Imaging device, authentication device, and imaging method

Abstract

To suppress lack of an amount of light to an image-capturing target.SOLUTION: An image capturing apparatus according to the present invention has a housing, an image capturing unit for acquiring blood vessel images of a plurality of fingers, a first light source, a second light source, and an upper surface plate part functioning as an upper surface of the housing. The image capturing 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 surface plate part in a direction in which the second light source is disposed. An optical axis of the second light source is included so as to pass through the upper surface plate part in a direction in which the first light source is disposed. The image capturing unit receives reflected light formed by reflecting irradiated light from the first light source and the second light source, on the plurality of fingers.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an imaging device for imaging a living body, an authentication device for imaging and authenticating a living body, and an imaging method for imaging a living body.

Background Art

[0002] A biometric authentication technique using a biometric image (vascular image) captured by utilizing the difference in the absorption characteristics of near-infrared light between hemoglobin in blood vessels and other biological tissues has been proposed. By irradiating a living body with near-infrared light, which is a wavelength with a high absorption rate of hemoglobin, and imaging the light that is transmitted or reflected, a vascular image can be obtained. Under the skin surface of a finger, there is a different vascular pattern (pattern) for each individual, and high-precision authentication can be achieved by clearly imaging this vascular pattern.

[0003] As one of the imaging methods for vascular images to realize an authentication technique using a finger vascular image with a small device size, there is a reflection type method. The reflection type method is a method in which a light source and an imaging unit are arranged close to each other, the irradiation light from the light source is irradiated onto the finger pad, and the reflected light is imaged to obtain a vascular image. The biometric authentication device of Patent Document 1, which is of the reflection type, includes a light source provided on the surface of a substrate that outputs light, and a diffractive optical element on which a plurality of diffraction gratings having different pitches and rotation directions are arranged to diffract the light and irradiate an illumination region of an illumination target with the illumination light, and the illumination region is configured to be larger than the occupied areas of the diffractive optical element and the light source on a plane parallel to the surface of the substrate.

[0004] In addition, in order to achieve higher authentication accuracy, not only one finger but also an authentication method using vascular images of a plurality of fingers captured simultaneously is effective. The reflection type method can achieve both high convenience and miniaturization of the device because it is possible to simultaneously capture vascular images of a plurality of fingers even when the living body is in a non-contact state with the device.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Since the surface shape of the finger is three-dimensional and has many curved surfaces, in the reflection type method, the amount of reflected light varies for each part of the finger, and sufficient brightness cannot be obtained in the areas of the fingertip and the side surface (near the contour) of the finger. Therefore, there is a problem that it is difficult to capture a clear blood vessel image. In an unclear blood vessel image where sufficient brightness has not been obtained, the finger area cannot be accurately detected, and there is a risk of a decrease in authentication accuracy. Therefore, especially when trying to capture blood vessel images of multiple fingers simultaneously, it becomes a problem to clearly capture the blood vessels of all the fingers to be captured.

[0007] An object of the present invention is to suppress insufficient light quantity to the imaging object.

Means for Solving the Problems

[0008] The imaging device which is the 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 a top plate portion that is the upper surface of the housing. The imaging unit, 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 top plate portion in the direction where the second light source exists. The optical axis of the second light source is inclined so as to pass through the top plate portion in the direction where the first light source exists. The imaging unit receives the reflected light reflected by the plurality of fingers from the irradiation light of the first light source and the second light source.

[0009] The authentication device according to the second 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 a top plate portion that is the upper surface of the housing. The imaging unit, 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 top plate portion in the direction where the second light source is present. The optical axis of the second light source is inclined so as to pass through the top plate portion in the direction where the first light source is present. The imaging unit receives the reflected light of the irradiation light from the first light source and the second light source reflected by the plurality of fingers, and an image processing unit that generates image data of the plurality of fingers based on the output signal from the imaging unit, and based on the first image data of the plurality of fingers generated by the image processing unit and the second image data of the plurality of fingers generated by the image processing unit, and an authentication unit that authenticates the plurality of fingers, and is characterized by having these components.

[0010] The authentication device according to the 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 a plurality of fingers, a first light source, a second light source, and a top plate portion that is the upper surface of the housing. The imaging unit, 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 top plate portion in the direction where the second light source is present. The optical axis of the second light source is inclined so as to pass through the top plate portion in the direction where the first light source is present. The imaging unit receives the reflected light of the irradiation light from the first light source and the second light source reflected by the plurality of fingers, and an image processing unit that generates image data of the plurality of fingers based on the output signal from the imaging unit, and based on the first image data of the plurality of fingers generated by the image processing unit and the second image data of the plurality of fingers generated by the image processing unit, and an authentication unit that authenticates the plurality of fingers, and is characterized by having these components.

[0011] The imaging method according to the fourth 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 a top plate portion that is the upper surface of the housing. The imaging unit, 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 top plate portion in the direction where the second light source is present, and the optical axis of the second light source is inclined so as to pass through the top plate portion in the direction where the first light source is present. The imaging method by the imaging device is characterized in that the first light source and the second light source irradiate light on the plurality of fingers, and the imaging unit receives the reflected light irradiated from the first light source and the second light source and reflected by the plurality of fingers.

[0012] The imaging method according to the fifth aspect of the invention disclosed in the present application includes a housing, an imaging unit that acquires blood vessel images and fingerprint images of a plurality of fingers, a first light source, a second light source, and a top plate portion that is the upper surface of the housing. The imaging unit, 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 top plate portion in the direction where the second light source is present, and the optical axis of the second light source is inclined so as to pass through the top plate portion in the direction where the first light source is present. The imaging method by the imaging device is characterized in that the first light source and the second light source irradiate light on the plurality of fingers, and the imaging unit receives the reflected light irradiated from the first light source and the second light source and reflected by the plurality of fingers.

Effect of the Invention

[0013] According to a typical embodiment of the present invention, it is possible to suppress insufficient light amount to the imaging object. Problems, configurations, and effects other than those described above will be clarified by the description of the following examples.

Brief Description of the Drawings

[0014]

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DETAILED DESCRIPTION OF THE INVENTION

EXAMPLE

[0015] <Configuration Example of Photographing Device and Authentication Device> FIG. 1 is an explanatory diagram showing Configuration Example 1 of the photographing device and the authentication device according to Embodiment 1. The photographing device 100 photographs the fingers of the hand 110 held above the upper surface plate portion 100B of the housing 100A as a subject. In Embodiment 1, for example, the index finger 111, the middle finger 112, and the ring finger 113 are used as the subjects (imaging targets). However, the fingers 111 to 113 serving as the subjects only need to include two or more of the ten fingers of both hands 110. The back side of the hand 110 of the fingers 111 to 113 is referred to as the front side of the fingers 111 to 113, and the palm side of the hand 110 of the fingers 111 to 113 is referred to as the back side of the fingers 111 to 113.

[0016] In FIG. 1, the photographing device 100 includes a housing 100A, an imaging unit 101, a light source 102, and a data memory 106. The authentication device 108 is a device in which a controller 107 is connected to the photographing device 100.

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

[0018] Inside the housing 100A, it includes an imaging unit 101 and a plurality of light sources 102 (in FIG. 1, light sources 102-1, 102-2). When not distinguishing between the light sources 102-1 and 102-2, it is simply denoted as the light source 102. Also, a first optical filter 103 is provided between the imaging unit 101 and the upper panel portion 100B of the housing 100A. The imaging unit 101 receives the subject light that has passed through the first optical filter 103. The subject light is the light (reflected light) obtained by reflecting the irradiation light from the light source 102 on the subject.

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

[0020] Also, in the region of the upper panel portion 100B existing in the +Z direction from the imaging unit 101, a light-transmitting plate 105 that allows the light reflected by a living body such as the fingers 111 to 113 to pass through the irradiation light of the light source 102 is provided. The light-transmitting plate 105 is composed of a transparent member such as acrylic or glass, for example. Also, a film that allows only light of a specific wavelength to pass through may be attached to the light-transmitting plate 105. Thereby, it is possible to make it difficult to visually recognize the inside of the imaging device 100 from the outside.

[0021] Also, a second optical filter 104 is provided in the region of the upper panel portion 100B existing in the +Z direction from the light source 102. The light that has passed through the second optical filter 104 from the light source 102 irradiates the subject. The second optical filter 104 may be a light diffusion filter. Thereby, the light source 102 can irradiate the subject with irradiation light of uniform intensity over a wide range.

[0022] Further, the second optical filter 104 may be a polarizing filter. Thereby, among the light components irradiated on a living body such as fingers 111 to 113 and reflected, the specular reflection component on the skin surface can be reduced. Therefore, the imaging device 100 can image the blood vessel image of the living body more clearly. Further, the second optical filter 104 may be a band-pass filter that transmits only a specific wavelength of the irradiation light from the light source 102. Thereby, it is possible to suppress the imaging unit 101 from receiving excess ambient light.

[0023] The imaging unit 101 is composed of an imaging element such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device) image sensor, for example. The imaging surface of the imaging unit 101 faces the upper panel portion 100B.

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

[0025] The light source 102 irradiates light onto a subject existing in the +Z direction from the upper panel portion 100B via the second optical filter 104. When photographing the blood vessels of a finger, the irradiation light from the light source 102 is, for example, near-infrared light. Also, when photographing a fingerprint, the irradiation light from the light source 102 is, for example, visible light (for example, blue or green). The light source 102 is provided at a position sandwiching the imaging unit 101. That is, the light sources 102 are arranged in the Y-axis direction. The light source 102 is arranged at a position 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 opposing region 130 toward the inside of the opposing region 130.

[0026] The spread of the irradiation light from the light source 102 is called the light beam. The light beam is the irradiation range of the fingers 111 to 113 serving as the subject. In other words, the light source 102 is arranged at a position such that its light beam includes the fingers 111 to 113. The central axis of the light beam is called the optical axis. The optical axis is the irradiation direction of the light. The optical axis is not parallel to the Z-axis, but is inclined by a predetermined angle toward the imaging unit 101 side from the Z-axis (+Z direction).

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

[0028] The light source 102 is connected to a controller 107 outside the housing 100A. The controller 107 controls the amount of light irradiated from the light source 102. Further, the controller 107 detects the positions of the fingers 111 to 113, and extracts features of blood vessels and fingerprints within the fingers 111 to 113 from the finger image data. Further, the controller 107 may authenticate a plurality 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 fingers 111, middle fingers 112, and ring fingers 113 of the two pieces of finger image data are the index fingers 111, middle fingers 112, and ring fingers 113 of the same person based on the features of the blood vessels and fingerprints of the fingers.

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

[0030] FIG. 3 is a block diagram showing a block configuration example 1 of the photographing device 100 and the authentication device 108 according to the first embodiment. The photographing device 100 includes a light source control unit 300. The light source control unit 300 controls the amount of irradiation light 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] Computer 310 includes a processor 311, a memory device 312, an input device 313, an output device 314, and a communication interface (communication IF) 315. The processor 311, the memory 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 memory device 312 serves as the working area of the processor 311. Also, the memory device 312 is a non-temporary or temporary recording medium that stores various programs and data. Examples of the memory device 312 include a ROM (Read Only Memory), a RAM (Random Access Memory), an HDD (Hard Disk Drive), 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] Examples of the programs stored in the memory device 312 described above include 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 the 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 irradiation light from the light source 102. The authentication program is a program that causes the processor 311 to authenticate the identity of two fingerprint image data stored in the memory device 312. Although examples of software implementation of each function of image processing, light source control, and authentication have been described, each function of image processing, light source control, and authentication may be implemented by a dedicated circuit.

[0033] That is, the imaging device 100 that does not include the light source control unit 300 is the imaging device 100 shown in FIG. 1, and the imaging device 100 that includes the light source control unit 300 is the imaging device 100 shown in FIG. 2. Further, the authentication device 108 having the functions of image processing, light source control, and authentication includes the light source control unit 300 and the computer 310, and corresponds to the authentication device 108 in FIGS. 1 and 2.

[0034] FIG. 4 is a block diagram showing a second block configuration example of the imaging device 100 and the authentication device 108 according to the first embodiment. The imaging device 100 and the authentication device 108 shown in FIG. 4 incorporate a computer 310. The data memory 106 is realized by a storage device 312. The light source control unit 300 is realized by causing the processor 311 to execute a program stored in the storage device 312. Further, the authentication function is realized by causing the processor 311 to execute a program stored in the storage device 312. If the computer 310 does not have an authentication function, it is the imaging device 100, and if the computer 310 has an authentication function, it is the authentication device 108.

[0035] Note that at least one of the light sources 102 shown in FIGS. 1 to 4 may be a visible light source. In this case, when the controller 107 detects the hand 110 during standby, the controller 107 may control the visible light source to emit lights of different colors during authentication processing, upon successful authentication, and upon failed authentication, respectively. Thereby, the user can visually recognize the authentication state.

[0036] Also, at a stage prior to authentication, the computer 310 may receive a user ID and a password through the input device 313, or wirelessly receive a user ID and a password from an IC chip or a communication terminal possessed by the user through the communication IF 315, and register the user ID and the password in the storage device 312 in association with the finger image data of the user.

[0037] Further, the computer 310 may identify fingerprint data associated with the user ID and password stored in the storage device 312 by obtaining the user ID, password, and fingerprint image data from the input device 313 or the communication IF 315 as described above, and authenticate both pieces of fingerprint image data (so-called one-to-one authentication). Note that the computer 310 may identify fingerprint image data that matches the currently input fingerprint image data from the group of fingerprint image data stored in the storage device 312 (so-called one-to-N authentication).

[0038] Also, in the imaging device 100 and the authentication device 108 shown in FIGS. 1 to 4, the irradiation light from the light source 102 may include light of a plurality of different wavelengths. For example, when the imaging unit 101 is composed of a plurality of sensors having different wavelength sensitivity characteristics such as a color camera, the imaging unit 101 irradiates the fingers 111 to 113 with a plurality of different wavelength lights simultaneously and captures the fingers 111 to 113 by the reflected light from the fingers 111 to 113. Thereby, the controller 107 can efficiently separate the finger region irradiated with light from the light source 102 and the background region not irradiated with light by utilizing the difference in the wavelength sensitivity characteristics of each sensor.

[0039] Also, the light source 102 may irradiate light having a wavelength suitable for capturing not only the near-infrared light for blood vessel imaging but also the fingerprints, which are the uneven structures on the surface of the skin. In this case, the computer 310 can perform multi-modal authentication using the blood vessels and fingerprints of the fingers 111 to 113. Thus, when using different wavelength lights for each light source 102, each of the second optical filters 104 may be a band-pass filter that transmits only each wavelength. Also, the second optical filter 104 may be a band-pass filter that transmits a wide range of wavelength bands including a plurality of wavelengths.

[0040] <Irradiation example from light source 102> When a single light source is arranged directly below a plurality of fingers 111 to 113, that is, near the imaging unit 101, the vicinity of the center of the palms of the fingers 111 to 113 is regarded as being substantially horizontal and strong irradiation light hits it. As a result, the imaging unit 101 can receive reflected light with sufficient brightness. On the other hand, near the contours of other fingers far from the palms of the fingers 111 to 113 and near the fingertips, due to the curved surface shape of the fingers 111 to 113, it becomes difficult for the irradiation light to hit. With such an arrangement of a single light source, the imaging unit 101 becomes dark because it cannot receive reflected light with sufficient brightness, and the controller 107 cannot generate finger image data that results in a clear finger image.

[0041] FIG. 5 is an explanatory diagram showing an irradiation example 1 from the light source 102. The light source 102 is pre-arranged to be located further outside than the outer fingers along the arrangement direction Y of the fingers 111 to 113. The optical axis I is a direction inclined by a predetermined angle θ around the X-axis from the Z-axis toward the direction in which the other light source 102 exists. As a result, the light source 102-1 irradiates the back surface and the thumb-side side surface 111A of the index finger 111, the back surface and the index-finger side side surface 112A of the middle finger 112, and the back surface and the middle-finger side side surface 113A of the ring finger 113 (included in the light rays 500). Also, the light source 102-2 irradiates the back surface and the middle-finger side side surface 113B of the ring finger 113, the back surface and the index-finger side side surface 112B of the middle finger 112, and the back surface and the thumb-side side surface 111B of the index finger 111.

[0042] In this way, each light source 102 can irradiate sufficient light near the contour of the finger far from the position of the light source 102. Instead of tilting the optical axis I toward the imaging unit 101 side, a lens may be used such that the amount of irradiation light increases as the distance from the irradiation position increases. As a result, the light source 102 can irradiate sufficient light near the contour of the finger far from its irradiation position.

[0043] In this way, the irradiation light from the light source 102 hits not only near the center of the ventral side of the fingers 111 to 113 but also near the contours of the fingers 111 to 113, and the imaging unit 101 receives reflected light with sufficient brightness across the entire finger region. As a result, the controller 107 can generate finger image data that results in a clear finger image. When multiple light sources 102 are irradiated simultaneously, there are regions where the respective irradiation lights overlap. Therefore, considering that the irradiation lights overlap and reinforce each other, the arrangement of the light sources 102 is determined so that all regions of all fingers have a uniform brightness, and the controller 107 adjusts the intensity of the irradiation light. Specifically, for example, in each light source 102, the distance to the nearest finger is the same or the difference between these distances is within the tolerance range, and the distance to the farthest finger is the same or the difference between these distances is within the tolerance range.

[0044] FIG. 6 is an explanatory diagram showing an irradiation example 2 from the light source 102. FIG. 6 shows an example in which a distance measuring sensor 600 is provided near the imaging unit 101 in the configuration of FIG. 5. The distance measuring sensor 600 is installed at a position within the housing 100A such that the distance in the +Z direction from the installation surface 120 is the same. The distance measuring 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 measuring sensor 600 detects the distance D to the fingers 111 to 113 based on the time difference from when it irradiates the fingers 111 to 113 with infrared light until it receives the reflected light from the fingers 111 to 113. Also, the distance measuring sensor 600 may detect the distance D to the fingers 111 to 113 based on the capacitance between the fingers 111 to 113.

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

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

[0047] Note that in step S701, the authentication device 108 may perform imaging with the light source 102 blinking, and execute detection of the fingers 111 to 113 by using the luminance change of the captured image data. Also, when the distance measuring sensor 600 is built in, the authentication device 108 may detect the presence of the hand 110 approaching within a predetermined position or a certain range by using the distance measuring sensor 600. Further, the blinking of the light source 102 and the distance measurement by the distance measuring 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 of controlling the light amount of the light source 102. The details of the light source control (step S703) will be described later with reference to FIG. 10. As a result of irradiation from the light source 102 with the light amount adjusted by the light source control (step S703), the imaging unit 101 receives the reflected light 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 the magnification and distortion due to the position variation and posture variation of the finger based on the detected position of the finger. Then, the authentication device 108 extracts feature data of finger blood vessels or fingerprints 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 in step S708, although the authentication device 108 stores the feature data, the finger image data may be stored in the data memory 106 or the storage device 312 without executing the extraction of the feature data (step S707).

[0050] <Authentication processing procedure for finger image data> FIG. 8 is a flowchart showing an example of the authentication processing procedure for finger image data. In FIG. 8, as an example, the execution entity is the authentication device 108, but it may also be the imaging device 100. However, when the imaging device 100 is the execution entity, steps S808 to S811 are executed by the controller 107 or the computer 310 outside the imaging device 100. Note that steps S701 to S707 are processes for the finger to be collated, but since they are the same processes as those in FIG. 7, the description thereof is omitted. Also, in FIG. 7, when the finger image data is stored without executing the feature data extraction (step S707), the feature data extraction is also executed for the finger image data of the comparison target to be compared with the collation target in step S707.

[0051] After the execution of step S707, the authentication device 108 reads out the feature data of the comparison target that is already registered from the data memory 106 or the storage device 312, and collates it with the feature data of the collation target (step S808). Specifically, for example, the authentication device 108 calculates a collation score based on the identity of the positions of the feature data and the identity of the features.

[0052] The identity of a position is, for example, the presence or absence of feature data to be compared within the same or an acceptable range as the position of the feature data to be collated. The identity of features is, for example, that the shape of the blood vessels or fingerprints indicated by each piece of feature data is the same or the difference in shape is within an acceptable range between the feature data to be collated with the same position identity and the feature data to be compared. The authentication device 108 has a higher collation score as there is more feature data that satisfies the identity of the position of the feature data and the identity of the features.

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

[0054] <Light source control (step S703)> FIG. 9 is a flowchart showing a detailed processing procedure example of the light source control (step S703) shown in FIGS. 7 and 8. After step S702, the authentication device 108 acquires the image data used for the detection of fingers 111 to 113 (step S901), and specifies each region of the plurality of fingers 111 to 113 (step S902). The authentication device 108 calculates the brightness of the specified finger region from the luminance information of the finger image data acquired in step S901. Next, the authentication device 108 determines the light quantity value of the light source 102 so that the finger region has an appropriate brightness based on the brightness of the finger region calculated in step S903 (step S904). Then, the authentication device 108 lights the light source 102 with the light quantity value determined in step S904 (step S905), and proceeds to step S704.

[0055] Incidentally, the brightness of the finger region calculated in step S903 may be, for example, the average luminance value of the finger region in the finger image data. The average luminance value may be calculated individually for each detected finger 111 to 113, or may be the average of the luminance values of all the detected fingers 111 to 113. Further, as the finger region for calculating the average luminance value, not only the entire regions of the fingers 111 to 113 can be used, but also local regions such as intermediate positions between the fingertips and the bases of the fingers can be used.

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

[0057] As a specific method for determining the light quantity value, there is a method of changing the light quantity value step by step. The light quantity value irradiated by the light source 102 is set in advance in several steps. When the brightness of the finger region in the image data generated by irradiating with the initial light quantity value is darker than the target value, the authentication device 108 increases the light quantity value by one step. On the other hand, when the brightness of the finger region is brighter than the target value, the authentication device 108 decreases the light quantity value by one step.

[0058] As another method for determining the light quantity value, there is a method of using the correlation between the light quantity value of the irradiation light from the light source 102 and the brightness of the finger region. The authentication device 108 (controller 107) controls the light source 102 to irradiate with the light quantity value corresponding to the brightness of the finger region that becomes the target value based on the value of the function representing the relationship between the light quantity value and the brightness of the finger region.

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

[0060] y = αx + β ··· (1)

[0061] α and β in the above formula (1) are parameters that change depending on the environment and the difference of fingers, and are obtained by calculation each time the brightness x of the finger region is calculated. After the function of formula (1) is determined, the authentication device 108 substitutes the target brightness x' of the finger region into the above formula (1) to obtain the light amount value y' corresponding to the brightness x', and lights the light source 102 with the light amount value y'.

[0062] In FIG. 10, the case where the relationship between the light amount value and the brightness of the finger region can be linearly approximated is taken as an example for explanation. However, even when the linear approximation cannot be made (the relationship is non-linear), it is similarly possible to control the light amount.

[0063] FIG. 11 is an explanatory diagram showing the change in the position of the hand 110 with respect to the imaging device 100 and the authentication device 108. When irradiating a certain light amount from the light source 102, if the height of the hand 110 presented by the user fluctuates in the Z-axis direction, the light amount irradiated to the fingers 111 to 113 varies according to the Z-direction distance between the hand 110 and the light source 102, and an excess or deficiency of the reflected light amount from the fingers 111 to 113 occurs. As a result, the brightness of the finger region is different for each of the fingers 111 to 113, and there is a risk that stable finger image data cannot be generated. When the distance measuring sensor 600 can be used, the authentication device 108 can control the irradiation light amount of the light source 102 according to the measured distance D, and irradiate the fingers 111 to 113 with light of a uniform intensity at all times. That is, the authentication device 108 controls the increase and decrease of the light amount from the light source 102 according to the distance D. For example, the authentication device 108 decreases the light amount from the light source 102 as the distance D becomes shorter, and increases the light amount from the light source 102 as the distance D becomes longer.

[0064] <Example of Light Quantity Adjustment According to Posture Variation of Hand 110> FIG. 12 is an explanatory diagram showing Example 1 of light quantity adjustment according to the posture variation of hand 110. In FIG. 12, a state where hand 110 is rotating around the X-axis is shown. The rotation around the X-axis is roll (rotation). Due to the posture variation of the fingers caused by the roll rotation, the heights of 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, controller 107 can generate finger image data by equalizing the brightness of all finger regions by changing the irradiation light quantity of each of light sources 102-1 and 102-2. For example, controller 107 determines the irradiation light quantity of light source 102-1 based on the brightness of the finger region of index finger 111 in the generated finger image data, and determines the irradiation light quantity of light source 102-2 based on the brightness of the finger region of ring finger 113. In this way, controller 107 determines the irradiation light quantity for light sources 102-1 and 102-2 based on the brightness of the finger closest in distance. Therefore, in the case of roll rotation as shown in FIG. 12, controller 107 controls light source 102-1 to irradiate with a stronger light quantity than light source 102-2, and the imaging unit 101 captures the entire finger with uniform brightness.

[0066] Further, controller 107 may adjust the light quantity of light sources 102-1 and 102-2 based on the brightness of the finger regions including middle finger 112 in addition to index finger 111 and ring finger 113. Not limited to middle finger 112, the brightness of all fingers 111 to 113 is affected by the irradiation light of both light sources 102-1 and 102-2. Therefore, considering the influence on the brightness of the finger regions by the irradiation light quantity of light sources 102-1 and 102-2 for each of fingers 111 to 113, controller 107 can determine the optimal irradiation light quantity of light sources 102-1 and 102-2 so that all fingers 111 to 113 have uniform brightness.

[0067] FIG. 13 is an explanatory diagram showing Example 2 of light quantity adjustment according to the posture variation 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. Note that the optical axis of the light source 102-3 is not I but the Z axis. Accordingly, 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, the controller 107 determines the irradiation light quantity of the light source 102-1 based on the brightness of the finger region of the index finger 111, determines the irradiation light quantity of the light source 102-2 based on the brightness of the finger region of the ring finger 113, and determines the irradiation light quantity of the light source 102-3 based on the brightness of the finger region of the middle finger 112. In this way, the controller 107 determines the irradiation light quantity for the light sources 102-1 to 102-3 based on the brightness of the finger closest in distance. Therefore, in the case of roll rotation as shown in FIG. 13, the controller 107 controls the light source 102-1 to irradiate with a stronger light quantity than the light sources 102-2 and 102-3, and controls the light source 102-3 to irradiate with a stronger light quantity than the light source 102-2, so that the imaging unit 101 captures the entire finger with uniform brightness.

[0069] In this way, the controller 107 can generate clearer finger image data that is more robust against position variation and posture variation of the fingers 111 to 113 by adjusting the irradiation light quantity from the light sources 102 corresponding to each finger. Further, in the apparatus configurations of FIGS. 12 and 13, although not shown, a plurality of the light sources 102-1 to 102-3 may be arranged along the X direction, respectively.

Example

[0070] Example 2 is an example in which, in Example 1, the light sources 102 are further arranged in the X-axis direction. The same components as those in Example 1 are denoted by the same reference numerals, and the description thereof is omitted.

[0071] FIG. 14 is an explanatory diagram showing a configuration example 1 of the imaging device 100 and the authentication device 108 according to the second embodiment. (A) shows a side sectional view of the imaging device 100 and the authentication device 108, and (B) shows a plan view of the imaging device 100 and the authentication device 108.

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

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

[0074] Note that, in the +Z direction from the second optical filter 104 corresponding to the light sources 102-1 and 102-4, a fingertip presentation plate 1400 is provided on the housing 100A parallel to the X axis. The fingertip presentation plate 1400 is a transparent plate-like member such as acrylic or glass, and the fingers 111 to 113 can be placed thereon. Thereby, the position of the fingertip of the hand 110 presented by the user can be guided to the fingertip presentation plate 1400. Therefore, even when the finger is placed on the fingertip presentation plate 1400 or held non-contact, the imaging unit 101 can capture the entire finger.

[0075] Near the contour of the side surface in the array direction Y of the fingers 111 to 113, the amount of reflected light of the irradiation light from the light source 102 is likely to be insufficient. Near the contour of the fingertip, it has a three-dimensional shape with many curved surfaces, and the amount of reflected light of the irradiation light from the light source 102 is particularly likely to be insufficient, and the area near the fingertip in the finger image data is very likely to become very dark. Therefore, by providing the light sources 102-4 and 102-5 corresponding to the finger base, the light sources 102-4 and 102-5 and the light sources 102-1 and 102-2 irradiate with different amounts of irradiation light. Specifically, for example, the light sources 102-1 and 102-2 irradiate with a stronger light amount than the light sources 102-4 and 102-5. Thereby, the imaging unit 101 can photograph the entire fingers 111 to 113 with appropriate brightness.

[0076] Note that the light sources 102-1 and 102-2 and the light sources 102-4 and 102-5 may irradiate with preset light amounts respectively. Also, the set light amount values may be individually adjustable.

[0077] Also, as in the first embodiment, when the authentication device 108 generates and authenticates a plurality of modality image data such as blood vessels and fingerprints using a plurality of wavelength lights for a plurality of light sources 102, the authentication device 108 may adjust the irradiation light amounts of the light sources 102-1 and 102-2 and the irradiation light amounts of the light sources 102-4 and 102-5 to the irradiation light amounts suitable for the modality to be photographed respectively.

[0078] For example, for the area on the root side of the fingers 111 to 113, in order to perform blood vessel imaging, the authentication device 108 may control the irradiation light amount of the near-infrared light of the light sources 102-1 and 102-2, and for the area on the fingertip side, in order to perform fingerprint imaging, the authentication device 108 may control the irradiation light amount of the visible light of the light sources 102-4 and 102-5.

[0079] FIG. 15 is an explanatory diagram showing an example of light amount control according to the posture variation of fingers 111 to 113 in Configuration Example 1 of the imaging device 100 and the authentication device 108 according to the second embodiment. As shown in FIG. 15, in the posture where the fingertips are lowered in the -Z axis direction from the finger bases, when the light sources 102-1 and 102-2 and the light sources 102-4 and 102-5 are irradiated with the same light amount, the intensity of the irradiated light attenuates according to the distance. For this reason, the light amount irradiated to the finger base side becomes less than that to the fingertip side, and the finger base side becomes relatively darker in the finger image data. Therefore, clear finger image data is not generated as compared with the case where the postures of fingers 111 to 113 are parallel to the X axis direction.

[0080] Therefore, the controller 107 individually adjusts the light amounts of the light sources 102-4 and 102-5 that irradiate the finger base side and the light sources 102-1 and 102-2 that irradiate the fingertip side. Thereby, clear finger image data is generated in the same manner as in the case where the postures of fingers 111 to 113 are parallel to the X axis direction.

[0081] As a method for this light amount adjustment, the controller 107 uses the distance D measured by the distance measurement sensor 600 provided for each light source 102 to adjust the light amounts of the light sources 102-1 and 102-2. For example, the controller 107 controls the increase and decrease of the irradiation light amount from the light source 102 so that the light amount of the light source 102 with the longer distance D becomes larger than the light amount of the light source 102 with the shorter distance D.

[0082] Further, the controller 107 adjusts the light amounts of the 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 amounts of the light sources 102-1 and 102-2 based on the brightness of the finger region on the fingertip side in the generated finger image data. When performing light amount control based on the brightness of the finger region, the irradiation light from the light sources 102-1 and 102-2 and the irradiation light from the light sources 102-4 and 102-5 may overlap in a part of the finger region. Thus, when affecting the brightness of the finger region, the controller 107 may determine the light amount values of the light sources 102-1 and 102-2 and the 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 irradiation light from the light sources 102-1 and 102-2 and the irradiation light from the light sources 102-4 and 102-5 have uniform brightness.

[0083] FIG. 16 is an explanatory diagram showing a configuration example 2 of the imaging device 100 and the authentication device 108 according to the second embodiment. The difference from the configuration example 1 in FIG. 14 is that a light source 1600 is provided at a position facing the side surface of the fingertip presentation plate 1400 at the +Z side end of the front panel portion 100C of the housing 100A. The irradiation light from the light source 1600 enters from the side surface of the fingertip presentation plate 1400.

[0084] When the user touches or holds a fingertip on the fingertip presentation plate 1400 and the authentication device 108 executes an authentication process, the imaging unit 101 captures the fingerprint of the fingertip in contact with the fingertip presentation plate 1400 with the light source 1600 irradiating light.

[0085] Specifically, for example, the light incident from the light source 1600 into the fingertip presentation plate 1400 propagates while undergoing total internal reflection at the interface between the fingertip presentation plate 1400 and the air. At this time, when the user touches the fingertip on the fingertip presentation plate 1400, at the ridge portions that are the convex portions of the fingerprint of the touching fingertip, the refractive index of the moisture on the fingertip surface and the fingertip presentation plate 1400 becomes larger than the refractive index of the air. For this reason, the total internal reflection condition is not satisfied and the light from the light source 1600 is scattered.

[0086] Accordingly, the ridge portions of the fingerprint on the fingertip are dark while the other regions are bright. The imaging unit 101 captures such a fingerprint, and the controller 107 can generate fingerprint image data. In this way, the controller 107 can execute the generation of image data of blood vessels near the base of the finger and image data of the skin surface (on the back side of the finger) by the light sources 102-4 and 102-5, and the generation of fingerprint image data by the light source 1600. In this way, since the controller 107 can acquire a plurality of biometric information for one user in a single authentication process, highly accurate authentication can be realized without sacrificing convenience.

[0087] FIG. 17 is an explanatory diagram showing a configuration example 3 of the imaging device 100 and the authentication device 108 according to the second embodiment. The difference from the configuration example 1 in 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 flush with the fingertip presentation board 1400. The optical axis J of the light source 1700 is in a direction inclined from the Z axis toward the fingertip presentation board 1400 around the Y axis. Thereby, the light source 1700 can irradiate light toward the fingertip presented on the fingertip presentation board 1400.

[0088] The light from the light sources 102-1 and 102-2 passes through the fingertip presentation board 1400 and irradiates the fingertip. When the light passes through the fingertip presentation board 1400, even if the amount of light is greatly attenuated and the fingertip is not irradiated with a sufficient amount of light, the irradiation light from the light source 1700 makes it easier for the irradiation light to hit near the contour of the fingertip. Therefore, the controller 107 can generate clear blood vessel image data for the entire finger region.

[0089] When the irradiation light from the light sources 102-1 and 102-2 is scattered in the housing 100A by the fingertip presentation board 1400 or specular reflection occurs, and the influence of noise increases, the controller 107 may decrease the amount of irradiation light from the light source 1700 instead of increasing the amount of irradiation light from the light sources 102-1 and 102-2, and image the fingertip with the imaging unit 101.

[0090] In FIG. 17, the light source 1700 is arranged at a position in the +Z direction with respect to the fingertip display board 1400, but the light source 1700 may be arranged at a position in the -Z direction with respect to the fingertip display board 1400. In this case, the irradiation light from the light source 1700 passes through the fingertip display board 1400 and irradiates the fingertip. Thereby, compared with the configuration shown in FIG. 17, the height of the housing 100A in the Z-axis direction can be reduced, and further miniaturization can be achieved. Note that although the second embodiment has been described with an example in which the fingertip display board 1400 is provided, it goes without saying that the same effect can be obtained even when the fingertip display board 1400 is not provided.

Embodiment

[0091] The third embodiment is an example in which an auxiliary light source is provided on the inner surface of the housing 100A in the first and second embodiments. By providing the auxiliary light source, the controller 107 stably detects the contour of the finger. The same components as those in the first and second embodiments are denoted by the same reference numerals, and the description thereof is omitted.

[0092] FIG. 18 is an explanatory diagram showing a configuration example of the imaging device 100 and the authentication device 108 according to the third embodiment. (A) is a plan view of the imaging device 100 and the authentication device 108, and (B) is a cross-sectional view of the imaging device 100 and the authentication device 108. The front panel portion 100C, the first side panel portion 100D, and the second side panel portion 100E protrude in the +Z direction from the top panel portion 100B. These protruding portions are respectively referred to as the front protruding end 100Ca of the front panel portion 100C, the first side protruding end 100Da of the first side panel portion 100D, and the second side protruding end 100Ea of the second side panel portion 100E. The user's hand 110 is presented in the space 1800 outside the housing 100A surrounded by the front protruding end 100Ca, the first side protruding end 100Da, the second side protruding end 100Ea, and the top panel portion 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 not distinguishing the auxiliary light sources 1801C, 1801D, and 1801E, they are simply denoted as the auxiliary light source 1801.

[0094] The auxiliary light sources 1801C, 1801D, and 1801E surround the fingers 111 to 113 presented in the space 1800. Thereby, the auxiliary light source 1801C irradiates light along the Y-axis direction toward the fingertips of the index finger 111, the middle finger 112, and the ring finger 113, and between each finger. The auxiliary light source 1801D irradiates light along the X-axis direction toward the side surface of the index finger 111. The auxiliary light source 1801E irradiates light along the X-axis direction toward the side surface of the ring finger 113. In this way, the irradiation light from the auxiliary light source 1801 is irradiated near the contour of the finger. Assuming the case where the user presents a finger to the authentication device 108 in a non-contact manner, the auxiliary light source 1801 may be further arranged in the +Z direction.

[0095] In this way, even when the brightness near the finger contour is insufficient, by adding the irradiation light 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 irradiation light from the auxiliary light source 1801 may be the same as the wavelength of the irradiation light from the light source 102. This facilitates the generation of bright blood vessel image data throughout the finger region. Also, the wavelength of the irradiation light from the auxiliary light source 1801 may be different from the wavelength of the light source 102. By setting the wavelength of the irradiation light from the auxiliary light source 1801 to a wavelength that is less likely to be included in the ambient light, the background region and the finger region can be more clearly distinguished, thereby improving the accuracy of finger detection.

[0097] In addition, when using multiple wavelengths of near-infrared light and visible light for the plurality of light sources 102 and performing finger detection from finger image data obtained by irradiating the finger with visible light, the wavelength of the auxiliary light source 1801 may be the same visible light wavelength as that of the light source 102. Thereby, the contour line of the finger can be stably detected by the color of the irradiation light.

[0098] Also, in the standby state before the authentication process, the controller 107 may control the auxiliary light source 1801 to irradiate with visible light having a wavelength different from that of the light source 102. Thereby, it is possible to visually recognize that the authentication device 108 is in the 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 irradiation light from the auxiliary light source 1801 to the same wavelength as that of the light source 102, irradiates with visible light, and executes the authentication process (authentication state). Since the light source 102 and the auxiliary light source 1801 irradiate visible light of the same wavelength, the controller 107 can brightly photograph the entire finger area. In addition, since the wavelength of the irradiation light 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 making the wavelength of the irradiation light from the auxiliary light source 1801 only one wavelength, the controller 107 may change the amount of light irradiated in the standby state and the authentication state, or change the lighting pattern of the auxiliary light source 1801 from the blinking state to the always-on state to represent the state transition. The controller 107 controls the auxiliary light source 1801 to irradiate with light of a wavelength different from that in the standby state or the authentication state, or a different light amount, or the lighting pattern changes like turning off when authentication is successful or failed. Thereby, the controller 107 can notify the user of the authentication result.

[0101] In addition, the imaging device 100 and the authentication device 108 according to the above-described Example 1 and Example 2 can also be configured as follows (1) to (15).

[0102] (1) For example, the imaging device 100 described above is disposed at a position facing a plurality of presented fingers 111 to 113, and includes an imaging unit 101 that images the plurality of fingers 111 to 113, and a plurality of light sources 102 that are arranged in the arrangement direction of the plurality of fingers 111 to 113 and irradiate light from the outside of the opposing region 130 where the imaging unit 101 faces the plurality of fingers 111 to 113 toward the inside of the opposing region 130. Thereby, the light source 102 can irradiate light not only on the back surfaces of the fingers 111 to 113 but also on the side surfaces of the fingers 111 to 113, and can suppress the occurrence of locations with insufficient light amount. That is, it is possible to suppress unevenness in the light amount over the entire plurality of fingers 111 to 113.

[0103] (2) Further, in the imaging device 100 of (1) above, the plurality of light sources 102 may be arranged in the arrangement direction Y of the plurality of fingers 111 to 113 and also arranged in the longitudinal direction X of the fingers 111 to 113. Thereby, the light source 102 can irradiate light from the fingertips to the roots of the fingers 111 to 113.

[0104] (3) Further, in the imaging device 100 of (2) above, the first irradiation light amount from the first light sources (102-1, 102-2) arranged in the longitudinal direction of the fingers 111 to 113 and the second irradiation light amount from the second light sources (102-4, 102-5) arranged in the longitudinal direction of the fingers 111 to 113 and on the root side of the fingers 111 to 113 with respect to the first light sources are different. Thereby, the irradiation light amount can be changed according to the irradiation position on the fingers 111 to 113.

[0105] (4) Further, in the imaging device 100 of (3) above, the first irradiation light amount is larger than the second irradiation light amount. Thereby, it is possible to suppress insufficient light amount on the fingertip side and achieve uniform light amount over the entire fingers 111 to 113.

[0106] (5) Also, in the imaging device 100 of (1) above, each of the plurality of light sources 102 is arranged such that the first distance to the closest finger among the plurality of fingers 111 to 113 is the same or the difference in the first distance is within the first tolerance range, and the second distance to the farthest finger among the plurality of fingers 111 to 113 is the same or the difference in the second distance is within the second tolerance range. Thereby, it is possible to equalize the amount of light over the entire fingers 111 to 113.

[0107] (6) Also, in the imaging device 100 of (1) above, the plurality of light sources 102 includes a light source that irradiates visible light. Thereby, it is possible to image the patterns (fingerprints) on the back surfaces of the fingers 111 to 113.

[0108] (7) Also, in the imaging device 100 of (1) above, the plurality of light sources 102 includes a light source that irradiates near-infrared light. Thereby, it is possible to image the blood vessels of the fingers 111 to 113.

[0109] (8) Also, in the imaging device 100 of (1) above, at least one of the plurality of light sources 102 has a second optical filter 104 that allows light of a specific wavelength to pass through in the irradiation direction (optical axis I) to the plurality of fingers 111 to 113. Thereby, a light source that irradiates light including a specific wavelength can be applied to the imaging device 100.

[0110] (9) Also, in the imaging device 100 of (8) above, the second optical filter 104 is a filter that allows visible light to pass through. Thereby, it is possible to image the patterns (fingerprints) on the back surfaces of the fingers 111 to 113.

[0111] (10) Also, in the imaging device 100 of (8) above, the second optical filter 104 is a filter that allows near-infrared light to pass through. Thereby, it is possible to image the blood vessels of the fingers 111 to 113.

[0112] (11) Also, in the imaging device 100 of (2) above, the first wavelength of the first irradiation 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 irradiation light from the second light sources (102-4, 102-5) arranged in the longitudinal direction of the fingers 111 to 113 and on the base side of the fingers 111 to 113 with respect to the first light sources. Thereby, light of different wavelengths can be irradiated onto the fingers 111 to 113 according to the irradiation positions on the fingers 111 to 113.

[0113] (12) Also, in the imaging device 100 of (11) above, the first irradiation light is visible light, and the second irradiation light is near-infrared light. Thereby, the patterns (fingerprints) and blood vessels on the back surface of the fingers 111 to 113 can be imaged.

[0114] (13) Also, in the imaging device 100 of (1) above, it may have a fingertip presentation plate 1400 on which a plurality of fingers 111 to 113 can be placed and through which the light from the plurality of light sources 102 passes. Thereby, the user can be induced to present the fingertips on the fingertip presentation plate 1400. Also, a light source 1600 for irradiating the inside of the fingertip presentation plate 1400 may be provided. Thereby, the shortage of the light amount on the fingertip side can be suppressed, and the light amount can be made uniform over the entire fingers 111 to 113.

[0115] (14) Also, in the imaging device 100 of (1) above, it may have a light source control unit 300 that controls the increase and decrease of the irradiation light amount from the plurality of light sources 102. Thereby, the imaging device 100 can autonomously control the increase and decrease of the irradiation light amount. Also, the imaging device 100 may have a distance measurement sensor 600 that measures the distance D to the plurality of fingers 111 to 113. Thereby, the light source control unit 300 can control the increase and decrease of the irradiation light amount for each light source 102 according to the distance D. For example, the light source control unit 300 controls the increase and decrease so that the irradiation light amount of the light source 102 with the longer distance D to the fingers 111 to 113 is larger than the irradiation light amount of the light source 102 with the shorter distance D to the fingers 111 to 113. Thereby, even when the plurality of fingers 111 to 113 are not equidistant from the imaging unit 101, it is possible to irradiate the plurality of fingers 111 to 113 with a uniform light amount by adjusting the light amount and perform imaging.

[0116] (15) Further, for example, the authentication device 108 described above is disposed at a position facing a plurality of fingers 111 to 113 to be presented, and includes an imaging unit 101 that images the plurality of fingers 111 to 113, and a plurality of light sources 102 that are arranged in the arrangement direction of the plurality of fingers 111 to 113 and irradiate light from the outside of the facing region 130 where the imaging unit 101 faces the plurality of fingers 111 to 113 toward the inside of the facing region 130. An image processing unit (controller 107, computer 310) that generates image data of the plurality of fingers 111 to 113 based on the output signal from the imaging unit 101, and the first image data of the plurality of fingers 111 to 113 generated by the image processing unit (controller 107, computer 310), and the second image data of the plurality of fingers 111 to 113 generated by the image processing unit (controller 107, computer 310). Based on this, the plurality of fingers 111 to 113 are authenticated. As a result, the light source 102 can irradiate not only the back surfaces of the fingers 111 to 113 but also the side surfaces of the fingers 111 to 113, thereby enhancing the sharpness of the finger images obtained from the finger image data and improving the authentication accuracy.

[0117] Note that the present invention is not limited to the above-described embodiments, and includes various modifications and equivalent configurations within the scope of the appended claims. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and the present invention is not necessarily limited to those having all the configurations described. Also, a part of the configuration of one embodiment may be replaced with the configuration of another embodiment. Further, the configuration of another embodiment may be added to the configuration of one embodiment. Also, for a part of the configuration of each embodiment, addition, deletion, or replacement with another configuration may be made.

[0118] In addition, each of the above-described configurations, functions, processing units, processing means, etc. may be realized in hardware, for example, by designing a part or all of them with an integrated circuit, or may be realized in software by the processor 311 interpreting and executing a program that realizes each function.

[0119] Information such as programs, tables, and files that implement each function can be stored in a storage device such as a memory, a hard disk, an SSD (Solid State Drive), or a recording medium such as an IC (Integrated Circuit) card, an SD card, or a DVD (Digital Versatile Disc).

[0120] In addition, the control lines and information lines show those considered necessary for explanation, and do not necessarily show all the control lines and information lines required for implementation. In practice, it may be considered that almost all components are interconnected.

Explanation of Signs

[0121] 100 Imaging device 100A Housing 100B Upper panel 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 measurement sensor 1400 Finger tip display board 1600 Light source 1700 Light source

Claims

1. A housing and An imaging unit for acquiring blood vessel images of a plurality of fingers; A first light source; A second light source; An upper surface plate portion which is an upper surface of the housing, the imaging unit, the first light source and the second light source are provided inside the housing, an optical axis of the first light source is inclined so as to pass through the upper plate portion in a direction in 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 plate portion in a direction in which the first light source is present, The imaging unit receives reflected light of irradiation light from the first light source and the second light source reflected by the plurality of fingers. An imaging device characterized by:

2. The imaging device according to claim 1 , the imaging unit acquires blood vessel images of the plurality of fingers and fingerprint images of the plurality of fingers; An imaging device characterized by:

3. 3. The imaging device according to claim 1, a third light source disposed in a direction perpendicular to a direction in which the second light source is present with respect to the first light source and in a direction parallel 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; The 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 the 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 amount of irradiation light from the first light source and the second light source, is different from a second irradiation light amount, which is an amount of irradiation light from the third light source and the fourth light source; An imaging device characterized by:

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

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

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

8. 3. The imaging device according to claim 1, 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. 9. The imaging device according to claim 8, The filter passes visible light. An imaging device characterized by:

10. 9. 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 4, 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. 3. The imaging device according to claim 1, a fingertip presentation unit that presents fingertip presentation positions of the plurality of fingers, The fingertip presentation unit is a light source provided in the housing and 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. 3. The imaging device according to claim 1, a light source control unit that controls an increase or decrease in an amount of light emitted from the first light source and the second light source; 13. An imaging device comprising:

15. A housing and An imaging unit for acquiring blood vessel images of a plurality of fingers; A first light source; A second light source; An upper surface plate portion which is an upper surface of the housing, the imaging unit, the first light source and the second light source are provided inside the housing, an optical axis of the first light source is inclined so as to pass through the upper plate portion in a direction in 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 plate portion in a 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:

16. A housing and an imaging unit for acquiring blood vessel images and fingerprint images of a plurality of fingers; A first light source; A second light source; An upper surface plate portion which is an upper surface of the housing, the imaging unit, the first light source and the second light source are provided inside the housing, an optical axis of the first light source is inclined so as to pass through the upper plate portion in a direction in 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 plate portion in a 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:

17. an imaging method using an imaging device having a housing, an imaging unit that acquires blood vessel images of a plurality of fingers, a first light source, a second light source, and a top plate that is a top surface of the housing, the imaging unit and the first and second light sources being provided inside the housing, an optical axis of the first light source being inclined so as to pass through the top plate in a direction in which the second light source is present, and an optical axis of the second light source being inclined so as to pass through the top plate in the direction in which the first light source is present, the first light source and the second light source irradiate light onto the plurality of fingers; the imaging unit receives light irradiated from the first light source and the second light source and reflected by the plurality of fingers; A photographing method characterized by the above.

18. An imaging method using an imaging device having a housing, an imaging unit that acquires blood vessel images and fingerprint images of a plurality of fingers, a first light source, a second light source, and a top plate that is a top surface of the housing, the imaging unit and the first and second light sources being provided inside the housing, an optical axis of the first light source being inclined so as to pass through the top plate in a direction in which the second light source is present, and an optical axis of the second light source being inclined so as to pass through the top plate in the direction in which the first light source is present, the first light source and the second light source irradiate light onto the plurality of fingers; the imaging unit receives light irradiated from the first light source and the second light source and reflected by the plurality of fingers; A photographing method characterized by the above.

Images