limit of the target, the light intensity value is reduced, the light source is controlled so as to irradiate, and then the process returns to step 1902. On the other hand, if the CPU 1810 determines in step 1911 that the average brightness is between the upper and lower limits of the target value (step 1911; YES), the process proceeds to step 1913, and the blood vessel pattern recorded in advance and the presented finger are used. The extracted blood vessel patterns are collated, and the score of the degree of mismatch between the blood vessel patterns is calculated as the collation score. To calculate the score, the CPU 1810 performs template matching to check whether a pattern of one image exists in another image, and checks the number of matching pixels while shifting the position of the image pattern to be checked little by little, and matches. It is calculated by counting the number of pixels that do not match in the place where the number of pixels is the largest.

Next, the process proceeds to step 1914, and the CPU 1810 checks whether the calculated collation score is below the threshold value. If the CPU 1810 determines that the collation score is below the threshold value (step 1914; NO), the CPU 1810 proceeds to step 1915, performs post-authentication processing such as displaying to the display device 1808 that the authentication is successful, and then steps 1917. Ends the authentication process with. On the other hand, if the CPU 1810 determines that the calculated collation score does not fall below the threshold value (step 1914; YES), the process proceeds from step 1914 to step 1916, and authentication fails such as displaying on the display device 1808 that the authentication has failed. Post-processing is performed, and the authentication process is terminated in step 1917.

As described above, the person in the present embodiment is provided with a control unit (for example, CPU1810) that authenticates the person using the finger vein image taken by the blood vessel image imaging device according to any one of Examples 1 to 7. By using the authentication device, it is possible to perform small and accurate personal authentication in combination with the finger vein authentication device.

101 Authentication device 102, 103 Protective cover 104 to 107 Light source 108 Finger stand on fingertip side 109 Finger stand on finger base side 110, 111 Light-shielding plate 112, 113 Notch of light-shielding plate 301, 302 Anti-reflection plate 501 Protective cover 601, 602 Guide of finger presentation 1202 Curved mirror 1205 Optical filter 1207 Imaging means 1401 Openable and closable blood vessel image image pickup device lower part 1501 Curved mirror 1502 Optical filter 1503 Imaging window 1504 Imaging device side imaging window 1505 Imaging means 1506 Solectoral actuator 1507 Plunger 1508 stay 1510 Proximity sensor 1701 Display device 1802 Image pickup means 1803 Near infrared image input unit 1804 Interface 1805 Near infrared light source control unit 1806 Speaker 1807 Keyboard 1808 Display device 1809 Memory 1810 CPU
1811 external storage

Claims (9)

A light source that is placed facing each other and irradiates light from the left and right of the finger,
An imaging unit for capturing finger vein patterns from below,
A light-shielding plate arranged below the light source so that the light source is not reflected in the captured image, and is provided with the light-shielding plate having a notch.
The image pickup unit captures an image including a background and a finger contour with the notch together with the finger.
A blood vessel image imaging device characterized by this. The blood vessel image imaging apparatus according to claim 1.
A transparent cover that protects the light source and allows the light of the light source to pass through, and the transparent cover is covered with a curved surface up to the upper part of the light source.
A blood vessel image imaging device characterized by being provided with. The blood vessel image imaging apparatus according to claim 1.
It has at least a finger rest placed at the base of the finger,
The finger rest has a guide extending toward the base of the finger at a central height of the presented finger thickness on the left and right portions of the finger rest.
A blood vessel image imaging device characterized by this. The blood vessel image imaging apparatus according to claim 1.
A control unit that reduces the search range for alignment by shrinking an image of a finger taken by the imaging unit closer than a certain distance in the length direction of the finger.
A blood vessel image imaging device characterized by comprising. The blood vessel image imaging apparatus according to claim 1.
A curved mirror for the image pickup unit to take a wide picture of the finger,
It is provided between the finger and the curved mirror, and is provided with an optical filter for passing light in a predetermined wavelength range emitted from the light source and preventing dust from entering the inside of the device.
The optical filter is provided with an antireflection coating for suppressing the bright spots that the light transmitted through the optical filter and reflected on the curved mirror is further reflected on the curved mirror by the optical filter.
A blood vessel image imaging device characterized by this. The blood vessel image imaging device according to claim 1.
A curved mirror for the image pickup unit to take a wide picture of the finger,
It is provided between the finger and the curved mirror, and is provided with an optical filter for passing light in a predetermined wavelength range emitted from the light source and preventing dust from entering the inside of the device.
A control unit whose authentication target area is a portion of the finger image captured by the imaging unit, excluding a portion excluding a portion where the light reflected by the curved mirror is further reflected by the optical filter on the curved mirror. ,
A blood vessel image imaging device characterized by comprising. An imaging unit for capturing finger vein patterns from below,
A control unit that opens and closes the lower part of the device and opens the lower part of the device when the vein pattern of the finger is photographed by the imaging unit.
A blood vessel image imaging device characterized by comprising. Display unit for displaying encrypted registered vessel pattern or encrypted matching vessel pattern,
A blood vessel image imaging device characterized by comprising. A control unit that authenticates a person using a finger vein image taken by the blood vessel image imaging device according to claim 1.
A personal authentication system characterized by being equipped with.

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