Title of Invention: Judgment System, Judgment Method, Computer Program, and Authentication System
Technical field
[0001]
　TECHNICAL FIELD The present invention relates to a technical field of a determination system, a determination method, a computer program, and an authentication system for determining a subject.
Background technology
[0002]
　As this type of system, a system that detects fraud when performing biometric authentication is known. For example, Patent Literature 1 discloses a technique for detecting spoofing by using the difference between the biological distance and the non-biological distance. Patent Document 2 discloses a technique for detecting spoofing by comparing a video captured in the eyes of a subject with a specific image. Patent Document 3 discloses a technique of displaying a specific background image at an authentication location and detecting spoofing using the luminance value of the captured image.
prior art documents
patent literature
[0003]
Patent Document 1: International Publication No. 2009/110323
Patent Document 2: JP-A
-2007-072861 Patent Document 3: JP-A-2007-026330
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0004]
　Various methods are used to determine spoofing. However, the techniques described in the above-mentioned patent documents have technical problems, such as complicated device configurations and processing details, or lower determination accuracy depending on the situation.
[0005]
　The present invention has been made in view of the above problems, and provides a determination system, a determination method, a computer program, and an authentication device capable of accurately determining whether or not a subject is a living body. is the subject.
Means to solve problems
[0006]
　One aspect of the determination system of the present invention includes projection control means for projecting a random marker onto a projection means within an angle of view of an imaging means, and acquisition means for acquiring an image of a subject including the marker from the imaging means. and determination means for determining whether or not the subject imaged by the imaging means is a living body based on the state of the marker included in the image.
[0007]
　According to one aspect of the determination method of the present invention, a projecting means projects random markers within an angle of view of an imaging means, an image of a subject including the markers is acquired from the imaging means, and the Based on the state of the marker, it is determined whether or not the subject imaged by the imaging means is a living body.
[0008]
　According to one aspect of the computer program of the present invention, a projecting means projects a random marker within an angle of view of an imaging means, an image of a subject including the marker is acquired from the imaging means, and the A computer is operated to determine whether or not the subject imaged by the imaging means is a living body based on the state of the marker.
[0009]
　One aspect of the authentication system of the present invention comprises projection control means for projecting a random marker onto a projection means within an angle of view of an imaging means, and acquisition means for acquiring an image of a subject including the marker from the imaging means. a determining means for determining whether or not the subject imaged by the imaging means is a living body based on the state of the marker included in the image; and executing means for executing the authentication process of the subject.
Effect of the invention
[0010]
　According to one aspect of each of the determination system, determination method, computer program, and authentication system described above, it is possible to accurately determine whether or not the subject is a living body. As a result, for example, spoofing using a photograph or the like can be detected, and biometric authentication can be performed appropriately.
Brief description of the drawing
[0011]
1 is a block diagram showing the functional configuration of a determination system according to an embodiment; FIG.
2 is a block diagram showing the hardware configuration of the determination system according to the embodiment; FIG.
3 is a block diagram showing the overall configuration of an authentication system according to an embodiment; FIG.
4 is a flow chart showing the operation flow of the authentication system according to the embodiment; FIG.
5 is an image diagram showing an example of marker projection at normal time; FIG.
6 is an image diagram showing an example of marker projection at the time of attack; FIG.
7 is a comparison diagram showing the difference between an image captured during normal times and an image captured during an attack. FIG.
8 is a comparison diagram showing an example of projecting markers so as to overlap a subject; FIG.
MODE FOR CARRYING OUT THE INVENTION
[0012]
　Hereinafter, embodiments of a judgment system, a judgment method, a computer program, and an authentication system will be described with reference to the drawings.
[0013]
A determination system
　according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG.
[0014]
　(Functional Configuration)
　First, the functional configuration of the determination system according to this embodiment will be described with reference to FIG. FIG. 1 is a block diagram showing the functional configuration of the determination system according to the embodiment.
[0015]
　In FIG. 1, a determination system 10 according to the present embodiment is configured as a device for determining whether or not a person to be authenticated (in other words, a face image capture target) is a living body. The determination system 10 includes a projection control unit 101, an image acquisition unit 102, and a living body determination unit 103 as processing blocks for realizing its functions.
[0016]
　The projection control unit 101 is configured to control the operation of projection means (for example, a projector 20 to be described later) that projects a marker. The projection control unit 101 can control the projection means to project random markers so as to overlap the background of the subject or the subject. The projection control unit 101 stores, for example, a plurality of types of markers (specifically, markers having different colors, shapes, sizes, etc.) in advance, and randomly selects one or a plurality of markers from among them. Project. Alternatively, the projection control unit 101 may automatically generate and project a marker each time.
[0017]
　The image acquisition unit 102 is configured to be able to acquire an image of a subject for determination as to whether or not the subject is a living body. The image acquisition unit 102 acquires an image of the subject including the marker projected by the projection control unit 101 . Further, the image acquisition unit 102 may be configured to acquire a plurality of temporally continuous images (in other words, moving images). The image acquired by the image acquisition unit 102 is configured to be output to the living body determination unit 103 .
[0018]
　Based on the image acquired by the image acquisition unit 102, the living body determination unit 103 determines whether the subject is a living body. More specifically, the living body determination unit 103 determines whether the subject is actually present in front of an imaging means (for example, a camera 30 to be described later), or whether the subject is being "impersonated" using a photograph or the like. judge. The living body determination unit 103 determines whether the subject is a living body based on the state of the marker included in the image of the subject (that is, the marker projected by the projection control unit 101). A specific determination method in the living body determination unit 103 will be described in detail later. The determination result by the biometric determination unit 103 is configured to be output to an external device (for example, an authentication device 40 described later).
[0019]
　(Hardware Configuration)
　Next, the hardware configuration of the determination system 10 according to the present embodiment will be described with reference to FIG. FIG. 2 is a block diagram showing the hardware configuration of the determination system according to the embodiment.
[0020]
　As shown in FIG. 2, the determination system 10 according to the present embodiment includes a CPU (Central Processing Unit) 11, a RAM (Random Access Memory) 12, a ROM (Read Only Memory) 13, and a storage device 14. ing. Decision system 10 may further comprise an input device 15 and an output device 16 . The CPU 11 , RAM 12 , ROM 13 , storage device 14 , input device 15 and output device 16 are connected via a data bus 17 .
[0021]
　The CPU 11 reads computer programs. For example, the CPU 11 is configured to read computer programs stored in at least one of the RAM 12, ROM 13 and storage device 14. FIG. Alternatively, the CPU 11 may read a computer program stored in a computer-readable recording medium using a recording medium reader (not shown). The CPU 11 may acquire (that is, read) a computer program from a device (not shown) arranged outside the determination system 10 via the network interface. The CPU 11 controls the RAM 12, the storage device 14, the input device 15 and the output device 16 by executing the read computer program. Particularly in this embodiment, when the computer program read by the CPU 11 is executed, a functional block for determining whether or not the subject is a living body is realized in the CPU 11 .
[0022]
　The RAM 12 temporarily stores computer programs executed by the CPU 11 . RAM 12 temporarily stores data temporarily used by CPU 11 while CPU 11 is executing a computer program. The RAM 12 may be, for example, a D-RAM (Dynamic RAM).
[0023]
　The ROM 13 stores computer programs executed by the CPU 11 . The ROM 13 may also store other fixed data. The ROM 13 may be, for example, a P-ROM (Programmable ROM).
[0024]
　The storage device 14 stores data that the determination system 10 saves for a long time. The storage device 14 may operate as a temporary storage device for the CPU 11 . The storage device 14 may include, for example, at least one of a hard disk device, a magneto-optical disk device, an SSD (Solid State Drive), and a disk array device.
[0025]
　The input device 15 is a device that receives input instructions from the user of the determination system 10 . Input device 15 may include, for example, at least one of a keyboard, mouse, and touch panel.
[0026]
　The output device 16 is a device that outputs information about the determination system 10 to the outside. For example, output device 16 may be a display device (eg, display) capable of displaying information about determination system 10 .
[0027]
　
　Next, an authentication system including the determination system 10 described above will be described with reference to FIGS. 3 to 8. FIG.
[0028]
　(System Configuration)
　First, the overall configuration of the authentication system according to this embodiment will be described with reference to FIG. FIG. 3 is a block diagram showing the overall configuration of the authentication system according to the embodiment.
[0029]
　In FIG. 3, an authentication system 1 according to this embodiment is configured as a system that executes authentication processing (so-called face authentication) using a face image of a subject. The authentication system 1 includes the determination system 10 described above, the projector 20 , the camera 30 and the authentication device 40 .
[0030]
　The projector 20 is configured to project random markers according to instructions from the projection control unit 101 in the determination system 10 . The projector 20 is arranged at a position where the marker can be projected within the angle of view of the camera 30 . The light projector 20 may project the marker with visible light, or may project the marker with invisible light such as near-infrared light.
[0031]
　The camera 30 is configured to be able to capture an image of a person to be authenticated (especially, an image around the face). In addition, the camera 30 is arranged at a position capable of capturing an image of the subject and the marker projected from the projector 20 . The image acquired by the camera 30 is configured to be output to the image acquiring section 102 in the determination system 10 . In addition, when the light projector 20 projects the marker with invisible light, the camera 30 may be configured as a camera capable of imaging invisible light.
[0032]
　The authentication device 40 performs face authentication of the subject based on the image captured by the camera 30 . Further, the authentication device 40 is particularly configured to be able to execute authentication processing based on the determination result of the determination system 10 (that is, whether or not the subject is a living body). A method of using the determination result of the determination system 10 in the authentication device 40 will be described later in detail. Note that the authentication device 40 may be configured to be capable of executing biometric authentication other than face authentication (for example, iris authentication, etc.) instead of face authentication. As for the specific contents of the authentication process executed by the authentication device 40, existing methods can be appropriately employed, and thus detailed description thereof will be omitted here. The authentication device 40 may be configured as a cloud, for example.
[0033]
　(Flow of Operation)
　Next, the flow of operation of the authentication system 1 according to this embodiment will be described with reference to FIG. FIG. 4 is a flowchart showing the operation flow of the authentication system according to this embodiment.
[0034]
　As shown in FIG. 4, the authentication system 1 according to this embodiment first determines whether or not there is a person to be authenticated (step S101). Whether or not the target person exists can be determined, for example, by detecting the presence of an object within the angle of view of the camera. The presence of the subject may be detected by the camera 30, or may be detected by other sensors (not shown). Alternatively, the presence of the target person may be detected when the target person operates the terminal or the like. Note that if it is determined that the target person does not exist (step S101: NO), the subsequent processing is omitted, and the series of operations ends. In this case, the process of step S101 may be resumed after the predetermined period of time has elapsed.
[0035]
　If it is determined that the target person exists (step S101: YES), the projection control unit 101 randomly selects a marker to be projected (step S102). The projection control unit 101 then controls the projector 20 to project the selected marker. At this time, the projection control unit 101 may specify the projection position of the marker. Specifically, the projection control unit 101 may instruct to project a marker on the background of the subject (in other words, a position that does not overlap the subject), or a position that at least partially overlaps the subject. may be instructed to project a marker on the . However, when the marker is projected so as to overlap the target person, it is preferable to project the marker while avoiding the position of the eyes so as not to make the target person feel glare, or to project the marker using invisible light. Also, it may be instructed to project a plurality of markers at different positions.
[0036]
　When the marker is projected, the image acquisition unit 102 acquires an image of the subject from the camera 30 (step S104). This image also includes the markers projected by the projector 20 . Note that when acquiring a moving image of a subject, the image acquiring unit 102 may continuously acquire images of the subject.
[0037]
　Subsequently, the living body determination unit 103 determines whether the subject is a living body based on the image of the subject acquired by the image acquisition unit 102 (step S105). The living body determination unit 103 determines whether or not the target person is a living body based on whether or not the image of the target person is captured in a state in which the marker included in the image of the target person is assumed. Specifically, the living body determination unit 103 determines that the subject is a living body when the state of the marker included in the image of the subject is as expected, and determines that the subject is a living body when the state is unexpected. It is determined that the subject is not a living body. The living body determination unit 103 determines whether or not the state of the marker is as expected, for example, using at least one of the position, angle, and size of the marker. However, the living body determination unit 103 may determine whether or not the subject is a living body using parameters other than the position, angle, and size of the marker (for example, color, shape, etc.).
[0038]
　For example, the living body determination unit 103 projects a marker toward a wall in a state where no target person is present in advance, and stores the captured image at that time as a reference image. By doing so, it is possible to determine whether or not the state of the marker is as expected by comparison with the reference image. More specifically, the living body determination unit 103 determines the matching degree (or at least one) of the position, angle, and size between the marker included in the image of the subject and the marker in the reference image. , it is possible to determine whether or not the subject is a living body. Regarding the derivation of the matching degree, an existing method may be appropriately adopted, but general template matching in image processing such as SSD (Sum Of Squared Difference), SAD (Sum of Absolute Difference), etc. A pattern matching technique may be used.
[0039]
　When it is determined that the target person is a living body (step S105: YES), the authentication device 40 executes the target person authentication processing (here, face authentication using a face image) (step S106). Specifically, the authentication device 40 extracts a face area from the image of the subject and determines whether or not the face of the subject matches a pre-registered face. For face authentication, the image of the subject may be used as it is, or a feature amount (such as luminance) extracted from the image of the subject may be used. After completing the authentication process, the authentication device 40 outputs the result (for example, "authentication OK" or "authentication NG").
[0040]
　On the other hand, when it is determined that the subject is not a living body (step S105: NO), the authentication device 40 does not perform face authentication of the subject (that is, step S106 is omitted). This is because if the subject is not a living body, there is a suspicion of "spoofing" using a photograph or the like. As a result of not executing the authentication process, for example, it is possible to avoid an attack from a user who attempts to break through the authentication process illegally. Note that the living body determination unit 103 may notify that impersonation is being performed when it determines that the target person is not a living body. Specifically, the living body determination unit 103 may output a warning display or a warning sound to the system administrator or the like.
[0041]
　(Specific Example of Operation)
　Next, a specific example of operation of the authentication system 1 (especially, the determination system 10) according to the present embodiment will be described with reference to FIGS. 5 to 7. FIG. FIG. 5 is an image diagram showing an example of marker projection during normal operation. FIG. 6 is an image diagram showing an example of marker projection at the time of attack. FIG. 7 is a comparison diagram showing the difference between an image captured during normal times and an image captured during an attack.
[0042]
　As shown in FIG. 5, when the subject 500 actually exists in front of the projector 20 and the camera 30 (in other words, when the subject 500 is a living body), the marker 200 projected from the projector 20 is 500 background (eg, a wall behind the subject 500). In this case, since the positional relationship between the light projector 20 and the background is known in advance, it is possible to accurately predict how the marker will be projected on the background. For example, by projecting a marker onto a background (for example, a wall, etc.) without a target person in advance and storing the captured image at that time as a reference image, the positional relationship between the projector 20 and the background can be grasped in advance. It is possible to
[0043]
　On the other hand, as shown in FIG. 6, when an attacker 600 directs a photograph of a target person 500 toward the camera 30 (in other words, when the target person 500 is not a living body), the marker 200 projected from the projector 20 is Projected onto a photograph of the subject 500 . In this case, since the marker 200 is projected at a position closer than expected, the size of the marker 200 becomes smaller than expected, for example.
[0044]
　As shown in FIG. 7, when the images of the subject 500 captured in the situations of FIGS. 5 and 6 are compared, there is a clear difference in how the markers 200 are captured. Specifically, when the subject 500 is a living body, the marker 200 appears in the captured image in the expected state, as shown in FIG. 7A. On the other hand, when the target person 500 is not a living body, as shown in FIG. be reflected. By analyzing how the marker 200 appears in the captured image in this manner, it is possible to accurately determine whether the subject 500 is a living body.
[0045]
　In the example described above, the marker 200 is assumed to be a circle for convenience of explanation, but the shape of the marker is not particularly limited. For example, the markers 200 may include more complex patterns, letters, or the like. Also, a plurality of markers 200 may be projected on the background of the subject. In this case, if at least one marker 200 among the plurality of projected markers 200 appears in the captured image in an unexpected state, it may be determined that the subject 500 is not a living body.
[0046]
　(Modification)
　Next, a specific operation example of the authentication system 1 according to the modification will be described with reference to FIG. FIG. 8 is a comparison diagram showing an example of projecting markers so as to overlap the subject.
[0047]
　As shown in FIG. 8 , the marker 200 may be projected so as to overlap the subject 500 . Even in such a case, there is a clear difference in how the marker 200 is captured in the captured image depending on whether the subject 500 is a living body or not. Specifically, when the subject 500 is a living body, the marker 200 is distorted (shifted) at the boundary of the living body, as shown in FIG. 8A. Alternatively, even if the marker 200 is projected so as to completely overlap the target person 500 , the unevenness of the target person 500 causes the marker 200 to be slightly distorted. On the other hand, when the target person 500 is not a living body (for example, in the case of a planar object such as a photograph), the marker 200 is not distorted as shown in FIG. 8(b). By projecting the marker 200 so as to overlap the subject 500 in this way, it is possible to determine whether the subject 500 is a living body based on whether the marker 200 is distorted in the captured image. Even if the marker 200 is distorted, if the distortion is unnatural, it may be determined that the subject 500 is not a living body.
[0048]
　(Modification 2)
　The projector 20 (that is, projection means for projecting the marker 200 ) may be provided independently of the determination system 10 . For example, the light projector 20 may be configured to project the marker 200 manually (that is, by an operator's operation). In this way, the marker 200 can be projected at any timing of the operator. In this case, the determination system 10 does not have to include the projection control section 101 .
[0049]
　(Modification 3)
　Projection of the marker 200 may be started in a state where the target person 500 does not exist. Specifically, after projecting the marker 200, it may be determined whether or not the target person 500 exists, and if the target person 500 exists, the image of the target person 500 may be acquired. In this way, the subject 500 can see the position of the marker 200 in advance (that is, the position of the marker 200 can be confirmed before the image is captured by the camera 30). Therefore, subject 500 can adjust its own position according to the position of marker 200 . For example, the subject 500 can adjust his standing position so that the marker 200 does not hit his eyes.
[0050]
　(Technical Effects)
　Next, technical effects obtained by the authentication system 1 according to this embodiment will be described.
[0051]
　As described with reference to FIGS. 1 to 7, in the authentication system 1 according to the present embodiment, when performing authentication processing, the marker 200 is projected to determine whether or not the subject 500 is a living body. . Therefore, for example, it is possible to avoid an attack by "spoofing" using a photograph or the like. By using the marker 200 as in the present embodiment, it is possible to avoid unauthorized breach of authentication with a relatively simple device configuration. Moreover, since no special action is required of the target person 500, the burden on the target person 500 in the authentication process is not increased.
[0052]
　
　The above-described embodiments can be further described as the following additional remarks, but are not limited to the following.
[0053]
　(Supplementary note 1)
　The determination system according to Supplementary note 1 includes projection control means for projecting a random marker within an angle of view of an imaging means, acquisition means for acquiring an image of a subject including the marker from the imaging means, and determination means for determining whether or not the subject imaged by the imaging means is a living body based on the state of the marker included in the image.
[0054]
　(Supplementary note 2)
　In the determination system according to Supplementary note 2, the determination means determines whether the subject imaged by the imaging means is based on at least one of the position, angle, and size of the marker in the image. The determination system according to appendix 1, characterized by determining whether or not the object is a living body.
[0055]
　(Supplementary Note 3)
　The determination system according to Supplementary Note 3 is characterized in that, when the determination means determines that the subject imaged by the imaging means is not a living body, it notifies that spoofing is being performed. The determination system according to Supplementary Note 1 or 2.
[0056]
　(Appendix 4)
　The judgment system according to any one of appendices 1 to 3, wherein the projection control means projects the marker on a background portion of the subject. is.
[0057]
　(Supplementary note 5)
　The determination system according to Supplementary note 5 is characterized in that the projection control means projects the marker so as to at least partially overlap the subject. A determination system as described.
[0058]
　(Appendix 6)
　The judgment system according to appendix 6 is the judgment system according to any one of appendices 1 to 5, wherein the projection control means projects the marker with invisible light.
[0059]
　(Supplementary note 7)
　In the determination system according to Supplementary note 7, the acquisition means acquires a plurality of temporally continuous images from the imaging means, and the determination means determines the state of the marker included in the plurality of images. 7. The determination system according to any one of appendices 1 to 6, wherein it is determined whether or not the subject imaged by the imaging means is a living body based on.
[0060]
　(Supplementary Note 8)
　The determination method according to Supplementary Note 8 includes projecting a random marker on the projection means within the angle of view of the imaging means, obtaining an image of the subject including the marker from the imaging means, and obtaining an image of the subject including the marker from the imaging means. and determining whether or not the subject imaged by the imaging means is a living body based on the state of the marker.
[0061]
　(Supplementary note 9)
　The computer program according to Supplementary note 9 causes the projecting means to project a random marker within the angle of view of the imaging means, acquires an image of the subject including the marker from the imaging means, and includes the marker in the image. The computer program causes a computer to determine whether or not the subject imaged by the imaging means is a living body based on the state of the marker.
[0062]
　(Supplementary note 10)
　The authentication system according to Supplementary note 10 includes: projection control means for projecting a random marker onto a projection means within an angle of view of an imaging means; determining means for determining whether or not the subject imaged by the imaging means is a living body based on the state of the marker included in the image; and determining means for determining that the subject is a living body. and executing means for executing the authentication process of the subject when the subject is authenticated.
[0063]
　The present invention can be appropriately modified within the scope not contrary to the gist or idea of ​​the invention that can be read from the scope of claims and the entire specification, and a judgment system, a judgment method, a computer program, and an authentication system that accompany such modifications is also included in the technical idea of ​​the present invention.
Code explanation
[0064]
　1 authentication system
　10 determination system
　20 projector
　30 camera
　40 authentication device
　101 projection control unit
　102 image acquisition unit
　103 biometric determination unit
　200 marker
　500 subject
　600 attacker
The scope of the claims
[Claim 1]
　Projection control means for projecting a random marker onto a projection means within an angle of view of an
　imaging means; Acquisition means for acquiring an image of a subject including the marker from the imaging means
　; and determination means for determining whether or not the subject imaged by the imaging means is a living body based on the above
　.
[Claim 2]
　The determination means determines whether or not the subject imaged by the imaging means is a living body based on at least one of the position, angle and size of the marker in the image. The determination system according to claim 1.
[Claim 3]
　3. The determination system according to claim 1, wherein, when the determination means determines that the subject imaged by the imaging means is not a living body, the determination system notifies that spoofing is being performed.
[Claim 4]
　4. The determination system according to any one of claims 1 to 3, wherein the projection control means projects the marker on a background portion of the subject.
[Claim 5]
　4. The determination system according to any one of claims 1 to 3, wherein the projection control means projects the marker so as to at least partially overlap the subject.
[Claim 6]
　6. The determination system according to claim 1, wherein said projection control means projects said marker with invisible light.
[Claim 7]
　The acquiring means acquires a plurality of temporally continuous images from the imaging means, and the
　determining means determines the target imaged by the imaging means based on the states of the markers included in the plurality of images.
　7. The determination system according to any one of claims 1 to 6, wherein it is determined whether or not a person is a living body .
[Claim 8]
　A random marker is projected onto the projection means within the angle of view of the imaging means,
　an image of the subject including the marker is acquired from the
　imaging means, and based on the state of the marker contained in the image, the imaging means
　A determination method, comprising determining whether or not the imaged subject is a living body .
[Claim 9]
　Random markers are projected onto the projection means within an angle of view of the imaging means,
　an image of the subject including the markers is acquired from the
　imaging means, and based on the state of the markers contained in the image, the imaging means
　A computer program characterized by causing a computer to operate so as to determine whether or not the imaged subject is a living body .
[Claim 10]
　Projection control means for projecting a random marker onto a projection means within an angle of view of an
　imaging means; Acquisition means for acquiring an image of a subject including the marker from the imaging means
　; determining means for determining whether or not the subject imaged by the imaging means is a living
　body, and performing authentication processing of the subject when the subject is determined to be a living body based on
　an authentication system, comprising: an execution means ;