Non-contact biometric authentication device, non-contact biometric authentication system, and non-contact biometric authentication method

Abstract

To provide a non-contact biometric authentication device capable of accurately performing non-contact authentication.SOLUTION: A non-contact biometric authentication device 101 comprises: an insertion chamber 119 into which a finger is inserted; a photographing device 102 which photographs a cushion side of a finger 116; a first light source 109 which is installed on a deeper side than the photographing device 102 and irradiates the light whose advancement is shielded by the finger 116 inserted into the insertion chamber 119 in a direction of the photographing device 102; a second light source 110 which irradiates the light absorbed into a blood vessel of the finger 116 within a range including the photographing device 102 when the light from the first light source 109 is shielded by the finger 116; and a reflection surface which is provided in the insertion chamber 119 and in which light from the second light source 110 is reflected. The position and direction of the reflection surface are adjusted so that light of a rate according to the height of the finger 116 among light from the second light source 110 is reflected when light from the first light source 109 is shielded by the finger 116. The photographing device 102 photographs an image including the light reflected by the reflection surface and the cushion side of the inserted finger 116.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a non-contact biometric authentication device, a non-contact biometric authentication system, and a non-contact biometric authentication method. [Background technology]

[0002] One type of biometric authentication device that identifies people using biometric information is one that uses a person's blood vessels. This device takes advantage of the fact that blood vessel patterns vary from person to person, and performs identity authentication by, for example, irradiating a finger with near-infrared light from a predetermined light source to highlight the blood vessel pattern and comparing this blood vessel pattern with pre-registered information on the person's blood vessel pattern. For example, Patent Document 1 describes an example of a personal authentication device that irradiates a finger held over the device with near-infrared light from above and photographs the blood vessel pattern of the finger to authenticate the person. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4207717 Summary of the Invention [Problem to be solved by the invention]

[0004] The device described in Patent Document 1 authenticates a person by directly touching a finger to the device, but in recent years, from the standpoint of hygiene and infection prevention, there has been a growing need for contactless authentication of a person without touching the device.

[0005] However, when authentication is performed without touching the device, it becomes difficult to fix the finger position. As a result, the finger position varies for each authentication, which may result in a decrease in authentication accuracy. Furthermore, it becomes difficult to ensure compatibility with conventional contact-type authentication devices.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a contactless biometric authentication device, a contactless biometric authentication system, and a contactless biometric authentication method that are capable of performing authentication with high accuracy. [Means for solving the problem]

[0007] One aspect of the present invention for solving the above problem is a non-contact biometric authentication device comprising: an insertion chamber having an opening on the side and a space into which an authenticator's finger is inserted from the opening toward the back; an imaging device installed in a position to image the pad side of the finger inserted into the insertion chamber; a first light source installed in the insertion chamber at a position deeper than the imaging device and irradiating light whose progress is blocked by the finger inserted into the insertion chamber toward the imaging device; a second light source installed at a position higher than the height at which the finger is inserted and irradiating light absorbed by the blood vessels of the finger toward a predetermined area including the imaging device when the light from the first light source is blocked by the finger; and a reflective surface installed in the insertion chamber and receiving and reflecting the light from the second light source, the position and direction of the reflective surface being adjusted so that when the light from the first light source is blocked by the finger, a proportion of the light from the second light source corresponding to the height of the inserted finger is reflected; and the imaging device capturing an image including the light reflected by the reflective surface and the pad side of the inserted finger. [Effects of the Invention]

[0008] According to the present invention, contactless authentication can be performed with high accuracy. Configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration of a non-contact biometric authentication system according to a first embodiment. [Figure 2] 1 is a cross-sectional view of a non-contact biometric authentication device according to a first embodiment, as viewed from the side. [Figure 3] FIG. 1 is a diagram illustrating an example of a configuration of an information processing device. [Figure 4] FIG. 10 is a flow diagram illustrating an example of personal authentication processing. [Figure 5] 10A and 10B are diagrams illustrating the principle of finger height detection processing. [Figure 6] FIG. 10 is a diagram illustrating an example of correction processing. [Figure 7] 1A and 1B are diagrams illustrating the principle of finger detection processing. [Figure 8] 1A and 1B are diagrams showing an example of a photographing range of a photographing object by a conventional photographing device and an example of a photographing range of a photographing object by the photographing device according to the present embodiment. [Figure 9] 10 is a graph showing the relationship between the size of a cylinder as a subject photographed by a conventional imaging device and the size of a cylinder photographed by an imaging device with a long focal length, which is the result of an experiment conducted by the inventors. [Figure 10] FIG. 10 is a diagram illustrating an example of normalization processing. [Figure 11] FIG. 10 is a diagram illustrating an example of a region extraction process. [Figure 12] FIG. 2 is a cross-sectional side view of the non-contact biometric authentication device. [Figure 13] 10A and 10B are diagrams illustrating an example in which the information processing device erroneously recognizes a background structure as a finger part. [Figure 14] FIG. 10 is a flowchart illustrating an example of finger contour correction processing. [Figure 15] 10A and 10B are diagrams illustrating an example of estimating the contour of the base of the finger by finger contour correction processing. [Figure 16] 10A and 10B are diagrams showing a non-contact biometric authentication device according to a second embodiment as viewed from the opening side of an insertion chamber and an example of an image captured by the non-contact biometric authentication device. [Figure 17] 10A and 10B are diagrams showing a non-contact biometric authentication device according to a third embodiment as viewed from an opening of an insertion chamber and an example of an image captured by the non-contact biometric authentication device. [Figure 18] 10 is a diagram for explaining the configuration of an additional second light source according to Example 4. FIG. [Figure 19] FIG. 10 is a cross-sectional view of the non-contact biometric authentication device according to the fifth embodiment when a finger is inserted, as viewed from the fingertip direction. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the accompanying drawings.

[0011] Example 1 1 is a diagram illustrating a schematic configuration of a contactless biometric authentication system 1 according to a first embodiment. The contactless biometric authentication system 1 includes a contactless biometric authentication device 101 and an information processing device 10. The contactless biometric authentication system 1 is an information processing system that irradiates near-infrared rays onto the finger of a person to be authenticated (an authenticated person) to capture an image of the blood vessels in the veins and identify the authenticated person.

[0012] The non-contact biometric authentication device 101 includes an insertion chamber 119 into which the finger 116 of the person to be authenticated is inserted with its ventral side facing downward and which includes a plurality of light sources (not shown) that emit near-infrared light toward the finger 116, and an imaging device 102.

[0013] The photographing device 102 takes an image of the vein blood vessels of the inserted finger 116 (hereinafter referred to as an authentication image) by taking advantage of the fact that near-infrared light emitted from the non-contact biometric authentication device 101 is easily absorbed by the vein blood vessels of the finger 116.

[0014] The information processing device 10 recognizes the vein pattern of the finger 116 in the authentication image captured by the image capturing device 102, and performs authentication by comparing the recognized vein pattern with a pre-registered image of the vein pattern of the authenticated person (hereinafter referred to as a comparison image). 0 is communicably connected to the non-contact biometric authentication device 101 via a communication line 5 or the like.

[0015] <Contactless biometric authentication device> FIG. 2 is a cross-sectional side view of the non-contact biometric authentication device 101 according to the first embodiment.

[0016] The non-contact biometric authentication device 101 is fixed to, for example, a predetermined installation surface 121. The non-contact biometric authentication device 101 has an insertion chamber 119 that has an opening 117 on the side thereof to form an insertion space into which a finger 116 (here, one finger) of an authenticator to be authenticated is inserted in a substantially horizontal direction. The authenticator's finger 116 is inserted through the opening 117 with its ventral side facing downward.

[0017] The insertion chamber 119 includes a back wall portion 107 forming the wall on the back side (the side where the tip of the finger 116 is inserted), two side wall portions 113 forming the walls on the left and right sides (sides in a direction substantially perpendicular to the insertion direction of the finger 116), a plate-shaped ceiling portion 108 forming the ceiling, and the opening 117 on the front side. The back wall portion 107 and each side wall portion 113 are erected substantially perpendicular to the installation surface 121.

[0018] An imaging device 102 is provided at the bottom of the insertion chamber 119 to capture an image of the blood vessels of the veins in the pad of a finger inserted into the insertion chamber 119. The imaging direction of the lens of the imaging device 102 is set upward, and the pad of the inserted finger 116 is captured.

[0019] An optical filter 501 is provided above the image capturing device 102 and below the inserted finger 116. The image capturing device 102 captures an image of the finger 116 through the optical filter 501.

[0020] A first light source 109 and a plurality of second light sources 110, 111, 112 are provided on a ceiling portion 108 of the insertion chamber 119. The first light source 109 and the second light sources 110, 111, 112 are provided at a position higher than at least the height at which the finger 116 is inserted.

[0021] First light source 109 emits near-infrared light having directionality (optical axis) for detecting that finger 116 has been inserted into insertion chamber 119. First light source 109 is installed at a position that is deeper in insertion chamber 119 than image capturing device 102.

[0022] The irradiation direction of near-infrared light from first light source 109 is adjusted to be diagonally downward toward opening 117 toward image capturing device 102. In other words, the irradiation direction of near-infrared light from first light source 109 is adjusted to a direction in which direct light from first light source 109 reaches image capturing device 102 when finger 116 is not inserted in insertion chamber 119.

[0023] Next, when the finger 116 is inserted into the insertion chamber 119, the second light sources 110, 111, and 112 irradiate near-infrared light in a predetermined range (at a predetermined irradiation angle) to capture an image of the veins of the finger 116.

[0024] The irradiation range of the near-infrared light from the second light sources 110, 111, and 112 is adjusted so as to widely irradiate the space below the insertion chamber 119. Specifically, the direct light is adjusted so as to entirely illuminate the back side of the inserted finger 116 and also to be able to irradiate the reflector 106, which will be described later.

[0025] Provided at the bottom of the insertion chamber 119 are a base-side finger rest 103 on which the base side of the pad of the finger 116 is placed, and a fingertip-side finger rest 104 on which the tip side of the pad of the finger 116 is placed. The base-side finger rest 103 and the fingertip-side finger rest 104 can be used to perform conventional contact-type authentication.

[0026] Next, a reflector 106 having a reflective surface that receives and reflects near-infrared light is provided on the lower side of the inner surface of back wall portion 107 of insertion chamber 119. The height of this reflector 106 is set within a range that blocks light from second light sources 110, 111, and 112 depending on the height of inserted finger 116.

[0027] Specifically, when the light from the first light source 109 is blocked by the fingertip of the finger 116 inserted in the insertion chamber 119, a proportion of the light from the second light sources 110, 111, 112 corresponding to the height of the inserted finger 116 reaches and is reflected by the reflective surface of the reflector 106, and the position and direction of the reflected light are adjusted so that it is photographed by the photographing device 102. Details will be described later. The reflector 106 is also provided to prevent external light from directly hitting the finger rests (base-side finger rest 103, fingertip-side finger rest 104).

[0028] Here, the operation of the non-contact biometric authentication system 1 when the finger 116 is inserted into the insertion chamber 119 will be briefly described.

[0029] When the finger 116 is inserted into the insertion chamber 119, the information processing device 10 detects, by the first light source 109, that the tip of the finger 116 has reached a predetermined position in the insertion chamber 119 (this horizontal position differs depending on the height of the finger 116, as will be described later). Then, the second light source 110 irradiates near-infrared light 114.

[0030] Of the near-infrared light 114 from the second light sources 110, 111, 112, most of the direct light that reaches the dorsal side of the finger 116 is blocked by the inserted finger 116, forming a shadow 115 of the finger in the space below the ventral side of the finger 116. However, part of the near-infrared light 114 that reaches the surface of the dorsal side of the finger 116 (specifically, the near-infrared light 114 that reaches the part where the venous blood vessels are present) is blocked by the finger 116. This is because hemoglobin contained in the blood absorbs the near-infrared light 114 more strongly than other parts of the body. Then, the near-infrared light 114 that passes through parts of the body other than the blood vessels reaches the imaging device 102, and as a result, the blood vessel pattern is captured by the imaging device 102 as a black line.

[0031] On the other hand, a dark area 105 due to a shadow 115 of the finger is formed on the lower side of the reflecting surface of the reflector 106 of the non-contact biometric authentication device 101. The upper end of the dark area 105 moves upward as the height of the finger 116 increases. The non-contact biometric authentication system 1 of this embodiment detects the height of the finger 116 by taking advantage of the fact that a portion corresponding to this dark area 105 is captured in the image captured by the image capturing device 102 (i.e., the authentication image). As a result, regardless of the height of the finger 116 inserted by the person to be authenticated, the authentication image can be corrected to an image more suitable for authentication, and accurate authentication can be performed based on this corrected image. Details will be described later.

[0032] Next, the information processing device 10 will be described. FIG. 3 is a diagram illustrating an example of the configuration of the information processing device 10. As shown in FIG. The information processing device 10 includes a processor such as a CPU (Central Processing Unit), a DSP (Digital Signal Processor), a GPU (Graphics Processing Unit), and an FPGA (Field-Programmable Gate Array). a processing device 506, a memory 507 such as a ROM (Read Only Memory) or a RAM (Random Access Memory), an external storage device 505 such as a HDD (Hard Disk Drive) or an SSD (Solid State Drive), an input device 509 such as a mouse or a keyboard, a display device 508 such as a liquid crystal display or an organic EL (Electro-Luminescence) display, a printing device 510 such as a printer, and various light sources. The information processing device 10 includes a near-infrared light source control unit 503 that turns the light source on and off and adjusts the brightness, a near-infrared image input unit 502, and a communication interface 504 that is configured with a communication module or the like. The photographing device 102 and the optical filter 501 may be provided inside the information processing device 10, or may be configured as components of the non-contact type biometric authentication device 101 as described above. Furthermore, the non-contact type biometric authentication device 101 and the information processing device 10 may be configured as an integrated device.

[0033] The near-infrared image input unit 502 of the information processing device 10 converts the electrical signal of the image captured by the image capturing device 102 into image data (digital data), and records the converted image data in the memory 507 via the communication interface 504.

[0034] The processing device 506 executes a predetermined analysis program stored in the memory 507, and this analysis program analyzes the image recorded in the memory 507 and detects that the light from the first light source 109 has been blocked by the finger 116 of the authenticated person. Then, the processing device 506 executes a predetermined control program stored in the memory 507. This control program instructs the near-infrared light source control unit 503 via the communication interface 504 to irradiate near-infrared light from the second light sources 110, 111, and 112.

[0035] Thereafter, the processing device 506 generates image data of the finger 116 of the person to be authenticated taken with the second light sources 110, 111, and 112 irradiating near-infrared light (i.e., an authentication image), and records this in the memory 507. The processing device 506 performs identity authentication by comparing this authentication image with a matching image of the person that is pre-recorded in the external storage device 505. The processing device 506 outputs information on the result of identity authentication to the printing device 510, or to the display device 508 based on an instruction from the input device 509.

[0036] Next, the processing performed in the non-contact biometric authentication system 1 will be described.

[0037] <Personal authentication process> FIG. 4 is a flow diagram illustrating an example of processing related to personal authentication (hereinafter referred to as personal authentication processing) performed by the information processing device 10 or the like.

[0038] When the person to be authenticated inserts his / her finger 116 into the non-contact biometric authentication device 101 (s601), the light from the first light source 109 is blocked by the finger 116, and an image of the blocked light is transmitted from the photographing device 102 to the information processing device 10. The information processing device 10 detects from the image that the finger 116 of the person to be authenticated has been inserted into the non-contact biometric authentication device 101.

[0039] Then, the information processing device 10 instructs the non-contact biometric authentication device 101 to emit near-infrared rays from the second light sources 110, 111, and 112 (s602).

[0040] When the information processing device 10 acquires an image (authentication image) in which the veins of the finger 116 of the authenticated person are revealed by the second light sources 110, 111, and 112, photographed by the photographing device 102 (s603), the information processing device 10 executes finger detection processing s604 to detect whether the authentication image is an image of the finger 116 inserted in the insertion chamber 119. Details of the finger detection processing s604 will be described later.

[0041] If the authentication image is not an image of the finger 116 inserted in the insertion chamber 119 (s605: NO), the information processing device 10 repeats the process of s602. If the authentication image is an image of the finger 116 inserted in the insertion chamber 119 (s605: YES), the information processing device 10 executes the process of s606.

[0042] In step s606, the information processing device 10 extracts only the portion of the authentication image necessary for authentication and executes area extraction processing s606 for detecting the outline of the finger in the authentication image. Details of the area extraction processing s606 will be described later.

[0043] Then, the information processing device 10 executes a finger height detection process s607 for calculating the finger height from the size of the shining portion (the portion other than the dark portion 105) of the reflector 106 shown in the authentication image.

[0044] (Detecting fingertip height) Here, FIG. 5 is a diagram for explaining the principle of the finger height detection process s607.

[0045] First, FIG. 5(a) shows a case (first case) in which a finger 116 is inserted at a low position in the insertion chamber 119 of the non-contact biometric authentication device 101. In this case, as shown in the figure, the tip of the finger 116 is located on the optical axis center line 201 of the near-infrared light that the first light source 109 irradiates onto the image capturing device 102. Therefore, the direct light of the near-infrared light from the first light source 109 is not captured in the image captured by the image capturing device 102. On the other hand, the direct light of the near-infrared light 114 from the second light source 110 is captured when the finger 116 is located at a low position in the insertion chamber 119. Therefore, the near-infrared light 114 is blocked by reaching the dorsal side of the finger 116, and a finger shadow 115, which is the space below the pad side of the finger, is small. As a result, no dark area due to the finger shadow 115 exists on the reflector 106.

[0046] 5(b) is a diagram showing an example of an image captured by the image capturing device 102 in the first case. A finger region 203 is captured in this captured image 200. Here, as described above, the finger 116 is blocking the near-infrared light emitted from the second light source 110 at a low position in the insertion chamber 119, and therefore the finger's shadow 115 in the insertion chamber 119 is small. Therefore, a bright region 202 corresponding to the reflective surface of the reflector 106, which is brightly shining all over, is captured in the captured image 200.

[0047] Next, FIG. 5(c) shows a case (second case) in which the finger 116 is inserted at approximately the middle height of the insertion chamber 119 of the non-contact biometric authentication device 101 (the middle height between the installation surface 121 and the ceiling 108). In this case, as shown in the figure, the fingertip of the finger 116 is located on the optical axis center line 201 of the near-infrared light that the first light source 109 irradiates onto the image capturing device 102, and therefore the near-infrared light from the first light source 109 does not appear in the image captured by the image capturing device 102. Meanwhile, the finger 116 is located at the middle height of the insertion chamber 119, and in this embodiment, the first light source 109 is located further back in the insertion chamber 119 than the image capturing device 102. Therefore, part of the direct light of the near-infrared light 114 from the second light source 110 reaches the back side of the finger 116 and is blocked, resulting in the formation of a shadow 115 of the finger below the finger 116. Therefore, a dark area 105 due to the finger shadow 115 is also formed in a part of the lower side of the reflecting surface of the reflecting plate 106. On the other hand, the remaining surface of the reflecting surface of the reflecting plate 106 is directly irradiated with near-infrared light from the reflecting plate 106, and this surface receives and reflects the near-infrared light.

[0048] FIG. 5(d) is a diagram showing an example of an image captured by the image capturing device 102 in the second case. This captured image 200 shows a finger region 206. The shape of this finger region 206 is similar to that of the finger region 203 in FIG. 5(b), but its size is smaller in accordance with the height of the finger 116 from the image capturing device 102 because the finger 116 is higher above the image capturing device 102. As described above, the authenticated person's finger 116 blocks the near-infrared light emitted from the second light source 110 at approximately the middle height of the insertion chamber 119. Therefore, a dark area 105 due to the finger's shadow 115 is formed on a portion of the lower surface of the reflecting surface of the reflecting plate 106, but the remaining upper reflecting surface is directly irradiated with the near-infrared light reflected by the reflecting plate 106. Therefore, the captured image 200 includes a dark area 205 corresponding to the dark portion 105 of the reflector 106 and a bright area 204 that is directly irradiated with near-infrared light reflected by the reflector 106.

[0049] Next, FIG. 5(e) shows a case (third case) in which the finger 116 is inserted at a high position (close to the ceiling 108) in the insertion chamber 119 of the non-contact biometric authentication device 101. In this case, as shown in the figure, the fingertip of the finger 116 is located on the optical axis center line 201 of the near-infrared light irradiated by the first light source 109 to the image capturing device 102, so the near-infrared light from the first light source 109 does not appear in the image captured by the image capturing device 102. On the other hand, the finger 116 is located at a high position in the insertion chamber 119 (close to the second light source 110). Therefore, most of the direct light of the near-infrared light 114 from the second light source 110 is reflected by the fingertip. The light reaches the back of the finger 116 and is blocked, forming a finger shadow 115. As a result, a dark area 105 due to the finger shadow 115 is formed on the entire reflective surface of the reflector 106.

[0050] FIG. 5(f) is a diagram showing an example of an image captured by the image capturing device 102 in the third case. A finger region 208 is captured in this captured image 200. The shape of this finger region 208 is similar to that of the finger region 203 in FIG. 5(d), but its size is smaller in accordance with the height of the finger 116 from the image capturing device 102 because the finger 116 is higher above the image capturing device 102. Furthermore, as described above, the authenticated person's finger 116 blocks the near-infrared light emitted from the second light source 110 at a high position in the insertion chamber 119. Therefore, dark areas 105 due to the finger's shadow 115 are formed on the entire surface of the reflector 106. Therefore, only dark areas 207 corresponding to the dark areas 105 of the reflector 106 are captured in the captured image 200.

[0051] As described above, in the image captured by the photographing device 102 when the finger 116 is inserted, the size of the dark area 105 (the size of the bright area) on the reflector 106 has a certain correlation (for example, a proportional relationship) with the insertion height of the finger 116 at that time.

[0052] Therefore, before executing the finger height detection process s607, the information processing device 10 calculates in advance through experiments a correlation equation between the size of the dark area 105 on the captured image and the insertion height of the finger 116. For example, the information processing device 10 creates a correlation equation between the number of pixels on the authentication image of the dark area 105 of the reflector (or the bright area of ​​the reflector) and the insertion height of the finger 116.

[0053] Thereafter, in finger height detection processing s607, the information processing device 10 calculates the size of the dark area 105 on the captured image captured by the image capturing device 102, and calculates the height of the authenticated person's finger 116 from the calculated size. For example, the information processing device 10 calculates the number of pixels in the dark area 105 of the reflector 106 (or the bright area of ​​the reflector 106) on the authentication image. The information processing device 10 can calculate the current insertion height of the authenticated person's finger 116 by substituting the calculated number of pixels in the dark area 105 (or the bright area of ​​the reflector 106) into the correlation equation.

[0054] It is preferable that the second light sources 110, 111, and 112 are arranged in a row from the opening 117 of the insertion chamber 119 toward the back wall 107 so that the finger 116 is inserted into the center of the insertion chamber 119, and the center of the finger 116 can be uniformly illuminated.

[0055] Furthermore, of the multiple second light sources 110, 111, 112, the second light source 110 on the fingertip side needs to be placed at a position where it can illuminate an area including the fingertip with sufficient brightness so that the insertion of the finger 116 can be reliably detected. Furthermore, if the second light source 110 on the fingertip side is placed too close to the back wall 107, the light emitted from the second light source 110 on the fingertip side may directly reach and be reflected by the reflector 106 of the back wall 107, and this reflected light may appear as a bright spot in the image captured by the imaging device 102, which may hinder the capture of a clear blood vessel image. Therefore, it is preferable to place the second light source 110 on the fingertip side as far away from the back wall 107 as possible so that no bright spot will appear.

[0056] Furthermore, because the ease with which infrared light penetrates varies depending on the position on the authenticated person's finger 116, it is preferable that the brightness of each of the second light sources 110, 111, and 112 can be controlled independently by the control of the near-infrared light source control unit 503, and that the brightness can be adjusted so that the average brightness of the finger 116 matches a predetermined target brightness. Furthermore, if light sources that spread their light widely are used as the second light sources 110, 111, and 112, the direct light from the second light sources 110, 111, and 112 may be reflected by the back wall 107, and the reflected light may appear as a bright spot in the image captured by the imaging device 102. Therefore, it is preferable that the second light sources 110, 111, and 112 be light sources that do not spread their light and have strong directionality.

[0057] The position of the first light source 109 for detecting the position of the fingertip is set so that it faces the image capturing device 102. Since it is desirable that the emitted light be obliquely downward, it is desirable that first light source 109 be arranged in a line together with second light sources 110, 111, and 112 on an extension of the alignment direction of second light sources 110, 111, and 112, and be as far away as possible from second light sources 110, 111, and 112. However, if first light source 109 is arranged too far from second light sources 110, 111, and 112, first light source 109 will come close to rear wall portion 107. In this case, direct light from first light source 109 will be reflected by the inner surface of rear wall portion 107, and the reflected light will appear as a bright spot in the image captured by imaging device 102, which may interfere with capturing a clear image of the blood vessels. Therefore, it is desirable to position the first light source 109 at a certain distance from the rear wall portion 107 so that no bright spots occur (a position where light of a predetermined amount or more is not reflected on the inner surface of the rear wall portion 107).

[0058] Furthermore, if the first light source 109 for detecting the position of the authenticated person's fingertip is made brighter than necessary, it becomes difficult to determine whether the light source is visible in the captured image or whether the finger appears bright due to brightness saturation. Therefore, it is desirable for the first light source 109 to emit a constant amount of light that is the minimum amount of light that allows the light source to appear at the maximum brightness of the imaging device 102 in the captured image.

[0059] Furthermore, if a light source that spreads light widely is used as first light source 109 for detecting the position of the authenticated person's fingertip, the irradiated light may directly reach and be reflected from back wall 107, and the reflected light may appear as a bright spot in the image captured by image capture device 102, preventing a clear image of the finger's blood vessels from being captured. Therefore, it is desirable to use a light source with strong directionality that does not spread light as first light source 109.

[0060] Next, as shown in FIG. 4, the information processing device 10 executes a correction process s608 for correcting distortion of the shape of the finger in the authentication image.

[0061] FIG. 6 is a diagram for explaining an example of the correction process in step s608. First, as shown in FIG. 6(a), when the finger 116 is correctly inserted parallel to the installation surface 121, the authentication image 701 is an undistorted image of the veins photographed from the front, as shown in (b).

[0062] However, as shown in FIG. 6(c), when the finger 116 is inserted with the fingertip pointing downwards (when the finger 116 is inclined toward the placement surface 121 as it moves toward the fingertip), the authentication image 702 becomes a distorted image in which the width of the finger is wider on the fingertip side 7021 and narrower on the base side 7022, as shown in (d).

[0063] Furthermore, as shown in FIG. 6(e), when the finger 116 is inserted with the tip pointing upward (when the finger 116 is inclined toward the ceiling 108 as it approaches the tip), the authentication image 703 becomes a distorted image in which the width of the finger is narrow on the fingertip side 7031 and wide on the base side 7032, as shown in (f).

[0064] In this way, when the insertion direction of the finger 116 is not parallel to the installation surface 121 and the authentication image 702 is distorted, the information processing device 10 recognizes the contour shape of the distorted authentication images 702 and 703 (for example, recognizes them as a trapezoid), and then performs trapezoid correction based on the height of the finger 116 calculated in s607 to make the shape similar to the contour shape of the undistorted authentication image 701 registered in advance.

[0065] 4, the information processing device 10 executes normalization processing s609 for normalizing the width of the finger 116. Specifically, based on the information on the contour shape of the finger 116 recognized in s608, the information processing device 10 enlarges or reduces the authentication image so that the average width of the finger 116 in the image becomes a predetermined reference width. Details of the normalization processing s609 will be described later.

[0066] Then, the information processing device 10 calculates the average brightness of the authentication image normalized in the normalization process s609 (s610).

[0067] The information processing device 10 determines whether the average brightness of the authentication image is equal to or greater than a predetermined lower limit and equal to or less than a predetermined upper limit (s611). If the average brightness is equal to or greater than the predetermined lower limit and equal to or less than the predetermined upper limit (s611: YES), the information processing device 10 executes the process of s613.

[0068] On the other hand, if the average brightness is less than the predetermined lower limit or exceeds the predetermined upper limit (s611: NO), the information processing device 10 adjusts the average brightness of the authentication image (s612). Specifically, if the average brightness is less than the predetermined lower limit, the information processing device 10 increases the light intensity values ​​of the second light sources 110, 111, and 112 by a predetermined value, and then executes the process of s602. On the other hand, if the average brightness exceeds the predetermined upper limit, the information processing device 10 decreases the light intensity values ​​of the second light sources 110, 111, and 112 by a predetermined value, and then executes the process of s602.

[0069] On the other hand, in s613, the information processing device 10 generates a pattern image of the blood vessels (veins) of the finger 116 based on the authentication image corrected by the processes up to s610.

[0070] The information processing device 10 compares the generated blood vessel pattern image with a comparison image registered in the external storage device 505, and calculates the degree of mismatch in the comparison as a comparison score (s614).

[0071] For example, the information processing device 10 performs template matching between the image for matching and the blood vessel pattern image generated in s613. The information processing device 10 compares each image obtained by thinning out the pixels of the blood vessel pattern image generated in s613 with the image for matching, and calculates the number of mismatching pixels when the number of matching pixels is the largest as the degree of mismatch (matching score).

[0072] The information processing device 10 determines whether the matching score calculated in s614 is equal to or less than a predetermined threshold (s615). If the matching score is equal to or less than the predetermined threshold (s615: YES), the information processing device 10 executes the process of s616, and if the matching score exceeds the predetermined threshold (s615: NO), the information processing device 10 executes the process of s618.

[0073] In s618, the information processing device 10 displays error information indicating that the authentication has failed, and the personal authentication process ends.

[0074] On the other hand, in s616, the information processing device 10 displays information indicating that the authentication was successful, and ends the personal authentication process so as to execute the subsequent predetermined process.

[0075] <Finger detection processing> In the finger detection process s604, the information processing device 10 may detect the insertion of a finger by determining whether the brightness of a predetermined position in the authentication image (for example, the central part that is definitely blocked by the finger 116 and has high brightness) exceeds a predetermined threshold, or may perform the detection process described below.

[0076] FIG. 7 is a diagram for explaining the principle of the finger detection process s604. First, Fig. 7(a) is an example of a captured image (authentication image) captured without inserting the finger 116. This captured image 800 has a bright area 802 where light from the first light source 109 is captured, and areas 803, 804, and 805 where light from the second light sources 110, 111, and 112 is captured. In this case, the three second light sources 110, 111, and 112 are bright areas 802, 804, and 805. 2, only the second light source 111 is turned on, so only one area 804 is bright, and the other areas 803 and 805 are slightly dark. That is, the brightness of the bright area 802 and the corresponding area 804 is at its maximum. In addition, the area 801 surrounding the bright area 802 is dark.

[0077] 7(b) is an example of a captured image captured when the second light sources 110, 111, and 112 emit near-infrared light at a target brightness and the finger 116 is inserted. This captured image 800 does not have a bright area based on the light from each light source. That is, the captured image 800 does not have a part with maximum brightness, including the area 802 corresponding to the first light source 109 (the area corresponding to the fingertip) and its surrounding area 801.

[0078] 7(c) is another example of a captured image captured with the second light sources 110, 111, and 112 emitting near-infrared light at a target brightness and the finger 116 inserted. In this captured image 800, there are no bright areas due to the second light sources 110, 111, and 112. However, the area 802 corresponding to the first light source 109 is bright because brightness saturation occurs due to the fingertip's high light transmittance.

[0079] That is, it is not possible to determine whether the bright region 802 exists because the light from the first light source 109 reaches it (i.e., the finger 116 is not held up), or because the finger 116 is held up but the brightness is saturated. However, if the bright region 802 exists due to brightness saturation, the surrounding region 801 of the region 802 corresponding to the first light source 109 should also be a bright region due to orbital saturation.

[0080] Therefore, in the finger detection process s604, the information processing device 10 determines whether or not the finger 116 is inserted by determining whether or not the brightness of not only the area 802 corresponding to the first light source 109 but also the brightness of its surrounding area 801 is equal to or greater than a predetermined threshold (here, whether or not it is at maximum brightness).

[0081] For example, in the case of Fig. 7(c), the information processing device 10 detects that the area 802 corresponding to the first light source 109 and its surrounding area 801 are also at maximum brightness, and determines that a finger is inserted. On the other hand, in the case of Fig. 7(a), the information processing device 10 determines that a finger is not inserted because the area 802 corresponding to the first light source 109 is at maximum brightness but the surrounding area 801 is not at maximum brightness.

[0082] 7, the surrounding area 801 of the area 802 corresponding to the first light source 109 does not include the area around the fingertip side. This is because such an area is likely to have maximum brightness due to reflected light from the back wall portion 107 when the light from the first light source 109 becomes stronger. However, this is not intended to exclude such an area on the fingertip side from being included in the surrounding area 801, and the information processing device 10 may detect the brightness of the entire area around the area 802.

[0083] As described above, the information processing device 10 not only detects the luminance of the area illuminated by the light from the first light source 109 from the captured image, but also detects the luminance of the surrounding area and the luminance of the second light sources 110, 111, and 112, thereby identifying whether or not the finger 116 is inserted.

[0084] <Normalization process> It is preferable to adopt a lens of the image capturing device 102 of the non-contact biometric authentication device 101 that has a longer focal length than the lens of the image capturing device in a conventional contact type authentication device (hereinafter referred to as a conventional device) that has the same configuration and structure as the non-contact type biometric authentication device 101. This is because in the case of a non-contact type authentication device such as the non-contact type biometric authentication device 101 of this embodiment, the height of the finger 116 inserted by the person to be authenticated is not constant. In other words, if the focal length is longer, This is because the range of the object to be photographed becomes wider and the change in the photographed image due to the change in the distance to the object to be photographed (the height of the finger 116) can be reduced.

[0085] However, if this is done, the outline of the fingers in the captured image will differ from the outline of the fingers in the matching image of the authenticator obtained with the conventional device, which will cause inconveniences such as the inability to reuse the matching image obtained with the conventional device. This point will be explained in detail below.

[0086] FIG. 8 is a diagram showing an example of the photographing range of the subject photographed by the photographing device of a conventional device and the photographing range of the subject photographed by the photographing device 102 according to this embodiment.

[0087] First, the image capturing device 902 of the conventional device is placed at a position away from the surface of the cylindrical object 909 (assuming a finger) that is the image capturing target, by the lens focal length of the image capturing device 902 of the conventional device. The image capturing range 904 of the image capturing device 902 of the conventional device with respect to the surface of the cylindrical object 909 is defined by two contact points 907a, 908a on the cylindrical object 909 at both ends of two tangent lines 907, 908 that form a predetermined angle and are drawn from the lens position of the image capturing device 902 of the conventional device to the surface of the cylindrical object 909.

[0088] On the other hand, the lens of the image capturing device 102 according to this embodiment has a longer focal length (predetermined shooting distance d) than the lens of the image capturing device 902 of the conventional device, and therefore the distance between the image capturing device 102 and the surface of the cylindrical object 909 is also longer than in the case of the image capturing device 902 of the conventional device. Consequently, the image capturing range 903 of the image capturing device 102 according to this embodiment with respect to the surface of the cylindrical object 909 is also wider than the image capturing range 904 of the image capturing device 902 of the conventional device. In other words, the image capturing range 903 of the image capturing device 102 according to this embodiment has two tangent lines 905, 906 drawn from the lens position of the image capturing device 102 to the surface of the cylindrical object 909, and the two tangent lines 905, 906 that form a larger angle with each other are at two tangent points 905a, 906a on the cylindrical object 909 that are farther apart.

[0089] For the above reasons, if the contactless biometric authentication device 101 of this embodiment uses a matching image collected using a conventional photographing device to perform authentication, the authentication image will not function properly. For example, if the vein pattern image is normalized with respect to the width of the finger 116 in s608, the size of the normalized image will not match the size of the matching image.

[0090] Here, the inventors have discovered that there is a certain linear relationship between the width of the object photographed by the conventional photographing device and the width of the object photographed by the photographing device 102 of this embodiment.

[0091] 9 is a graph showing the relationship between the size (here, width) of a cylinder (shown in FIG. 8) as a subject photographed by a conventional imaging device and the size (here, width) of a cylinder photographed by imaging device 102 with a long focal length (imaging device 102 of this embodiment), which is the result of an experiment conducted by the inventors. As shown in the figure, the relationship between the two widths is a linear relationship represented by linear equation 1001, regardless of the thickness of the cylinder or the distance between each imaging device and the cylinder.

[0092] Therefore, in the normalization process s609, the information processing apparatus 10 performs correction related to the focal length of the lens by using a linear formula 1001, as will be described below.

[0093] 10 is a diagram showing an example of the normalization process in step S609. First, the information processing device 10 calculates the average width of the finger based on contour lines 1102 and 1105 on both the left and right sides of the finger extracted from a finger region 1101 in the authentication image.

[0094] For example, the information processing device 10 calculates the vertical direction of each successive point on the image center line 1106 in the center of the authentication image in the horizontal direction (the direction of insertion of the finger into the non-contact biometric authentication device 101) from that point. The information processing device 10 searches for changes in brightness at each point in the horizontal direction and identifies the transition point where the brightness of adjacent points (pixels) changes most significantly from bright to dark. The information processing device 10 identifies the contour by connecting the identified transition points horizontally. Then, the information processing device 10 calculates the (average) width of the finger in the image captured by the conventional imaging device using the calculated average finger width and the above-mentioned linear formula 1001. The information processing device 10 then performs correction to narrow the finger width so that it matches the calculated finger width, thereby calculating corrected finger contours 1103 and 1104.

[0095] Next, the region extraction process will be described. <Area extraction processing> In conventional devices, an image of the central part of the finger excluding the fingertip and base (an image of the part corresponding to the blood vessel pattern image) is sufficient as an authentication image. However, the non-contact biometric authentication device 101 of this embodiment performs contactless authentication, so it is necessary to acquire an image of a finger in a wider area than in conventional devices. Therefore, the authentication image acquired by the non-contact biometric authentication device 101 will be incompatible with images acquired by conventional devices, for example, with matching images of an authenticated person previously acquired by conventional devices.

[0096] However, when maintaining compatibility and reusing the verification image of the authenticator acquired by a conventional device, it is preferable that the information processing device 10 extracts a necessary area corresponding to the verification image from the authentication image. Therefore, the information processing device 10 of this embodiment executes the following area extraction process.

[0097] FIG. 11 is a diagram for explaining an example of the region extraction process s606. First, the information processing device 10 recognizes contour lines 1206 and 1207 on both the left and right sides of the finger by identifying pixel parts with large changes in luminance in the authentication image 1200. Then, the information processing device 10 calculates a center line 1208 that is equidistant from the recognized contour lines 1206 and 1207 on both the left and right sides.

[0098] The information processing device 10 identifies the tip point 1202 of the finger by starting from this center line 1208 and identifying the point (change point) where the brightness of adjacent pixel points changes most significantly from bright to dark for each consecutive pixel point on the center line 1208 in the direction from the base of the finger to the tip of the finger.

[0099] Furthermore, the information processing device 10 obtains an average finger width 1209 from the finger contour lines 1206 and 1207 in the authentication image 1200 .

[0100] Then, the information processing device 10 multiplies the average finger width 1209 by a predetermined constant A to calculate a distance 1204 from the tip point 1202 of the finger to a rectangular area 1203 to be extracted as an authentication image.

[0101] Furthermore, the information processing device 10 calculates the length 1205 of the rectangular area 1203 to be extracted in the longitudinal direction by multiplying the average finger width 1209 by a predetermined constant B. Note that the information processing device 10 may calculate the length of the short side of the rectangular area 1203 to be extracted based on a preset aspect ratio of the image, or may calculate a finger width that is longer by a processing percentage than the maximum finger width as the length of the short side of the area 1203.

[0102] The position and size of the rectangular area 1203 to be extracted can be calculated based on the finger tip point 1202 and the average finger width 1209 because it is known that there is a certain degree of correlation between a person's finger width, finger length, and the position of each joint in the finger length direction, regardless of the person. Therefore, the constants A and B can be empirically determined by collecting information on the finger shapes of many people.

[0103] As described above, the information processing device 10 can appropriately extract an authentication image that is compatible with the verification image of a conventional device.

[0104] <Ceiling shape> In the non-contact biometric authentication device 101 of this embodiment, the shape of the ceiling portion 108 is modified to make it easier for the person to authenticate to check the position of the finger.

[0105] 12 is a cross-sectional side view of the non-contact biometric authentication device 101. For example, in a conventional device, the portion corresponding to the ceiling portion 108 of the non-contact biometric authentication device 101 is flat.

[0106] However, the ceiling 108 of the non-contact biometric authentication device 101 is generally flat, but has an extension 1401 that extends upward at the end on the opening 117 side. This extension direction faces the line of sight of the person to be authenticated. This extension direction is preferably such that the line of sight 1402 from the person to be authenticated who is about to insert a finger 116 follows the underside of the extension 1401 of the ceiling 1305 (the underside of the ceiling 108) and reaches the surface 1161 on the back side of the fingertip of the finger 116 to be inserted.

[0107] This allows the authenticator to insert finger 116 into insertion chamber 119 while checking the position of finger 116 to be inserted without unnaturally changing his / her line of sight or posture. This reduces the authenticator's psychological resistance to inserting a finger into insertion chamber 119, which is difficult for the authenticator to see.

[0108] On the other hand, since the extension portion 1401 extends upward, there is a possibility that external light (such as a fluorescent light on the ceiling of the room) may enter the insertion chamber 119 and be reflected in the background of the authentication image.

[0109] 13, a background structure 1502 appears in an area 1503 on the base of the finger in an authentication image 1500. In this case, the information processing device 10 may mistakenly recognize the background structure 1502 as a finger. For example, the information processing device 10 may mistakenly recognize a finger outline 1504 on the base of the finger based on both the actual finger part and the boundary line of the background structure 1502. Such a mistaken recognition of the finger outline occurs when, for example, a fluorescent light on the ceiling appears in the authentication image.

[0110] Therefore, the information processing apparatus 10 of this embodiment may perform the following process in the contour extraction process s606 to correct the contour of the finger.

[0111] FIG. 14 is a flowchart illustrating an example of the finger contour correction process that corrects the contour of the finger in the authentication image, which is performed in the contour extraction process S606.

[0112] First, the information processing device 10 acquires an authentication image (s1602, similar to the above-mentioned s603 to s605).

[0113] The information processing device 10 identifies pixel portions in the authentication image where there is a large change in brightness, thereby recognizing the outline of the finger on the fingertip side (s1603).

[0114] Then, the information processing device 10 estimates the contour of the base of the finger based on the authentication image acquired in s1603 (s1604).

[0115] Specifically, the information processing device 10 preliminarily calculates the contour of the finger on the base side from the contour of the finger on the tip side. A trained model for estimating the contour portion is created. For example, the information processing device 10 collects images of fingers of many people and divides them into an image of the contour of the fingertip side and an image of the contour of the base side. Then, the information processing device 10 uses the image of the contour of the fingertip side as input data and performs machine learning based on training data in which the contour portion of the finger on the base side is used as correct answer data, thereby creating a trained model for estimating the contour of the finger on the base side from the contour of the finger on the fingertip side.

[0116] The distinction between the fingertip and base regions in the authentication image may be made by, for example, registering each region in the authentication image in advance, or by estimating it from the distribution of the finger contours.

[0117] Then, the information processing device 10 inputs the data of the contour of the fingertip side acquired in s1603 into the created trained model, thereby estimating the contour of the finger on the base side of the authentication image.

[0118] 15 is a diagram illustrating an example of estimating the contour of the base side of a finger by finger contour correction processing. The information processing device 10 inputs contours 1507 and 1508 of the finger on the fingertip side as input data to a trained model, thereby estimating contours 1505 and 1506 of the finger on the base side, thereby correctly recognizing the contour of the finger on the base side regardless of a background structure 1502.

[0119] <Example 2> In the first embodiment, the height of the finger 116 is detected by providing a reflector 106 on the back wall 107 of the insertion chamber 119, but in the second embodiment, the height of the finger 116 is detected by providing a similar reflector on the side wall 113 (the inner surface of the insertion chamber 119).

[0120] 16 is a diagram showing a non-contact biometric authentication device 131 according to the second embodiment as viewed from the opening 117 side of the insertion chamber 119, and an example of an image captured by the non-contact biometric authentication device 131. The non-contact biometric authentication device 131 of this embodiment includes a reflector 301 extending from the bottom of the side wall 113 to the vicinity of the central height, thereby detecting the height of the part of the finger 116. Other configurations of the non-contact biometric authentication device 131 are the same as those of the non-contact biometric authentication device 101 of the first embodiment.

[0121] The height and direction of the reflecting surface of the reflector 301 on the side wall 113 (inner surface) are adjusted based on the same principle as in Example 1 so that when the tip of the finger 116 inserted into the insertion chamber 119 is blocked by the light from the second light source 110, a proportion of the light from the second light source 110 corresponding to the height of the inserted finger reaches and is reflected by the reflector 301. Specifically, this is as follows.

[0122] 16(a) shows a case (fourth case) in which the finger 116 is inserted at a low position in the insertion chamber 119 of the non-contact biometric authentication device 131, and the fingertip side of the finger 116 is placed on the fingertip-side finger rest 104 as in the conventional device. As shown in the figure, since the finger 116 is at a low position in the insertion chamber 119, the direct light of the near-infrared light 114 from the second light source 110 is irradiated onto the entire reflective surface of the reflector 301 without being blocked by the finger 116.

[0123] 16(b) is a diagram showing an example of an image captured by the image capturing device 102 in the fourth case. As shown in the figure, a finger area 304 is captured in the captured image 300. Here, as described above, the direct light of the near-infrared light 114 from the second light source 110 is irradiated onto the entire reflective surface of the reflector 301. Therefore, a bright area 303 corresponding to the reflective surface of the reflector 301 that is brightly shining all over is captured in the captured image 300.

[0124] Next, Fig. 16(c) shows a case (fifth case) in which the finger 116 is inserted at an intermediate height in the insertion chamber 119 of the non-contact biometric authentication device 131. As shown in the figure, the finger 116 is at an intermediate height in the insertion chamber 119. Therefore, the direct light of the near-infrared light 114 from the second light source 110 is partially blocked by reaching the back side of the finger 116, and the light is not transmitted to the bottom of the finger 116. On the other hand, a finger shadow 115 is formed in the space below the pad of the finger. As a result, a dark area 302 due to the finger shadow 115 is also formed on a part of the surface below the reflective surface of the reflector 301. On the other hand, the light from the near-infrared light 114 is directly irradiated onto the remaining surface of the reflective surface of the reflector 301, and the near-infrared light received by that surface is reflected.

[0125] FIG. 16(d) is a diagram showing an example of an image captured by the image capturing device 102 in the fifth case. This captured image 300 shows a finger region 307. The shape of this finger region 307 is similar to that of the finger region 304 in FIG. 16(b), but its size is smaller in accordance with the height of the finger 116 from the image capturing device 102 because the finger 116 is higher from the image capturing device 102. As described above, the authenticated person's finger 116 blocks the near-infrared light emitted from the second light source 110 at approximately the middle height of the insertion chamber 119. Therefore, a dark area 302 due to the finger's shadow 115 is formed on a portion of the lower surface of the reflecting surface of the reflector 301, but the remaining upper surface is directly irradiated with the near-infrared light reflected by the reflector 301. Therefore, the captured image 200 includes a dark area 305 corresponding to the dark portion 302 of the reflector 301 and a bright area 306 that is directly irradiated with near-infrared light reflected by the reflector 301.

[0126] 16(e) shows a case (sixth case) in which the finger 116 is inserted at a high position (close to the ceiling 108) in the insertion chamber 119 of the non-contact biometric authentication device 131. In this case, as shown in the figure, the finger 116 is at a high position in the insertion chamber 119 (close to the second light source 110). Therefore, most of the direct light of the near-infrared light 114 from the second light source 110 reaches the back side of the finger 116 and is blocked, forming a finger shadow 115. As a result, a dark area 302 due to the finger shadow 115 is formed on the entire reflective surface of the reflector 301.

[0127] FIG. 16(f) is a diagram showing an example of an image captured by the image capturing device 102 in the sixth case. A finger region 309 is captured in this captured image 300. The shape of this finger region 309 is similar to that of the finger region 307 in FIG. 16(d), but its size is smaller in accordance with the height of the finger 116 from the image capturing device 102 because the finger 116 is higher above the image capturing device 102. Furthermore, as described above, the authenticated person's finger 116 blocks the near-infrared light emitted from the second light source 110 at a high position in the insertion chamber 119. Therefore, dark areas 302 due to the finger's shadow 115 are formed on the entire reflective surface of the reflector 301. Therefore, only dark areas 308 corresponding to the dark areas 302 of the reflector 301 are captured in the captured image 200.

[0128] From the above, in the image captured by the photographing device 102 when the finger 116 is inserted, the surface area of ​​the dark area 302 (or the area of ​​the bright area) of the reflector 301 has a certain correlation (for example, a proportional relationship) with the insertion height of the finger 116 at that time.

[0129] Therefore, similar to the first embodiment, when an authenticated person inserts a finger 116, the information processing device 10 calculates the size of the dark area 302 on the captured image captured by the photographing device 102, and can calculate the height of the authenticated person's finger 116 from the calculated size.

[0130] The reflecting surface of reflector 301 is preferably set at a height such that, when finger 116 is inserted at about the middle height of insertion chamber 119, a dark area 302 is formed when near-infrared light 114 from second light source 110 is blocked by finger 116, and other bright areas are formed.

[0131] Furthermore, if the distance between the inserted finger 116 and the side wall 113 varies, the size of the dark area 302 will also vary, which may result in an error in detecting the height of the finger 116. Therefore, it is possible to install reflectors 301 on both the left and right side wall 113 and use the average value of the height of the authenticated person's finger 116 obtained from each of these side wall 113. This makes it possible to reduce calculation errors in the height of the finger 116.

[0132] Example 3 In the first embodiment, the information processing device 10 detects the height of the dorsal side of the finger, but in the third embodiment, the information processing device 10 detects the height of the ventral side of the finger by providing a new light source on the side wall. The reason for this is that the thickness of fingers varies from person to person, so if the height of the dorsal side of the finger is calculated, the height of the veins on the ventral side of the finger will contain an error due to the variation in the thickness of each person's finger. Therefore, the non-contact biometric authentication device 101 of the third embodiment calculates the height of the ventral side of the finger, thereby calculating the accurate distance from the image capturing device to the veins in the finger, and can perform vein authentication with high accuracy.

[0133] 17 is a diagram showing a non-contact biometric authentication device 401 according to a third embodiment as viewed from the opening of an insertion chamber 449, and an example of an image captured by the non-contact biometric authentication device 401. Similar to the first embodiment, the non-contact biometric authentication device 401 of this embodiment includes a finger rest 403 for a fingertip, left and right side walls 406, a ceiling 407, a first light source 408 that irradiates near-infrared rays from diagonally above to capture an image of a finger 411, a second light source (not shown), and an image capturing device 402.

[0134] Furthermore, one of the side walls 406 is provided with a third light source 404 fixed to a lower part of the inner surface thereof and irradiating near-infrared light laterally into the insertion chamber 449. Further, the other of the side walls 406 is provided with a reflector 410 having a reflecting surface that receives and reflects near-infrared light 405 from the third light source 404. The other configurations are the same as those in the first embodiment.

[0135] The height of the third light source 404 is set low enough that when the finger 441 is inserted in the upper part of the insertion chamber 449, the direct light of the near-infrared light 405 from the third light source 404 does not strike the ventral side of the finger 441.

[0136] More specifically, the height of third light source 404 and the height (range) of the reflective surface of reflector 410 are adjusted to a height such that when direct light from third light source 404 is blocked by the fingertip of a finger inserted into insertion chamber 449 at a predetermined height or less, a proportion of the light from third light source 404 corresponding to the height of the inserted finger does not reach the reflective surface of reflector 410.

[0137] 17(a) shows a case (seventh case) in which a finger 441 is inserted at a high position (close to the ceiling 407) in the insertion chamber 449 of the non-contact biometric authentication device 401. The near-infrared light 405 from the third light source 404 is not blocked by the finger 411 and hits the entire reflective surface of the reflector 410 because the finger 411 is at a high position.

[0138] 17(b) is a diagram showing an example of an image captured by the image capturing device 402 in the seventh case. A finger region 415 is captured in this captured image 400. Furthermore, since the authenticated person's finger 411 does not block the near-infrared light from the third light source 404 as described above, a bright region 414 corresponding to the reflective surface of the reflector 410, which shines brightly all over, is captured in the captured image 400.

[0139] Next, FIG. 17(c) shows a case (eighth case) in which the finger 411 is inserted at an intermediate height in the insertion chamber 449 of the non-contact biometric authentication device 401 (when the ventral side of the finger 411 reaches a predetermined height or lower). The near-infrared light 405 from the third light source 404 is emitted when the finger 411 is at an intermediate height in the insertion chamber 449. Therefore, part of the near-infrared light 405 is blocked by the ventral side of the finger 411 depending on the height of the finger 411, and a space of the finger shadow 412 is formed on the reflector 410 side of the finger 411. As a result, a dark area 413 due to the finger shadow 412 is formed on a part of the upper surface of the reflector 410. Meanwhile, the light from the reflector 410 is directly irradiated onto the remaining surface of the reflector 410, and the surface receives and reflects the light.

[0140] FIG. 17(d) shows an example of an image captured by the image capturing device 402 in the eighth case. 4. This photographed image 400 shows a finger region 418. As described above, the authenticated person's finger 441 blocks the near-infrared light emitted from the third light source 404 at approximately the middle height of the insertion chamber 449. Therefore, a dark region 413 caused by the finger's shadow 412 is formed on a portion of the lower surface of the reflecting surface of the reflector 410, but the near-infrared light reflected by the reflector 410 is directly irradiated on the remaining upper surface. Therefore, the photographed image 400 shows a dark region 417 corresponding to the dark region 413 of the reflector 410 and a bright region 416 that is directly irradiated with the near-infrared light reflected by the reflector 410.

[0141] 17(e) shows a case (ninth case) in which a finger 411 is inserted at a low position in the insertion chamber 449 of the non-contact biometric authentication device 401. Because the finger 441 is at a low position in the insertion chamber 449, the near-infrared light 405 from the third light source 404 is entirely blocked by the finger 441, forming a space of the finger shadow 412, and the near-infrared light 405 does not reach the reflector 410. As a result, a dark area 413 due to the finger shadow 412 is formed on the entire reflective surface of the reflector 410.

[0142] 17(f) is a diagram showing an example of an image captured by the image capturing device 402 in the third case. A finger region 420 is captured in this captured image 400. Furthermore, since the authenticated person's finger 116 blocks the near-infrared light emitted from the third light source 404 as described above, a dark region 413 due to the finger's shadow 412 is formed on the entire reflective surface of the reflector 410. Therefore, only a dark region 419 corresponding to the dark region 413 of the reflector 410 is captured in the captured image 200.

[0143] As described above, the size of the dark area 413 (or the size of the bright area) on the reflector 410 in the image captured by the imaging device 402 when the finger 411 is inserted has a certain correlation (for example, a proportional relationship) with the insertion height of the finger 411 at that time. In particular, the dark area 413 on the reflector 410 appears when the height of the lower surface, i.e., the ventral side, of the finger 411 is equal to or lower than a predetermined height.

[0144] Therefore, similarly to the first embodiment, when an authenticated person inserts a finger 411, the information processing device calculates the size of the dark area 413 on the captured image captured by the photographing device 402, and can more accurately calculate the height of the ventral side of the authenticated person's finger 411, i.e., the height of the veins, from the calculated size.

[0145] Note that if the distance between the authenticated person's finger 411 and the side wall 406 varies, the size of the dark area 413 also varies, which may result in an error in detecting the height of the finger 411. Therefore, by installing a reflector 410 on each of the opposing side wall 406 on both the left and right sides and using the average value of the height of the ventral side of the authenticated person's finger 411 obtained from each of these side wall 406, it is possible to further reduce the calculation error in the height of the ventral side of the finger 411.

[0146] Example 4 In this embodiment, the non-contact biometric authentication device 101 includes a fourth light source for guiding the insertion of the finger 116 .

[0147] Fig. 18 is a diagram illustrating the configuration of a fourth light source 1310 according to Example 4. Specifically, Fig. 18(a) is a diagram illustrating the non-contact biometric authentication device 1301 as viewed from above on the opening 117 side. Fig. 18(b) is a cross-sectional view illustrating the state in which a finger 1302 is inserted into the non-contact biometric authentication device 1301 as viewed from the side.

[0148] As shown in FIG. 18, an insertion chamber 1308 of a non-contact biometric authentication device 1301 includes a ceiling portion 1305 and two side walls 1306 and 1307, similar to the first embodiment.

[0149] A fourth light source 1310 is attached to the center of the inner surface of the ceiling portion 1305 to indicate the insertion direction of the finger 1302 to the person to be authenticated.

[0150] Specifically, the illumination range of the fourth light source 1310 is the central part in the insertion direction of the insertion chamber 1319, from the opening of the insertion chamber 1319 toward the back side (the side of the back wall 1311) of the insertion chamber 1319. That is, the illumination direction of the illumination light 1309 of the fourth light source 1310 is adjusted along the insertion direction of the finger 1302 so as to illuminate the central part of the dorsal side of the finger 1302.

[0151] The irradiated light 1309 is visible light, for example, red or blue visible light that is easily recognized by the authenticator.

[0152] As a result, when the authenticator inserts the finger 1302 with the back facing up along the light 1309 emitted from the fourth light source 1310, the finger 1302 will naturally be inserted into the appropriate position in the insertion chamber 1319 (the position where the correct authentication image is obtained).

[0153] In this way, the non-contact biometric authentication device 1301 of this embodiment can irradiate visible light that indicates the position and direction in which the finger 1302 should be inserted, thereby prompting the person to insert their finger in a position suitable for authentication.

[0154] <Example 5> Although the side wall 113 in the non-contact biometric authentication device 101 of the first embodiment is provided perpendicular to the installation surface 12, the installation direction of the side wall 113 may be changed as follows.

[0155] Fig. 19 is a cross-sectional view of the non-contact biometric authentication device 1711 according to the fifth embodiment when a finger is inserted, as viewed from the fingertip direction. Specifically, Fig. 19(a) is a cross-sectional view when the central finger 1702 of three fingers 1701, 1702, and 1703 is inserted from above the insertion chamber 1719, and Fig. 19(b) is a cross-sectional view when the central finger 1713 of three fingers 1712, 1713, and 1714 is inserted from below the insertion chamber 1719.

[0156] As shown in the figure, this non-contact biometric authentication device 1711 includes an image capturing device 1709, a fingertip-side finger rest 1710, side walls 1704 and 1705, a ceiling 1706, a second light source 1707, and the like, similar to the first embodiment.

[0157] Here, the side walls 1704 and 1705 are provided facing each other, but the direction in which they are erected is different from that in the first embodiment.

[0158] That is, the space in the insertion chamber 1719 in the insertion direction of the finger 1702 is formed so that the upper space is wider than the lower space. In the example shown in the figure, the side walls 1704, 1705 do not extend vertically relative to the installation surface 1722, but rather extend in a wedge shape. In other words, the side walls 1704, 1705 are inclined outward so that the space formed by the side walls 1704, 1705 and the rear wall becomes wider as it goes towards the top of the insertion chamber 1719.

[0159] The width of the opening at the top of the insertion chamber 119 is set to a width that allows adjacent fingers 1701 and 1703 to abut against a finger 1702 that is advanced toward the opening.

[0160] For example, the gap between the side walls 1704 and 1705 at the bottom is slightly wider than the width of the finger to be inserted. Also, the gap between the side walls 1704 and 1705 at the top is adjusted so that the finger adjacent to the inserted finger 1702 can easily contact the side walls 1704 and 1705.

[0161] As a result, if the authenticator attempts to insert finger 1702 at a high position, the fingers 1701 and 1703 adjacent to that finger 1702 will hit the side walls 1704 and 1705 of the insertion chamber 1719 unless the authenticator consciously spreads the fingers 1701 and 1703 apart, so the authenticator will insert finger 1702 at a lower position.

[0162] As shown in Figure 19(a), in order to insert one finger 1702 of three fingers 1701, 1702, and 1703 held out by an authenticator into insertion chamber 1719 so that the finger 1702 does not come into contact with the upper parts of side walls 1704 and 1705, the authenticator needs to consciously spread the three fingers 1701, 1702, and 1703. In contrast, as shown in Figure 19(b), in the case where one finger 1702 of three fingers 1701, 1702, and 1703 held out by an authenticator is to be inserted into insertion chamber 1719 so that the finger 1702 does not come into contact with the lower parts of side walls 1704 and 1705, there is little need to spread the three fingers 1701, 1702, and 1703 widely.

[0163] This allows the person to be guided not to insert their finger at a high position in the insertion chamber 1719. This allows the non-contact biometric authentication device 1711 to acquire an authentication image in which the finger is photographed larger, enabling highly accurate authentication.

[0164] The degree of inclination of the side walls 1704 and 1705 can be changed as appropriate depending on the height to which the authentication person's finger is to be guided in the insertion chamber 119. The side walls 1704 and 1705 may also be curved to fit the shape of the finger to be inserted.

[0165] As described above, the non-contact biometric authentication device of this embodiment includes an insertion chamber, an imaging device that images the pad side of a finger inserted into the insertion chamber, a first light source for finger detection located further back in the insertion chamber than the imaging device, a second light source that emits near-infrared light, and a reflective surface (reflector) that reflects light from the second light source, and the position and direction of the reflective surface are adjusted so that when the first light source detects the insertion of a finger, it receives a proportion of light from the second light source that corresponds to the height of the inserted finger, and the imaging device captures an image including the light reflected by the reflector and the finger.

[0166] That is, in the non-contact biometric authentication device of this embodiment, the amount of light from the second light source that is reflected from the reflector and reaches the image capturing device varies depending on the height of the inserted finger, so that the image captured by the image capturing device contains information about the height of the inserted finger.

[0167] In a contactless authentication device such as this embodiment, the position of the biometric subject to be authenticated (in this embodiment, the height of the finger) often differs for each authentication operation by the authenticator, which causes a decrease in authentication accuracy. Therefore, the contactless biometric authentication device of this embodiment can improve authentication accuracy by performing predetermined image correction (correction of image distortion, etc.) using finger height information contained in the captured image.

[0168] As described above, the non-contact biometric authentication device of this embodiment can perform non-contact authentication with high accuracy, and in this case, there is no need to introduce an additional sensor or the like.

[0169] Furthermore, the non-contact biometric authentication device of this embodiment includes a plurality of second light sources and a near-infrared light source control unit that adjusts the light intensity of each second light source, and the second light sources are aligned in a direction in which light from the second light sources illuminates the center of the insertion direction on the dorsal side of the finger.

[0170] This makes it easier to adjust the average brightness of the finger 116 in the authentication image to a predetermined target brightness, and makes it possible to capture an authentication image of stable quality suitable for authentication.

[0171] Furthermore, the first light source in the non-contact biometric authentication device of this embodiment emits directional light, and is provided at a position deeper in the insertion chamber than the second light source and where direct light from the first light source is not reflected by the back wall of the insertion chamber by more than a predetermined amount, and emits directional light.

[0172] This prevents direct light from the first light source from appearing in an image taken by the image capturing device 102 or interfering with light from the second light source, thereby preventing the first light source from interfering with the detection of finger insertion.

[0173] Furthermore, the non-contact biometric authentication device of this embodiment has a reflective surface on the side wall that reflects light from the second light source, and the height of the reflective surface on the side wall is adjusted to a height that receives a proportion of light from the second light source according to the height of the inserted finger when the finger inserted into the insertion chamber is blocked by light from the second light source.

[0174] As a result, the amount of light from the second light source that is reflected from the reflective surface and reaches the image capture device varies depending on the height of the inserted finger. As a result, the image captured by the image capture device contains information about the height of the inserted finger. Using this image, contactless authentication can be performed with high accuracy.

[0175] Furthermore, the non-contact biometric authentication device of this embodiment is provided with a third light source at the bottom of one of the inner surfaces of the inner walls, and a reflective surface that reflects light from the third light source at the bottom of the other inner wall, and the height of the third light source and the reflective surface on the inner surface is adjusted to a height such that when the light from the third light source is blocked by a finger inserted into the insertion chamber at a predetermined height or below, a proportion of the light from the third light source that corresponds to the height of the inserted finger does not reach the reflective surface.

[0176] As a result, the amount of light from the third light source that is reflected by the reflective surface and reaches the image capture device varies depending on the height of the inserted finger. As a result, the image captured by the image capture device contains information about the height of the inserted finger, particularly the height of the lower part of the finger (the height of the ventral side). Using this image, contactless authentication can be performed with high accuracy.

[0177] Furthermore, when the information processing device 10 of the non-contact biometric authentication system 1 of this embodiment determines that the light from the first light source is blocked by the fingertip of the finger inserted into the insertion chamber, it instructs the second light source to emit light, identifies the vein pattern of the inserted finger based on the area of ​​light from the second light source included in the image captured by the photographing device, and compares the identified vein pattern of the finger with the matching image to authenticate the finger to be authenticated.

[0178] In this way, the first light source detects that the fingertip has been inserted into the insertion chamber, and the second light source begins irradiating light to obtain an authentication image, thereby ensuring reliable authentication of the finger to be authenticated.

[0179] Furthermore, the information processing device 10 of the non-contact biometric authentication system 1 of this embodiment calculates the brightness around the portion of the authentication image where light is emitted from the first light source, and only when the calculated brightness is equal to or greater than a predetermined threshold value, determines that the light from the first light source is blocked by the fingertip of the finger inserted into the insertion chamber and instructs the second light source to emit light.

[0180] Because the tip of a finger is thin, the first light source may transmit a lot of light at the tip of the finger, causing brightness saturation. In this case, it may be difficult to determine whether the image captured by the imaging device is bright due to brightness saturation at the tip of the inserted finger, or whether the image is bright due to the light from the first light source because the finger has not yet been inserted. Therefore, by determining that the tip of the finger has been inserted when the brightness around the light from the first light source is high, it is possible to accurately determine whether the finger has been inserted.

[0181] Furthermore, the information processing device 10 of the non-contact biometric authentication system 1 of this embodiment identifies the relationship between the width of the image of the cylindrical object photographed by the photographing device and the width of the image of the cylindrical object photographed by a conventional device having a focal length different from that of the photographing device, and corrects the size of the photographed image for authentication based on the identified relationship.

[0182] Due to the nature of contactless authentication, images captured by a photographing device in a contactless authentication device are likely to show a living body differently in each image. This means that a photographing device with a longer focal length than conventional devices is used (for example, a lens with a deep depth of field is used so that the difference in how the subject is viewed is reduced). This creates a problem in compatibility between the contactless biometric authentication device of this embodiment and conventional devices. However, with the above configuration, it is possible to reuse images for verification captured by conventional devices with different focal lengths, ensuring compatibility with conventional devices.

[0183] Furthermore, the information processing device 10 of the non-contact biometric authentication system 1 of this embodiment calculates the position of the tip of the finger and the width of the finger from the authentication image, extracts an area required for finger authentication from the authentication image based on the calculated tip of the finger and width of the finger (for example, an image of the same size as an authentication image obtained by a conventional device), and identifies the finger vein pattern based on the image of the extracted area.

[0184] Contactless authentication devices capture a wider range of finger images than conventional devices because the captured finger image tends to vary with each operation. In this case, to ensure compatibility with images obtained by conventional devices, it is necessary to extract a portion of the image. According to the above configuration, an image from a conventional device, for example, an image compatible with a matching image obtained by a conventional device, can be reused to ensure compatibility with conventional devices. In particular, since there is a certain relationship between the width and length of a person's finger, the above configuration can utilize this relationship to extract an appropriate image area.

[0185] In addition, the non-contact biometric authentication device of this embodiment is provided with a visible light source that is located above the height at which a finger is inserted and that illuminates the central part of the insertion chamber from the opening of the insertion chamber toward the back of the insertion chamber.

[0186] This prompts the person to be authenticated to insert their finger into the insertion chamber in a certain direction, and the photographing device can take an authentication image with high authentication accuracy.

[0187] Furthermore, an extension portion that extends toward the line of sight of the person to be authenticated is formed at the end of the opening in the ceiling of the insertion chamber of the non-contact biometric authentication device of this embodiment.

[0188] The inside of the insertion chamber where the finger is inserted is difficult for the authenticator to see, and the authenticator may feel psychologically reluctant to insert a finger. Therefore, by providing the extension section on the opening side of the ceiling section as described above, the authenticator can easily see the internal space of the insertion chamber and the finger inserted therein, making it easier for the authenticator to use the contactless biometric authentication device.

[0189] Furthermore, in this case, the information processing device 10 of the non-contact biometric authentication system 1 of this embodiment estimates the contour of the base side of the finger by inputting information about the contour of the fingertip side included in the image captured by the photographing device into a numerical model that estimates the contour shape of the base side of the finger from the contour shape of the fingertip side of the finger.

[0190] When the extension part is provided as described above, the base of the finger in the authentication image may become brighter due to the intrusion of external light, resulting in an image with a blurred outline. Therefore, a numerical model that estimates the outline of the base of the finger from the outline of the fingertip is used to capture the image of the base of the finger. The contour of the object can be estimated to obtain an authentication image suitable for authentication.

[0191] Furthermore, the space in the insertion direction of the finger in the insertion chamber of the non-contact biometric authentication device of this embodiment is formed so that the upper space is wider than the lower space, and the width of the opening at the top of the insertion chamber is set to a width that allows the finger adjacent to the finger entering the opening to abut.

[0192] In the non-contact biometric authentication device of this embodiment, inserting a finger at a lower position reduces the distance between the finger and the image capture device, making it easier for the image capture device to capture a clearer image and improving authentication accuracy. Therefore, with the above configuration, the authentication person places less strain on the finger by inserting the finger lower than higher into the insertion chamber. That is, if the authentication person attempts to insert their finger at the top of the insertion chamber, the adjacent finger will touch the side wall, so they will try to insert the finger at a lower position. This allows for an authentication image that is more suitable for authentication.

[0193] The present invention is not limited to the above-described embodiments, and can be implemented using any components within the scope of the present invention. The above-described embodiments and modifications are merely examples, and the present invention is not limited to these contents as long as the characteristics of the invention are not impaired. Furthermore, although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other aspects conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention.

[0194] For example, the configurations of the embodiments described in this specification may be combined.

[0195] Furthermore, some of the hardware included in each device of this embodiment may be provided in another device. Furthermore, some of the functional units included in each device of this embodiment may be provided in another device, or functional units included in another device may be provided in the same device. [Explanation of symbols]

[0196] 1. Contactless biometric authentication system 101 Contactless biometric authentication device 102 Imaging equipment 106 Reflector 109 1st light source 110 Second light source 111 Second light source 112 Second light source 119 Insertion Room 116 fingers

Claims

1. an insertion chamber having an opening on a side thereof and a space into which the finger of the authenticated person is inserted from the opening to the rear; an imaging device installed at a position to image the pad side of the finger inserted into the insertion chamber; a first light source that is installed in a position deeper than the imaging device in the insertion chamber and that irradiates light in the direction of the imaging device, the light being blocked by a finger inserted into the insertion chamber; a second light source that is provided at a position higher than the height at which the finger is inserted and that, when light from the first light source is blocked by the finger, irradiates a predetermined area including the imaging device with light that is absorbed by blood vessels in the finger; a reflecting surface that is provided in the insertion chamber and receives and reflects light from the second light source, a position and a direction of the reflecting surface are adjusted so that, when the light from the first light source is blocked by the finger, a proportion of the light from the second light source corresponding to a height of the inserted finger is reflected; the photographing device photographs an image including the light reflected by the reflecting surface and the pad side of the inserted finger; Contactless biometric authentication device.

2. 2. The non-contact biometric authentication device of claim 1, a plurality of second light sources; and a control unit that adjusts the light intensity of each of the second light sources; The second light sources are aligned in a direction in which light from the second light sources irradiates a central portion of the dorsal side of the inserted finger in the insertion direction. Contactless biometric authentication device.

3. 2. The non-contact biometric authentication device of claim 1, The first light source is provided at a position deeper than the second light source in the insertion chamber, and at a position where direct light from the first light source is not reflected by an inner surface at the deeper side of the insertion chamber by a predetermined amount or more, and irradiates light having directionality. Contactless biometric authentication device.

4. 2. The non-contact biometric authentication device of claim 1, a reflecting surface having a surface that receives and reflects light from the second light source on an inner surface of the insertion chamber; The height of the reflecting surface on the inner surface is adjusted to a height at which, when the finger inserted in the insertion chamber is blocked by the light from the second light source, the surface receives a proportion of the light from the second light source that corresponds to the height of the inserted finger. Contactless biometric authentication device.

5. 2. The non-contact biometric authentication device of claim 1, A third light source is provided at a lower portion of one of the opposing inner surfaces of the insertion chamber, and a reflective surface that receives and reflects light from the third light source is provided at a lower portion of the other inner surface, The heights of the third light source and the inner surface of the reflecting surface are adjusted to a height such that, when the light from the third light source is blocked by the finger inserted into the insertion chamber at a predetermined height or less, a proportion of the light from the third light source corresponding to the height of the inserted finger does not reach the reflecting surface. Contactless biometric authentication device.

6. an insertion chamber having an opening on a side thereof and a space into which the finger of the authenticated person is inserted from the opening to the rear; an imaging device installed at a position to image the pad side of the finger inserted into the insertion chamber; a first light source that is installed in a position deeper than the imaging device in the insertion chamber and that irradiates light in the direction of the imaging device, the light being blocked by a finger inserted into the insertion chamber; a second light source that is provided at a position higher than the height at which the finger is inserted and that, when light from the first light source is blocked by the finger, irradiates a predetermined area including the imaging device with light that is absorbed by blood vessels in the finger; a reflecting surface that is provided in the insertion chamber and receives and reflects light from the second light source, a position and a direction of the reflecting surface are adjusted so that, when the light from the first light source is blocked by the finger, a proportion of the light from the second light source corresponding to a height of the inserted finger is reflected; the photographing device is configured to include a non-contact biometric authentication device that photographs an image including the light reflected on the reflecting surface and the pad side of the inserted finger, and an information processing device that is communicably connected to the non-contact biometric authentication device, The information processing device includes: instructing the second light source to emit light when it is determined that the light from the first light source is blocked by the fingertip of the finger inserted into the insertion chamber; a vein pattern of the inserted finger is identified based on the area of ​​light of the second light source included in the image captured by the imaging device, and the identified vein pattern of the finger is compared with a vein pattern registered in advance, thereby authenticating the finger of the person to be authenticated; Contactless biometric authentication system.

7. 7. The non-contact biometric authentication system according to claim 6, The information processing device includes: When a portion of light from the first light source is detected based on the image captured by the photographing device, the photographing device calculates the luminance around the portion, determines whether the calculated luminance is equal to or greater than a predetermined threshold, and only when it is determined that the calculated luminance is equal to or greater than the predetermined threshold, determines that the light from the first light source is blocked by the fingertip of the finger inserted into the insertion chamber, and instructs the second light source to emit light. Contactless biometric authentication system.

8. 7. The non-contact biometric authentication system according to claim 6, The information processing device includes: Identifying a relationship between the size of a predetermined object on an image photographed by the photographing device and the size of the same object on an image photographed by another photographing device having a focal length different from that of the photographing device; after instructing the second light source to emit light, correcting the size of the image captured by the image capturing device based on the specified relationship; Contactless biometric authentication system.

9. 7. The non-contact biometric authentication system according to claim 6, The information processing device includes: after instructing the second light source to emit light, calculating the position of the tip of the finger on the image and the width of the finger on the image from the image captured by the imaging device, extracting an area required for authenticating the finger from the captured image based on the calculated tip of the finger and width of the finger, and identifying the vein pattern of the finger based on the image of the extracted area; Contactless biometric authentication system.

10. 2. The non-contact biometric authentication device of claim 1, The insertion chamber is provided above the height at which the finger is inserted, and the insertion chamber is provided above the height at which the finger is inserted. A visible light source is provided that illuminates the central portion of the insertion chamber toward the back of the chamber. Contactless biometric authentication device.

11. 2. The non-contact biometric authentication device of claim 1, An extension portion extending toward the line of sight of the authentication person is formed at an end of the opening in the ceiling portion of the insertion chamber. Contactless biometric authentication device.

12. 7. The non-contact biometric authentication system of claim 6, an extension portion extending toward the line of sight of the authentication person is formed at an end of the opening in the ceiling portion of the insertion chamber, The information processing device includes: storing a numerical model for estimating the shape of the contour of the base of the finger from the shape of the contour of the fingertip side of the finger; after instructing the second light source to emit light, estimating the outline of the base of the finger in the captured image based on the outline of the fingertip side included in the image captured by the imaging device and the numerical model, thereby identifying the vein pattern of the finger. Contactless biometric authentication system.

13. 2. The non-contact biometric authentication device of claim 1, A non-contact biometric authentication device, wherein the space in the insertion chamber in the direction of finger insertion is formed so that the upper space is wider than the lower space, and the width of the opening at the top of the insertion chamber is set to a width that allows a finger adjacent to the finger entering the opening to abut.

14. an insertion chamber having an opening on a side thereof and a space into which the finger of the authenticated person is inserted from the opening to the rear; an imaging device positioned to image the pad side of the finger inserted into the insertion chamber; a first light source that is located at a position deeper than the imaging device in the insertion chamber and that irradiates light in the direction of the imaging device, the light being blocked by a finger inserted into the insertion chamber; a second light source, which is located at a position higher than the height at which the finger is inserted, and which irradiates a predetermined area including the imaging device with light that is absorbed by blood vessels of the finger when light from the first light source is blocked by the finger; The insertion chamber is provided with a reflecting surface that receives and reflects light from the second light source, a position and a direction of the reflecting surface are adjusted so that, when the light from the first light source is blocked by the finger, a proportion of the light from the second light source corresponding to a height of the inserted finger is reflected; a contactless biometric authentication method in a contactless biometric authentication system including a contactless biometric authentication device, the image capture device capturing an image including light reflected on the reflecting surface and the pad side of the inserted finger, and an information processing device communicably connected to the contactless biometric authentication device, The information processing device, instructing the second light source to emit light when it is determined that the light from the first light source is blocked by the fingertip of the finger inserted into the insertion chamber; a vein pattern of the inserted finger is identified based on the area of ​​light of the second light source included in the image captured by the imaging device, and the identified vein pattern of the finger is compared with a vein pattern registered in advance, thereby authenticating the finger of the person to be authenticated; Contactless biometric authentication method.

Images