Photography and authentication devices

Abstract

To provide a method for suppressing a lack in the amount of light to an object to be picked up.SOLUTION: An image pickup device is provided with a housing, an image pickup unit for acquiring blood vessel images of a plurality of fingers, a first light source, a second light source, and an upper surface plate portion of the housing. The image pickup unit and the first and second light sources are provided inside the housing, the optical axis of the first light source is inclined to pass through the upper surface plate portion in a direction in which the second light source is located, the optical axis of the second light source is inclined to pass through the upper surface plate portion in a direction in which the first light source is located, and the image pickup unit receives reflected light obtained by reflecting irradiation light from the first light source and the second light source by the plurality of fingers.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an imaging device for capturing a biometric image, an authentication device for capturing a biometric image and authenticating the biometric image, and an imaging method for capturing a biometric image. [Background technology]

[0002] A biometric authentication technology has been proposed that uses biometric images (blood vessel images) taken by utilizing the differences in the near-infrared light absorption characteristics of hemoglobin in blood vessels and other biological tissues. Blood vessel images can be obtained by irradiating the living body with near-infrared light, a wavelength that is highly absorbed by hemoglobin, and capturing an image of the transmitted or reflected light. Beneath the surface of the skin on the fingers is a unique blood vessel pattern that varies from person to person, and capturing a clear image of this blood vessel pattern makes it possible to achieve highly accurate authentication.

[0003] A reflective method is one of the methods for capturing blood vessel images that allows authentication technology using finger blood vessel images to be realized in a compact device. The reflective method involves arranging a light source and an imaging unit in close proximity, irradiating the finger pad with light from the light source, and capturing the reflected light to obtain a blood vessel image. The biometric authentication device disclosed in Patent Document 1 below, which uses the reflective method, includes a light source that is provided on the surface of a substrate and outputs light, and a diffractive optical element that has multiple diffraction gratings with different pitches and rotation directions arranged thereon and diffracts the light to irradiate an illumination area of ​​an illumination target, with the illumination area being configured to be larger than the area occupied by the diffractive optical element and the light source on a plane parallel to the surface of the substrate.

[0004] Furthermore, to achieve higher authentication accuracy, it is effective to use an authentication method that uses blood vessel images of not just one finger but multiple fingers taken simultaneously. The reflective method can simultaneously take blood vessel images of multiple fingers even when the living body is not in contact with the device, which makes it possible to achieve both high convenience and a compact device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2015-170320 A Summary of the Invention [Problem to be solved by the invention]

[0006] Because the surface of a finger is three-dimensional and has many curves, the amount of reflected light varies from part to part of the finger when using the reflective method, and sufficient brightness cannot be obtained at the fingertip or the side of the finger (near the outline). This poses a challenge as it is difficult to capture a clear image of the blood vessels. An unclear image that does not provide sufficient brightness cannot accurately detect the finger area, which could result in reduced authentication accuracy. Therefore, when attempting to capture blood vessel images of multiple fingers simultaneously, it is particularly important to capture a clear image of the blood vessels of all the fingers being photographed.

[0007] The present invention aims to prevent a lack of light intensity on a subject to be photographed. [Means for solving the problem]

[0008] The photographing device according to a first aspect of the invention disclosed in the present application includes a housing, an imaging unit that acquires blood vessel images of a plurality of fingers, a first light source, a second light source, and an upper panel that is an upper surface of the housing, wherein the imaging unit and the first and second light sources are provided inside the housing, an optical axis of the first light source is inclined so as to pass through the upper panel in a direction toward which the second light source is present, and an optical axis of the second light source is inclined so as to pass through the upper panel in a direction toward which the first light source is present, and the imaging unit receives reflected light that is emitted from the first light source and the second light source and reflected by the plurality of fingers.

[0009] An authentication device according to a second aspect of the invention disclosed in the present application includes a housing, an imaging unit that acquires blood vessel images of multiple fingers, a first light source, a second light source, and an upper panel that is the upper surface of the housing, wherein the imaging unit and the first and second light sources are provided inside the housing, the optical axis of the first light source is inclined so as to pass through the upper panel in the direction in which the second light source is located, and the optical axis of the second light source is inclined so as to pass through the upper panel in the direction in which the first light source is located, the imaging unit receives light irradiated from the first light source and the second light source reflected by the multiple fingers, an image processing unit that generates image data of the multiple fingers based on an output signal from the imaging unit, and an authentication unit that authenticates the multiple fingers based on the first image data of the multiple fingers generated by the image processing unit and the second image data of the multiple fingers generated by the image processing unit.

[0010] An authentication device according to a third aspect of the invention disclosed in the present application includes a housing, an imaging unit that acquires blood vessel images and fingerprint images of multiple fingers, a first light source, a second light source, and an upper panel that is the upper surface of the housing, wherein the imaging unit and the first and second light sources are provided inside the housing, the optical axis of the first light source is inclined so as to pass through the upper panel in the direction in which the second light source is present, and the optical axis of the second light source is inclined so as to pass through the upper panel in the direction in which the first light source is present, the imaging unit receives light irradiated from the first light source and the second light source reflected by the multiple fingers, an image processing unit that generates image data of the multiple fingers based on an output signal from the imaging unit, and an authentication unit that authenticates the multiple fingers based on the first image data of the multiple fingers generated by the image processing unit and the second image data of the multiple fingers generated by the image processing unit.

[0011] A fourth aspect of the invention disclosed in the present application is an imaging method using an imaging device having a housing, an imaging unit that acquires blood vessel images of multiple fingers, a first light source, a second light source, and an upper panel that is the upper surface of the housing, wherein the imaging unit and the first and second light sources are provided inside the housing, and the optical axis of the first light source is inclined so as to pass through the upper panel in a direction toward which the second light source is present, and the optical axis of the second light source is inclined so as to pass through the upper panel in a direction toward which the first light source is present, wherein the first light source and the second light source irradiate light onto the multiple fingers, and the imaging unit receives light that is irradiated from the first light source and the second light source and reflected by the multiple fingers.

[0012] A fifth aspect of the invention disclosed in the present application is an imaging method using an imaging device having a housing, an imaging unit that acquires blood vessel images and fingerprint images of multiple fingers, a first light source, a second light source, and an upper panel that is the upper surface of the housing, wherein the imaging unit and the first and second light sources are provided inside the housing, the optical axis of the first light source is inclined so as to pass through the upper panel in a direction toward which the second light source is present, and the optical axis of the second light source is inclined so as to pass through the upper panel in a direction toward which the first light source is present, wherein the first light source and the second light source irradiate light onto the multiple fingers, and the imaging unit receives light that is irradiated from the first light source and the second light source and reflected by the multiple fingers. [Effects of the Invention]

[0013] According to the exemplary embodiment of the present invention, it is possible to prevent the insufficient amount of light reaching the subject to be photographed. Problems, configurations, and effects other than those described above will become clear from the following description of the embodiment. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is an explanatory diagram of a first configuration example of an image capturing device and an authentication device according to a first embodiment. [Figure 2] FIG. 2 is an explanatory diagram of a second configuration example of the photographing device and the authentication device according to the first embodiment. [Figure 3] FIG. 3 is a block diagram illustrating a first example of a block configuration of the photographing device and the authentication device according to the first embodiment. [Figure 4] FIG. 4 is a block diagram illustrating a second example of the block configuration of the photographing device and the authentication device according to the first embodiment. [Figure 5] FIG. 5 is an explanatory diagram showing an example 1 of irradiation from a light source. [Figure 6] FIG. 6 is an explanatory diagram showing a second example of irradiation from a light source. [Figure 7] FIG. 7 is a flowchart illustrating an example of a procedure for registering finger image data. [Figure 8] FIG. 8 is a flowchart illustrating an example of a procedure for authenticating finger image data. [Figure 9] FIG. 9 is a flowchart showing a detailed example of the processing procedure of the light source control (step S703) shown in FIGS. [Figure 10] FIG. 10 is a graph showing an example of the relationship between the amount of light emitted from the light source and the brightness of the finger area. [Figure 11] FIG. 11 is an explanatory diagram showing changes in the position of the hand relative to the image capturing device and the authentication device. [Figure 12] FIG. 12 is an explanatory diagram showing Example 1 of light intensity adjustment according to a change in hand posture. [Figure 13] FIG. 13 is an explanatory diagram showing a second example of light intensity adjustment according to a change in hand posture. [Figure 14] FIG. 14 is an explanatory diagram of a first configuration example of the photographing device and the authentication device according to the second embodiment. [Figure 15] FIG. 15 is an explanatory diagram illustrating an example of light amount control according to a change in finger posture in the first configuration example of the image capturing device and the authentication device according to the second embodiment. [Figure 16] FIG. 16 is an explanatory diagram of a second configuration example of the photographing device and the authentication device according to the second embodiment. [Figure 17] FIG. 17 is an explanatory diagram of a third configuration example of the photographing device and the authentication device according to the second embodiment. [Figure 18]FIG. 18 is a diagram illustrating an example of the configuration of the photographing device and the authentication device according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION [Example]

[0015] <Configuration example of imaging device and authentication device> FIG. 1 is an explanatory diagram illustrating a first configuration example of an imaging device and an authentication device according to a first embodiment. The imaging device 100 captures an image of the fingers of a hand 110 held over an upper panel 100B of a housing 100A as an object. In the first embodiment, for example, an index finger 111, a middle finger 112, and a ring finger 113 are taken as the objects (image capture targets). However, the fingers 111 to 113 as objects may include two or more of the ten fingers of both hands 110. Note that the surfaces of the fingers 111 to 113 on the back side of the hand 110 are referred to as the front surfaces of the fingers 111 to 113, and the surfaces of the fingers 111 to 113 on the palm side of the hand 110 are referred to as the back surfaces of the fingers 111 to 113.

[0016] 1, the image capturing device 100 includes a housing 100A, an image capturing unit 101, a light source 102, and a data memory 106. An image capturing device 100 to which a controller 107 is connected constitutes an authentication device 108.

[0017] The housing 100A is attached to or placed on (hereinafter collectively referred to as "installed") an installation surface 120, for example. The installation surface 120 may be the ground, a ceiling, or the surface of a table parallel to the ground, such as a desk, or may be a surface perpendicular to the ground, such as a wall. The axis perpendicular to the installation surface 120 is the Z-axis, the direction along the Z-axis away from the installation surface 120 is the +Z direction, and the direction toward the installation surface 120 is the -Z direction. The installation surface 120 is parallel to the XY plane. The XY plane is a plane defined by the X-axis and the Y-axis. As shown in FIG. 1, the imaging device 100 and the authentication device 108 are installed so that the hand 110 is held over the upper panel 100B. In this case, the X-axis is the longitudinal direction of the fingers when the hand 110 is held over the upper panel 100B. The Y-axis is the arrangement direction of the fingers 111 to 113.

[0018] The housing 100A contains an imaging unit 101 and a plurality of light sources 102 (light sources 102-1 and 102-2 in FIG. 1). When there is no need to distinguish between the light sources 102-1 and 102-2, they are simply referred to as light sources 102. A first optical filter 103 is provided between the imaging unit 101 and the top panel 100B of the housing 100A. The imaging unit 101 receives subject light that has passed through the first optical filter 103. The subject light is light that is emitted from the light source 102 and reflected by the subject (reflected light).

[0019] The imaging unit 101 and the top panel 100B of the housing 100A face the presented hand 110. In particular, the surface of the top panel 100B facing the fingers 111 to 113 is referred to as the facing surface 100Ba. The area in the +Z direction from the facing surface 100Ba is a facing area 130 where the presented fingers 111 to 113 face the imaging unit 101 and the facing surface 100Ba. The width of the facing surface 100Ba and the facing area 130 in the X-axis direction is, for example, a width that encompasses the length from the tip to the base of the fingers 111 to 113.

[0020] Furthermore, a light-transmitting plate 105 is provided in an area of ​​the top panel 100B located in the +Z direction from the imaging unit 101, which transmits light emitted from the light source 102 and reflected by living bodies such as the fingers 111-113. The light-transmitting plate 105 is made of a transparent material such as acrylic or glass. A film that transmits only light of a specific wavelength may be attached to the light-transmitting plate 105. This makes it difficult to see the inside of the imaging device 100 from the outside.

[0021] Additionally, a second optical filter 104 is provided in an area of ​​the top panel 100B that is located in the +Z direction from the light source 102. Light from the light source 102 that passes through the second optical filter 104 is irradiated onto the subject. The second optical filter 104 may be a light diffusion filter. This allows the light source 102 to irradiate the subject with light of uniform intensity over a wide range.

[0022] The second optical filter 104 may also be a polarizing filter. This can reduce specular reflection components from the skin surface among light components irradiated onto and reflected from a living body such as the fingers 111-113. Therefore, the imaging device 100 can capture a clearer image of the blood vessels of the living body. The second optical filter 104 may also be a bandpass filter that transmits only specific wavelengths of the light irradiated from the light source 102. This can prevent the imaging unit 101 from receiving unnecessary ambient light.

[0023] The imaging unit 101 is configured with an imaging element such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device) image sensor. The imaging surface of the imaging unit 101 faces the top panel 100B.

[0024] The imaging unit 101 receives light incident from outside the housing 100A through the light-transmitting plate 105 and the first optical filter 103 of the top panel 100B on its imaging surface and performs photoelectric conversion. The imaging unit 101 is connected to a data memory 106, and stores photoelectrically converted image data in the data memory 106. The image data may be image data showing the blood vessels of a finger (finger vein image data) or image data showing a fingerprint (fingerprint image data). The finger vein image data and fingerprint image data are collectively referred to as finger image data. The data memory 106 is connected to a controller 107. Note that in this specification, a fingerprint refers to a pattern of at least the fingertip (pad) and may also include a pattern on the back of the finger from the fingertip to the base of the finger.

[0025] The light source 102 irradiates a subject located in the +Z direction from the top panel 100B with light via the second optical filter 104. When photographing blood vessels in a finger, the light irradiated from the light source 102 is, for example, near-infrared light. When photographing a fingerprint, the light irradiated from the light source 102 is, for example, visible light (e.g., blue or green). The light sources 102 are provided at positions sandwiching the imaging unit 101. That is, the light sources 102 are arranged in the Y-axis direction. The light sources 102 are arranged in positions between the fingertip and the base of the finger in the X-axis direction. In this way, each light source 102 irradiates light onto the fingers 111 to 113 from the outside of the facing region 130 toward the inside of the facing region 130.

[0026] The spread of light emitted from the light source 102 is called a beam of light. The beam of light is the range of illumination of the fingers 111 to 113, which are the subjects. In other words, the light source 102 is positioned so that the beam of light includes the fingers 111 to 113. The central axis of the beam of light is called the optical axis. The optical axis is the direction of light illumination. The optical axis is not parallel to the Z axis, but is tilted by a predetermined angle from the Z axis (+Z direction) toward the imaging unit 101.

[0027] When the optical axis is parallel to the Z axis, a sufficient amount of light is irradiated onto the side surface of the index finger 111 on the thumb side and the side surface of the ring finger 113 on the little finger side, but an insufficient amount of light is irradiated onto the middle finger 112, the side surface of the index finger 111 on the middle finger side, and the side surface of the ring finger 113 on the middle finger side. Therefore, by tilting the irradiation direction toward the imaging unit 101 by a predetermined angle, a sufficient amount of light can be irradiated onto each of the index finger 111, middle finger 112, and ring finger 113, and the insufficient amount of light on the side surface of any of the index finger 111, middle finger 112, and ring finger 113 can be prevented.

[0028] The light source 102 is connected to a controller 107 outside the housing 100A. The controller 107 controls the amount of light emitted from the light source 102. The controller 107 also detects the positions of the fingers 111 to 113 and extracts blood vessels and fingerprint features in the fingers 111 to 113 from the finger image data. The controller 107 may also authenticate multiple pieces of finger image data stored in the data memory 106. Specifically, for example, the controller 107 acquires two pieces of finger image data from the data memory 106 and authenticates whether the index finger 111, middle finger 112, and ring finger 113 in both finger image data belong to the same person based on the blood vessel features and fingerprint features of the fingers.

[0029] 2 is an explanatory diagram illustrating a second configuration example of the image capturing device 100 and the authentication device 108 according to the first embodiment. The image capturing device 100 and the authentication device 108 illustrated in Fig. 2 are examples in which the controller 107 illustrated in Fig. 1 is mounted inside a housing 100A. If the controller 107 does not have an authentication function, it is the image capturing device 100, and if the controller 107 has an authentication function, it is the authentication device 108.

[0030] 3 is a block diagram illustrating a first example of a block configuration of the image capturing device 100 and the authentication device 108 according to the first embodiment. The image capturing device 100 includes a light source control unit 300. The light source control unit 300 controls the amount of light emitted from the light source 102. The light source control unit 300 is included in the controller 107 shown in FIGS. 1 and 2. The computer 310 includes an authentication function. The computer 310 is included in the controller 107 shown in FIGS. 1 and 2.

[0031] The computer 310 includes a processor 311, a storage device 312, an input device 313, an output device 314, and a communication interface (communication IF) 315. The processor 311, the storage device 312, the input device 313, the output device 314, and the communication IF 315 are connected by a bus 316. The processor 311 controls the computer 310. The storage device 312 serves as a working area for the processor 311. The storage device 312 is a non-transitory or temporary recording medium that stores various programs and data. Examples of the storage device 312 include a read-only memory (ROM), a random access memory (RAM), a hard disk drive (HDD), and a flash memory. The input device 313 inputs data. Examples of the input device 313 include a keyboard, a mouse, a touch panel, a numeric keypad, and a scanner. The output device 314 outputs data. Examples of the output device 314 include a display, a printer, and a speaker. The communication IF 315 connects to a network and transmits and receives data.

[0032] The programs stored in the storage device 312 described above include, for example, an image processing program, a light source control program, and an authentication program. The image processing program is a program that causes the processor 311 to generate image data based on an output signal from the imaging unit 101. The light source control program is a program that causes the processor 311 to increase or decrease the amount of light emitted from the light source 102. The authentication program is a program that causes the processor 311 to authenticate the identity of two finger image data stored in the storage device 312. Note that, although examples of realizing the image processing, light source control, and authentication functions using software have been described, the image processing, light source control, and authentication functions may also be realized using dedicated circuits.

[0033] That is, the photographing device 100 that does not include the light source control unit 300 is the photographing device 100 shown in Fig. 1, and the photographing device 100 that includes the light source control unit 300 is the photographing device 100 shown in Fig. 2. Furthermore, the authentication device 108, which has the functions of image processing, light source control, and authentication, includes the light source control unit 300 and a computer 310, and corresponds to the authentication device 108 in Figs. 1 and 2.

[0034] 4 is a block diagram illustrating a second block configuration example of the image capturing apparatus 100 and the authentication apparatus 108 according to the first embodiment. The image capturing apparatus 100 and the authentication apparatus 108 illustrated in FIG. 4 include a built-in computer 310. The data memory 106 is implemented by a storage device 312. The light source control unit 300 is implemented by causing the processor 311 to execute a program stored in the storage device 312. The authentication function is implemented by causing the processor 311 to execute a program stored in the storage device 312. If the computer 310 does not have the authentication function, it is the image capturing apparatus 100, and if the computer 310 has the authentication function, it is the authentication apparatus 108.

[0035] 1 to 4 may be a visible light source. In this case, the controller 107 may control the visible light source to emit light of different colors when a hand 110 is detected during standby, when authentication processing is performed, when authentication is successful, and when authentication fails. This allows the user to visually recognize the authentication status.

[0036] Furthermore, prior to the authentication, the computer 310 may accept a user ID and a PIN number via the input device 313, or wirelessly receive the user ID and the PIN number via the communication IF 315 from an IC chip or a communication terminal carried by the user, thereby registering the user ID and the PIN number in association with the finger image data of the user in the storage device 312.

[0037] Furthermore, the computer 310 may acquire the user ID, the password, and the finger image data from the input device 313 or the communication IF 315 as described above, thereby identifying the finger image data associated with the user ID and the password stored in the storage device 312, and authenticating both sets of finger image data (so-called one-to-one authentication).The computer 310 may also identify finger image data that matches the currently input finger image data from the group of finger image data stored in the storage device 312 (so-called one-to-N authentication).

[0038] 1 to 4, the light emitted from the light source 102 may include light of a plurality of different wavelengths. For example, if the image capturing unit 101 is configured with a plurality of sensors with different wavelength sensitivity characteristics, such as a color camera, the image capturing unit 101 simultaneously emits light of a plurality of different wavelengths from the light source 102 and captures images of the fingers 111 to 113 using the light reflected from the fingers 111 to 113. This allows the controller 107 to efficiently separate the finger area illuminated with light from the light source 102 from the background area not illuminated by light, by utilizing the difference in wavelength sensitivity characteristics of the sensors.

[0039] Furthermore, the light source 102 may emit not only near-infrared light for angiography but also light of a wavelength suitable for capturing fingerprints, which are the uneven structure of the skin surface. In this case, the computer 310 can perform multimodal authentication using the blood vessels and fingerprints of the fingers 111 to 113. In this way, when light of a different wavelength is used for each light source 102, each of the second optical filters 104 may be a bandpass filter that transmits only the corresponding wavelength. Alternatively, the second optical filter 104 may be a bandpass filter that transmits a single wide wavelength band that includes multiple wavelengths.

[0040] <Example of illumination from light source 102> When a single light source is placed directly below the multiple fingers 111 to 113, i.e., near the imaging unit 101, the areas near the centers of the pads of the fingers 111 to 113 are considered to be a nearly horizontal plane and are illuminated with strong light. This allows the imaging unit 101 to receive reflected light with sufficient brightness. On the other hand, the areas near the outlines and tips of the other fingers that are far from the pads of the fingers 111 to 113 are less likely to be illuminated with light due to the curved shapes of the fingers 111 to 113. With such a single light source placement, the imaging unit 101 cannot receive reflected light with sufficient brightness, making the area dark, and the controller 107 is unable to generate finger image data that results in clear finger images.

[0041] FIG. 5 is an explanatory diagram showing example 1 of illumination from light source 102. Light source 102 is pre-positioned so as to be located further outward than the outer fingers along arrangement direction Y of fingers 111 to 113. Optical axis I is tilted by a predetermined angle θ about the X axis from the Z axis toward the direction in which the other light source 102 is located. As a result, light source 102-1 illuminates the back surface and thumb-side lateral surface 111A of index finger 111, the back surface and index-side lateral surface 112A of middle finger 112, and the back surface and middle-side lateral surface 113A of ring finger 113 (included in light beam 500). Light source 102-2 illuminates the back surface and middle-side lateral surface 113B of ring finger 113, the back surface and index-side lateral surface 112B of middle finger 112, and the back surface and thumb-side lateral surface 111B of index finger 111.

[0042] In this way, each light source 102 can irradiate a sufficient amount of light around the outline of the finger that is far from the position of the light source 102. Note that instead of tilting the optical axis I toward the imaging unit 101, a lens that increases the amount of light irradiated the farther the distance from the irradiation position may be used. This allows the light source 102 to irradiate a sufficient amount of light around the outline of the finger that is far from the irradiation position.

[0043] In this way, the light emitted from the light source 102 is strongly incident not only on the center of the pads of the fingers 111 to 113 but also on the contours of the fingers 111 to 113, and the imaging unit 101 receives reflected light of sufficient brightness over the entire finger area. This allows the controller 107 to generate finger image data that results in a clear finger image. Note that when multiple light sources 102 emit light simultaneously, there are areas where the light emitted from each light source overlaps. Therefore, taking into consideration the overlapping and reinforcement of the emitted light, the arrangement of the light sources 102 is determined so that the entire area of ​​all fingers is uniformly bright, and the controller 107 adjusts the intensity of the emitted light. Specifically, for example, the light sources 102 are arranged so that the distances to the closest fingers are the same or the difference between these distances is within a tolerance range, and the distances to the farthest fingers are the same or the difference between these distances is within a tolerance range.

[0044] FIG. 6 is an explanatory diagram showing a second example of irradiation from the light source 102. FIG. 6 shows an example in which a distance measurement sensor 600 is provided near the imaging unit 101 in the configuration of FIG. 5. The distance measurement sensor 600 is installed at a position in the housing 100A such that the distance in the +Z direction from the installation surface 120 is the same. The distance measurement sensor 600 detects the distance D to the fingers 111 to 113, that is, the distance D between the fingers 111 to 113 and the imaging unit 101. Specifically, for example, the distance measurement sensor 600 detects the distance D to the fingers 111 to 113 based on the time difference between when the infrared light is applied to the fingers 111 to 113 and when the reflected light from the fingers 111 to 113 is received. Alternatively, the distance measurement sensor 600 may detect the distance D to the fingers 111 to 113 based on the capacitance between the fingers 111 to 113 and the fingers 111 to 113.

[0045] In this way, the controller 107 controls the amount of light emitted from the light source 102 to increase or decrease depending on the distance D. For example, the controller 107 decreases the amount of light emitted by the light source 102 as the distance D becomes shorter, and increases the amount of light emitted by the light source 102 as the distance D becomes longer.

[0046] <Finger image data registration process> 7 is a flowchart showing an example of a registration process procedure for finger image data. In FIG. 7, the execution entity is the authentication device 108 as an example, but it may be the imaging device 100. When the hand 110 is held over the top panel 100B, the authentication device 108 executes detection of the fingers 111-113 (step S701). Specifically, for example, the imaging unit 101 receives reflected light from the ambient light of the fingers 111-113 (or a predetermined amount of light emitted from the light source 102), performs photoelectric conversion, and generates binary image data. Then, the controller 107 separates the main subject from the background of the binary image data and determines whether the shape of the main subject is a finger 111-113.

[0047] In step S701, the authentication device 108 may capture an image with the light source 102 blinking, and may use the change in brightness of the captured image data to detect the fingers 111 to 113. If the authentication device 108 has a built-in distance measurement sensor 600, the authentication device 108 may use the distance measurement sensor 600 to detect the presence of the hand 110 approaching at a predetermined position or within a certain range. Alternatively, the blinking of the light source 102 and distance measurement by the distance measurement sensor 600 may be used in combination.

[0048] If the fingers 111 to 113 are not detected (step S702: No), the process returns to step S701. If the fingers 111 to 113 are detected (step S702: Yes), the authentication device 108 executes light source control (step S703). The light source control (step S703) is a process for controlling the light intensity of the light source 102. Details of the light source control (step S703) will be described later with reference to FIG. 10. As a result of irradiating the light source 102 with the light intensity adjusted by the light source control (step S703), the imaging unit 101 receives the light reflected from the fingers 111 to 113 and generates finger image data by image processing (step S704). The generated finger image data is stored in the data memory 106 or the storage device 312.

[0049] The authentication device 108 detects a finger region from the generated finger image data by image processing (step S705) and normalizes the finger image data by image processing (step S706). Normalization is a process of correcting magnification and distortion due to changes in the position and posture of the finger based on the detected finger position. The authentication device 108 then extracts feature data of the finger blood vessels or fingerprint from the normalized finger image data by image processing (step S707). The authentication device 108 stores the feature data in the data memory 106 or the storage device 312 (step S708). Note that although the authentication device 108 stores the feature data in step S708, the finger image data may also be stored in the data memory 106 or the storage device 312 without extracting the feature data (step S707).

[0050] <Finger image data authentication process> Fig. 8 is a flowchart showing an example of the authentication processing procedure for finger image data. In Fig. 8, the execution entity is, for example, authentication device 108, but it may also be image capturing device 100. However, if image capturing device 100 is the execution entity, steps S808 to S811 are executed by controller 107 or computer 310 outside image capturing device 100. Note that steps S701 to S707 are processes for the finger to be compared, but since these processes are common to Fig. 7, their explanation will be omitted. Also, in Fig. 7, if finger image data is stored without executing feature data extraction (step S707), feature data extraction is also executed for the finger image data to be compared with the finger to be compared in step S707.

[0051] After executing step S707, the authentication device 108 reads out the registered feature data to be compared from the data memory 106 or the storage device 312, and compares it with the feature data to be matched (step S808). Specifically, for example, the authentication device 108 calculates a matching score based on the identity of the positions of the feature data and the identity of the features.

[0052] The sameness of position refers to, for example, whether or not there is comparison feature data that is identical in position to the feature data to be matched or within an acceptable range. The sameness of feature refers to, for example, whether the blood vessel or fingerprint shapes indicated by the feature data to be matched and the feature data to be compared, which have the same position, are the same or the difference in shape is within an acceptable range. The authentication device 108 obtains a higher matching score the more feature data that satisfy the sameness of position and feature of the feature data.

[0053] Then, the authentication device 108 determines whether the matching score is greater than the threshold value TH (step S809). If the matching score is equal to or less than the threshold value TH (step S809: No), the authentication device 108 determines whether a timeout has occurred (step S810). If the timeout time has not elapsed (step S810: No), the process returns to step S703. On the other hand, if the timeout time has elapsed (step S810: Yes), the authentication process ends. Also, if the matching score is greater than the threshold value TH in step S809 (step S809: Yes), the authentication device 108 executes post-authentication success processing (step S811), and the authentication process ends.

[0054] <Light Source Control (Step S703)> FIG. 9 is a flowchart showing a detailed example of the processing procedure of the light source control (step S703) shown in FIGS. 7 and 8. After step S702, the authentication device 108 acquires image data used in detecting the fingers 111 to 113 (step S901) and identifies each area of ​​the multiple fingers 111 to 113 (step S902). The authentication device 108 calculates the brightness of the identified finger area from the luminance information of the finger image data acquired in step S901. Next, based on the brightness of the finger area calculated in step S903, the authentication device 108 determines the light intensity value of the light source 102 so that the finger area has appropriate brightness (step S904). Then, the authentication device 108 turns on the light source 102 at the light intensity value determined in step S904 (step S905) and proceeds to step S704.

[0055] The brightness of the finger region calculated in step S903 may be, for example, an average brightness value of the finger region in the finger image data. The average brightness value may be calculated individually for each of the detected fingers 111 to 113, or may be the average of the brightness values ​​of all the detected fingers 111 to 113. Furthermore, the finger region for which the average brightness value is calculated may not only use the entire region of the fingers 111 to 113, but also use a local region, such as an intermediate position between the fingertip and the finger base.

[0056] Furthermore, when determining the light intensity value in step S904, the authentication device 108 first presets an appropriate brightness (for example, average brightness) of the finger region in the image data as a specific target value. Then, the authentication device 108 adjusts the irradiated light intensity so that the brightness calculated in step S903 becomes the target brightness, thereby enabling the light source 102 to irradiate the fingers 111-113 with light of uniform intensity even if the distance D (height) to the fingers 111-113 varies.

[0057] A specific method for determining the light intensity value is to change the light intensity value step by step. The light intensity value emitted by the light source 102 is set in advance to several steps, and if the brightness of the finger area in the image data generated by irradiating the finger area with the initial light intensity value is darker than the target value, the authentication device 108 increases the light intensity value by one step. On the other hand, if the brightness of the finger area is brighter than the target value, the authentication device 108 decreases the light intensity value by one step.

[0058] Another method for determining the light intensity value is to utilize the correlation between the light intensity value of the light emitted from the light source 102 and the brightness of the finger area. Based on the value of a function that represents the relationship between the light intensity value and the brightness of the finger area, the authentication device 108 (controller 107) controls the light source 102 to emit light at a light intensity value that corresponds to the target brightness of the finger area.

[0059] 10 is a graph showing an example of the relationship between the amount of light emitted by the light source 102 and the brightness of the finger area. The horizontal axis of graph 1000 represents the brightness of the finger area (for example, average luminance), and the vertical axis represents the amount of light from the light source. Assuming that the relationship between the brightness x of the finger area and the amount of light y emitted by the light source can be linearly approximated, the relationship between the brightness x and the amount of light y can be expressed by the following formula (1).

[0060] y = αx + β (1)

[0061] The parameters α and β in the above formula (1) are parameters that change depending on the environment and the finger, and are calculated each time the brightness x of the finger area is calculated. After the function of formula (1) is determined, the authentication device 108 substitutes the brightness x' of the target finger area into the above formula (1) to obtain the light intensity value y' corresponding to the brightness x', and turns on the light source 102 at the light intensity value y'.

[0062] FIG. 10 illustrates an example in which the relationship between the light quantity value and the brightness of the finger area can be linearly approximated, but even if linear approximation is not possible (the relationship is nonlinear), it is possible to control the light quantity in the same way.

[0063] FIG. 11 is an explanatory diagram showing changes in the position of the hand 110 relative to the image capture device 100 and the authentication device 108. When a constant amount of light is emitted from the light source 102, if the height of the hand 110 presented by the user in the Z-axis direction fluctuates, the amount of light emitted to the fingers 111 to 113 fluctuates depending on the distance between the hand 110 and the light source 102 in the Z direction, resulting in an excess or deficiency of the amount of light reflected from the fingers 111 to 113. As a result, the brightness of the finger areas of the fingers 111 to 113 may differ, making it difficult to generate stable finger image data. When the distance measurement sensor 600 is available, the authentication device 108 controls the amount of light emitted by the light source 102 depending on the measured distance D, thereby enabling the fingers 111 to 113 to always be illuminated with light of a uniform intensity. That is, the authentication device 108 increases or decreases the amount of light from the light source 102 depending on the distance D. For example, the authentication device 108 decreases the amount of light from the light source 102 as the distance D decreases, and increases the amount of light from the light source 102 as the distance D increases.

[0064] <Example of light intensity adjustment according to changes in hand posture> Fig. 12 is an explanatory diagram showing Example 1 of light intensity adjustment according to a change in posture of a hand 110. Fig. 12 shows a state in which the hand 110 is rotating around the X axis. Rotation around the X axis is called roll. Due to a change in the posture of the fingers caused by the roll rotation, the heights of the index finger 111, middle finger 112, and ring finger 113, which are the subjects, in the Z axis direction are different.

[0065] In such a case, the controller 107 can generate finger image data with uniform brightness across all finger regions by changing the intensity of light emitted by each of the light sources 102-1 and 102-2. For example, the controller 107 determines the intensity of light emitted by the light source 102-1 based on the brightness of the finger region of the index finger 111 in the generated finger image data, and determines the intensity of light emitted by the light source 102-2 based on the brightness of the finger region of the ring finger 113. In this way, the controller 107 determines the intensity of light emitted by the light sources 102-1 and 102-2 based on the brightness of the finger that is closest to the light source 102-1. Therefore, in the case of a roll rotation as shown in FIG. 12 , the controller 107 controls the light source 102-1 to emit a stronger light intensity than the light source 102-2, and the entire finger is captured by the imaging unit 101 with uniform brightness.

[0066] Furthermore, the controller 107 may adjust the light intensity of the light sources 102-1 and 102-2 based on the brightness of the finger area including not only the index finger 111 and the ring finger 113 but also the middle finger 112. The brightness of all fingers 111 to 113, not just the middle finger 112, is affected by the light emitted by both the light sources 102-1 and 102-2. Therefore, taking into consideration the effect on the brightness of the finger area of ​​each finger 111 to 113 of the light intensity of the light sources 102-1 and 102-2, the controller 107 can determine the optimal light intensity of the light sources 102-1 and 102-2 so that all fingers 111 to 113 have a uniform brightness.

[0067] Fig. 13 is an explanatory diagram showing a second example of light intensity adjustment according to a change in posture of the hand 110. The difference from Fig. 12 is that a light source 102-3 is provided between the light sources 102-1 and 102-2. The optical axis of the light source 102-3 is the Z axis instead of the I axis. As a result, the index finger 111 corresponds to the light source 102-1, the ring finger 113 corresponds to the light source 102-2, and the middle finger 112 corresponds to the light source 102-3.

[0068] For example, controller 107 determines the amount of light emitted by light source 102-1 based on the brightness of the finger area of ​​index finger 111, determines the amount of light emitted by light source 102-2 based on the brightness of the finger area of ​​ring finger 113, and determines the amount of light emitted by light source 102-3 based on the brightness of the finger area of ​​middle finger 112. In this way, controller 107 determines the amount of light emitted by light sources 102-1 to 102-3 based on the brightness of the finger that is closest. Therefore, in the case of roll rotation as shown in FIG. 13 , controller 107 controls light source 102-1 to emit a stronger light intensity than light sources 102-2 and 102-3, and controls light source 102-3 to emit a stronger light intensity than light source 102-2, thereby allowing imaging unit 101 to capture an image of the entire finger with uniform brightness.

[0069] In this way, by adjusting the amount of light emitted from the light source 102 corresponding to each finger, the controller 107 can generate clear finger image data that is more robust against positional and pose variations of the fingers 111 to 113. Although not shown in the device configurations of Figs. 12 and 13, a plurality of light sources 102-1 to 102-3 may be arranged along the X direction. [Example]

[0070] The second embodiment is an example in which the light sources 102 are further arranged in the X-axis direction in the first embodiment. The same components as those in the first embodiment are given the same reference numerals, and the description thereof will be omitted.

[0071] 14 is an explanatory diagram illustrating a first configuration example of the image capturing device 100 and the authentication device 108 according to the second embodiment. (A) shows a side cross-sectional view of the image capturing device 100 and the authentication device 108, and (B) shows a plan view of the image capturing device 100 and the authentication device 108.

[0072] Light sources 102-1 and 102-4 corresponding to index finger 111 are arranged in the X direction. For example, light source 102-1 is provided at a position corresponding to the tip of index finger 111, and light source 102-4 is provided at a position corresponding to the base of index finger 111. Similar to light source 102-1, optical axis I of light source 102-4 is tilted by a predetermined angle θ around the X axis from the Z axis toward the other light source 102-5.

[0073] Light sources 102-2 and 102-5 corresponding to ring finger 113 are arranged in the X direction. For example, light source 102-2 is provided at a position corresponding to the tip of ring finger 113, and light source 102-5 is provided at a position corresponding to the base of ring finger 113. Like light source 102-2, the optical axis I of light source 102-5 is tilted by a predetermined angle θ around the X axis from the Z axis toward the other light source 102-4.

[0074] Note that a fingertip presentation board 1400 is provided in the housing 100A in parallel to the X-axis in the +Z direction from the second optical filters 104 corresponding to the light sources 102-1 and 102-4. The fingertip presentation board 1400 is a transparent plate-like member such as acrylic or glass, on which the fingers 111 to 113 can be placed. This allows the positions of the fingertips of the hand 110 presented by the user to be guided to the fingertip presentation board 1400. Therefore, even when the fingers are placed on the fingertip presentation board 1400 or held over it without contact, the imaging unit 101 can capture an image of the entire finger.

[0075] The amount of reflected light from the light source 102 is likely to be insufficient near the contours of the sides of the fingers 111 to 113 in the arrangement direction Y. The area near the contours of the fingertips has a three-dimensional shape with many curved surfaces, so the amount of reflected light from the light source 102 is particularly likely to be insufficient, and the area near the fingertips in the finger image data is likely to be very dark. Therefore, by providing light sources 102-4 and 102-5 corresponding to the bases of the fingers, the light sources 102-4 and 102-5 and the light sources 102-1 and 102-2 each emit light with a different amount of light. Specifically, for example, the light sources 102-1 and 102-2 emit light with a stronger amount of light than the light sources 102-4 and 102-5. This allows the imaging unit 101 to capture the entire fingers 111 to 113 with appropriate brightness.

[0076] The light sources 102-1 and 102-2 and the light sources 102-4 and 102-5 may each emit light at a preset light intensity, and the preset light intensity values ​​may be individually adjustable.

[0077] Furthermore, as in the first embodiment, when the authentication device 108 generates and authenticates multiple modality image data such as blood vessels and fingerprints using multiple light sources 102 with different wavelengths of light, the authentication device 108 can adjust the amount of light emitted by the light sources 102-1 and 102-2 and the amount of light emitted by the light sources 102-4 and 102-5 to be appropriate for the modality to be photographed.

[0078] For example, in order to take angiograms of the regions on the base side of the fingers 111 to 113, the authentication device 108 controls the amount of near-infrared light emitted by the light sources 102-1 and 102-2, and in order to take fingerprint images of the regions on the fingertip side, the authentication device 108 controls the amount of visible light emitted by the light sources 102-4 and 102-5.

[0079] FIG. 15 is an explanatory diagram illustrating an example of light intensity control according to a change in the posture of the fingers 111 to 113 in the configuration example 1 of the image capturing device 100 and the authentication device 108 according to the second embodiment. As shown in FIG. 15, when the light sources 102-1 and 102-2 and the light sources 102-4 and 102-5 irradiate the same amount of light in a posture in which the fingertips are lowered in the −Z-axis direction than the bases of the fingers, the intensity of the irradiated light attenuates depending on the distance. As a result, the amount of light irradiated on the bases of the fingers is less than that on the tip side, and the bases of the fingers appear relatively dark in the finger image data. Therefore, the finger image data generated is not as clear as when the postures of the fingers 111 to 113 are parallel to the X-axis direction.

[0080] Therefore, the controller 107 adjusts the light intensity individually for the light sources 102-4 and 102-5 that illuminate the base of the fingers and the light sources 102-1 and 102-2 that illuminate the tip of the fingers. This allows clear finger image data to be generated, just as when the orientations of the fingers 111 to 113 are parallel to the X-axis direction.

[0081] As a method of adjusting the light intensity, the controller 107 adjusts the light intensity of the light sources 102-1 and 102-2 using the distance D measured by the distance measuring sensor 600 provided for each light source 102. For example, the controller 107 controls the increase / decrease of the light intensity emitted from the light source 102 so that the light intensity of the light source 102 with the longer distance D is greater than the light intensity of the light source 102 with the shorter distance D.

[0082] Furthermore, controller 107 adjusts the light intensity of light sources 102-4 and 102-5 based on the brightness of the finger region on the base side of the finger in the generated finger image data, and adjusts the light intensity of light sources 102-1 and 102-2 based on the brightness of the finger region on the tip side of the finger in the generated finger image data. When controlling the light intensity based on the brightness of the finger region, the light emitted from light sources 102-1 and 102-2 and the light emitted from light sources 102-4 and 102-5 may overlap in part of the finger region. If this affects the brightness of the finger region, controller 107 may determine the light intensity values ​​of light sources 102-1 and 102-2 and light sources 102-4 and 102-5 so that the three regions of the finger base region, the fingertip region, and the overlapping region of the light emitted from light sources 102-1 and 102-2 and the light emitted from light sources 102-4 and 102-5 have uniform brightness.

[0083] 16 is an explanatory diagram illustrating a second configuration example of the image capturing device 100 and the authentication device 108 according to the second embodiment. The difference from the first configuration example of FIG. 14 is that a light source 1600 is provided at a position facing the side surface of the fingertip presentation board 1400 at the +Z side end of the front panel 100C of the housing 100A. Irradiation light from the light source 1600 is incident on the side surface of the fingertip presentation board 1400.

[0084] When a user touches or holds a fingertip over the fingertip presentation board 1400 and the authentication device 108 executes authentication processing, the imaging unit 101 captures an image of the fingerprint of the fingertip that is touching the fingertip presentation board 1400 while irradiating light from the light source 1600.

[0085] Specifically, for example, light incident on fingertip presentation board 1400 from light source 1600 propagates while being totally reflected at the interface between fingertip presentation board 1400 and air. At this time, when a user touches fingertip presentation board 1400 with their fingertip, the refractive index between moisture on the fingertip surface and fingertip presentation board 1400 becomes larger than the refractive index of air at the ridges, which are the convex parts of a fingerprint on the touching fingertip. As a result, the total reflection condition is no longer satisfied, and the light from light source 1600 is scattered.

[0086] Therefore, the ridges of the fingerprint at the fingertip are dark, while the other areas are bright. The imaging unit 101 captures an image of such a fingerprint, and the controller 107 can generate image data of the fingerprint. In this way, the controller 107 can generate image data of the blood vessels near the base of the finger and image data of the skin surface (the back side of the finger) using the light sources 102-4 and 102-5, and generate image data of the fingerprint using the light source 1600. In this way, the controller 107 can obtain multiple pieces of biometric information for one user in a single authentication process, thereby achieving highly accurate authentication without sacrificing convenience.

[0087] 17 is an explanatory diagram illustrating a third configuration example of the imaging device 100 and the authentication device 108 according to the second embodiment. The difference from the first configuration example of FIG. 14 is that a light source 1700 is provided on the +Z side end surface of the front panel portion 100C of the housing 100A that is flush with the fingertip presentation board 1400. The optical axis J of the light source 1700 is inclined from the Z axis toward the fingertip presentation board 1400 around the Y axis. This allows the light source 1700 to irradiate light toward the fingertip presented on the fingertip presentation board 1400.

[0088] Light from light sources 102-1 and 102-2 passes through fingertip presentation board 1400 and is irradiated onto the fingertips. Even if the amount of light is significantly attenuated when passing through fingertip presentation board 1400 and a sufficient amount of light is not irradiated onto the fingertip, the light irradiated from light source 1700 makes it easier for the irradiated light to hit the vicinity of the outline of the fingertip. Therefore, controller 107 can generate clear image data of blood vessels over the entire finger area.

[0089] If the light emitted from the light sources 102-1 and 102-2 is scattered within the housing 100A by the fingertip presentation board 1400 or specular reflection occurs, resulting in a large influence of noise, the controller 107 may reduce the amount of light emitted from the light source 1700 instead of increasing the amount of light emitted from the light sources 102-1 and 102-2, and capture an image of the fingertip with the imaging unit 101.

[0090] 17, the light source 1700 is disposed at a position in the +Z direction relative to the fingertip presentation board 1400, but the light source 1700 may also be disposed at a position in the -Z direction relative to the fingertip presentation board 1400. In this case, the light emitted from the light source 1700 passes through the fingertip presentation board 1400 and is irradiated onto the fingertips. This allows the height of the housing 100A in the Z-axis direction to be lowered compared to the configuration shown in FIG. 17, thereby achieving further miniaturization. Note that, although an example in which the fingertip presentation board 1400 is provided has been described in the second embodiment, it goes without saying that the same effect can be obtained even if the fingertip presentation board 1400 is not provided. [Example]

[0091] Example 3 is an example in which an auxiliary light source is provided on the inner surface of the housing 100A in Example 1 and Example 2. By providing the auxiliary light source, the controller 107 can stably detect the outline of the finger. The same components as those in Example 1 and Example 2 are denoted by the same reference numerals, and the description thereof will be omitted.

[0092] FIG. 18 is an explanatory diagram illustrating an example of the configuration of the image capturing device 100 and the authentication device 108 according to the third embodiment. (A) is a plan view of the image capturing device 100 and the authentication device 108, and (B) is a cross-sectional view of the image capturing device 100 and the authentication device 108. The front panel 100C, the first side panel 100D, and the second side panel 100E protrude in the +Z direction from the top panel 100B. These protruding portions are referred to as a front protruding end 100Ca of the front panel 100C, a first side panel protruding end 100Da of the first side panel 100D, and a second side panel protruding end 100Ea of the second side panel 100E, respectively. A user's hand 110 is presented in a space 1800 outside the housing 100A, surrounded by the front panel protruding end 100Ca, the first side panel protruding end 100Da, the second side panel protruding end 100Ea, and the top panel 100B.

[0093] The auxiliary light source 1801C is provided on the inner wall surface of the front protruding end 100Ca. The auxiliary light source 1801D is provided on the inner wall surface of the first side protruding end 100Da. The auxiliary light source 1801E is provided on the inner wall surface of the second side protruding end 100Ea. The auxiliary light source 1801C is a light source along the Y-axis direction, and the auxiliary light sources 1801D and 1801E are light sources along the X-axis direction. The auxiliary light sources 1801C, 1801D, and 1801E are connected to the controller 107. When there is no need to distinguish between the auxiliary light sources 1801C, 1801D, and 1801E, they will be simply referred to as auxiliary light sources 1801.

[0094] Auxiliary light sources 1801C, 1801D, and 1801E surround the fingers 111 to 113 presented in the space 1800. As a result, the auxiliary light source 1801C emits light along the Y-axis direction toward the fingertips of the index finger 111, middle finger 112, and ring finger 113 and the spaces between the fingers. The auxiliary light source 1801D emits light along the X-axis direction toward the side of the index finger 111. The auxiliary light source 1801E emits light along the X-axis direction toward the side of the ring finger 113. In this way, the light emitted from the auxiliary light source 1801 is emitted near the outline of the fingers. Note that, assuming a case where the user presents a finger to the authentication device 108 without contacting it, the auxiliary light source 1801 may be further arranged in the +Z direction.

[0095] In this way, even if the brightness around the finger contour is insufficient, by adding light emitted from the auxiliary light source 1801, the imaging unit 101 can receive reflected light with sufficient brightness, enabling stable and highly accurate finger detection.

[0096] The wavelength of the light emitted from the auxiliary light source 1801 may be the same as the wavelength of the light emitted from the light source 102. This makes it easier to generate image data of bright blood vessels across the entire finger area. The wavelength of the light emitted from the auxiliary light source 1801 may also be different from that of the light source 102. By using a wavelength of the light emitted from the auxiliary light source 1801 that is less likely to be included in ambient light, the finger area can be more easily distinguished from the background area, improving the accuracy of finger detection.

[0097] Furthermore, when multiple light sources 102 use near-infrared light and multiple wavelengths of visible light, and finger detection is performed from finger image data obtained by irradiating a finger with visible light, the wavelength of auxiliary light source 1801 may be the same visible light wavelength as light source 102. This allows stable detection of the finger outline based on the color of the irradiated light.

[0098] Furthermore, in a standby state before the authentication process, the controller 107 may control the auxiliary light source 1801 to emit visible light having a wavelength different from that of the light source 102. This allows the user to visually recognize that the authentication device 108 is in a standby state.

[0099] When the user presents the finger in the space 1800 and the controller 107 detects the finger (step S702: Yes), the controller 107 switches the wavelength of the light emitted from the auxiliary light source 1801 to the same wavelength as the light source 102, emits visible light, and executes authentication processing (authentication state). Because the light source 102 and the auxiliary light source 1801 emit visible light of the same wavelength, the controller 107 can brightly capture the entire finger area. Furthermore, because the wavelength of the light emitted from the auxiliary light source 1801 changes, the user can visually recognize that the authentication device 108 has transitioned from the standby state to the authentication state.

[0100] When the wavelength of light emitted from the auxiliary light source 1801 is limited to one wavelength, the controller 107 may change the intensity of light emitted between the standby state and the authentication state, or may change the lighting pattern of the auxiliary light source 1801 from blinking to constantly lighting, to indicate the transition of the state. The controller 107 controls the auxiliary light source 1801 so that, when authentication is successful or unsuccessful, it emits light of a different wavelength or with a different light intensity than in the standby state or authentication state, or changes the lighting pattern, such as turning off the light. This allows the controller 107 to notify the user of the authentication result.

[0101] The image capturing device 100 and the authentication device 108 according to the first and second embodiments can also be configured as follows (1) to (15).

[0102] (1) For example, the above-described photographing device 100 includes an imaging unit 101 disposed in a position facing the presented fingers 111 to 113 and capturing images of the fingers 111 to 113, and a plurality of light sources 102 disposed in the direction of arrangement of the fingers 111 to 113 and irradiating the fingers 111 to 113 with light from the outside of an opposing area 130 in which the imaging unit 101 faces the fingers 111 to 113 toward the inside of the opposing area 130. This allows the light source 102 to irradiate light not only onto the back surfaces of the fingers 111 to 113 but also onto the side surfaces of the fingers 111 to 113, thereby reducing the occurrence of areas where the amount of light is insufficient. In other words, it is possible to reduce unevenness in the amount of light across the fingers 111 to 113.

[0103] (2) In the photographing device 100 described in (1) above, the light sources 102 may be arranged in a direction Y in which the fingers 111 to 113 are arranged, and in a direction X in which the fingers 111 to 113 are longitudinally aligned. This allows the light sources 102 to irradiate the fingers 111 to 113 with light from the tips to the bases.

[0104] (3) In the photographing device 100 described in (2) above, the first amount of light emitted from the first light sources (102-1, 102-2) arranged in the longitudinal direction of the fingers 111 to 113 is different from the second amount of light emitted from the second light sources (102-4, 102-5) arranged in the longitudinal direction of the fingers 111 to 113 and closer to the base of the fingers 111 to 113 than the first light sources. This makes it possible to change the amount of light emitted depending on the position of the fingers 111 to 113.

[0105] (4) In the photographing device 100 described in (3) above, the first irradiation light amount is greater than the second irradiation light amount. This prevents a lack of light on the fingertip side and makes it possible to uniform the amount of light across the fingers 111 to 113.

[0106] (5) In the photographing device 100 described in (1) above, the plurality of light sources 102 are arranged so that the first distances to the nearest fingers among the plurality of fingers 111 to 113 are the same or the difference in the first distances is within a first tolerance range, and the second distances to the farthest fingers among the plurality of fingers 111 to 113 are the same or the difference in the second distances is within a second tolerance range. This makes it possible to uniform the amount of light across all of the fingers 111 to 113.

[0107] (6) In the image capturing device 100 described in (1) above, the plurality of light sources 102 includes a light source that emits visible light. This makes it possible to capture images of the patterns (fingerprints) on the backs of the fingers 111 to 113.

[0108] (7) In the photographing device 100 described in (1) above, the plurality of light sources 102 includes a light source that emits near-infrared light. This makes it possible to photograph the blood vessels of the fingers 111 to 113.

[0109] (8) In the image capturing device 100 described in (1) above, at least one of the light sources 102 has a second optical filter 104 that passes light of a specific wavelength in the direction of irradiation (optical axis I) toward the fingers 111 to 113. This allows a light source that emits light containing a specific wavelength to be applied to the image capturing device 100.

[0110] (9) In the image capturing device 100 described in (8) above, the second optical filter 104 is a filter that passes visible light, thereby making it possible to capture images of the patterns (fingerprints) on the backs of the fingers 111 to 113.

[0111] (10) In the photographing device 100 described in (8) above, the second optical filter 104 is a filter that transmits near-infrared light, thereby making it possible to photograph the blood vessels of the fingers 111 to 113.

[0112] (11) In the photographing device 100 described in (2) above, the first wavelength of the first illumination light from the first light sources (102-1, 102-2) arranged in the longitudinal direction X of the fingers 111 to 113 is different from the second wavelength of the second illumination light from the second light sources (102-4, 102-5) arranged in the longitudinal direction of the fingers 111 to 113 and closer to the base of the fingers 111 to 113 than the first light sources. This makes it possible to illuminate the fingers 111 to 113 with light of different wavelengths depending on the illumination position on the fingers 111 to 113.

[0113] (12) In the photographing device 100 of (11) above, the first irradiated light is visible light and the second irradiated light is near-infrared light, thereby making it possible to photograph the patterns (fingerprints) and blood vessels on the back surfaces of the fingers 111 to 113.

[0114] (13) Furthermore, the photographing device 100 of (1) above may have a fingertip presentation board 1400 on which a plurality of fingers 111 to 113 can be placed and through which light from a plurality of light sources 102 passes. This allows the user to be guided to present their fingertips on the fingertip presentation board 1400. Also, a light source 1600 that illuminates the inside of the fingertip presentation board 1400 may be provided. This prevents a lack of light on the fingertip side and makes it possible to make the light amount uniform across the fingers 111 to 113.

[0115] (14) The image capturing device 100 described in (1) above may further include a light source control unit 300 that controls the increase and decrease of the amount of light emitted from the plurality of light sources 102. This allows the image capturing device 100 to autonomously control the increase and decrease of the amount of light emitted. The image capturing device 100 may further include a distance measuring sensor 600 that measures the distance D to the plurality of fingers 111 to 113. This allows the light source control unit 300 to control the increase and decrease of the amount of light emitted for each light source 102 according to the distance D. For example, the light source control unit 300 controls the increase and decrease of the amount of light emitted by the light source 102 that is farther away from the fingers 111 to 113 than the light source 102 that is closer to the fingers 111 to 113. This allows the plurality of fingers 111 to 113 to be captured with a uniform amount of light irradiated thereon by adjusting the amount of light, even if the plurality of fingers 111 to 113 are not equidistant from the image capturing unit 101.

[0116] (15) For example, the authentication device 108 described above includes an imaging unit 101 that is arranged at a position facing the presented fingers 111 to 113 and captures images of the fingers 111 to 113, a plurality of light sources 102 that are arranged in the arrangement direction of the fingers 111 to 113 and that irradiate the fingers 111 to 113 with light from the outside of a facing area 130 in which the imaging units 101 face the fingers 111 to 113 toward the inside of the facing area 130, an image processing unit (controller 107, computer 310) that generates image data of the fingers 111 to 113 based on an output signal from the imaging unit 101, and authenticates the fingers 111 to 113 based on first image data of the fingers 111 to 113 generated by the image processing unit (controller 107, computer 310) and second image data of the fingers 111 to 113 generated by the image processing unit (controller 107, computer 310). This allows the light source 102 to irradiate light not only onto the back surfaces of the fingers 111 to 113 but also onto the sides of the fingers 111 to 113, thereby making it possible to clarify the finger images obtained from the finger image data and improving authentication accuracy.

[0117] It should be noted that the present invention is not limited to the above-described embodiments, and includes various modifications and equivalent configurations within the spirit and scope of the appended claims. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to configurations including all of the described configurations. Furthermore, part of the configuration of one embodiment may be replaced with the configuration of another embodiment. Furthermore, the configuration of another embodiment may be added to the configuration of one embodiment. Furthermore, part of the configuration of each embodiment may be added to, deleted from, or replaced with other configurations.

[0118] Furthermore, the aforementioned configurations, functions, processing units, processing means, etc. may be realized in part or in whole by hardware, for example by designing them as integrated circuits, or may be realized in software by having processor 311 interpret and execute programs that realize the respective functions.

[0119] Information such as programs, tables, and files that realize each function can be stored in storage devices such as memory, hard disks, and SSDs (Solid State Drives), or on recording media such as IC (Integrated Circuit) cards, SD cards, and DVDs (Digital Versatile Discs).

[0120] In addition, the control lines and information lines shown are those that are considered necessary for the explanation, and do not necessarily show all the control lines and information lines that are necessary for implementation. In reality, it can be considered that almost all components are interconnected. [Explanation of symbols]

[0121] 100 Imaging device 100A housing 100B Top plate part 100Ba opposing surface 101 Imaging unit 102 Light source 103 First Optical Filter 104 Second Optical Filter 106 Data Memory 107 Controller 108 Authentication Device 120 Installation surface 130 Opposing area 300 Light source control unit 310 Computer 600 Distance Sensor 1400 Fingertip presentation board 1600 light source 1700 light source

Claims

1. An imaging unit that is arranged in a position facing a plurality of presented fingers and captures images of the plurality of fingers; a first light source disposed at a first position on one side of the arrangement direction of the plurality of fingers; a second light source disposed at a second position on the other side of the arrangement direction; The housing and an upper surface plate portion that is an upper surface of the housing, the imaging unit and the first and second light sources are provided inside the housing, The upper surface plate portion is a first optical filter above the first light source; a second optical filter above the second light source; a light-transmitting plate disposed above the imaging unit; an optical axis of the first light source is tilted in a direction in which the second light source exists so as to pass through the first optical filter; an optical axis of the second light source is tilted in a direction in which the first light source exists so as to pass through the second optical filter; the imaging unit receives reflected light that is emitted from the first light source and the second light source and is reflected by the plurality of fingers and passes through the light-transmitting plate; An imaging device characterized by:

2. An imaging unit that is arranged in a position facing a plurality of presented fingers and captures images of the plurality of fingers; a first light source disposed at a first position on one side of the arrangement direction of the plurality of fingers; a second light source disposed at a second position on the other side of the arrangement direction; The housing and an upper surface plate portion that is an upper surface of the housing, the imaging unit and the first and second light sources are provided inside the housing, the housing has a first wall portion between the first light source and the imaging unit, a second wall portion between the second light source and the imaging unit; an optical axis of the first light source is inclined in a direction in which the second light source is present; the optical axis of the second light source is inclined toward the direction in which the first light source is present; the imaging unit receives reflected light of light emitted from the first light source and the second light source and reflected by the plurality of fingers; An imaging device characterized by:

3. The imaging device according to claim 1 or 2, a third light source disposed in a direction perpendicular to a direction in which the second light source is present relative to the first light source and in a direction horizontal to an installation surface of the housing; a fourth light source disposed in a direction perpendicular to a direction in which the first light source is present relative to the second light source and in a direction horizontal to the installation surface of the housing; an optical axis of the third light source is inclined so as to pass through the upper plate portion in a direction in which the fourth light source is present, and an optical axis of the fourth light source is inclined so as to pass through the upper plate portion in a direction in which the third light source is present; An imaging device characterized by:

4. The imaging device according to claim 3, a first irradiation light amount, which is an irradiation light amount from the first light source and the second light source, and a second irradiation light amount, which is an irradiation light amount from the third light source and the fourth light source, are different from each other; An imaging device characterized by:

5. The imaging device according to claim 4, The first irradiation light amount is greater than the second irradiation light amount. An imaging device characterized by:

6. An imaging device according to claim 1 or 2, the first light source and the second light source are light sources that emit visible light; An imaging device characterized by:

7. The imaging device according to claim 1 or 2, the first light source and the second light source are light sources that emit near-infrared light; An imaging device characterized by:

8. The imaging device according to claim 2, the first light source and the second light source each have a filter that passes light of a specific wavelength in a direction away from the ground surface of the housing; The optical axis of the first light source and the optical axis of the second light source are tilted so as to pass through the filter. An imaging device characterized by:

9. The imaging device according to claim 8, The filter passes visible light. An imaging device characterized by:

10. The imaging device according to claim 8, the filter passes near-infrared light; An imaging device characterized by:

11. The imaging device according to claim 3, a first wavelength of the first irradiation light from the first light source and the second light source is different from a second wavelength of the second irradiation light from the third light source and the fourth light source; An imaging device characterized by:

12. The imaging device according to claim 11, The first irradiation light is visible light, and the second irradiation light is near-infrared light. An imaging device characterized by:

13. The imaging device according to claim 1 or 2, a fingertip presentation unit that presents fingertip presentation positions of the plurality of fingers, The fingertip presentation unit the light source is provided in the housing and is disposed in a direction away from an installation surface of the housing with respect to the first light source and the second light source; an optical axis of the first light source is inclined so as to pass through the fingertip presentation unit in a direction in which the second light source exists, and an optical axis of the second light source is inclined so as to pass through the fingertip presentation unit in a direction in which the first light source exists; An imaging device characterized by:

14. The imaging device according to claim 1 or 2, a light source control unit that controls an increase or decrease in the amount of light emitted from the first light source and the second light source; An imaging device comprising:

15. The imaging device according to claim 1, the first optical filter and the second optical filter are bandpass filters. An imaging device characterized by:

16. The imaging device according to claim 1, the first optical filter and the second optical filter are polarizing filters. An imaging device characterized by:

17. The imaging device according to claim 1, the first optical filter and the second optical filter are light diffusion filters. An imaging device characterized by:

18. An imaging unit that is arranged at a position facing a plurality of presented fingers and captures images of the plurality of fingers; a first light source disposed at a first position on one side of the arrangement direction of the plurality of fingers; a second light source disposed at a second position on the other side of the arrangement direction; The housing and an upper surface plate portion that is an upper surface of the housing, the imaging unit and the first and second light sources are provided inside the housing, The upper surface plate portion is a first optical filter above the first light source; a second optical filter above the second light source; a light-transmitting plate disposed above the imaging unit; an optical axis of the first light source is tilted in a direction in which the second light source exists so as to pass through the first optical filter; an optical axis of the second light source is tilted in a direction in which the first light source exists so as to pass through the second optical filter; the imaging unit receives reflected light that is emitted from the first light source and the second light source and is reflected by the plurality of fingers and passes through the light-transmitting plate; an image processing unit that generates image data of the plurality of fingers based on an output signal from the imaging unit; an authentication unit that authenticates the plurality of fingers based on first image data of the plurality of fingers generated by the image processing unit and second image data of the plurality of fingers generated by the image processing unit; An authentication device comprising:

19. An imaging unit arranged at a position facing a plurality of presented fingers, and imaging the plurality of fingers; a first light source disposed at a first position on one side of the arrangement direction of the plurality of fingers; a second light source disposed at a second position on the other side of the arrangement direction; The housing and an upper surface plate portion that is an upper surface of the housing, the imaging unit and the first and second light sources are provided inside the housing, the housing has a first wall portion between the first light source and the imaging unit, a second wall portion between the second light source and the imaging unit; an optical axis of the first light source is inclined in a direction in which the second light source is present; the optical axis of the second light source is inclined toward the direction in which the first light source is present; the imaging unit receives reflected light of light emitted from the first light source and the second light source and reflected by the plurality of fingers; an image processing unit that generates image data of the plurality of fingers based on an output signal from the imaging unit; an authentication unit that authenticates the plurality of fingers based on first image data of the plurality of fingers generated by the image processing unit and second image data of the plurality of fingers generated by the image processing unit; An authentication device comprising:

Images