JP2006068328A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of imaging an object to be authenticated present inside a living body with a high image quality. <P>SOLUTION: Vascular projection light in the direction nearly perpendicular or perpendicular to the imaging face of a CCD imaging element 23, among the vascular projection light emitted from a near-infrared light source to a finger and passing through the inside of the finger, is selectively guided to the imaging face. In this case, non-vascular projection light from the finger without passing through the blood vessel or the visible light coming from the back of the finger can be removed as most part of the light obtained in the direction nearly perpendicular or perpendicular to the imaging face, which is not the intrinsically required vascular projection light, and therefore, noise components generated from the light other than the vascular projection light can be greatly removed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an imaging apparatus, and is suitably applied to an imaging apparatus that images, for example, a blood vessel that is present inside a living body as an authentication target.

  Conventionally, there is a blood vessel as a target for biometric authentication. It is known that this blood vessel has a property of specifically absorbing near-infrared light (near-infrared light) with intrinsic deoxygenated hemoglobin (venous blood) or oxygenated hemoglobin (arterial blood).

  There has been proposed an imaging apparatus configured to image blood vessels using such properties (see, for example, Patent Document 1).

  This imaging device irradiates the finger pad with near-infrared light having an intensity stronger than the intensity of reflected light reflected from the living body (normal light in an atmosphere such as visible light), and is inherent in the blood vessel tissue inside the finger. Near-infrared light obtained by being absorbed by hemoglobin and scattered in tissues other than blood vessel tissue is guided to a CCD (Charge Coupled Device) through a macro lens that transmits the near-infrared light.

  Then, the image sensor converts the amount of charge per unit time charged to the CCD by photoelectrically converting the near infrared light so that the imaging sensitivity of the CCD with respect to the near infrared light is sharper than the normal light. Is adjusted so as to obtain a blood vessel image signal.

Therefore, according to this imaging apparatus, since the reduction of noise components based on normal light in an atmosphere such as visible light is electrically controlled, a physical shielding member that blocks the normal light is not provided, and the macro is also provided. A blood vessel can be imaged without strictly pursuing the transmission wavelength range of near-infrared light in the lens, and thus miniaturization can be realized.
JP 2004-135609 A

  However, in the imaging apparatus having such a configuration, since the near infrared light obtained by reflecting the surface of the living body without passing through the inside of the living body is also guided to the CCD, the noise component of the blood vessel image signal is accordingly increased. As a result, there is a problem that the image quality of the blood vessel image is lowered.

  The present invention has been made in consideration of the above points, and an object of the present invention is to propose an imaging apparatus capable of imaging an authentication target in a living body with high image quality.

  In order to solve such a problem, the present invention is an imaging apparatus that images an authentication target interposed inside a living body, the irradiation means for irradiating the living body with imaging light, the irradiation means irradiating the living body, An imaging element that captures imaging light obtained via the direction and imaging light obtained via the inside of the living body is selectively selected to be imaging light that is substantially perpendicular to or perpendicular to the imaging surface. A light guiding means for guiding light to the imaging surface is provided.

  Therefore, in this imaging apparatus, light that is obtained from a direction other than the direction that is substantially vertical or vertical by being scattered inside the living body is excluded, and the reflected light of the authentication target is substantially vertical or vertical inside the living body. Since the imaging light obtained from the direction can be guided to the imaging surface, noise components caused by light that is not originally required can be significantly removed from the signal output from the imaging element.

  According to the present invention, an irradiating unit that irradiates a living body with imaging light, an imaging element that irradiates the living body from the irradiating unit and obtains imaging light obtained through the inside of the living body, and the inside of the living body The light guide means for selectively guiding the imaging light that is substantially perpendicular to or perpendicular to the imaging surface out of the imaging light obtained in this way to the inside of the living body Since light obtained from a direction other than a direction that is substantially vertical or vertical can be eliminated by scattering in the noise, noise components can be greatly removed from the signal output from the imaging device, and thus in vivo The object to be authenticated can be imaged with high image quality.

  Embodiments to which the present invention is applied will be described in detail below with reference to the drawings.

(1) First Embodiment (1-1) Overall Configuration of Blood Vessel Imaging Device In FIG. 1 and FIG. 2 taken along the line AA ′ of FIG. 1, 1 is the first embodiment as a whole. The blood-vessel imaging device 1 by is shown. The blood vessel imaging device 1 has a substantially rectangular parallelepiped-shaped casing 2, and an operation unit 3 and a display unit 4 including various operation buttons such as an imaging start button are provided on a side surface of the casing 2 corresponding to the front surface of the imaging apparatus 1. Is provided.

  On the other hand, a curved concave portion 5 simulating a finger is formed on the upper surface of the housing 2, and an imaging opening 6 is provided on the bottom surface of the concave portion 5. Therefore, the blood vessel imaging device 1 guides the finger FG arranged so as to be applied to the imaging opening 6 to the imaging opening 6 and applies to the finger FG arranged so that the fingertip comes into contact with the curved tip of the recess 5. The position of the imaging opening 6 can be determined according to the person who takes the image.

  A colorless and transparent opening cover portion 7 (FIG. 2) made of a predetermined material is provided on the surface of the imaging opening 6, while an imaging portion 8 is provided immediately below the imaging opening 6 inside the housing 2. Is provided. Therefore, this blood vessel imaging device 1 prevents the inflow of foreign matter from the imaging opening 6 into the housing 2 and prevents the imaging unit 8 from being soiled due to the finger FG being placed in the imaging opening 6. It is made to be able to do.

  Further, a pair of near-infrared light sources 9 that irradiate near-infrared light as imaging light on the side surface of the recess 5 at an opposing position that is orthogonal to the finger difference direction of the finger FG disposed in the recess 5. (9A and 9B) are provided. In the near-infrared light source 9, in order to reduce surface reflection at the finger pad, as shown in FIG. 3, near-infrared light is irradiated from an irradiation direction id that forms an acute angle α with the imaging surface F1 in the imaging unit 8. It is made to do. In this case, an irradiation direction that forms 30 ° to 60 ° with the imaging surface of the imaging unit 8 is effective.

  Therefore, in this blood vessel imaging device 1, near infrared light is irradiated from the near infrared light source 5 to the finger pad side portion of the finger FG disposed in the recess 5. The near-infrared light is absorbed by hemoglobin present in the blood vessel tissue inside the finger FG and scattered in a tissue other than the blood vessel tissue, thereby causing the imaging opening 6 and the opening cover portion from the finger FG as blood vessel projection light. 7 sequentially enters the image pickup unit 8.

  The imaging unit 8 has a CCD imaging device in which a plurality of photodiodes are arranged in a grid pattern corresponding to the pixels, and guides blood vessel projection light incident through the opening cover unit 7 to the imaging surface of the CCD imaging device. In this way, blood vessels are imaged, and the imaging results are sequentially output to the signal processing unit 10 as blood vessel image signals S10.

  The signal processing unit 10 drives and controls the near-infrared light source 9 and the imaging unit 8 according to the imaging command supplied from the operation unit 3, and based on the blood vessel image signal S10 sequentially output from the imaging unit 8, Information including an angiogenesis pattern unique to the photographer (hereinafter referred to as authentication information) is generated.

  The signal processing unit 10 transmits authentication information to the authentication device connected to the blood vessel imaging device 1 via a predetermined communication path, and as an authentication processing result based on the authentication information in the authentication device. Only when a determination result of being an authorized user is obtained, various data such as data relating to electronic commerce are exchanged with the authentication device.

  As described above, the blood vessel imaging device 1 images a blood vessel in the living body as an authentication target, and subsequently performs subsequent processing according to the authentication processing result based on the authentication information generated from the imaging result. Yes.

(1-2) Blood vessel projection light Here, blood vessel projection light incident through the opening cover portion 7 will be described. As described above, the blood vessel projection light is emitted from the finger FG by irradiating the finger FG from the irradiation direction id (FIG. 3) that forms an acute angle α with the imaging surface F1, and is scattered inside the finger FG. However, it can be obtained from various directions due to individual differences in scattering elements in the living body, environmental changes during imaging, and the like. Therefore, for example, as shown in FIG. 4A, near-infrared light (hereinafter referred to as non-vascular projection light) obtained from the finger FG without reflecting the blood vessel is used as the blood vessel projection light obtained from various directions. Many) are also mixed.

  In addition, since the blood vessel imaging device 1 does not have a member that physically blocks visible light coming from the finger back direction, which is disposed in the recess 5, the blood vessel projection light includes, for example, as shown in FIG. Visible light is also mixed.

  In addition, when the non-blood vessel projection light and the visible light are mixed and the blood vessel projection light incident through the opening cover portion 7 is condensed on the image pickup surface of the CCD image pickup device by an optical system such as a macro lens, it is originally necessary. Non-blood vessel projection light (FIG. 4A) and visible light (FIG. 4B) other than the blood vessel projection light to be taken are also guided to the imaging surface. As a result, imaging by the CCD imaging device 23 is performed. As a result, the blood vessel image signal S10 has a situation in which the ratio of noise caused by the non-blood vessel projection light and the visible light increases.

  However, these non-vascular projection light and visible light are incident from a direction substantially perpendicular to the imaging surface or a direction other than the vertical direction mainly due to the irradiation direction and the presence of bone in the center of the finger cross section. Often done.

  Therefore, in the imaging unit 8, among the blood vessel projection light incident through the opening cover unit 7, blood vessel projection light (hereinafter referred to as “vertical direction blood vessel projection light”) incident on the imaging surface from a substantially vertical direction or a vertical direction. Is selectively guided to the imaging surface of the CCD imaging device.

(1-3) Specific Configuration of the Imaging Unit In practice, as shown in FIG. 4, the imaging unit 8 includes an optical fiber bundle 21, a condensing lens 22, and an incident optical path incident through the aperture cover unit 7. The CCD imaging device 23 is arranged, and the vertical blood vessel projection light incident through the opening cover portion 7 is guided to the imaging surface of the CCD imaging device 23 by the optical fiber bundle 21 and the condenser lens 22. It is made to do.

  The optical fiber bundle 21 is configured by bundling optical fibers OF1 to OFn having the same number as the number of photodiodes corresponding to the pixels so that the cross sections thereof have the same circular shape. These optical fibers OF1 to OFn cover a core with a medium (hereinafter referred to as a core) formed of a dielectric having a predetermined refractive index and a dielectric having a lower refractive index than the core. Each of these is formed by a formed medium (hereinafter referred to as a grad).

  A hemispherical lens that collects vertical blood vessel projection light incident through the opening cover 7 and enters the core at one end of these optical fibers OF1 to OFn (hereinafter referred to as a core incident lens). CIL1 to CILn are respectively provided.

  Therefore, the optical fiber bundle 21 transmits the vertical blood vessel projection light incident from the corresponding core incident lens CIL without attenuation and without causing mutual interference, and emits the light from the core end to the condenser lens 22. Has been made.

  The condensing lens 22 condenses the vertical blood vessel projection light emitted from the core end of each optical fiber OF in the optical fiber bundle 21 on the imaging surface of the CCD image sensor 23.

  In this way, the imaging unit 8 selectively guides the blood vessel projection light in the vertical direction to the imaging surface of the CCD imaging device 23 by the optical fiber bundle 21 and the condensing lens 22 arranged on the CCD imaging device 23. As a result, noise components caused by light other than the blood vessel projection light that should be originally required can be largely removed from the blood vessel image signal S10 output as the imaging result of the CCD image pickup device 23. Yes.

(1-4) Specific Processing Contents of Signal Processing Unit Next, specific processing contents of the signal processing unit 10 will be described in detail with reference to FIG.

  In FIG. 6, the signal processing unit 10 includes a light source drive control unit 31, a CCD image sensor drive control unit 32, an image processing unit 33, and a communication unit 34 with respect to the control unit 30 that controls the entire imaging apparatus 1. Each is configured by being connected via a bus 35.

  The control unit 30 includes a CPU (Central Processing Unit), a ROM (Read Only Memory) in which various programs are stored, a RAM (Random Access Memory) as a work memory, and the like, and is supplied from the operation unit 3 according to the program. The light source drive control unit 31, the CCD image sensor drive control unit 32, the image processing unit 33, and the communication unit 34 are appropriately controlled according to various commands.

  Further, the control unit 30 displays the contents of data sent from the communication unit 34 via the display unit 4 (FIG. 1) as necessary.

  The light source drive control unit 31 is activated under the control of the control unit 30 and generates a light source drive control signal S31 having a predetermined voltage level. The light source drive control unit 31 drives the near-infrared light source 9 by applying the light source drive control signal S31 to the near-infrared light source 9.

  As a result, near-infrared light is irradiated to the finger pad side portion of the finger FG disposed in the recess 5.

  The CCD image sensor drive control unit 32 is activated under the control of the control unit 30, and generates a CCD image sensor drive signal S32 having a predetermined duty ratio. The CCD image sensor drive control unit 32 drives the CCD image sensor 23 by outputting the CCD image sensor drive signal S32 to the CCD image sensor 23.

  As a result, with the trailing edge (or rising edge) of the CCD image sensor driving signal S32 as the readout time point, the charges charged in the CCD image sensor 23 up to the readout time point are sequentially output as the blood vessel image signal S10.

  The image processing unit 33 performs A / D (Analog / Digital) conversion processing, for example, on the first blood vessel image signal S10 among the blood vessel image signals S10 sequentially output from the CCD image pickup device 23, and the blood vessel image obtained as a result thereof. The noise component included in the blood vessel image signal S10 is removed by performing median filter processing on the data.

  Thereafter, the image processing unit 33 extracts the blood vessel contour in the blood vessel image by performing, for example, Laplacian processing on the blood vessel image data from which the noise component has been removed, and the blood vessel image from which the blood vessel contour has been extracted is extracted. The authentication information D33 is sent to the communication unit 34.

  The communication unit 34 subjects the data supplied from the control unit 30 or the authentication information D33 supplied from the communication unit 34 to modulation processing or the like based on a predetermined communication method, and the signal obtained as a result of this processing is used as an authentication device. On the other hand, the signal transmitted from the authentication device is received, the received signal is subjected to demodulation processing or the like based on the same communication method as the modulation processing, and the data obtained as a result of this processing is The data is sent to the control unit 30.

  In this way, the signal processing unit 10 controls to image blood vessels in the living body as authentication targets, and sends the imaging results to the authentication device as authentication information D33.

(1-5) Operation and Effect According to First Embodiment In the above configuration, the blood vessel imaging device 1 captures an image of the CCD image sensor 23 out of the blood vessel projection light obtained via the inside of the finger FG. Blood vessel projection light (vertical blood vessel projection light) in a direction substantially perpendicular or perpendicular to the surface is selectively guided to the imaging surface.

  Therefore, in this blood vessel imaging device 1, the blood vessel projection light that should be originally required as most of light obtained from directions other than the direction that is substantially perpendicular or perpendicular to the imaging surface via the inside of the finger FG is used. In addition, non-vascular projection light (FIG. 4A) obtained from the finger FG without passing through the blood vessel and visible light arriving from the finger back direction (FIG. 4B) can be excluded.

  For this reason, in the blood vessel imaging device 1, noise components caused by light other than the blood vessel projection light that should be originally required can be largely removed from the blood vessel image signal S10 output from the CCD image pickup device 23. It is possible to take an image of an authentication target in the body with high image quality.

  In this case, the blood vessel imaging device 1 is a light composed of a core formed in a tubular shape with a medium having a predetermined refractive index and a grad formed so as to cover the core with a medium having a lower refractive index than the core. An imaging surface is selectively picked up by the optical fiber bundle 21 in which the fibers OF are bundled and the core incident lenses CIL1 to CILn that are provided at one end of the core and enter the vertical blood vessel projection light into the core. Transmit to.

  Therefore, in this blood vessel imaging device 1, since the vertical direction blood vessel projection light can be guided to the imaging surface without causing mutual interference, the contrast ratio of the blood vessel image as the imaging result is reduced. Can be maintained sharply, and as a result, it is possible to capture an image of the authentication target in the living body with higher image quality.

  According to the above configuration, the vertical direction blood vessel projection light out of the blood vessel projection light obtained via the inside of the finger FG is selectively guided to the image pickup surface of the CCD image pickup device 23. Since light other than blood vessel projection light, which is most of light obtained from a direction other than a direction substantially perpendicular to or perpendicular to the surface, can be excluded, noise components caused by light other than the blood vessel projection light can be eliminated. Thus, the authentication object that is inside the living body can be imaged with high image quality.

(2) Second Embodiment (2-1) Overall Configuration of Blood Vessel Imaging Device As shown in FIG. 7 in which parts corresponding to those in FIG. An imaging unit 108 is provided instead of the imaging unit 8 in the embodiment.

  The imaging unit 108 includes a CCD imaging device in which a plurality of photodiodes are arranged in a line (hereinafter referred to as a line-shaped CCD imaging device). This is different from the image pickup unit 8 having the CCD image pickup elements arranged in a lattice shape.

  The imaging unit 108 has a near-infrared light source having the same configuration as the near-infrared light source 9 (FIGS. 1 and 2), and designates near-infrared light emitted from the near-infrared light source. In addition to selectively guiding the blood vessel to be authenticated inside the FG, the vertical blood vessel projection light obtained via the finger FG is selectively guided to the line CCD image sensor. This is different from the imaging unit 8 (FIG. 2) in which the blood vessel is imaged only by imaging the blood vessel by guiding the vertical blood vessel projection light to the CCD image sensor 23 corresponding to the pixel. .

  In this blood vessel imaging device 100, a signal processing unit 110 is provided instead of the signal processing unit 10 in the first embodiment.

  The signal processing unit 110 simply irradiates the near infrared light in that it controls the irradiation pattern of the near infrared light emitted from the near infrared light source (not shown) to change every unit time. This is different from the signal processing unit 10 (FIG. 2) that has been controlled to do so. Further, in the signal processing unit 110, as a result of such control, the processing content for the blood vessel image signal S100 output as the imaging result in the imaging unit 108 is different from that in the first embodiment.

  Further, in this blood vessel imaging device 100, the finger FG placed with the finger pad placed on the concave portion 5 and the fingertip abutting against the curved tip of the concave portion 5 is set as the imaging start position, and thereafter, the direction opposite to the finger differential direction is obtained. A finger FG moving at a predetermined speed in a direction (hereinafter referred to as a reverse finger pointing direction) is imaged for a predetermined imaging period, and the finger FG fixed at the imaging start position is imaged for a predetermined imaging period. It is different from the blood vessel imaging device 1 of the first embodiment.

  In this case, the blood vessel imaging device 100 changes the irradiation pattern irradiated from the near-infrared light source to the blood vessel inside the finger FG moving at a predetermined speed in the direction opposite to the finger difference from the imaging start position. The blood vessel is imaged for a predetermined imaging period by selectively irradiating infrared light and guiding the vertical direction blood vessel projection light obtained via the inside of the finger FG to the linear CCD image sensor.

  The blood vessel imaging device 100 generates authentication information based on the blood vessel image signal S100 obtained as the imaging result, transmits the authentication information to the authentication device, and authenticates based on the authentication information in the authentication device. Only when a determination result of an authorized user is obtained as a processing result, various types of data such as data relating to electronic commerce are exchanged with the authentication apparatus.

  In this way, the blood vessel imaging device 100 images a blood vessel over a wider range than the blood vessel imaging device 1 by the amount of imaging of the moving finger FG, and according to the authentication processing result based on the authentication information generated from the imaging result. Subsequent processing is subsequently executed.

(2-2) Specific Configuration of Imaging Unit Next, a specific configuration of the imaging unit 108 will be described. The imaging unit 108 has a rectangular parallelepiped base 121 on the incident optical path incident through the aperture cover unit 7 as shown in FIG. 8 and FIG. 9 taken along the line BB ′ of FIG. The near-infrared light source 122 is provided inside the base 121 and the near-infrared light emitted from the near-infrared light source 122 is guided to the surface of the base 121 facing the opening cover portion 7. A line-shaped optical fiber bundle (hereinafter referred to as an irradiation optical fiber bundle) 123 that emits light is provided.

  In this irradiation optical fiber bundle 123, a plurality of optical fibers OF1 to OFn are arranged in a row so as to be adjacent to each other, and the row direction is arranged so as to be orthogonal to the finger pointing direction of the finger FG disposed in the recess 5. Configured.

  In this case, the irradiation optical fiber bundle 123 uses the finger FG placed so that the fingertip is applied to the concave portion 5 and the tip of the finger is in contact with the curved tip of the concave portion 5 as an imaging start position, and then the finger difference direction Attenuating near-infrared light incident from one end of the core of the corresponding optical fibers OF1 to OFn with respect to a finger FG moving at a predetermined speed in the opposite direction (hereinafter referred to as the finger pointing reverse direction). The light can be guided without causing mutual interference.

  Here, since the distance of near infrared light emitted from the core ends of the optical fibers OF1 to OFn is short, it is generally known that the depth of focus is relatively short in the optical fiber OF. ing.

  Therefore, if the depth of focus in the optical fiber OF can be adjusted to the layer in which the blood vessel inside the living body is interposed, as described above also in FIG. 4A, near-infrared light reflected on the surface of the living body, The situation of being affected by non-vascular projection light such as near-infrared light reflected at a non-intervening portion can be greatly reduced.

  Therefore, in the irradiation optical fiber bundle 123, the position of the core and the core are set so that the reach distance of the near-infrared light emitted from the core ends of the corresponding optical fibers OF1 to OFn is a layer in which the blood vessel is interposed. The transmission conditions such as the reflection path are selected.

  As a result, the imaging unit 108 selects the near-infrared light emitted from the near-infrared light source 122 for the blood vessels inherent in the finger FG disposed in the recess 5 via the irradiation optical fiber bundle 123. Light can be guided.

  On the other hand, in this imaging unit 8, a linear CCD imaging device 124 is integrally formed on the side surface of the base 121, and a blood vessel obtained via the inside of the finger FG is formed on the imaging surface of the linear CCD imaging device 124. A linear optical fiber bundle (hereinafter referred to as an imaging optical fiber bundle) 125 that guides projection light is provided.

  This imaging optical fiber bundle 125 is a finger in which optical fibers OF1 to OFn are arranged in a line corresponding to the photodiodes of the line-shaped CCD image pickup element 124 arranged in a line, and the column direction is arranged in the recess 5. They are arranged so as to be orthogonal to the finger pointing direction of FG.

  At one end of these optical fibers OF1 to OFn, hemispherical core incident lenses CIL1 to CILn that collect vertical blood vessel projection light incident through the opening cover portion 7 and enter the core are provided. .

  In this case, the imaging optical fiber bundle 125 selectively irradiates the blood vessel inside the finger FG disposed in the recess 5 from the irradiation optical fiber bundle 123, and the vertical direction blood vessel projection light obtained from the finger FG is The light is selectively guided to the imaging surface so as to be incident from the corresponding core incident lens CIL.

  In addition to such a configuration, a liquid crystal shutter 126 that switches the irradiation pattern of near-infrared light to each of the optical fibers OF1 to OFn in the illumination optical fiber bundle 123 every predetermined unit time is provided on the surface of the base in the imaging unit 108. Is provided.

  In this embodiment, the liquid crystal shutter 126 switches the irradiation pattern every unit time so that the near-infrared light is irradiated only to the optical fibers OF1, OF2,..., OFn of the optical fiber bundle 123 for illumination. Has been made.

  Therefore, in this imaging unit 108, it is possible to avoid interference between near-infrared light guided from each optical fiber OF of the illumination optical fiber bundle 123 to the blood vessel inside the finger FG. .

  In this case, since the imaging unit 108 houses the near-infrared light source 122 inside the base, the near-infrared light emitted from the near-infrared light source 122 is directly applied to the line CCD image sensor 124. It is possible to avoid incidents such as incidents.

  In this manner, the imaging unit 108 selectively guides near-infrared light to the blood vessel to be authenticated inside the finger FG and obtains a vertical blood vessel projection obtained via the finger FG inside. A blood vessel is imaged by selectively guiding light to a linear CCD image sensor.

(2-3) Specific Processing Contents of Signal Processing Unit Next, specific processing contents of the signal processing unit 110 will be described in detail with reference to FIG.

  In FIG. 10, the signal processing unit 110 is provided with a liquid crystal shutter drive control unit 135 for driving and controlling the liquid crystal shutter 126, and an image processing unit 133 instead of the image processing unit 33. This is different from the signal processing unit 10 of the first embodiment.

  As shown in FIG. 11A, the liquid crystal shutter drive control unit 135 irradiates only the portion corresponding to, for example, the optical fiber OF1 of the optical fibers OF1 to OFn in the illumination optical fiber bundle 123 with near infrared light. A mask image IM signal is generated as an irradiation pattern signal S <b> 135 and sent to the liquid crystal shutter 126. As a result, in the liquid crystal shutter 126, as shown in FIG. 11B, only the optical fiber OF1 of the illumination optical fiber bundle 123 is irradiated with near infrared light.

  Similarly, the liquid crystal shutter drive control unit 135 irradiates only the portion corresponding to the optical fiber OF2 with the irradiation pattern signal S135 for irradiating only the portion corresponding to the optical fiber OF2, and only the portion corresponding to the optical fiber OF3. Irradiating pattern signal S135 for irradiating near-infrared light only to the portion corresponding to optical fiber OFn, and sequentially generating irradiation pattern signal S135 for a predetermined unit time. The image is sent to the shutter 126.

  As a result, the liquid crystal shutter 126 sequentially irradiates the optical fibers OF2,..., OFn of the optical fiber bundle 123 of the illumination optical fiber bundle 123 sequentially with near-infrared light for a unit time. .

  In this way, the liquid crystal shutter drive control unit 135 controls the liquid crystal shutter 126 so as to switch the irradiation pattern of the near infrared light on each of the optical fibers OF1 to OFn in the illumination optical fiber bundle 123 every predetermined unit time. Has been made.

  At this time, the signal processing unit 110 performs near-red light via the light source drive control unit 31 so as to selectively irradiate blood vessels inside the finger FG moving at a predetermined speed in the direction opposite to the finger difference from the imaging start position. While driving and controlling the external light source 122, the image processing unit 133 sequentially outputs the imaging result of the vertical direction blood vessel projection light selectively guided to the imaging surface via the inside of the finger FG as the blood vessel image signal S100. As described above, the linear CCD imaging device 124 is driven and controlled via the CCD drive control unit 32.

  The image processing unit 133 temporarily stores the blood vessel image signals S100 sequentially output from the line-shaped CCD image pickup device 124 in the internal memory, and stores the blood vessel image signals S100 having a prescribed number of data in the internal memory. One blood vessel image signal having a predetermined number of lines is generated based on the signal S100.

  Then, the image processing unit 133 sequentially performs A / D conversion processing, median filter processing, and Laplacian processing on the blood vessel image signal in the same manner as in the first embodiment. The blood vessel contour is extracted, and the blood vessel image from which the blood vessel contour has been extracted is sent to the communication unit 34 as authentication information D133. The authentication information D133 is transmitted to the authentication device via the communication unit 34 under the control of the control unit 30, and is used as a criterion for determining whether or not there is a regular user in the authentication device.

  In this way, the signal processing unit 110 performs control so that the blood vessels in the living body are imaged in a wider range than the blood vessel imaging device 1, and sends the imaging result to the authentication device as authentication information D133. Has been made.

(2-4) Operation and effect according to the second embodiment In the above configuration, the blood vessel imaging device 100 selectively irradiates near-infrared light to a blood vessel located inside the finger FG. The near-infrared light obtained from the inside of the finger FG is imaged. Therefore, in this blood vessel imaging device 100, the influence of non-blood vessel projection light such as near infrared light reflected on the surface of a living body or near infrared light reflected at a portion where no blood vessel is present can be greatly reduced. The imaging can be performed while paying attention only to near-infrared light (blood vessel projection light) reflecting the blood vessel.

  In this case, the blood vessel imaging device 100 is a light composed of a core formed in a tubular shape with a medium having a predetermined refractive index and a grad formed so as to cover the core with a medium having a lower refractive index than the core. The near-infrared light irradiated from the near-infrared light source 122 is selectively irradiated to the blood vessel existing in the living body by the fiber OF.

  Therefore, in this blood vessel imaging device 1, the focal distance is easily set so that the near-infrared light is irradiated onto the blood vessel, and the near-infrared light is selectively selected with respect to the blood vessel so as to avoid the enlargement of the device itself. Can be irradiated.

  Further, in the blood vessel imaging device 100, a plurality of optical fibers OF1 to OFn are arranged in a line shape, and the irradiation pattern of near infrared light on these optical fibers OF1 to OFn is switched every predetermined unit time.

  Therefore, in this blood vessel imaging device 1, the influence of non-blood vessel projection light such as near-infrared light reflected at a portion where no blood vessel is present is greatly reduced, and light is guided from the optical fibers OF1 to OFn to the blood vessel. Since interference between near-infrared light can be avoided in advance, a blood vessel to be authenticated can be imaged in a wide range and with high accuracy.

  Furthermore, in this blood vessel imaging device 100, the near-infrared light is selectively irradiated to the blood vessel intervening inside the finger FG, and the vertical direction blood vessel projection out of the near-infrared light obtained from the inside of the finger FG. The blood vessel is imaged so that light is selectively guided to the imaging surface.

  Therefore, in this blood vessel imaging device 100, the influence of non-blood vessel projection light such as near infrared light reflected on the surface of the living body both at the time of irradiation and at the time of imaging, or near infrared light reflected at a portion where a blood vessel does not intervene. Since it can be greatly reduced, noise components caused by light other than the blood vessel projection light that should be originally required can be greatly removed, and thus the authentication target possessed inside the living body can be imaged with high image quality. it can.

  According to the above configuration, the near-infrared light obtained from the inside of the finger FG is imaged by selectively irradiating the blood vessel interposed inside the finger FG with near-infrared light. Since the influence of non-blood vessel projection light such as near infrared light reflected on the surface of a living body or near infrared light reflected at a site where a blood vessel does not intervene can be greatly reduced, It is possible to take an image while paying attention only to infrared light (blood vessel projection light), and thus it is possible to take an image of an authentication target that is inside the living body with high image quality.

(3) Other Embodiments In the above-described embodiments, the blood vessel imaging device irradiates near infrared light from the finger pad side of the finger FG, and passes through the finger FG inward, so that from the finger pad side. Although the case where the blood vessel imaging devices 1 and 100 for imaging the obtained blood vessel projection light are applied has been described, the present invention is not limited to this, and near infrared light is irradiated from the finger back side of the finger FG. You may make it apply the blood-vessel imaging device which images the blood-vessel projection light obtained from the finger pad side via the inside of the finger FG. Even when this blood vessel imaging device is applied, the same effects as those of the above-described embodiment can be obtained. Although the blood vessel imaging devices 1 and 100 are configured as shown in FIGS. 1, 2, and 7, various other configurations may be employed.

  Further, in the above-described embodiment, the case where a blood vessel is imaged as an authentication target interposed inside the living body has been described. However, the present invention is not limited to this, and for example, the surface of the dermis layer (of the dermis layer Other than the intervening inside of the living body, such as an uneven distribution pattern at the boundary with the skin layer, can be used as an authentication target. In this case, the case where the finger FG is applied as the imaging region to be authenticated has been described. However, the present invention is not limited to this, and other than the finger FG may be applied.

  Furthermore, in the above-described embodiment, as the irradiation unit that irradiates the living body with imaging light, in the first embodiment, near-infrared light that irradiates near-infrared light from an irradiation direction id that forms an acute angle α with the imaging surface F1. Although the case where the light source 9 is applied and the near-infrared light source 122 that irradiates near-infrared light from the direction orthogonal to the imaging surface F1 is applied in the second embodiment, the present invention has been described. In addition to the near-infrared light source 9 or the near-infrared light source 122 that irradiates from the side facing the imaging surface (finger belly side) of the living body surface, the side opposite to the facing side (finger You may make it apply the near-infrared light source irradiated from a back side.

  Further, in the above-described embodiment, out of the imaging light obtained via the inside of the living body, the guiding light that selectively guides the imaging light that is substantially perpendicular to or perpendicular to the imaging surface to the imaging surface. In the first embodiment, an optical fiber bundle 21 in which the optical means OF1 to OFn having the same number as the number of photodiodes corresponding to the pixels are bundled so as to have the same circular cross section, and the optical fiber OF1. To the core incident lenses CIL1 to CILn provided at one end of the optical fiber OFn and the condensing lens 22 that collects the light emitted from the other end of the optical fibers OF1 to OFn on the imaging surface. However, the present invention is not limited to this, and the condensing lens 22 may be omitted.

  In this case, four optical fibers OF1 to OFn having the same number as the number of photodiodes corresponding to the pixels are used in place of the optical fiber bundle 21 as shown in FIG. By providing the optical fiber bundle 140 bundled in the shape of a truncated pyramid, light emitted from the optical fibers OF1 to OFn can be directly guided to the imaging surface without being collected by the condenser lens 22. As shown in FIG. 13, instead of the optical fiber bundle 21, an optical fiber bundle 150 having a length d shorter than the optical fibers OF1 to OFn in the optical fiber bundle 140 is provided, and the optical fibers OF1 to OFn are provided. It is also possible to guide the light emitted from the light directly to the imaging surface without condensing it by the condenser lens 22. In this way, the entire blood vessel imaging device can be reduced in size.

  Further, in the above-described embodiment, out of the imaging light obtained via the inside of the living body, the guiding light that selectively guides the imaging light that is substantially perpendicular to or perpendicular to the imaging surface to the imaging surface. In the second embodiment, the optical unit is described as using the imaging optical fiber bundle 125 in which a plurality of optical fibers OF1 to OFn are arranged in a row so as to be adjacent to each other. However, the imaging optical fiber bundles arranged in a plurality of rows may be used. In short, imaging optical fiber bundles arranged in a line can be used.

  Further, in the above-described embodiment, as the irradiation pattern switching means for switching the irradiation pattern of the imaging light from the light source with respect to each light transmission member, only the optical fibers OF1, OF2,. Although the case where the liquid crystal shutter 126 that switches the irradiation pattern every unit time so as to be irradiated with infrared light is used has been described, the present invention is not limited to this, for example, the optical fibers OF1 and OF2, OF3 and OF4, ......, two optical fibers OF adjacent to each other such as OFn-1 and OFn may be switched as a unit, or switched every three like optical fibers OF1, OF5, OF9,. The point is that the irradiation pattern for irradiating a predetermined number of optical fibers as independent units It can be switched every time.

  The present invention can be used when authenticating a blood vessel characteristic of a living body as an authentication target.

It is a basic diagram which shows the external appearance structure of the blood vessel imaging device by 1st Embodiment. It is a basic diagram which shows the internal structure of the blood vessel imaging device by 1st Embodiment. It is a basic diagram with which it uses for description of the irradiation direction of near-infrared light. It is an approximate line figure used for explanation of irradiation of light other than blood vessel projection light. It is a basic diagram which shows the structure (1) of an imaging part. It is a block diagram which shows the structure (1) of a signal processing part. It is a basic diagram which shows the structure of the blood vessel imaging device by 2nd Embodiment. It is a basic diagram which shows the structure (2-1) of an imaging part. It is a basic diagram which shows the structure (2-2) of an imaging part. It is a block diagram which shows the structure (2) of a signal processing part. It is a basic diagram with which it uses for description of irradiation of near-infrared light. It is a basic diagram which shows the structure (1) of the imaging part by other embodiment. It is a basic diagram which shows the structure (2) of the imaging part by other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,100 ... Blood vessel imaging device, 2 ... Housing, 3 ... Operation part, 4 ... Display part, 5 ... Recessed part, 6 ... Imaging opening part, 7 ... Opening cover part, 8, 108 ... Imaging unit 9, 122 ... Near infrared light source 10, 110 ... Signal processing unit, 21 ... Optical fiber bundle, 22 ... Condensing lens, 23, 124 ... CCD imaging device, 30 ... Control , 31... Light source drive controller, 32... CCD drive controller, 33, 133... Image processor, 34 .. communication unit, 121. Line CCD imaging device, 125 ... Optical fiber bundle for imaging, 126 ... Liquid crystal shutter, 135 ... Liquid crystal shutter drive controller, FG ... Finger, OF1-OFn ... Optical fiber, CIL1-CILn ... Core incidence Lens, S10, S100 ... Blood vessel image signal, S 1 ...... light source drive control signal, S32 ...... CCD image sensor drive signal, S135 ...... irradiation pattern signal, D33, D133 ...... authentication information, IM ...... mask image.

Claims (6)

In an imaging device that images an authentication target that is inside the living body,
An irradiation means for irradiating the living body with imaging light;
An image sensor that irradiates the living body from the irradiation means and captures the imaging light obtained via the inside of the living body;
A light guide means for selectively guiding the imaging light, which is substantially perpendicular to or perpendicular to the imaging surface, of the imaging light obtained via the inside of the living body to the imaging surface; An imaging device characterized by that. The irradiation means is
The imaging apparatus according to claim 1, wherein the imaging light is irradiated from an irradiation direction that forms an acute angle with the imaging surface of the surface of the living body facing the imaging surface. The light guiding means is
A first medium provided on the imaging surface and formed of a dielectric having a predetermined refractive index, and the first medium covered with a dielectric having a lower refractive index than the first medium. An optical transmission member comprising the second medium formed,
The imaging apparatus according to claim 1, further comprising an incident member configured to enter the first medium with the imaging light obtained via the inside of the living body. The irradiation means is
The imaging apparatus according to claim 1, wherein the imaging light is selectively irradiated to the authentication target from a side of the surface of the living body facing the imaging surface. The irradiation means is
A light source that emits the imaging light;
A first medium formed in a tubular shape with a dielectric having a predetermined refractive index, and a second medium formed so as to cover the first medium with a dielectric having a lower refractive index than that of the first medium And an optical transmission member arranged to transmit the imaging light emitted from the light source to the authentication target from a side of the surface of the living body facing the imaging surface. The imaging apparatus according to 1. The optical transmission members are arranged in a line,
The imaging apparatus according to claim 4, further comprising an irradiation pattern switching unit that switches an irradiation pattern of the imaging light from the light source to each of the light transmission members.

Images