JP2006288872A - Blood vessel image input apparatus, blood vessel image constituting method, and personal authentication system using the apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To raise an authentication rate by providing a miniaturized low-cost apparatus for more stably acquiring high-definition images. <P>SOLUTION: A blood vessel image input apparatus includes: LED light sourses; refractive-index distributed lens arrays; and solid-state imaging elements. The apparatus includes: LEDs 1a, 1b; the three strings of refractive-index distributed lens arrays 2a-2c; and the three linear solid-state imaging elements 3a-3c. The LEDs 1a, 1b radiates near infrared light which transmits the inner part of a finger FG. The refractive-index distributed lens arrays 2a-2c are arranged on an optical path between the finger FG and the linear solid-state imaging elements 3a-3c, so as to have a focal point at a different position inside the finger FG. The blood vessel images of venous vessels which are three-dimensionally distributed inside the finger FG are formed in the linear solid-state imaging elements 3a-3c via the three strings of refractive-index distributed lens arrays 2a-2c. The linear solid-state imaging elements 3a-3c acquire the formed blood vessel images. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a blood vessel image input device, a blood vessel image construction method, and a personal authentication system using the blood vessel image input device that receive a finger blood vessel image illuminated by light emitted from an illuminating means and illuminated by light transmitted through a finger. . In particular, the present invention relates to a blood vessel that receives an image of a finger blood vessel that is irradiated from illumination means and illuminated by light transmitted through the finger by moving the position of the finger and the solid-state image sensor relative to each other. The present invention relates to an image input device, a blood vessel image construction method, and a personal authentication system using the same.

  In recent years, as economic activities such as electronic commerce spread due to remarkable progress in information technology, the necessity of digitizing personal authentication for the purpose of preventing unauthorized use of information is also increasing. Therefore, as a personal authentication method that does not require a mobile phone like a key, is highly convenient, and is less likely to be illegally exercised due to loss or theft, a part of the body of a person such as a fingerprint, iris, or blood vessel pattern is used as a key. Biometric authentication is attracting attention. In particular, the authentication method using a blood vessel pattern has little psychological resistance because it is not associated with criminal investigations like fingerprints or irradiates light directly on eyes like irises, and is easily observed. There is an advantage that forgery is difficult because of the characteristics inside the living body, not the surface of the living body.

  Such a blood vessel pattern inside a living body is obtained by illuminating a target site with a near-infrared light source and photographing it with an imaging system such as a camera or an image sensor sensitive to near-infrared light. Hemoglobin in blood absorbs near-infrared light well, so light is absorbed in blood vessels and appears darker than surrounding tissues. The pattern due to the difference in brightness becomes a blood vessel pattern.

  As a blood vessel image input apparatus using a blood vessel pattern, there are an apparatus using a back vein image of the hand described in Patent Document 1 and an apparatus using a palm vein image described in Patent Document 2. In these blood vessel image input devices, the image pickup means is a two-dimensional image pickup device for acquiring a large area image such as the back of the hand or the palm, and the image pickup object becomes larger than the image acquisition by the imaging optical system. There was a problem that the whole became quite large.

  In order to avoid such an increase in the size of the imaging device, Patent Document 3 or Patent Document 4 describes a blood vessel image input device that inputs a blood vessel image of a finger of a hand.

  The finger vein image input device described in Patent Document 4 will be described with reference to FIG.

The blood vessel image input apparatus shown in FIG. 11 makes the near-infrared light emitted from the near-infrared light source 114 in the light source unit 104 provided in the housing 100 through the light source opening 106 enter the finger FG, and the imaging aperture A blood vessel image is taken by using the light beam transmitted through the finger by the camera unit 112 via the unit 110 (108 in the figure is a guide groove, 118 is a button switch, and 116 is a light shielding plate, respectively).
JP-A-10-295664 JP 2004-062826 A JP 7-21373 A JP 2004-265269 A

  The imaging means in the configuration of FIG. 11 is a two-dimensional imaging device, which is not explicitly specified in Patent Document 4, and in order to image from the tip of the finger to the base of the finger, imaging corresponding to the length of the finger An area is required. This imaging region is shown in a simplified manner in FIG. As can be seen from FIG. 12, a fingerprint image sensor 120 composed of a two-dimensional image sensor and a light beam transmitted through the inside of the finger are imaged on the fingerprint image sensor 120 as a blood vessel image reflecting the vein pattern VP of the finger FG. The camera unit 112 having the lens optical system 121 as an image optical system needs to be installed apart from the finger FG in order to secure the imaging region 10 of the entire finger. In general, a two-dimensional image sensor is required to be as small as possible from the viewpoint of cost, and the reduction ratio of the lens optical system tends to be large. As a result, the distance between the finger and the image sensor tends to be large. It is also necessary to increase the lens diameter and wide angle of view.

  Therefore, in the above-described apparatus form, a camera having a reduction optical system is used for imaging a blood vessel pattern, so that a fixed focal length is necessary, and the camera itself has a thickness such as a lens (the lens is also a considerable amount). Therefore, the housing of the imaging unit tends to be large. There is also a problem that the degree of freedom for a small design is low.

  Further, since the blood vessels of the finger exist three-dimensionally inside the finger unlike the fingerprint, the relative position of the blood vessel with respect to the lens differs depending on the location. Further, the blood vessel position fluctuates with respect to the lens due to the vertical movement of the finger during photographing. When acquiring such an image, it is necessary to make the depth of field of the optical system as deep as possible. If the depth of field is increased, the optical length becomes longer, which is in conflict with the problem of miniaturization. The method of using a dedicated wide-angle lens increases the cost of designing and manufacturing, which conflicts with the problem of cost reduction. Therefore, Patent Document 4 discloses a folding structure with a mirror for miniaturization, but uses a two-dimensional image sensor as the image sensor and optically displays the disclosed drawings. The configuration is not a direction suitable for folding, and it cannot be said that the optical examination is sufficiently performed. Although proposals have been made in consideration of downsizing of the apparatus in this way, downsizing with the above configuration is insufficient.

  The present invention has been made in view of such conventional circumstances, and aims to reduce the size and cost, and to acquire a more stable and fine image and improve the authentication rate. .

  In order to achieve the above object, a blood vessel image input device according to the present invention is distributed in a three-dimensional manner inside a finger by illumination means for irradiating light passing through the inside of the finger and light emitted by the illumination means. In a blood vessel image input device having imaging means for acquiring a blood vessel image of a venous blood vessel and imaging means for forming a blood vessel image of the finger on the imaging means, the imaging means includes the finger and the imaging means. A refractive index distribution type lens array disposed on the optical path between them, and forming a blood vessel image of the finger on the imaging means via the refractive index distribution type lens array.

  In the present invention, the imaging unit has a plurality of gradient index lens arrays arranged on an optical path between the finger and the imaging unit, and the imaging unit includes the plurality of gradient index lenses. You may have several image pick-up elements according to an array. The plurality of gradient index lens arrays may have focal points at different positions inside the finger. The imaging means forms a blood vessel image of a venous blood vessel distributed three-dimensionally inside the finger by the plurality of gradient index lens arrays, and the imaging means forms the imaged blood vessel image May be obtained. The imaging unit may further include a reflection unit disposed on an optical path between the finger and the imaging unit. You may further have an image acquisition means to acquire the surface image of the finger.

  The blood vessel image input device according to the present invention acquires a blood vessel image of a venous blood vessel that is three-dimensionally distributed inside the finger by illumination means that emits light that passes through the inside of the finger, and light that is emitted by the illumination means. In a blood vessel image input apparatus having an imaging means for performing imaging and an imaging means for forming an image of the finger on the imaging means, a surface of a region where the finger contacts the installation member A surface image acquisition unit that acquires an image, wherein the imaging unit acquires a blood vessel image of a finger region other than the region.

  In the present invention, the installation member includes a light transmission member that transmits light irradiated by the illumination unit, and the surface image acquisition unit is generated in an area where the finger contacts the light transmission member due to the light. An optical fingerprint image may be acquired. The imaging unit may include a plurality of gradient index lens arrays, and the imaging unit may include a plurality of imaging units corresponding to the plurality of gradient index lens arrays. The gradient index lens array may have focal points at different positions inside the finger. The imaging means forms a blood vessel image of a venous blood vessel that is distributed three-dimensionally inside the finger by the plurality of gradient index lens arrays, and the imaging means displays the imaged blood vessel image. You may get it. The imaging unit may further include a reflection unit disposed on an optical path between the finger and the imaging unit.

  In the present invention, the scanning amount of the finger is detected based on at least one of a plurality of image signals forming a surface image acquired by the image acquisition unit and a plurality of image signals forming a blood vessel image acquired by the imaging unit. And a means for forming a blood vessel image or a surface image of the entire finger according to the detected scanning amount of the finger.

  The blood vessel image construction method according to the present invention is characterized by acquiring a plurality of partial blood vessel images focused on different positions in a finger, and reconstructing the entire blood vessel image from the acquired plurality of partial blood vessel images. . In the present invention, the entire blood vessel image may be reconstructed using a series of partial blood vessel images.

  The personal authentication system according to the present invention includes any one of the above-described blood vessel image input devices, a blood vessel image registration means for previously registering a blood vessel image of the finger read by the blood vessel image input device as identification information of a subject, and the blood vessels A blood vessel image collating unit that collates whether or not the finger blood vessel image read by the image input device matches the registered image of the blood vessel image registration unit, and outputs the collation result as a personal authentication signal; It is characterized by that.

  In the present invention, surface image registration means for registering in advance the surface image of the finger read by the blood vessel image input device as subject identification information, the surface image of the finger read by the blood vessel image input device, and the It may further comprise surface image collating means for collating whether or not the registered image of the surface image registering means matches and outputting the collation result as a personal authentication signal.

  According to the present invention, a blood vessel image input device, a blood vessel image construction method, and a personal authentication system using the same, which are smaller than before, obtain a stable and fine image, and have an improved authentication rate, are provided at low cost. be able to.

  Hereinafter, embodiments of a blood vessel image input device, a blood vessel image construction method, and a personal authentication system using these according to the present invention will be described with reference to the drawings.

  Finger veins are distributed three-dimensionally inside the finger. In the sweep type (finger scanning type) blood vessel image input device, the movement of the finger becomes unstable. For this reason, the focus of the vein tends to shift. Vein pattern photography is particularly problematic because it is basically contactless. As a countermeasure, if the depth of field is obtained with a lens and an image without blur is obtained in any case, the optical path length becomes long and the whole becomes large. Designing a dedicated lens to reduce the size increases the cost.

  Therefore, in the blood vessel image input apparatus according to the present embodiment, a general-purpose inexpensive gradient index lens array is used as the imaging optical system. By using a gradient index lens array having an appropriate depth of field, the size can be reduced as compared with the case of using a general lens optical system. In other words, as shown in the following embodiments, the refractive index distribution array is a one-dimensional optical system in which a plurality of refractive index distribution type rod lenses are arranged in a line to form a plate shape, and further, since it is an equal-magnification optical system, it is a focal point. Since the distance can be shortened, the degree of freedom in design, such as the arrangement in the housing, is high, and it is easy to downsize. The blood vessel used for personal authentication mainly uses a subcutaneous vein pattern with a diameter of about 100 μm or more, and this blood vessel pattern is captured as an image in an optical scatterer called a finger (has a blur in the first place). A rate distribution lens array can be used. However, when an image of a blood vessel is taken using a general-purpose gradient index lens array, there is a problem that the image quality tends to be lowered because the depth of field is generally shallow. In particular, since the blood vessel in the finger is in close contact with a plane like a fingerprint and the focal position is not fixed, the focal position is changed by the movement of the finger, and it is difficult to photograph a blood vessel pattern having a three-dimensional distribution.

In view of this point, particularly in a sweep type (finger scanning type) blood vessel image input apparatus, a plurality of refractive index distribution type lens arrays having different focal positions are used as the refractive index distribution type lens array to be used. In addition, a plurality of line sensors are used as sensors constituting imaging means corresponding to a plurality of gradient index lens arrays. Furthermore, in the image reconstruction, an image in which one of the images obtained by the plurality of line sensors is in focus is used. In addition, the entire finger is covered with a plurality of partial images, and images in focus are synthesized. As described above, general-purpose low-cost parts are applied to the imaging optical system and the imaging means.
[First Embodiment]
The configuration of the blood vessel image input apparatus according to the first embodiment of the present invention is shown in FIGS. FIG. 1 is a schematic diagram showing the overall configuration of the apparatus, and FIG. 2 is a perspective view showing the configuration of the basic part of the apparatus configuration of FIG.

  The blood vessel image input device shown in FIGS. 1 and 2 has a light source (illuminating means) that irradiates near-infrared light that passes through the inside of the finger FG and an image sensor that acquires a blood vessel image reflecting the vein pattern VP of the finger FG. And an optical imaging system that forms a blood vessel image of the finger FG on the imaging device. In this configuration, the first joint and the second joint of the finger FG are scanned by scanning the finger FG in a certain direction (horizontal direction indicated by an arrow P in the figure) along the guide plate 10 that transmits near-infrared light. A blood vessel image of the subcutaneous vein pattern VP existing between the two is taken.

  Near-infrared light is generally not easily absorbed by living bodies other than blood vessels, and it is possible to use a wavelength of 700 nm to 1000 nm that is easy to obtain blood vessel contrast. In this embodiment, a wavelength of 950 nm is used. In this embodiment, LEDs (Light Emitting Diodes) 1a and 1b are provided as light sources that emit near-infrared light having this wavelength. As shown in the figure, the LEDs 1a and 1b are arranged at positions before and after the finger FG so as to irradiate the finger FG from its abdominal surface. Near-infrared light from these LEDs 1a and 1b is applied to the finger FG, and the veins inside the finger are illuminated by the near-infrared light (scattered diffused light) scattered and transmitted through the finger (arrow Q in the figure). Shows scattered transmitted light inside the finger). Moreover, you may arrange | position LED1a and 1b which comprise a light source so that it may irradiate from the side surface or the back surface of the finger FG according to the product form of the blood vessel image input apparatus.

  As the imaging optical system, in this embodiment, three rows of linear gradient index lens arrays 2a, 2b, and 2c are provided. The three rows of linear gradient index lens arrays 2a, 2b, and 2c are arranged so that the focal points in the fingers are different in the height direction (broken lines in the figure indicate the positions h1, h2 and h3 are shown). Each of the linear gradient index lens arrays 2a, 2b, and 2c has the same focal point and depth of field. When the depth of field is 1 mm, an image can be taken over a range of about 3 mm by three rows of linear gradient index lens arrays 2a, 2b, and 2c. As the gradient index lens array used in the present embodiment, for example, a SELFOC lens array (“SLA (registered trademark)”) is applicable.

  An image sensor is provided in an image forming portion by the image forming optical system. As this imaging device, in this embodiment, three rows of line-shaped solid-state imaging devices 3a, 3b, and 3c are provided. The three rows of linear solid-state imaging devices 3a, 3b, and 3c are arranged in accordance with the three rows of linear gradient index lens arrays 2a, 2b, and 2c, respectively. The solid-state imaging devices 3a, 3b, and 3c are preferably in the form of strips in consideration of the scanning range and imaging range of the finger FG and further considering the arrangement of the imaging optical system. In the present embodiment, a strip-like form composed of a plurality of lines, that is, a line shape composed of a plurality of lines is used.

  By these three rows of line-shaped solid-state imaging devices 3a, 3b, and 3c, a part of finger vein images (trifocal images) at different focal positions h1, h2, and h3 inside the finger can be obtained. In the present embodiment, while scanning the finger FG, the three-focus image is used as one partial image set, a plurality of temporally continuous partial image sets are acquired, and blood is obtained using these acquired partial image sets. The vein pattern VP due to the flow is reconstructed as an entire image.

  The finger FG can scan in a direction perpendicular to the main scanning direction (line direction) of the solid-state imaging devices 3a, 3b, and 3c. By scanning the finger FG in the main scanning direction, the vein pattern image inside the line-shaped finger can be acquired. In addition, in this embodiment, the three rows of solid-state imaging devices 3a, 3b, and 3c scan in the order of the solid-state imaging devices 3a, 3b, and 3c. Thereby, in the solid-state imaging devices 3a, 3b, and 3c, the same area is sequentially overlapped and photographed one after another according to scanning. When the scanning direction of the finger FG is opposite to the direction shown in FIGS. 1 and 2, the scanning may be performed in the order of the solid-state imaging devices 3c, 3b, and 3a.

  Next, an image reading method when reconstructing the entire image from the partial image set of the vein pattern VP acquired by the solid-state imaging devices 3a, 3b, and 3c will be described with reference to FIG. The processing procedure of the image reading method shown in FIG. 3 is set in advance as a processing program executed by a processing unit (not shown) such as an image processing unit connected to the output side of the solid-state imaging devices 3a, 3b, and 3c, for example. Is done.

  First, in step A, three frames of images at the three focal positions h1 to h3 are captured by the solid-state imaging devices 3a, 3b, and 3c. In this case, three images are obtained per frame in accordance with the arrangement of the solid-state imaging devices 3a, 3b, and 3c. In the example of FIG. 3, the images IM11, IM21, IM31 of the first frame, the images IM12, IM22, IM32 of the first frame, the images IM13, IM23, IM33 of the third frame are respectively obtained by the solid-state imaging devices 3a, 3b, 3c. can get.

  Next, in step B, consecutive three frame images at the three focal positions h1 to h3 are classified for each focal point. In this case, images of three frames per focus are obtained, and the three-frame images IM11 to IM13, IM21 to IM23, and IM31 to M33 classified for each focus correspond to the entire scanning range, respectively. ing.

  In this case, as described above, the finger FG fluctuates up and down (the arrow R in FIG. 1 indicates the shake accompanying the scanning of the finger FG), or the vein pattern (blood vessel pattern) VP is distributed three-dimensionally. In each frame of the images at the three focal points, there is a possibility that an image out of focus (an image with blur) may be captured.

  Therefore, in step C, a composite image is generated by adopting only the frame in focus from among the three frame images IM11 to IM13, IM21 to IM23, and IM31 to M33 classified for each focus. For example, it is assumed that the images of the solid-state imaging devices 3a and 3b are in focus in the first and second frames, and that the image of the solid-state imaging device 3c is in focus in the third frame. In this case, the images IM11 and IM22 of the solid-state image pickup devices 3a and 3b are adopted in the first frame and the second frame, and the image IM33 of the solid-state image pickup device 3c is adopted in the third frame to generate a combined image, and the entire vein A blood vessel pattern image showing the pattern VP is reconstructed. Thereby, a clear image without blur can be reconstructed.

  The image at each focal point is acquired under a driving condition set in advance so that the frames forming the image of the entire scanning range overlap each other (see the example in the figure), and the overlap information of each frame is used. By doing so, it is possible to reconstruct the entire image by superimposing the strip images of each frame. Therefore, in the present embodiment, means for detecting the finger scanning amount (scanning speed) is not necessarily required. However, in order to measure a more accurate scanning amount, a means for detecting the scanning amount of the finger may be provided. As this means, for example, a roller-like rotation mechanism may be provided, and the scanning amount (scanning speed) of the finger may be acquired from the rotation mechanism by scanning along this.

  Therefore, according to the present embodiment, the following effects can be obtained.

  In general, the gradient index lens array cannot increase the depth of field, and its application is limited. However, by adopting the configuration of this embodiment, the general-purpose and low-cost used in general scanners and the like. A wide focal range can be imaged using the linear gradient index lens array. That is, even if the finger FG may slightly swing up and down during the operation of the finger FG, if the focus is in any of the three rows of linear gradient index lens arrays 2a, 2b and 2c, You can get no image.

  In addition, the venous blood vessels are three-dimensionally distributed in the finger. However, according to the configuration of the present embodiment, any one of the three-row linear gradient index lens array is focused on these venous blood vessels. If so, an image without blur can be acquired. Even if it is a three-dimensional distribution, the venous blood vessel that is about to be seen is distributed along the skin, so that a focal range of about 3 mm is sufficient. In addition, since the blood vessel image has a blood vessel pattern that is not as fine as a fingerprint, resolution as high as that of a fingerprint is not required, and such an optical system is sufficient.

  Furthermore, as the three sets of images having different focal points at the same time can be acquired in accordance with the scanning of the finger FG, temporally continuous image groups can be acquired, and the entire image of the finger blood vessel pattern is reconstructed using the optimal images from these image groups. be able to.

  In the present embodiment, the three-row linear gradient index lens array is used, but the number of columns is not limited to this, and may be three or more, for example. Even if the depth of field is as small as 0.5 mm, the same depth can be taken with 6 rows. The one with 0.5 mm is more general, and the cost can be reduced even if six rows are used. In addition, since the strip sensor can be manufactured at low cost due to mass production effects, increasing the number of rows to some extent does not lead to cost increase, and optimal design can be performed from the viewpoint of miniaturization and cost reduction. .

In this embodiment, the sweep-type blood vessel image input device that scans the finger FG is used. However, a scanner type that scans a movable module in which a gradient index lens array and an image sensor are integrated may be used. This also has the same effect on the movement of the finger FG during scanning. When the vein pattern is imaged with infrared light, the near infrared light is irradiated on the finger FG, and the vein inside the finger is illuminated by the near infrared light (scattered diffused light) scattered and transmitted through the finger. The light source in the form of irradiation from the side surface or the back surface of the finger FG does not need to be integrated with this module (in a scanner reading a general document, it is integrated with the light source and the movable module). As a result, the movable module can be further reduced in size. Furthermore, since the entire image can be reconstructed by synchronizing the operation of the movable module and the image capturing operation, it is not necessary to reconstruct the entire image using the acquired strip-shaped image.
[Second Embodiment]
FIG. 4 shows the configuration of a blood vessel image input apparatus according to the second embodiment of the present invention.

  In the blood vessel image input apparatus shown in FIG. 4, two rows of linear gradient index lens arrays 2a and 2b are arranged as an imaging optical system so that the focal points in each finger are different in the height direction ( (The broken lines in the figure indicate the positions h1 and h2 of the respective focal points). Further, reflecting mirrors 4a and 4b are provided between the respective linear gradient index lens arrays 2a and 2b and the finger FG, and between the linear solid-state imaging devices 3a and 3b and the finger FG via the reflecting mirror 4. The optical path is bent 90 degrees. The LED 1 serving as a near-infrared light source is installed between the reflecting mirrors 4a and 4b and irradiates the finger FG from its ventral side. With this configuration, further miniaturization can be achieved.

  Each of the linear gradient index lens arrays 2a and 2b has the same focal point and depth of field. When the depth of field is 1 mm, an image can be taken over a range of about 2 mm by the two rows of linear gradient index lens arrays 2a and 2b. Since the blood vessel pattern is not required to have a very fine resolution, an image that can sufficiently withstand the authentication can be obtained in a range wider than the theoretical 2 mm, but four rows can be arranged in two stages.

  An image sensor is provided in an image forming portion by the image forming optical system. In this embodiment, two rows of linear solid-state image sensors 3a and 3b are provided as the image sensors. The two rows of linear solid-state imaging devices 3a and 3b are respectively arranged in accordance with the two rows of linear gradient index lens arrays 2a and 2b. The solid-state imaging devices 3a and 3b are preferably in the form of strips in consideration of the scanning range and imaging range of the finger FG and further considering the arrangement of the imaging optical system. In the present embodiment, a strip-like form composed of a plurality of lines, that is, a line shape composed of a plurality of lines is used.

  By these two rows of linear solid-state imaging devices 3a and 3b, a part of finger vein images (bifocal images) at different focal positions h1 and h2 inside the finger can be obtained. In the present embodiment, while scanning the finger FG, a plurality of temporally continuous partial image sets are acquired using this bifocal image as one partial image set, and blood is obtained using these acquired partial image sets. The vein pattern VP due to the flow is reconstructed as an entire image.

The finger FG can scan in a direction perpendicular to the main scanning direction (line direction) of the solid-state imaging devices 3a and 3b. By scanning the finger FG in the main scanning direction, the vein pattern image inside the line-shaped finger can be acquired. In the present embodiment, the two rows of solid-state imaging devices 3a and 3b scan in the order of the solid-state imaging devices 3a and 3b. Thereby, in the solid-state imaging devices 3a and 3b, the same area is sequentially overlapped and photographed sequentially in accordance with the scanning. When the scanning direction of the finger FG is opposite to the direction shown in FIG. 4, the scanning may be performed in the order of the solid-state imaging devices 3b and 3a.
[Third Embodiment]
A configuration of a blood vessel image input apparatus according to the second embodiment of the present invention is shown in FIG. In this embodiment, in addition to the blood vessel image, a fingerprint image is further acquired to improve the authentication accuracy.

  The blood vessel image input apparatus shown in FIG. 5 includes a light source (illuminating means) that emits near-infrared light that passes through the inside of the finger FG, an image sensor that acquires a blood vessel image that reflects the vein pattern VP of the finger FG, An optical imaging system that forms an FG blood vessel image on an image sensor. In this configuration, the first joint and the second joint of the finger FG are scanned by scanning the finger FG in a certain direction (horizontal direction indicated by an arrow P in the figure) along the guide plate 10 that transmits near-infrared light. A blood vessel image of the subcutaneous vein pattern VP existing between the two is taken.

  Near-infrared light is generally not easily absorbed by living bodies other than blood vessels, and it is possible to use a wavelength of 700 nm to 1000 nm that is easy to obtain blood vessel contrast. In this embodiment, a wavelength of 950 nm is used. In this embodiment, an LED 1 is provided as a light source that emits near-infrared light having this wavelength. The near-infrared light from the LED 1 is applied to the finger FG, and the vein in the finger is illuminated by the near-infrared light (scattered diffused light) scattered and transmitted inside the finger (the arrow Q in the figure indicates the finger). Shows scattered light inside.) Moreover, you may arrange | position LED1 which comprises a light source so that it may irradiate from the side surface or back surface of the finger FG according to the product form of the blood vessel image input device.

  As the imaging optical system, the same three-row linear gradient index lens arrays 2a, 2b, and 2c as in the first embodiment are arranged so that the focal points in the fingers are different in the height direction.

  Three rows of linear solid-state imaging devices 3a, 3b, and 3c are arranged in the imaging portion by the imaging optical system in accordance with each of the linear gradient index lens arrays 2a, 2b, and 2c. These solid-state image pickup devices 3a, 3b, and 3c are designed to reduce costs by using strip-shaped solid-state image pickup devices of several lines.

  In addition, in order to acquire a fingerprint image of the first joint portion of the finger FG, the fingerprint solid-state imaging device 5 is arranged. The solid-state image sensor 5 for fingerprints uses a line-type close contact optical image sensor, so that a reduction optical system is not required, and a miniaturization design is facilitated. If a pressure-type or capacitive-type image sensor is used for obtaining a fingerprint image, a light source for fingerprints is not necessary, the light source design can be specialized for the vein pattern side, and it is preferable because the size can be reduced.

  In this embodiment, the guide plate 10 is a silicon thin plate having a thickness of 100 μm. Since silicon transmits near-infrared light and does not transmit visible light, unnecessary external light can be prevented from entering the apparatus.

  The finger FG is scanned in a certain direction (horizontal direction indicated by an arrow P in the figure) along the guide plate 10 that transmits near-infrared light. A fingerprint image of the fingertip part in close contact with the guide plate 4 is acquired according to the finger scanning. This is a series of strip-like images. Target partial images of a plurality of lines, and acquire the partial images so as to overlap each other. This can be realized by making the scanning speed of one frame of the solid-state imaging devices 3a, 3b, and 3c sufficiently higher than the assumed scanning speed of the finger FG. The whole fingerprint image is obtained by joining the partial images having these overlapping portions with reference to the overlapping portions.

  At the same time, the subcutaneous vein existing in the portion between the first joint and the second joint of the finger FG is photographed by the three rows of solid-state imaging devices 3a, 3b, and 3c. At this time, the fingerprint collection portion of the finger FG is in contact with the guide plate 10, and the vein pattern of the portion not in contact with the guide plate 10 is photographed. This is because the pressure of the vein is almost zero, and when the contact is made with the pressure on the guide plate 10, the vein collapses, the blood inside retreats to the surrounding capillaries, and the blood vessel pattern as an image disappears. Because. In order to avoid this problem, it is preferable that the fingertip is brought into contact with the guide plate 10 and the finger FG is scanned. Further, in order to stabilize the movement of the finger FG and the contact or non-contact with the guide plate 10, a guide or the like that supports the finger FG on the side surface may be provided. Since the tip portion of the finger FG is completely in contact with the guide plate 10, the scanning of the finger FG has a stable movement to some extent. However, when scanning is performed as shown in FIG. 5, since the variation in focus is large, the arrangement is adjusted accordingly.

  The vein pattern acquisition method is the same as in the first embodiment. However, in this embodiment, the finger scanning amount (scanning speed) is detected from the fingerprint overlap image, and the vein pattern is reconstructed using this information. Although the scanning amount can be detected from the partial image of the vein pattern as in the first embodiment, since the vein pattern is not as fine as the fingerprint, scanning amount information obtained from a finer fingerprint pattern is used. When cost reduction is achieved with a single-line solid-state image sensor 5 as the fingerprint solid-state image sensor 5, the entire image of the fingerprint can be reconstructed using the scanning amount obtained from the vein pattern.

In the present embodiment, the accuracy of authentication is improved by using fingerprint information on the finger surface, but the amount of scanning of the finger can also be obtained using surface image information (such as wrinkles, scratches, and dirt) other than the fingerprint. Regardless of the fingerprint authentication, the vein pattern can be reconstructed from the surface image information.
[Fourth Embodiment]
The configuration of a blood vessel image input device according to the fourth embodiment of the present invention is shown in FIG. Also in this embodiment, in the same way as the third embodiment, in addition to the blood vessel image, a fingerprint image is further acquired to improve the authentication accuracy.

  In the blood vessel image input apparatus shown in FIG. 6, three rows of linear gradient index lens arrays 2a, 2b, and 2c are arranged as an imaging optical system so that the focal points in each finger are different in the height direction. The Further, a reflecting mirror 4 is provided between each of the linear gradient index lens arrays 2a, 2b, 2c and the finger FG, and the linear solid-state imaging devices 3a, 3b, 3c and the finger FG are interposed via the reflecting mirror 4. The optical path between the two is bent 90 degrees.

  In the present embodiment, the folding direction can be set to one by making the bending direction as shown in the figure, so that mounting becomes easy, and further miniaturization, in particular, reduction in thickness can be realized. The LEDs 1a and 1b constituting the near-infrared light source are respectively installed at the tip and the base side of the finger FG, and irradiate the finger FG from the ventral side. Each image acquisition method and the like are the same as those in the third embodiment.

In addition, in order to acquire a fingerprint image of the first joint portion of the finger FG, the fingerprint solid-state imaging device 5 is arranged. The fingerprint solid-state imaging device 5 uses a line-type contact-type optical image sensor, so that a reduction optical system is not required, and a miniaturization design is facilitated. If a pressure-type or capacitive-type image sensor is used for obtaining a fingerprint image, a light source for fingerprints is not necessary, the light source design can be specialized for the vein pattern side, and it is preferable because the size can be reduced.
[Fifth Embodiment]
FIG. 7 shows the configuration of a blood vessel image input apparatus according to the fifth embodiment of the present invention. Also in the present embodiment, as in the third and fourth embodiments, in addition to the blood vessel image, a fingerprint image is further acquired to improve the authentication accuracy.

  In the blood vessel image input apparatus shown in FIG. 7, three rows of linear gradient index lens arrays 2a, 2b, and 2c are arranged as an imaging optical system so that the focal points in each finger are different in the height direction. The The linear gradient index lens arrays 2a, 2b, and 2c have different focal lengths. As a result, the optical path length can be made shorter than the one with the longest focal length, so that the size can be further reduced.

  Three rows of linear solid-state imaging devices 3a, 3b, and 3c are arranged in the imaging portion by the imaging optical system in accordance with each of the linear gradient index lens arrays 2a, 2b, and 2c. These solid-state image pickup devices 3a, 3b, and 3c are designed to reduce costs by using strip-shaped solid-state image pickup devices of several lines.

In addition, in order to acquire a fingerprint image of the first joint portion of the finger FG, the fingerprint solid-state imaging device 5 is arranged. The fingerprint solid-state imaging device 5 uses a line-type contact-type optical image sensor, so that a reduction optical system is not required, and a miniaturization design is facilitated. If a pressure-type or capacitive-type image sensor is used for obtaining a fingerprint image, a light source for fingerprints is not necessary, the light source design can be specialized for the vein pattern side, and it is preferable because the size can be reduced. Each image acquisition method and the like are the same as those in the third embodiment.
[Sixth Embodiment]
FIG. 8 shows the configuration of a blood vessel image input device according to the sixth embodiment of the present invention.

  Also in this embodiment, in the same way as the third to fifth embodiments, in addition to the blood vessel image, a fingerprint image is further acquired to improve the authentication accuracy.

  The blood vessel image input device shown in FIG. 8 has three rows of linear gradient index lens arrays 2a, 2b, and 2c arranged as an imaging optical system so that the focal points in each finger are different in the height direction. The The linear gradient index lens arrays 2a, 2b, and 2c have different focal lengths. As a result, the optical path length can be made shorter than that having the longest focal length, so that the size can be reduced.

  Three rows of linear solid-state imaging devices 3a, 3b, and 3c are arranged in the imaging portion by the imaging optical system in accordance with each of the linear gradient index lens arrays 2a, 2b, and 2c. These image sensors are designed to reduce costs by using strip-shaped solid-state image sensors of several lines. In this embodiment, the positions of the three rows of linear solid-state imaging devices 3a, 3b, and 3c are aligned to facilitate mounting.

In addition, in order to acquire a fingerprint image of the first joint portion of the finger FG, the fingerprint solid-state imaging device 5 is arranged. The fingerprint solid-state imaging device 5 uses a line-type contact-type optical image sensor, so that a reduction optical system is not required, and a miniaturization design is facilitated. If a pressure-type or capacitive-type image sensor is used for obtaining a fingerprint image, a light source for fingerprints is not necessary, the light source design can be specialized for the vein pattern side, and it is preferable because the size can be reduced. Each image acquisition method and the like are the same as those in the third embodiment.
[Seventh Embodiment]
The seventh embodiment of the present invention is a personal authentication system using the blood vessel image input device according to any of the first to sixth embodiments. The configuration of this personal authentication system is shown in FIGS.

  The personal authentication system shown in FIG. 9 includes a blood vessel image input device 200 and a blood vessel image matching device 300 connected to the blood vessel image device 200. The blood vessel image input apparatus 200 includes an imaging unit 201 configured by the above-described solid-state imaging device, a peripheral circuit unit 202 thereof, and an LED 203 mounted on the LED chip. The blood vessel image input device 200 is also equipped with an imaging optical system (not shown) using the above-described linear gradient index lens array.

  As shown in FIG. 10, the peripheral circuit unit 202 is formed in the solid-state imaging device 100, and a control circuit (driving circuit) 1021 that controls the operation of the imaging unit 201 and a finger blood vessel output from the imaging unit 201. An A / D converter 1023 that converts an analog imaging signal corresponding to an image according to an image from an analog signal to a digital signal via a clamp circuit 1022, and the digital signal converted by the A / D converter 1023 as an image signal of a blood vessel image Based on a reference pulse supplied from an external oscillator 1027, a communication control circuit 1024 for data communication with a device (such as an interface) and a register 1025 connected thereto, an LED control circuit 1026 for controlling light emission of the LED 203, and the like. Control pulses for controlling the operation timing of the circuits 1021 to 1026 And a timing generator 1028 to live. The circuit including the peripheral circuit unit 202 is not limited to the above, and may include other types of circuits. On the other hand, a part of the circuit may be a separate chip (not shown).

  The blood vessel image matching device 300 includes an input interface 211 for inputting communication data output from the communication control unit of the peripheral circuit unit 202, an image processing unit (blood vessel image matching unit) 212 connected to the input interface 211, A blood vessel image database (blood vessel image registration means) 213 and an output interface 214 connected to the image processing unit 212 are provided. The output interface 214 is connected to an electronic device (including software) that requires personal authentication in order to ensure security during use or login.

  Here, in the blood vessel image database 213, blood vessel images of the finger of the subject to be personally authenticated are registered in advance. The target person here may be one person or multiple persons.

  The target person's blood vessel image is input in advance from the blood vessel image input device 200 via the input interface 211 at the time of initial setting or when the target person is added as personal authentication information of the target person.

  The image processing unit 212 inputs a blood vessel image read by the blood vessel image input device 200 via the input interface 211, and uses a known blood vessel image matching image processing algorithm to determine whether or not the image matches the registered image in the blood vessel image database 213. The collation result (blood vessel image match or mismatch) is output through the output interface 214 as a personal authentication signal.

  In this example, the blood vessel image input device 200 and the blood vessel image matching device 300 are configured as separate devices. However, the present invention is not limited to this, and at least a part of the functions of the blood vessel image matching device 300 is performed as necessary. The peripheral circuit unit 202 of the blood vessel image input apparatus 200 may be integrated. In addition, the personal authentication system of this example may be configured integrally with an electronic device that requires personal authentication, or may be configured separately from the electronic device.

  In the personal authentication system using the blood vessel image input device according to any of the third to sixth embodiments, personal authentication can be performed using both the acquired fingerprint image and blood vessel image. For example, security can be improved when the blood vessel image matches the registered blood vessel image and when the fingerprint image matches the registered fingerprint image. If the authentication rate is low only by the image authentication of the blood vessel image or the fingerprint image, it is possible to acquire both images, perform authentication by matching one of the images, and reduce the authentication error rate.

1 is a schematic diagram illustrating an overall configuration of a blood vessel image input device according to a first embodiment of the present invention. It is a perspective view which shows the basic composition of the blood vessel image input device shown in FIG. It is the schematic explaining the image reading method using the blood-vessel image input device shown in FIG. It is the schematic which shows the whole structure of the blood-vessel image input device by the 2nd Embodiment of this invention. It is the schematic which shows the whole structure of the blood-vessel image input device by the 3rd Embodiment of this invention. It is the schematic which shows the whole structure of the blood-vessel image input device by the 4th Embodiment of this invention. It is the schematic which shows the whole structure of the blood-vessel image input device by the 5th Embodiment of this invention. It is the schematic which shows the whole structure of the blood-vessel image input device by the 6th Embodiment of this invention. It is a schematic block diagram which shows the whole structure of the personal authentication system by the 7th Embodiment of this invention. It is a schematic block diagram which shows the internal structure of the peripheral circuit part in the personal authentication system shown in FIG. It is the schematic which shows the structure of the finger blood-vessel image input device of a prior art example. It is a schematic diagram explaining the acquisition area | region of the finger image by the two-dimensional image sensor of the finger blood-vessel image input device shown in FIG.

Explanation of symbols

1, 1a, 1b LED (light source)
2a, 2b, 2c Refractive index distribution type lens array 3a, 3b, 3c Line-shaped solid-state imaging device 4, 4a, 4b Reflector 5 Fingerprint imaging device 10 Guide plate

Claims (17)

Illumination means for irradiating light that passes through the inside of the finger;
An imaging means for acquiring a blood vessel image of a venous blood vessel that is three-dimensionally distributed inside the finger by light emitted from the illumination means;
In a blood vessel image input device having an imaging means for forming a blood vessel image of the finger on the imaging means,
The imaging means has a refractive index distribution type lens array disposed on an optical path between the finger and the imaging means, and the blood vessel image of the finger is taken through the refractive index distribution type lens array. A blood vessel image input device characterized by forming an image on the blood vessel. The blood vessel image input device according to claim 1, wherein
The imaging means has a plurality of gradient index lens arrays arranged on an optical path between the finger and the imaging means,
The blood vessel image input device, wherein the imaging means includes a plurality of imaging elements corresponding to the plurality of gradient index lens arrays. The blood vessel image input device according to claim 2,
The blood vessel image input device, wherein the plurality of gradient index lens arrays have focal points at different positions inside the finger. The blood vessel image input device according to claim 3,
The imaging means forms a blood vessel image of a venous blood vessel distributed three-dimensionally inside the finger by the plurality of gradient index lens arrays,
The blood vessel image input device, wherein the imaging means acquires the imaged blood vessel image. The blood vessel image input device according to claim 3 or 4,
The blood vessel image input device, wherein the image forming means further includes a reflecting means arranged on an optical path between the finger and the imaging means. In the blood vessel image input device according to any one of claims 1 to 5,
A blood vessel image input device further comprising image acquisition means for acquiring a surface image of the finger. Illumination means for irradiating light that passes through the inside of the finger;
An imaging means for acquiring a blood vessel image of a venous blood vessel that is three-dimensionally distributed inside the finger by light emitted from the illumination means;
In a blood vessel image input device having imaging means for forming an image of the finger on the imaging means,
An installation member for installing the finger;
Surface image acquisition means for acquiring a surface image of a region where the finger contacts the installation member;
The blood vessel image input apparatus, wherein the imaging means acquires a blood vessel image of a finger region other than the region. The blood vessel image input device according to claim 7,
The installation member has a light transmission member that transmits the light irradiated by the illumination means,
The blood vessel image input device, wherein the surface image acquisition means acquires an optical surface image generated in an area where the finger contacts the light transmitting member by the light. The blood vessel image input device according to claim 7 or 8,
The imaging means has a plurality of gradient index lens arrays,
The blood vessel image input device, wherein the imaging means includes a plurality of imaging means corresponding to the plurality of gradient index lens arrays. The blood vessel image input device according to claim 7 or 8,
2. The blood vessel image input device according to claim 1, wherein the gradient index lens array has focal points at different positions inside the finger. The blood vessel image input device according to claim 10.
The imaging means forms a blood vessel image of a venous blood vessel distributed three-dimensionally inside the finger by the plurality of gradient index lens arrays;
The blood vessel image input device, wherein the imaging means acquires the imaged blood vessel image. The blood vessel image input device according to claim 10 or 11,
The blood vessel image input device, wherein the image forming means further includes a reflecting means arranged on an optical path between the finger and the imaging means. The blood vessel image input device according to any one of claims 6 to 12,
Means for detecting the scanning amount of the finger based on at least one of a plurality of image signals forming a surface image acquired by the image acquisition means and a plurality of image signals forming a blood vessel image acquired by the imaging means;
A blood vessel image input device further comprising means for forming a blood vessel image or a surface image of the entire finger in accordance with the detected scanning amount of the finger. Acquire multiple partial blood vessel images focused on different positions in the finger,
A blood vessel image construction method comprising reconstructing an entire blood vessel image from a plurality of acquired partial blood vessel images. The blood vessel image construction method according to claim 14,
A blood vessel image construction method comprising reconstructing an entire blood vessel image using a series of partial blood vessel images. The blood vessel image input device according to any one of claims 1 to 13,
A blood vessel image registration means for previously registering the blood vessel image of the finger read by the blood vessel image input device as identification information of a subject;
A blood vessel image collating unit that collates whether or not the blood vessel image of the finger read by the blood vessel image input device matches the registered image of the blood vessel image registration unit, and outputs the collation result as a personal authentication signal; A personal authentication system characterized by comprising. The personal authentication system according to claim 16, wherein
Surface image registration means for registering in advance the surface image of the finger read by the blood vessel image input device as subject identification information;
A surface image collating unit that collates whether or not the finger surface image read by the blood vessel image input device matches a registered image of the surface image registering unit, and outputs the collation result as a personal authentication signal; A personal authentication system further comprising: