JP2010039534A - Biological information acquisition device and personal authentication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To further miniaturize a personal authentication device that utilizes a finger vein pattern, while securing authentication accuracy. <P>SOLUTION: A compound-eye imaging system including a lens-array 3 and an imaging element 6 images a vein within a finger 1 as a subject. A three-dimensional image computing unit 102 creates a three-dimensional image of the subject based on a plurality of single-eye images in a plurality of compound-eye images taken. The three-dimensional image is used in personal authentication. Since information about the vein pattern can be utilized also for the direction of depth in a living body, it is possible to secure authentication accuracy without having to image a wide range of the finger. Thus, it is easy to reduce the thickness and volume of the compound-eye imaging system and miniaturize the entire device. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to the field of personal authentication using biometric information.

  In the information society, there is an increasing demand for personal authentication devices for determining whether an individual who accesses equipment or information is a predetermined person. Many personal authentication devices that already use biological information such as fingerprints, faces, irises of eyes, veins of fingers and hands, etc. have already been put into practical use. However, there are problems such as authentication accuracy, unauthorized access due to counterfeiting, device size and cost, etc. However, there are many cases where practical use is still restricted.

  As one of personal authentication methods, there is an authentication method using a finger or hand vein pattern. In this vein authentication method, a vein inside the living body is photographed with a camera, and the photographed vein pattern is collated with a vein pattern registered in a database in advance to determine whether or not the person to be authenticated is a predetermined person. judge. The vein pattern is biometric information concealed inside the living body part, and has the merit that it is difficult to make a counterfeit compared to other authentication methods using a fingerprint or a face, is simple, and has high authentication accuracy. Therefore, vein authentication is currently used in situations where high authentication accuracy is required.

  In vein authentication, there are a method for targeting the vein pattern of the palm and the back and a method for targeting the vein pattern of the finger. A relatively large fixed base is required to keep the palm and back in the correct position, but the fingers of the hand can be easily stopped in the correct position without providing such a large fixed base. . Therefore, a method using a finger vein pattern is generally advantageous in terms of downsizing of the apparatus, compared to a method using a palm or back vein pattern.

  As an apparatus for performing finger vein authentication, there are devices disclosed in Patent Documents 1 and 2, for example.

Japanese Patent No. 3630675 JP 2008-97327 A

  In the case of the device as disclosed in Patent Document 1, since the finger originally has few blood vessels, it is necessary to secure a certain distance between the finger and the camera and an imaging distance of the camera's photographing lens in response to a request for photographing the widest possible range of the finger. This is an obstacle to downsizing the apparatus.

  On the other hand, if the personal authentication apparatus is configured by a camera using a lens array as in Patent Document 2, the apparatus can be made thinner than a camera using a normal monocular lens. However, even with a configuration such as that of Patent Document 2, when using a general-purpose imaging device that is becoming smaller in area, it cannot be denied that there is a limit to photographing a wide range of a subject at a close distance. As the area of the image sensor further decreases with time, the need to shoot with a wider viewing angle for subjects at close distances increases, so due to the effects of optical defects such as shading and distortion, This is because it becomes difficult to obtain a high-quality vein pattern image.

  The present invention has been made in view of the above-described points, and enables further downsizing of a personal authentication device using biometric information while ensuring authentication accuracy, and also enables realization of such a personal authentication device. An object of the present invention is to provide a biological information acquisition device.

The invention of claim 1
It includes a lens array in which a plurality of lenses are arrayed and an image sensor located on the image side thereof, and is connected by each lens of the lens array with a blood vessel inside a living body part located on the subject side of the lens array as a subject. A compound eye imaging system that captures a compound eye image, which is a set of images to be imaged (denoted as a single eye image), with the imaging element;
Stereoscopic image generating means for generating a stereoscopic image of the subject based on a plurality of single-eye images in a compound eye image captured by the compound eye imaging system;
Have
It is a biological information acquisition device that acquires a stereoscopic image generated by the stereoscopic image generation means as biological information related to the biological part.

The invention of claim 2
It includes a lens array in which a plurality of lenses are arrayed and an image sensor located on the image side thereof, and is connected by each lens of the lens array with a blood vessel inside a living body part located on the subject side of the lens array as a subject. A compound eye imaging system that captures a compound eye image, which is a set of images to be imaged (denoted as a single eye image), with the imaging element;
Stereoscopic image generating means for generating a plurality of stereoscopic images of the subject based on a plurality of single-eye images in a compound eye image captured by the compound eye imaging system;
3D image synthesis means for generating a single 3D image by combining a plurality of 3D images generated by the 3D image generation means;
Have
It is a biological information acquisition device that acquires a stereoscopic image generated by the stereoscopic image synthesis means as biological information relating to the biological part.

The invention of claim 3
It includes a lens array in which a plurality of lenses are arrayed and an image sensor located on the image side thereof, and is connected by each lens of the lens array with a blood vessel inside a living body part located on the subject side of the lens array as a subject. A compound eye imaging system that captures a compound eye image, which is a set of images to be imaged (denoted as a single eye image), with the imaging element;
Stereoscopic image generating means for generating a stereoscopic image of the subject based on a plurality of predetermined single-eye images in a compound eye image captured by the compound eye imaging system;
Reconstructed image generating means for generating a planar reconstructed image of the subject based on a plurality of single-eye images other than the predetermined single-eye image in the compound-eye image captured by the image sensor;
Have
The biological information acquisition apparatus acquires a stereoscopic image generated by the stereoscopic image generation unit and a reconstructed image generated by the reconstructed image generation unit as biological information related to the biological part.

  According to a fourth aspect of the present invention, in the biological information acquiring apparatus according to the first, second, or third aspect of the invention, the compound-eye imaging system prevents crosstalk on the image plane of a light beam that passes through each lens of the lens array. The light-shielding means for this is included.

  According to a fifth aspect of the present invention, in the biological information acquiring apparatus according to any one of the first to fourth aspects, the compound eye imaging system includes an illuminating unit that irradiates light to the biological part.

  A sixth aspect of the present invention is the biological information acquiring apparatus according to the fifth aspect of the present invention, wherein the light emitting part of the illumination means is arranged so as to contact the surface of the biological part.

  According to a seventh aspect of the present invention, in the biological information acquiring apparatus according to the fifth aspect of the invention, the illumination means irradiates near infrared light.

The invention of claim 8
The biological information acquisition device according to any one of claims 1 to 7,
Authentication processing means for performing personal authentication by collating biometric information acquired by the biometric information acquisition apparatus or feature amounts extracted from the biometric information with pre-registered data;
Is a personal authentication device.

The invention of claim 9
The biological information acquisition device according to any one of claims 1 to 7,
An operation switching means for switching the operation to a registration operation or an authentication operation;
Database means for registering the biometric information acquired by the biometric information acquisition device or the feature quantity extracted from the biometric information as data for personal authentication when the operation is switched to the registration operation by the action switching means;
When the operation is switched to the authentication operation by the operation switching unit, the biometric information acquired by the biometric information acquisition device or the feature amount extracted from the biometric information is collated with the data registered in the database unit. Authentication processing means for performing personal authentication by
Is a personal authentication device.

  In the biological information acquisition apparatus according to the first to seventh aspects of the present invention, a three-dimensional image of a blood vessel in a biological part is acquired as biological information. This is not limited to a two-dimensional plane but also in the depth direction. Information is acquired. Therefore, if personal authentication is performed using the biometric information acquired by the biometric information acquisition apparatus, personal authentication is performed using blood vessel pattern information only in the two-dimensional plane (for example, in the case of the apparatus of Patent Document 2). ), The authentication accuracy can be ensured even if the imaging range of the living body part is narrow. And if you want to image a not so wide range of a living body part, the viewing angle can be narrowed even if the subject, that is, the blood vessel is at a close distance, so that the influence of optical defects such as shading and distortion can be suppressed and the compound eye imaging system The thickness can be reduced, and the contact area between the living body part and the compound-eye imaging system can be reduced, so that the entire apparatus can be reduced in size. Therefore, if this biometric information acquisition apparatus is applied to a personal authentication apparatus, it is possible to achieve further downsizing of the personal authentication apparatus while ensuring authentication accuracy.

  Now, in order to generate a stereoscopic image, it is sufficient to have at least two single-eye images having parallax, but the distance resolution increases as the parallax between the single-eye images increases. Therefore, in order to obtain a high distance resolution, a pair of single-eye images having a large parallax, for example, a pair of single-eye images farthest in a diagonal direction in a compound eye image may be used for generating a stereoscopic image. However, the subject distance can be obtained only in the overlapping area between the single-eye images, and the overlapping area becomes smaller as the parallax becomes larger. The size inside becomes smaller. Such a reduction in the size of a stereoscopic image as biometric information used for personal authentication may lead to a decrease in authentication accuracy due to insufficient information.

  In the biological information acquisition apparatus according to the second aspect of the present invention, a plurality of stereoscopic images of blood vessels in the biological part are generated based on a plurality of single-eye images in a compound eye image, and a stereoscopic image obtained by synthesizing them is converted into biological information. Get as. Therefore, it is possible to suppress the size reduction in the plane of the stereoscopic image as the biological information.

  In the biological information acquiring apparatus according to the third aspect of the invention, in addition to the three-dimensional image of the blood vessel in the living body region generated based on the plurality of predetermined single-eye images in the compound eye image, the other plurality of individual images in the compound eye image A planar reconstructed image of the blood vessel within the living body part generated based on the eye image is also acquired as biological information. Therefore, when performing personal authentication using the biometric information acquired by this biometric information acquisition apparatus, even if the size of the three-dimensional image in the plane is reduced as described above, a decrease in authentication accuracy due to lack of information is prevented. be able to.

  In the biometric information acquisition device according to the fourth aspect of the present invention, it is possible to prevent crosstalk on the image plane of the light beam passing through each lens of the lens array, and to image a blood vessel pattern with less noise such as coast and flare. Can do. In the biological information acquiring apparatus according to the fifth aspect of the present invention, the blood vessel pattern can be imaged with good contrast because the biological part is irradiated with light. In the biological information acquisition apparatus according to the sixth aspect of the invention, since the light emitting part of the illumination means is substantially in contact with the surface of the living body part, the halation noise and the illumination light amount loss due to the reflection of the illumination light on the living body part surface are reduced. be able to. In the biological information acquisition apparatus according to the seventh aspect of the invention, the near-infrared light is irradiated to the living body part, but the near-infrared light is well absorbed by the reduced hemoglobin in the blood, so that the vein pattern is imaged with high contrast. can do.

  The personal authentication device according to claims 8 and 9 includes the biometric information acquisition device described above and performs personal authentication using the biometric information acquired by the device while ensuring good authentication accuracy. The entire apparatus can be reduced in size. The personal authentication device according to the ninth aspect of the invention can perform the personal authentication operation and the registration operation of the personal authentication data with a single device.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is an explanatory diagram of a configuration of a personal authentication device according to the first embodiment of the present invention.

  This personal authentication apparatus is composed of a compound eye imaging system and a processing system. First, the compound eye imaging system will be described. In FIG. 1, 1 is a finger of a human hand. Reference numeral 10 denotes a flat plate for bringing the finger 1 into close contact during imaging. Here, the finger 1 is observed from the fingertip direction. Reference numeral 2 denotes a blood vessel existing inside the finger 1 and serves as a subject of the compound eye imaging system. Reference numeral 3 denotes a lens array for forming a subject image, in which a plurality of spherical single lenses are two-dimensionally arrayed in a plane substantially orthogonal to the lens optical axis. As each lens which comprises the lens array 3, an aspherical single lens, a double-sided spherical lens, or a double-sided aspherical lens may be used, or a Fresnel lens and a diffraction lens may be used. Reference numeral 4 denotes a light shielding member for preventing crosstalk on the image plane of light rays passing through each lens of the lens array 3 and suppressing noise light such as ghost and flare. Reference numeral 6 denotes an image pickup device for picking up an image by the lens array 3, in which a large number of pixels 6 a are two-dimensionally arranged in an array. Reference numeral 7 denotes a housing, which includes a side wall portion 7a and a bottom plate portion 7b.

  FIG. 2 is a view of the compound eye imaging system observed from the subject side without the finger 1. As shown in FIG. 2, the light shielding member 4 is a flat plate with a rectangular hole, and the length of one side of each rectangular hole substantially matches the effective diameter of each lens of the lens array 3 or from the diameter thereof. It is getting bigger. Each rectangular hole of the light-shielding member 4 extends to the vicinity of the imaging surface of the image sensor 6, and the size of the image by each lens of the lens array 3, that is, the size of the single-eye image is determined by the size of the rectangular hole. Since each lens constituting the lens array 3 is circular, the surface on the imaging side of the lens array 3 is used to prevent light from the subject from entering the imaging surface through a gap between the effective range of the lens and the rectangular hole. A thin film 5 for reflecting light incident from the subject side is formed in a portion other than the effective lens diameter. The thin film 5 provided on the lens array surface, together with the light shielding member 4, constitutes light shielding means for removing flare light caused by crosstalk between adjacent lenses. The thin film 5 can be formed by vapor deposition of a metal film or printing of a colored resin.

  The lens array 3 can be manufactured by using a transparent resin or glass material and processing methods such as a reflow method, an area gradation mask method, and a polishing method, or a molding method using a mold manufactured by these processing methods. . The light shielding member 4 is manufactured by punching a flat plate made of resin, glass, metal or the like by etching, drilling, laser processing or the like. If etching or laser processing is used, the height of the light shielding member 4 in the lens optical axis direction may be limited. In that case, by thinly bonding the light shielding member manufactured in the lens optical axis direction, What is necessary is just to ensure the required height. The light shielding member 4 is made of an opaque material, coated with a transparent material, or roughened on the wall surface so that light transmission and reflection can be suppressed.

  The image sensor 6 is, for example, a CMOS image sensor, but may be a CCD image sensor or the like. Some CMOS image sensors and the like are provided with a cover glass for protecting the imaging surface. In this embodiment, an image sensor without a cover glass is shown. An image sensor with a cover glass may be used. In that case, it is necessary to design the shape and position of the lens array 3 in consideration of the influence of light refraction by the cover glass. Some image pickup devices are provided with an optical low-pass filter for preventing aliasing in the vicinity of the image pickup surface. However, here, it is assumed that no low-pass filter is provided for thinning the apparatus. The light shielding member 4 is slightly lifted from the imaging surface of the imaging device 4 in order to prevent the imaging device 4 from being destroyed by contact between the light shielding member 4 and the imaging surface. The lens array 3 and the light shielding member 4 are held by the bottom plate portion 7 a of the housing 7. When the imaging surface of the image sensor 4 is protected by a cover glass or the like, the light shielding member 4 may be disposed in contact with the cover glass surface.

  In the configuration of FIG. 1, since the space with the imaging surface is sealed by the lens array 3 and the bottom plate portion 7b of the housing 7, it is possible to prevent dust and the like from adhering to the imaging surface. Further, since the light shielding member 4 is slightly lifted from the imaging surface, the light shielding member 4 is parallel to the imaging surface so that light does not pass through the space between the light shielding member bottom surface and the imaging surface to cause crosstalk of light rays. The lens pitch of the lens array 3 in the direction plane is set. As for the positional relationship between the subject and the image, the imaging relationship of the lens does not necessarily hold, and the position may be determined within a range where the lens cutoff frequency does not fall below the required frequency of the subject.

  The compound eye imaging system has illumination means for irradiating the finger 1 with light. In the present embodiment, the illuminating means is a casing so that a plurality of light emitting diodes (LEDs) 8 emitting light having a low absorption rate to the living body, preferably near infrared light, surround the lens array 3. 7 is provided on the side wall 7a. A light emission control unit 9 drives the LED 8. Although it is possible to link ON / OFF of the light emission of the LED 8 with the ON / OFF of the apparatus power supply, it is not desirable for safety reasons that the LED 8 always emits light while the apparatus power supply is ON. Therefore, preferably, for example, a switch (not shown) for detecting the finger 1 is provided, and when the finger 1 is detected by this switch, the light emission control unit 9 turns on the light emission of the LED 8.

  The flat plate 10 is made of a material having transmittance with respect to the light irradiated by the LED 8, for example, the same material as the lens array 3, and acts as a bandpass filter that allows light in the vicinity of the wavelength of the light irradiated by the LED 8 to pass through the inner surface. An optical thin film is deposited. The flat plate 10 is installed so as to provide the air layer 11 between the lens array 3, but the flat plate 10 may be in close contact with the lens array 3 without providing the air layer 11. When the air layer 11 is provided as shown in FIG. 1, the distance from the principal plane of each lens constituting the lens array 3 to the subject, that is, the subject distance, from the thickness of the flat plate 10, the air layer thickness, and the thickness of the lens array 3. Is defined. When the flat plate 10 and the lens array 3 are brought into close contact with each other, the subject distance is defined by the thickness of the flat plate 10 and the thickness of the lens array 3. The air layer 11 may be a vacuum layer or a layer filled with a gas other than air.

  When obtaining biometric information, as shown in FIG. 1, the finger 1 is brought into contact with the flat plate 10, and at this time, the finger 1 is substantially in contact with the upper end of the housing side wall portion 7a serving as a light emitting portion. Become. Infrared light is emitted from this light emitting part and applied to the finger. Since the light emitting part and the finger are substantially in contact with each other, halation noise and light loss due to reflection of infrared light on the finger surface are reduced. be able to. Near-infrared light has a transmissivity to living organisms, but it is known that it is well absorbed by reduced hemoglobin in the blood, so the irradiated near-infrared light is transmitted and scattered inside the organism. A pattern image of a portion that reaches the imaging surface of the imaging element 6 and is absorbed by the blood vessel 2 (particularly a vein) that is a subject is captured by the imaging element 6.

  In FIG. 1, the light from the LED 8 is emitted directly above, that is, in a direction perpendicular to the imaging surface, but the finger 1 is used so that a blood vessel pattern image having a more appropriate contrast can be obtained. You may make it radiate | emit diagonally upward toward the center or side surface. Further, in order to more efficiently irradiate the finger with the light from the LED 8, a lens 8a may be provided in the optical path between the LED 8 and the light emitting portion as shown in FIG.

  FIG. 3A is a schematic diagram of a blood vessel pattern of a finger to be actually observed, and 12 in the figure corresponds to a blood vessel. Such a blood vessel pattern is captured by the image sensor 6 as a compound eye image as shown in FIG. In FIG. 3 (b), 13 is an image of each lens of the lens array 3, that is, a single eye image, and 14 is a shadow image of the light shielding member 4. Since the field of view is slightly different for each lens, there is a parallax between individual images. In a compound eye image, the blood vessel pattern is an image that is inverted vertically and horizontally.

  The compound eye imaging system has been described above. Next, the processing system will be described. The processing system includes an image input unit 101, a stereoscopic image calculation unit 102, a registration / authentication switching unit 103, a stereoscopic image registration database unit (DB) 104, a stereoscopic image collation calculation unit 105, and a determination output unit 106.

  The image input unit 101 takes in data of a compound eye image as shown in FIG. 3B output from the image pickup device 6 of the compound eye imaging system, and removes a shadow area by the light shielding member 4 from the compound eye image. Is extracted. Since the shadow region of the light shielding member is darker than each single-eye image, the shadow region of the light shielding member can be easily removed by a method such as binarizing the compound eye image using an appropriate threshold. Alternatively, since the lens pitch of the lens array 3, the pixel size of the image sensor 6, and the wall thickness of the light shielding member 4 can almost predict which region in the compound eye image corresponds to a single eye image, the prediction was made in the compound eye image. Each individual eye image may be uniquely extracted from the position. The single eye image extracted from the compound eye image is input to the stereoscopic image calculation unit 102. Note that the single-eye image may be extracted by the stereoscopic image calculation unit 102.

The stereoscopic image calculation unit 102 is a unit (stereoscopic image generation unit) that generates one or more stereoscopic images of a subject by calculation processing based on a plurality of single-eye images. The arithmetic processing for obtaining a stereoscopic image is based on the stereo method. In the model as shown in FIG. 4, 15 represents an arbitrary point at the subject position, and 3 and 4 represent a lens array and a light shielding member. Reference numerals 3a and 3b denote lenses at arbitrary positions constituting the lens array. In FIG. 4, the lenses 3 a and 3 b are illustrated as adjacent lenses, but may be lenses that are not adjacent but are separated from each other. The subject distance is a, the imaging distance is b, the lens pitch is p, and the deviation of the image of the point 15 by the lens 3a and the image of the point 15 by the lens 3b on the monocular image, that is, the parallax is s. For any two single-eye images in FIG. 3B, s is detected by detecting a shift between the two images of the specific points constituting the subject image. Based on s, the subject distance a of the point 15 can be obtained from the following equation (1).
a = p ・ b / s (1)

For actual detection of s, the texture of the subject image can be used. When the texture exists over the entire single-eye image, for example, the deviation of the pixel luminance between the two images is obtained while moving a 5 × 5 pixel small area of one image on the other image. FIG. 5 is a diagram for explaining the situation. FIG. 5 (a) corresponds to the one image, and FIG. 5 (b) corresponds to the other image. An arbitrary small region 16a is displayed on the other image. To obtain the deviation of the pixel brightness of the small area between one image and the other image. When the deviation is minimized at the position 16a ′ in FIG. 5B, the movement amount sxa, sya is used as √ (sxa ² + sya ² ), and the parallax sa of the small area is set. Further, the parallax sb is obtained in the same manner as described above for the small region 16b in FIG. As described above, since s changes according to the subject distance of the subject included in the small area, s is obtained for all the small areas constituting the image while sequentially changing the small area of interest. When the subject distance a of each small region is calculated based on the equation (1), a distance image of the subject, that is, a stereoscopic image can be acquired. The in-plane spatial resolution in the stereoscopic image is determined by the size of the small area. For this reason, if the size of the small area is reduced, the in-plane spatial resolution is increased, but calculation time is required. The size of the small area may be determined according to the required in-plane spatial resolution and calculation time. Further, when it is desired to increase the distance resolution, the above-described processing may be executed after the image is interpolated and enlarged.

  If no texture is included in the small area, a deviation in pixel luminance between the small areas of the two images is less likely to occur, and the reliability of the distance calculation result is reduced. Therefore, when there are few textures like a blood vessel image, it is better to first extract the region corresponding to the blood vessel image in the image as an effective region where the texture exists, and obtain the subject distance only in the effective region, Thereby, the distance calculation result with low reliability can be eliminated and the calculation can be speeded up.

  The personal authentication device according to the present embodiment acquires the stereoscopic image of the subject generated as described above as biometric information unique to the finger 1, and uses this for personal authentication. That is, the personal authentication device according to the present embodiment includes a biometric information acquisition device that acquires biometric information for personal authentication.

  In the personal authentication apparatus according to the present embodiment, the registration / authentication switching unit 103 can switch the operation to an authentication operation or a registration operation.

  When it is desired to perform registration for a certain person, the operation is switched to the registration operation, and the person's finger is set as shown in FIG. 1 to acquire a stereoscopic image of the subject as the biological information. This stereoscopic image is transferred to the stereoscopic image registration database unit 104 via the registration / authentication switching unit 103 and registered as personal authentication data.

  When it is desired to perform personal authentication, the operation is switched to the authentication operation, and the finger of the person to be authenticated is set as shown in FIG. 1 to obtain a stereoscopic image of the subject as the biometric information. The three-dimensional image is transferred to the three-dimensional image matching calculation unit 105 via the registration / authentication switching unit 103. In addition, registered stereoscopic images are sequentially taken out from the stereoscopic image registration database unit 104 and input to the stereoscopic image matching calculation unit 105. The stereoscopic image matching calculation unit 105 performs a matching operation between the stereoscopic image input from the registration / authentication switching unit 103 (referred to as an acquired stereoscopic image) and the registered stereoscopic image extracted from the stereoscopic image registration database unit 104. The determination output unit 106 determines whether or not the person to be authenticated is a registered person based on the result of the collation operation by the stereoscopic image collation operation unit 105, and outputs the determination result. For example, when the acquired stereoscopic image matches one of the registered stereoscopic images, it is determined that the person to be authenticated is a registered person, and when the acquired stereoscopic image does not match any of the registered stereoscopic images, it is determined that the person is not a registered person. As described above, the determination output unit 106 constitutes an authentication processing unit together with the stereoscopic image matching calculation unit 105.

  A known pattern matching calculation or the like may be used for the matching calculation in the stereoscopic image matching calculation unit 105. In the registration operation, the stereoscopic image registration database unit 104 extracts feature quantities such as position coordinates and branching directions of the branch points of the blood vessel pattern from the stereoscopic image, and registers the feature quantities as authentication data. In operation, the same feature amount may be extracted from the acquired stereoscopic image by the stereoscopic image matching operation unit 105, and this feature amount may be compared with the feature amount registered in the stereoscopic image registration database unit 104. In this way, the verification operation time can be shortened. Such forms are also encompassed by the present invention.

  As can be understood from the above description, the personal authentication device according to the present embodiment includes a device that acquires biometric information and registers the acquired biometric information or a feature amount extracted therefrom as personal authentication data. Is. The stereoscopic image registration database unit 104 is not provided in the apparatus, but personal registration data (stereoscopic image or a feature amount thereof) is taken from the stereoscopic image registration database provided outside the apparatus and input to the stereoscopic image collation calculation unit 105. A personal authentication device having such a configuration is also included in the present invention.

  The lens array 3 shown in FIG. 1 was integrally formed as one member. However, the lens array 3 may be a two-dimensional array of a plurality of physically independent lenses, and FIG. 6 shows an example of a compound eye imaging system using such a lens array. In FIG. 6, reference numeral 22 denotes physically independent lenses constituting a lens array, which are two-dimensionally arrayed on a plane substantially perpendicular to the optical axis. In this example, the lenses 22 are arranged in two rows in a direction parallel to the paper surface and in, for example, two rows in a direction perpendicular to the paper surface, and each is held by the casing bottom plate portion 7b. The housing bottom plate portion 7b is formed by hollowing out a portion holding the lens 22 in a rectangular hole shape, and a portion located between the adjacent lenses 22 of the housing bottom plate portion 7b serves as a light shielding means for suppressing crosstalk between adjacent lenses. Works.

  FIG. 7 is an explanatory diagram of a configuration of the personal authentication device according to the second embodiment of the present invention. The difference between the personal authentication apparatus according to the present embodiment and the personal authentication apparatus according to the first embodiment is that a stereoscopic image synthesis calculation unit 107 (stereoscopic image synthesis unit) is added to the processing system, and a plurality of stereoscopic image calculation units 102 A plurality of three-dimensional images are generated based on each pair of single-eye images, and a one-dimensional image having a larger size is synthesized from the plurality of three-dimensional images by the three-dimensional image synthesis calculation unit 107 (this synthesized three-dimensional image is a living body image). Is acquired as information). This difference will be further described.

  In generating a stereoscopic image, it is only necessary to have at least two images having a parallax for distance detection, and the distance resolution increases as the parallax increases. Therefore, for example, a stereoscopic image may be generated using two single-eye images that are farthest in the diagonal direction in the compound eye image. However, on the other hand, since the subject distance can be obtained only in the overlapping area between the binocular images, the larger the parallax between both binocular images, the smaller the overlapping area, and in the plane of the generated stereoscopic image. The size becomes smaller. For example, when a stereoscopic image is generated from a pair of a single eye image by the lens 3a and a single eye image by the lens 3c of the lens array 3, a stereoscopic image can be obtained only in the overlapping region 2a of the field of view of the lenses 3a and 3c. When a stereoscopic image having a small size is used as biometric information for personal authentication in this way, there is a risk that authentication accuracy may be reduced due to insufficient information.

  Therefore, in this embodiment, a plurality of stereoscopic images are generated from each of a plurality of single-eye image pairs in a compound eye image, and the plurality of stereoscopic images are combined into a single stereoscopic image, whereby a stereoscopic image having a large in-plane size is obtained. I want to get an image. Hereinafter, a description will be given with reference to FIGS.

  FIG. 8 shows an example of the processing flow. In step 1, a compound eye image captured by the compound eye imaging system is taken into the image input unit 101, and each single-eye image of the compound eye image is extracted and input to the stereoscopic image calculation unit 102 (stereoscopic image generating means).

  Steps 2 to 10 are processing steps in the stereoscopic image calculation unit 102. Here, a single-eye image arrangement in a compound eye image as shown in FIG. 9 is assumed. M and N are the number of single-eye images in the x and y directions, where M = N = 5.

  Individual eye images A (1,1) and A (2,1) are selected as the first individual image pair, and one stereoscopic image is generated from this individual image pair. The method for generating a stereoscopic image from a single-eye image pair is as described in the first embodiment. A single eye image A (2,1), A (3,1) is selected as the next single eye image pair, and one stereoscopic image is generated based on this single eye image pair. Next, single-eye images A (3, 1) and A (4, 1) are selected, and one stereoscopic image is generated based on the single-eye image pair. Next, single-eye images A (4, 1) and A (5, 1) are selected, and one stereoscopic image is generated based on this single-eye image pair. Next, single-eye images A (1, 2) and A (2, 2) are selected, and one stereoscopic image is generated based on this single-eye image pair. In this way, a stereoscopic image is generated by sequentially selecting single-eye image pairs while shifting one by one in raster order in a compound eye image. Each generated stereoscopic image is sequentially transferred to the stereoscopic image composition calculation unit 107.

  Next, the stereoscopic image composition calculation unit 107 performs a process of synthesizing a single stereoscopic image from a plurality of stereoscopic images transferred from the stereoscopic image calculation unit 102 (step 11), and outputs the resultant combined stereoscopic image (step 11). step 12).

  FIG. 10 is an explanatory diagram of the stereoscopic image synthesis process. In FIG. 10, reference numeral 17 denotes a stereoscopic image generated from each single-eye image pair. The grid in each stereoscopic image 17 represents a small area used in the distance calculation, and the subject distance calculated corresponding to each small area is stored. In FIG. 10, each stereoscopic image 17 is arranged according to the position of the single eye image pair used for the generation. When a stereoscopic image is generated from a single eye image pair formed by adjacent lenses in the compound eye image shown in FIG. 9, 16 stereoscopic images 17 are obtained. Reference numeral 18 denotes a single stereoscopic image to be synthesized (synthesized stereoscopic image), which is virtually generated in the memory space. Each stereoscopic image 17 observes the subject from a position shifted by the lens pitch in the lens array. For example, the small area 17a and the small area 17b correspond to positions shifted in real space by the lens pitch. According to the shift amount, the distance data of each stereoscopic image 17 is sequentially arranged in the space 18 as shown in FIG. 10, and if all the stereoscopic image data are arranged, a single composite stereoscopic image can be obtained. In the space 18 of FIG. 10, the data arrangement interval is exactly 1 (the unit is a small area). However, if it exceeds 1 or includes a decimal number such as 0.5 or 2.1, it should be arranged by interpolation. The data value may be obtained.

  Here, the stereoscopic image calculation unit 102 generates a stereoscopic image using a pair of adjacent single-eye images, but the present invention is not limited to this. A stereoscopic image may be generated using a pair of non-adjacent single-eye images such as single-eye images A (1,1) and A (3,1), or a part of single-eye images in a compound-eye image. Only an image may be used for generating a stereoscopic image. What kind of single-eye image pair is used for generating a three-dimensional image, or how many single-eye images in a compound eye image are used, etc., the required calculation time, the size of the three-dimensional image, distance resolution, etc. May be determined as appropriate.

  When the registration / authentication switching unit 103 switches the operation to the registration operation, the stereoscopic image registration database unit 104 extracts the stereoscopic image output from the stereoscopic image composition calculation unit 107 or the stereoscopic image. The feature amount (position coordinates and branch direction of the branch point of the blood vessel pattern) is registered as personal authentication data. When the registration / authentication switching unit 103 switches the operation to the authentication operation, the stereoscopic image matching calculation unit 105 outputs the stereoscopic image output from the stereoscopic image synthesis calculation unit 107 or the feature amount extracted therefrom, and the stereoscopic image registration. A collation operation is performed on the stereoscopic image or the feature amount extracted from the database unit 104, and it is determined whether or not the person to be authenticated is a registered person based on the result of the collation operation. Is output.

  As can be understood from the description so far, the personal authentication device according to the present embodiment includes a biological information acquisition device that acquires a combined stereoscopic image by the stereoscopic image combining calculation unit 107 as biological information unique to the finger 1. In addition, the apparatus includes a device for registering the biometric information or the feature amount extracted therefrom as personal authentication data.

  The stereoscopic image registration database unit 104 is not provided in the apparatus, but personal registration data (stereoscopic image or a feature amount thereof) is taken from the stereoscopic image registration database provided outside the apparatus and input to the stereoscopic image collation calculation unit 105. A personal authentication device having such a configuration is also included in the present invention.

  In the second embodiment, a single stereoscopic image having a larger size is synthesized from a plurality of stereoscopic images generated based on a plurality of single-eye image pairs, and this is used for authentication. Even when the size of the generated single eye image is small, high authentication accuracy can be ensured. However, the point that calculation time increases for the process which synthesize | combines a some stereo image into one stereo image is a difficulty.

  In Embodiment 3 of the present invention, one or more stereoscopic images of a subject are generated using a plurality of predetermined single-eye images in a compound eye image, and a planar single image of the subject is generated from the other plurality of single-eye images. By generating one reconstructed image and using both the stereoscopic image and the reconstructed image of the subject for personal authentication, it is possible to prevent a decrease in authentication accuracy due to lack of information even when the size of the stereoscopic image is small. . Further, since the processing for generating a planar reconstructed image requires less calculation time than the processing for synthesizing a stereoscopic image, the necessary calculation time can be suppressed.

  FIG. 11 is a configuration explanatory diagram of such a personal authentication device according to the third embodiment. The compound eye imaging system is the same as in the first and second embodiments. The processing system is different from the first and second embodiments in that a reconstructed image calculation unit 202, a reconstructed image registration database unit (DB) 204, a reconstructed image matching operation unit 205 are added.

  In the present embodiment, the stereoscopic image calculation unit 102 (stereoscopic image generating means) is a pair of single-eye images by the lenses 3a and 3c at both ends of the lens array 3, that is, the single eye in the left end column and right end column shown in FIG. Image pair (A (1,1) and A (5,1) pair, A (1,2) and A (5,2) pair, A (1,3) and A (5,3) 5 stereoscopic images of the subject are generated on the basis of a pair of A (1,4) and A (5,4) and a pair of A (1,5) and A (5,5). The method for generating a stereoscopic image from each single-eye image pair is as described in the first embodiment. In the reconstructed image calculation unit 202 (reconstructed image generating means), a planar single image of a subject is obtained from a single-eye image by the remaining lenses of the lens array, that is, a single-eye image in the central three rows in the compound eye image shown in FIG. One reconstructed image is generated.

  An arithmetic process for generating a reconstructed image will be described below. The blood vessel (vein) pattern observed in a single-eye image originally has different parallax for each position in the depth direction, but in the case of generating a reconstructed image, the subject has a constant parallax in the single-eye image Treat as. That is, the distance from the lens main plane to the plane on which the blood vessel pattern is distributed is constant, and the parallax determined by the optical magnification and the lens spacing in the lens array is constant.

  FIG. 12 is an explanatory diagram of generation of a reconstructed image. As shown in FIG. 12, the pixel luminance 21a is extracted from the single-eye image 21 used for the generation of the reconstructed image, and the position of the reconstructed image 22 in the virtual space in the computing unit according to the position and parallax of the single-eye image. Then, the extracted pixel luminance is arranged. An enlarged image can be acquired by repeating the arrangement of the pixel luminances for all the pixels of each single-eye image. If the size of the reconstructed image 22 in the virtual space is made larger than the size of the single-eye image 21 and the above processing is performed in consideration of the parallax of the subpixels, the reconstructed image can be obtained with a resolution higher than that of the single-eye image. Can be generated. Note that the single-eye image constituting the compound-eye image is inverted up and down and left and right, but the single-eye image 21 in FIG.

  FIG. 13 shows a processing flow related to the above-described reconstruction image generation. In the image input unit 101, the central portion of the compound eye image captured from the image sensor 6 is extracted, a single eye image obtained by removing the shadow of the light shielding member is extracted from the central portion, and the extracted single eye image is reconstructed image calculation The data is transferred to the unit 202 (steps 21, 22). In the reconstructed image calculation unit 202, parallax uniquely determined by the lens interval of the lens array 3 or the like is obtained for the single eye image (step 23), and the single eye image as described in FIG. A reconstructed image is generated by rearranging the pixel luminances and output (steps 24 and 25).

  If the distance to the blood vessel plane changes due to individual differences in skin thickness, etc., and the parallax cannot be determined uniquely, the parallax between each eye image is detected by block matching calculation etc., and the detected parallax is reconstructed above It may be reflected in the processing. When there is little error in the lens pitch in the lens array, one single eye image as a reference and one single eye image for parallax detection are extracted from the single eye images constituting the compound eye image, and the distance between these single eye images is extracted. The parallax of the other single-eye image with respect to the reference single-eye image may be calculated based on the lens pitch, and in this way, the calculation load is reduced because only one parallax detection calculation is required. Can do.

  In the personal authentication apparatus according to the present embodiment, the registration / authentication switching unit 103 can switch the operation to a registration operation or an authentication operation.

  When the registration operation is switched, the stereoscopic image generated by the stereoscopic image calculation unit 10 and the reconstructed image generated by the reconstructed image calculation unit 202 are converted into the stereoscopic image registration database unit 104 and the reconstructed image database unit 205. Are registered as personal authentication data. In the case of the present embodiment, the personal authentication data for one person consists of five stereoscopic images and one reconstructed image.

  In the case of switching to the authentication operation, the stereoscopic image matching calculation unit 105 performs a matching calculation between the stereoscopic image generated by the stereoscopic image calculation unit 102 and the stereoscopic image extracted from the stereoscopic image registration database unit 104. In addition, the reconstructed image collation operation unit 205 performs a collation operation between the reconstructed image generated by the reconstructed image operation unit 202 and the reconstructed image extracted from the reconstructed image database unit 204. A known pattern matching calculation or the like may be used for the matching calculation of the stereoscopic image and the reconstructed image. Then, the determination output unit 206 determines that the registration data related to the same registrant has been matched by the matching of the stereoscopic image matching calculation unit 105 and has been found to be matched by the matching of the reconstructed image matching calculation unit 205. Only in this case, it is finally determined that the person to be authenticated is the same person as the registrant, and a message to that effect is output. Thus, the determination output unit 206 constitutes an authentication processing unit together with the stereoscopic image matching calculation unit 105 and the reconstructed image matching calculation unit 205. Note that the case where matching is obtained by the matching of the three-dimensional image matching calculation unit 105 is, specifically, for example, matching for a predetermined number or more of a plurality of stereoscopic images generated from a plurality of single-eye image pairs. In this case, the stereoscopic images generated from the single-eye image pairs at the predetermined positions are matched.

  During the registration operation, in the stereoscopic image registration database unit 104 and / or the reconstructed image registration database unit 204, feature quantities such as the position coordinates and branch direction of the branch point of the blood vessel pattern are extracted from the stereoscopic image or the reconstructed image, The feature amount may be registered as recognition data. In this case, at the time of the authentication operation, the stereoscopic image matching calculation unit 105 and / or the reconstructed image matching calculation unit 205 extracts the same feature amount from the stereoscopic image or the reconstructed image acquired for the person to be authenticated. A collation operation with the feature amount registered in each database unit 104, 204 is performed. Such a configuration is also included in the present invention.

  As understood from the description so far, the personal authentication device according to the present embodiment uses the stereoscopic image of the subject generated by the stereoscopic image calculation unit 102 and the reconstructed image calculation unit 202 as the biological information related to the finger 1. Including a biometric information acquisition device that acquires a planar reconstructed image of a subject generated by the method, and for registering the biometric information or a feature amount extracted therefrom as personal authentication data A data registration device is included.

  Note that the stereoscopic image registration database unit 104 and the reconstructed image registration database 204 are not provided in the apparatus, but individual registration data (stereoscopic image or its feature quantity and reconstructed image or its feature quantity) are provided from each database provided outside the apparatus. Can be configured to be input to the stereoscopic image matching calculation unit 105 and the reconstructed image matching calculation unit 205, respectively, and a personal authentication device having such a configuration is also included in the present invention.

1 is a configuration explanatory diagram of a personal authentication device according to Embodiment 1 of the present invention. FIG. It is the figure which observed the compound eye imaging system from the photographic subject side. It is a schematic diagram which shows a blood vessel pattern and its compound eye image. It is a figure explaining a stereo image production | generation from an optical side. It is a figure explaining the 3D image generation from the side of image processing. It is a figure which shows an example of the compound eye imaging system using the lens array which consists of a some physically independent lens. It is a structure explanatory drawing of the personal authentication apparatus which concerns on Example 2 of this invention. It is a flowchart which shows the example of a flow of the process which produces | generates a some stereo image and synthesize | combines a single stereo image from these stereo images. It is a figure for demonstrating the positional relationship of the single-eye image in a compound eye image. It is a figure explaining the process which synthesize | combines a single stereo image from a some stereo image. It is structure explanatory drawing of the personal authentication apparatus which concerns on Example 3 of this invention. It is a figure explaining the process which produces | generates the planar reconstruction image of a to-be-photographed object from several single-eye images. It is a flowchart which shows the example of a processing flow which produces | generates a reconstruction image from a compound eye image.

Explanation of symbols

1 finger (living part)
2 Blood vessels (subject)
DESCRIPTION OF SYMBOLS 3 Lens array 4 Light-shielding member 6 Image pick-up element 8 Light emitting diode 102 Three-dimensional image calculating part 103 Registration / authentication switching part 104 Three-dimensional image registration database part 105 Three-dimensional image collation calculating part 106 Judgment output part 107 Three-dimensional image composition calculating part 202 Reconstructed image calculation Unit 204 reconstruction image database unit 205 reconstruction image collation operation unit 206 determination output unit

Claims (9)

It includes a lens array in which a plurality of lenses are arrayed and an image sensor located on the image side thereof, and is connected by each lens of the lens array with a blood vessel inside a living body part located on the subject side of the lens array as a subject. A compound eye imaging system that captures a compound eye image, which is a set of images to be imaged (denoted as a single eye image), with the imaging element;
Stereoscopic image generating means for generating a stereoscopic image of the subject based on a plurality of single-eye images in a compound eye image captured by the compound eye imaging system;
Have
A biological information acquisition apparatus that acquires a stereoscopic image generated by the stereoscopic image generation means as biological information related to the biological part. It includes a lens array in which a plurality of lenses are arrayed and an image sensor located on the image side thereof, and is connected by each lens of the lens array with a blood vessel inside a living body part located on the subject side of the lens array as a subject. A compound eye imaging system that captures a compound eye image, which is a set of images to be imaged (denoted as a single eye image), with the imaging element;
Stereoscopic image generating means for generating a plurality of stereoscopic images of the subject based on a plurality of single-eye images in a compound eye image captured by the compound eye imaging system;
3D image synthesis means for generating a single 3D image by combining a plurality of 3D images generated by the 3D image generation means;
Have
A biological information acquisition apparatus that acquires a stereoscopic image generated by the stereoscopic image synthesis means as biological information related to the biological part. It includes a lens array in which a plurality of lenses are arrayed and an image sensor located on the image side thereof, and is connected by each lens of the lens array with a blood vessel inside a living body part located on the subject side of the lens array as a subject. A compound eye imaging system that captures a compound eye image, which is a set of images to be imaged (denoted as a single eye image), with the imaging element;
Stereoscopic image generating means for generating a stereoscopic image of the subject based on a plurality of predetermined single-eye images in a compound eye image captured by the compound eye imaging system;
Reconstructed image generating means for generating a planar reconstructed image of the subject based on a plurality of single-eye images other than the predetermined single-eye image in the compound-eye image captured by the image sensor;
Have
The biological information acquisition apparatus which acquires the three-dimensional image produced | generated by the said three-dimensional image production | generation means and the reconstruction image produced | generated by the said reconstruction image production | generation means as biological information regarding the said biological body part.   The biological information according to claim 1, wherein the compound-eye imaging system includes light shielding means for preventing crosstalk on an image plane of light rays passing through each lens of the lens array. Acquisition device.   5. The biological information acquisition apparatus according to claim 1, wherein the compound eye imaging system includes an illumination unit that irradiates light to the living body part.   The biological information acquiring apparatus according to claim 5, wherein the light emitting unit of the illuminating unit is disposed so as to contact the surface of the biological part.   The biological information acquiring apparatus according to claim 5, wherein the illumination unit irradiates near infrared light. The biological information acquisition apparatus according to any one of claims 1 to 7,
Authentication processing means for performing personal authentication by collating biometric information acquired by the biometric information acquisition apparatus or feature amounts extracted from the biometric information with pre-registered data;
A personal authentication device. The biological information acquisition apparatus according to any one of claims 1 to 7,
An operation switching means for switching the operation to a registration operation or an authentication operation;
Database means for registering the biometric information acquired by the biometric information acquisition device or the feature quantity extracted from the biometric information as data for personal authentication when the operation is switched to the registration operation by the action switching means;
When the operation is switched to the authentication operation by the operation switching unit, the biometric information acquired by the biometric information acquisition device or the feature amount extracted from the biometric information is collated with the data registered in the database unit. Authentication processing means for performing personal authentication by
A personal authentication device.

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