JP2005287878A - Living body distinguishing apparatus, identification apparatus, and method for distinguishing living body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a living body distinguishing apparatus capable of preventing successful pretending to be another person by simple constitution without using complicated constitution, and to provide an identification apparatus using the same and a method for distinguishing a living body. <P>SOLUTION: The living body distinguishing apparatus is provided with: an aperture 1; an aperture adjusting part 4 for adjusting the opening degree of the aperture 1; a photographing part 3 for photographing 3 pictures of different opening degrees of the aperture 1; a subject extraction part 10 for extracting a subject by using a first picture of the smallest opening degree and a second picture of the opening degree of the aperture 1 larger than that of the first picture among the 3 pictures; and a living body distinguishing part 11 for distinguishing the living body by comparing the second picture with the third picture of the opening degree of the aperture 1 larger than that of the second picture. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an authentication device that performs personal authentication using biometric information such as an image of a face or eye of a person to be authenticated, and in particular, an authentication having a biometric discrimination function that determines whether or not the person to be authenticated is a living body. Relates to the device.

  In recent years, as a method of personal authentication at the time of access in a device requiring high security, such as an entrance / exit management device, such as a fingerprint, iris, fundus blood vessel, facial features, blood vessel pattern of arms and fingers, etc. An authentication apparatus using an authentication method using biometric information unique to the person to be authenticated has been put into practical use.

  In such an authentication device, an unauthorized person uses a pre-registered photograph, picture, or video of another person's face and eyes to authenticate on behalf of another person, so-called “spoofing”. Is a big issue.

In order to solve such a problem, for example, in a face authentication apparatus, a subject is photographed under two different photographing conditions using the fact that a living body is a solid having a depth compared to a photograph or the like, and There has been proposed an authentication device having a biometric discrimination function capable of discriminating whether or not a subject is a living body by comparing differences in shadows (see, for example, Patent Document 1).
JP 2003-178306 A

  However, in the conventional authentication apparatus as described above, when determining whether or not the subject is a living body, it is necessary to photograph the subject while changing the photographing conditions such as the illumination condition and the photographing direction. In order to change the shooting conditions in this way, it is necessary to provide a dedicated light source control circuit, a plurality of lens systems, or a mechanism for moving the lens system, so the configuration is inevitably complicated. There was a problem of becoming.

  The present invention has been made in view of such a problem, and without using a complicated configuration as in the past, a biometric discrimination device capable of preventing spoofing with a simple configuration, an authentication device using the same, and An object of the present invention is to provide a living body discrimination method.

  The living body discrimination device according to the present invention was photographed by the photographing unit with different apertures by the aperture, the aperture adjusting unit for adjusting the aperture of the aperture, the imaging unit for imaging the subject, and the aperture adjusting unit. It is characterized by comprising a living body discriminating section that discriminates whether or not the subject is a living body by comparing a plurality of images with different opening degrees of the subject.

  According to such a configuration, there is provided a living body discrimination device capable of preventing spoofing with a simple configuration in which the aperture of the aperture is adjusted to take images with different apertures and compare the images. can do.

  In addition, the living body determination unit may be configured to determine whether or not the subject is a living body based on differences in the degree of focus in a plurality of images with different opening degrees of the subject.

  According to such a configuration, it is possible to realize a living body determination apparatus that can prevent spoofing with a simple configuration of comparing the degrees of focus of images.

  Further, the living body determination unit may be configured to determine that the subject is not a living body when the degrees of focus of the plurality of images having different opening degrees of the subject are substantially equal.

  According to such a configuration, it is further determined that the subject is not a living body when the in-focus degrees of the images having different aperture degrees are substantially equal, and thus impersonation by a planar object such as a photograph, a picture, or an image is performed. Can be effectively prevented.

  Further, the biometric determination unit may be configured to calculate the degree of focus in a plurality of images with different opening degrees of the subject based on a coefficient when DCT processing is performed.

  According to such a configuration, the degree of focus is calculated based on the coefficient using DCT processing widely used in image compression technology and the like, and whether the subject is a living body based on the degree of focus is determined. Therefore, it is possible to provide a living body discrimination device that can be easily configured using a DCT processing block or the like used in an image compression technique such as MPEG.

  Further, the biometric determination unit may be configured to calculate the degree of focus in a plurality of images with different opening degrees of the subject by integrating coefficient values of predetermined frequencies when DCT processing is performed.

  According to such a configuration, since the degree of focus is calculated by integrating the coefficient values of the predetermined frequency, it is possible to perform biometric discrimination more suitable for human detection.

  In addition, a configuration may be provided that includes a subject extraction unit that extracts a subject region image from a plurality of images having different opening degrees of the subject.

  According to such a configuration, it is further possible to extract only a subject existing at a predetermined distance from the imaging unit and perform biometric discrimination thereof.

  Further, the living body determination unit may be configured to determine whether or not the subject is a living body using an image of the subject area.

  According to such a configuration, since the discrimination process is further performed using the image of the area extracted by the subject extraction unit, it is possible to reduce the load of the biometric discrimination process in the arithmetic device.

  Further, the photographing unit photographs three images having different opening degrees, and the subject extracting unit, compared with the first image and the first image having the smallest opening degree among the three images having different opening degrees. A process of extracting a subject using the second image having a large opening degree is performed, and the living body determination unit uses the second image and the third image having a larger opening degree than the second image to detect the subject. The structure which discriminate | determines whether it is a biological body may be sufficient.

  According to such a configuration, a function of extracting a subject from an image and determining a subject's living body can be realized with a simple configuration of taking three images and comparing the images.

  Further, the diaphragm unit may have a liquid crystal shutter.

  According to such a configuration, it is possible to further improve the durability of the throttle portion.

  Further, the diaphragm adjustment unit may include a light amount adjustment unit that adjusts the amount of light so that the amount of light transmitted through the liquid crystal shutter is constant.

  According to such a configuration, since the amount of light passing through the liquid crystal shutter can be made constant, pre-processing such as brightness adjustment is required when images taken with different apertures are compared. Disappear.

  Next, the authentication device of the present invention includes the biometric determination device of the present invention and an authentication processing unit that performs subject authentication processing using an image in which the subject is determined to be a living body by the biometric determination unit. It is a feature.

  According to such a configuration, authentication processing can be performed on a subject that has been determined to be a living body by the living body determination device, so that it is possible to realize an authentication device that is less likely to be impersonated and has high security.

  Next, the living body discrimination method of the present invention includes a first step of capturing a first image of a subject with a first aperture opening degree, and a second aperture opening degree that is larger than the first aperture opening degree. A second step of photographing a second image of the subject, a third step of photographing a third image of the subject with a third aperture opening degree larger than the second aperture opening degree, A fourth step of calculating the degree of focus of each of the image and the second image is compared with the degree of focus to extract a subject region having a high degree of focus from the first image and the second image. Step 7 for determining whether the subject is a living body by comparing the degrees of focus with the sixth step for calculating the degrees of focus of the second image and the third image respectively. It is characterized by comprising the following steps.

  According to such a method, it is possible to extract a subject by a simple method of taking three images with different aperture apertures and comparing the images, and whether or not the subject is a living body. It is possible to provide a living body discriminating method capable of discriminating.

  As described above, by using the biometric discrimination device of the present invention, the authentication device using the biometric discrimination device, and the biometric discrimination method, the aperture of the aperture is adjusted and images with different apertures of the aperture are photographed. With a simple configuration of comparing images, it is possible to realize a biometric discrimination device, an authentication device, and a biometric discrimination method that can prevent spoofing.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
First, the biometric device according to the first embodiment of the present invention will be described.

  FIG. 1 is a block diagram showing the configuration of the biometric device according to the first embodiment of the present invention.

  In FIG. 1, a living body discrimination device 15 according to a first embodiment of the present invention includes an aperture 1 that can be controlled to be opened and closed, a single-focus lens 2 that collects light beams that have passed through the aperture 1, a diaphragm 1 and the lens 2. Based on the imaging unit 3 such as a CCD that captures a light image of the passed subject and outputs an image signal, the synchronization signal generation unit 5 that generates a predetermined synchronization signal, and the synchronization signal generated by the synchronization signal generation unit 5, An image signal corresponding to the difference in the aperture of the diaphragm 1 is acquired from the photographing unit 3 based on the synchronizing signal generated by the diaphragm adjusting unit 4 and the synchronizing signal generating unit 5 for adjusting the aperture of the diaphragm 1, and the image information is obtained. Is distributed to the storage unit according to the difference in the opening degree of the diaphragm unit 1 and output, the first image storage unit 7 that stores the image information distributed by the distribution unit 6, and the second image storage unit 8 And third image memory 9, a subject extraction unit 10, a second image storage unit 8 and a third image connected to the first image storage unit 7 and the second image storage unit 8, respectively, for extracting a subject from the stored image information A display that is connected to the storage unit 9 and that displays the image of the subject extracted by the biometric determination unit 11 and the subject extraction unit 10 for determining whether or not the subject is a living body by a method described later from the image information stored in each of them. And an alarm generation unit 13 that generates an alarm when it is determined by the living body determination unit 11 that the subject is not a living body, that is, impersonation.

  As long as the aperture can be adjusted, the aperture 1 may be configured by using a mechanically known aperture or by using a liquid crystal shutter. By using a liquid crystal shutter as the diaphragm 1, the durability is superior to that of a mechanical diaphragm, and the diaphragm adjustment unit 4 not only adjusts the aperture of the diaphragm 1 but also keeps the amount of light transmitted through the diaphragm 1 constant. Thus, since the transmittance of the liquid crystal shutter can be changed, it is not necessary to perform extra processing such as luminance correction when comparing image information as described later, and the liquid crystal shutter is used. Is desirable in view of practicality.

  The diaphragm adjusting unit 4 may be a mechanism that adjusts the aperture when a mechanical diaphragm is used as the diaphragm 1, and when a liquid crystal shutter is used as the diaphragm 1, the opening / closing control and A control circuit for adjusting the transmittance may be configured.

  In the first embodiment of the present invention, description will be made assuming that the diaphragm adjusting unit 4 can adjust the aperture of the diaphragm 1 so as to have three states of “large”, “medium”, and “small”. .

  In order to control the transmittance of the liquid crystal shutter so that the diaphragm adjusting unit 4 keeps the light amount of the light beam transmitted through the liquid crystal shutter constant, the transmittance corresponding to the aperture is set to be constant. However, although not shown in the figure, it has a sensor unit for measuring the amount of light transmitted through the liquid crystal shutter, and the transmittance of the liquid crystal shutter so that the output from the sensor unit is constant. The structure which adjusts may be sufficient.

  The lens 2 may be a single-focus simple lens system that is widely installed in portable imaging devices such as a mobile phone device with a camera.

  As the imaging unit 3, a well-known imaging device such as a CCD or a CMOS sensor can be used.

  As the synchronization signal generator 5, an oscillation circuit using crystal or the like can be used.

  The first image storage unit 7, the second image storage unit 8, and the third image storage unit 9 are each appropriately selected from known storage means such as a hard disk device (HDD) or a semiconductor memory. Is possible.

  In the biometric discrimination device 15 according to the first embodiment of the present invention, the biometric discrimination device 15 includes the first image storage unit 7, the second image storage unit 8, and the third image storage unit 9. Although a configuration including a storage unit is shown, this does not mean that the biological discrimination device of the present invention is limited to a configuration including three storage units, and the biological discrimination device has one storage unit. In addition, the configuration in which the area to be stored is assigned for each aperture of the diaphragm in the storage unit, and the image information stored in the storage unit is information indicating the aperture of the diaphragm 1 corresponding to each image. May be included as additional information.

  The distribution unit 6 uses the first image storage unit 7, the second image storage unit 8, or the third image storage unit 6 based on the image signal output from the imaging unit 3 based on the synchronization signal generated by the synchronization signal generation unit 5. A dedicated circuit that distributes to the image storage unit 9 can be used. As described above, when there is one storage unit, an area in which the image information is to be stored may be allocated according to the aperture of the diaphragm. Alternatively, it may be realized by software that stores additional information indicating the aperture of the diaphragm added to the image information.

  In the first embodiment of the present invention, image information when the size of the aperture of the diaphragm 1 is “small” in the first image storage unit 7 (hereinafter referred to as first image information) is stored in the first image storage unit 7. The image information (hereinafter referred to as second image information) when the size of the aperture of the diaphragm 1 is “medium” in the second image storage unit 8 is further stored in the third image storage unit 9. It is assumed that image information (hereinafter referred to as third image information) in the case where the size of each is “large” is stored.

  Using the first image information and the second image information described above, the subject extraction unit 10 determines whether the subject is a living body by using the difference in the object depth due to the difference in the aperture of the diaphragm 1. It is detected whether or not the subject to be photographed is within a predetermined range that can be photographed, and when the subject is within the photographable range, the subject region is extracted.

  As will be described later, the function of the subject extraction unit 10 can be realized by using either software or a dedicated circuit.

  The biometric determination unit 11 uses the second image information and the third image information to determine whether the subject is a living body, a photo, a picture, a video, or the like by a method described later. The biometric determination unit 11 can be realized using either software or a dedicated circuit.

  The display unit 12 can be appropriately selected from known display devices such as LCD, EL, or PDP.

  As the alarm generation unit 13, an alarm capable of notifying the surroundings of an abnormality by voice may be used, or an alarm capable of notifying the surroundings using vibration or light may be used.

  In the first embodiment of the present invention, the biometric discrimination device 15 will be described using a configuration including both the display unit 12 and the alarm generation unit 13, but the biometric discrimination device of the present invention is limited to this configuration. Not. For example, the display unit may not be provided, and an output unit that outputs the image information of the subject extracted by the subject extraction unit 10 to another device may be provided, or the living body determination device may include an alarm generation unit. Without being provided, the biometric determination unit may be configured to notify an abnormality to another device or the like via a network or cable connection.

  Here, the functions of the subject extraction unit 10 and the biometric determination unit 11 according to the first embodiment of the present invention will be described in more detail.

  The subject extraction unit 10 and the biometric discrimination unit 11 according to the first embodiment of the present invention perform subject extraction and biometric discrimination using the difference in the object depth Δ due to the difference in the aperture of the diaphragm.

  FIG. 2 is a diagram illustrating a basic principle of the function of the subject extraction unit 10 or the biological determination unit 11 of the biological determination device 15 according to the first embodiment of the present invention.

  As shown in FIG. 2, it is assumed that the object 31 passes through the lens 32 of the stop D and forms an image on the imaging surface of the image sensor 33.

  At this time, when the distance from the object 31 to the lens 32 is u, the distance (focal length) from the lens 32 to the imaging surface of the image sensor 33 is f, and the pixel pitch (resolution) of the image sensor 33 is ε. , The object depth Δ is

It is expressed.

  For example, when using a CCD with a pixel pitch ε = 0.001 mm, using a lens with a focal length f = 2 mm, and changing the aperture D to 0.3 mm, 0.5 mm, and 1.7 mm, the distance to the object The change in the value of the object depth Δ with respect to u is shown in FIG.

  As shown in FIG. 3, for example, when the distance u from the lens 32 to the object is 500 mm, the object depth Δ, which was about 70 mm when the diaphragm is opened (D = 1.7 mm), is about 3 mm. When the aperture is squeezed down by 1 (D = 0.5 mm), it is about 330 mm, and when the aperture is further reduced down to about 1/6 (D = 0.3 mm), it is about 1300 mm.

  The subject extraction unit 10 or the living body discrimination unit 11 of the present invention uses the difference in the object depth Δ due to such a difference in aperture.

  The operation principle of the subject extraction unit 10 and the biometric determination unit 11 according to the first embodiment of the present invention will be described in more detail with reference to FIG.

  FIG. 4 is a diagram for explaining the operation principle of the subject extraction unit 10 and the biometric discrimination unit 11 of the biometric discrimination device 15 according to the first embodiment of the present invention.

As shown in FIG. 4, a subject 41 to be photographed at a distance of 500 mm from the lens 2 of the living body discrimination device 15 and a person 42 other than the subject at a position farther than the subject 41 far from the lens 2 by 700 mm. And The lens 2 mounted on the living body discrimination device 15 has an object depth Δ ₁ = 1300 mm when the distance u to the object is 500 mm as described above and the aperture of the diaphragm is “small” (object In focus within the range of ± 650 mm (strictly speaking, the focus range closer to the camera than the focus position is slightly smaller than the focus range farther from the camera than the focus position. The discussion will proceed assuming that the in-focus range is the same before and after.)), And the object depth Δ ₂ = 330 mm (in the range of distance to the object ± 165 mm) when the aperture is “medium”, and the aperture Is the object depth Δ ₃ = 70 mm (focused at a distance of ± 35 mm to the object).

  FIG. 5 shows an example of image information to be taken by configuring in this way. FIG. 5 is a diagram illustrating an example of image information captured by the biometric device 15 according to the first embodiment of the present invention.

FIG. 5A is a diagram illustrating an example of image information (first image information) when the aperture of the diaphragm is “small”. Like the first image information 51 shown in FIG. 5A, it is possible to obtain image information focused on the entire area. That is, when the aperture of the diaphragm is "small", to the distance 500mm to the object, since the object depth delta ₁ is a ± 650 mm, the subject 41 (distance 500mm) to be imaged and non-object finisher 42 (distance 700 mm), image information in focus can be obtained.

Next, when the aperture of the diaphragm is “medium”, the second image information 52 as shown in FIG. 5B can be obtained. Second image information 52, the subject 41 is in focus because the position of the distance ± 165mm to an object, the shielding 42 other than the object (distance 700 mm), since more than an object depth delta _2, focusing The blurred image information can be obtained.

  In other words, the subject extraction unit 10 includes first image information 51 captured with the aperture opening degree “small” and second image information 52 captured with the aperture opening degree “medium”. And extracting a focused portion (a portion with a high degree of focus or a portion with a low degree of blur) in each of the first image information 51 and the second image information 52. It is possible to extract and output image information of the part.

  For the method of calculating the degree of blur in image information and determining the degree of focus, for example, “Depth distribution detection using moving images with continuously changing camera focus”, Akiyuki Kudo, Hidetoshi Miike, Information Processing Society of Japan, Computer Vision Research Group 98-2, published on January 18, 1996, “A New Sense for Depth of Field”, A.I. Pentlad, IEEE Trans. On Pattern Analysis and Machine Intelligence, vol. PAMI-9, No. 4 The method proposed in July 1987 can be used.

  It is also possible to use the method that the inventors have already proposed in JP-A-2001-227914. According to such a method, pixels constituting an image are divided into small blocks of vertical × horizontal = 8 × 8 pixels, and a coefficient obtained as a result of discrete cosine transform (hereinafter referred to as DCT) for each small block is a frequency. By arranging the components in a matrix and taking the square sum of the coefficients in a predetermined frequency region, it is possible to compare the degree of focusing of the images.

Furthermore, when the aperture of the diaphragm is “large”, image information such as the third image information 53 shown in FIG. 5C can be obtained. In other words, it when the aperture of the diaphragm is "large", relative to the distance 500mm to an object, the object depth delta ₃ because it is ± 70 mm, the portion of the face of the subject 41 to be photographed is also solid having a depth from a portion of the face that can not fall within the scope of the object depth delta ₃ is blurred picture. In FIG. 5C, the image is a blurred image in which the hair portion is in focus, but the eyes and nose are not in focus. On the other hand for the Shah 42 other than the object (distance 700 mm), since more than an object depth delta _3, not focused, it is possible to obtain an image information blurred.

  In other words, the biometric determination unit 11 compares the second image information 52 in which the aperture of the diaphragm is “medium” and the third image information 53 in which the aperture of the diaphragm is “large”. If there is a portion with a different degree of focus in the area of the subject 41, it is determined that the subject 41 is a living body, and the degree of focus between the second image information 52 and the third image information 53 is determined. Is not different in the area of the subject 41, that is, if any image is in focus and the degree of blur is not different, it can be determined that the subject 41 is due to impersonation.

  For example, as shown in FIG. 6, in the case where a photograph 60 taken in advance of the subject 41 is placed at a distance of 500 mm from the living body discrimination device 15, the first image information is displayed as shown in FIG. In any of the image information 61, the second image information 62, and the third image information 63, a focused image is obtained without blurring the area of the photograph 60 of the subject.

  Therefore, the biometric determination unit 11 calculates the degree of focus for the area where the subject of the second image information 62 and the third image information 63 is photographed, and when the degree of focus is equal, or the difference between them is When it is determined that they are within the predetermined error range and substantially equal, it is determined that the subject 41 is impersonated by a planar object such as the photograph 60, and the determination result is output. it can.

  Next, the operation of the living body discrimination device 15 in the first embodiment of the present invention will be described. FIG. 8 is a flowchart showing the operation steps of the living body discrimination device 15 according to the first embodiment of the present invention.

  As shown in FIG. 8, first, the living body discrimination device 15 causes the aperture adjustment unit 4 to set the aperture of the aperture 1 to the “small” state and captures the obtained optical image with the imaging unit 3 (S1).

  The distribution unit 6 stores the image information captured in step S1 in the first image storage unit 7 as the first image information 51 (S2).

  Next, the aperture adjusting unit 4 sets the aperture of the aperture 1 to the “medium” state, and the obtained optical image is captured by the imaging unit 3 (S3).

  The distribution unit 6 stores the image information captured in step S3 in the second image storage unit 8 as the second image information 52 (S4).

  Next, the aperture adjustment unit 4 sets the aperture of the aperture 1 to the “large” state, and the obtained optical image is captured by the imaging unit 3 (S5).

  The distribution unit 6 stores the image information captured in step S5 in the third image storage unit 9 as the third image information 53 (S6).

  Next, the subject extraction unit 10 determines the degree of focus between the first image information 51 stored in the first image storage unit 7 and the second image information 52 stored in the second image storage unit 8. Compare (S7).

  In step S7, if there is no difference in the degree of focus between the first image information 51 and the second image information 52 (S8), it is considered that the subject 41 is not yet present at the predetermined position. Then, returning to step S1 (S9), the first image information 51 is taken again.

  In step S7, if there is a difference in the degree of focus between the first image information 51 and the second image information 52, the subject 41 is considered to be present at a predetermined position from the biometric determination device 15. By extracting the difference between the image information 51 and the second image information 52 (S10), the subject area including the subject 41 can be extracted.

  Next, the biometric determination unit 11 determines the degree of focus between the second image information 52 stored in the second image storage unit 8 and the third image information 53 stored in the third image storage unit 9. Compare (S11).

  In step S11, when there is no difference in focus degree between the second image information 52 and the third image information 53, or when there is no substantial difference (S12), the subject 41 is impersonated. Therefore, the living body determination unit 11 causes the alarm generation unit 13 to generate an alarm (S14).

  On the other hand, if there is a difference in focus between the second image information 52 and the third image information 53 in step S11, the subject 41 is regarded as a living body, and the image information is displayed on the display unit. 12 is displayed, and the process is terminated (S13).

  By performing such an operation, if the biometric determination device 15 according to the first exemplary embodiment of the present invention is used, an image of the subject 41 within a predetermined distance range is extracted from the biometric determination device 15 and the display unit 12 is extracted. In addition, it is possible to determine whether the subject 41 is a living body or impersonation.

Further, in the first biological determination device 15 in the embodiment of the present invention, as shown in FIG. 9 (a), without opening degree of the diaphragm 1 is an object depth delta ₁ when the "small" and infinity In addition, it is configured to have a finite value, for example, about 500 to 1000 mm. As shown in FIG. 9B, a clear image can be taken with respect to the subject 41, while other than the subject. As for the image of the person 42, only a blurred image is displayed on the display unit 12. Therefore, when used for a monitoring device in a financial institution or the like, a clear image of the person 42 other than the subject is taken unconsciously. Privacy protection can be realized.

(Second Embodiment)
Next, an authentication apparatus according to the second embodiment of the present invention will be described.

  FIG. 10 is a block diagram showing the configuration of the authentication device 70 according to the second embodiment of the present invention. FIG. 11 is a flowchart for explaining the operation steps of the authentication device 70 according to the second embodiment of the present invention. is there.

  First, as shown in FIG. 10, the authentication device 70 in the second embodiment of the present invention is different from the biometric device 15 described in the first embodiment in that the subject extraction unit 10 and the display unit 12 is provided with an authentication processing unit 71 that performs an authentication process in comparison with image information registered in advance using the image information of the subject extracted by the subject extraction unit 10.

  Next, operation | movement of the authentication apparatus 70 in the 2nd Embodiment of this invention is demonstrated.

  As shown in FIG. 11, in the authentication device 70 according to the second embodiment of the present invention, the aperture adjustment unit 4 changes the aperture of the aperture 1 to the “small” state, and the obtained optical image is captured by the imaging unit 3. Shoot (S1).

  The distribution unit 6 stores the image information captured in step S1 in the first image storage unit 7 as the first image information 51 (S2).

  Next, the aperture adjusting unit 4 sets the aperture of the aperture 1 to the “medium” state, and the obtained optical image is captured by the imaging unit 3 (S3).

  The distribution unit 6 stores the image information captured in step S3 in the second image storage unit 8 as the second image information 52 (S4).

  Next, the aperture adjustment unit 4 sets the aperture of the aperture 1 to the “large” state, and the obtained optical image is captured by the imaging unit 3 (S5).

  The distribution unit 6 stores the image information captured in step S5 in the third image storage unit 9 as the third image information 53 (S6).

  Next, the subject extraction unit 10 determines the degree of focus between the first image information 51 stored in the first image storage unit 7 and the second image information 52 stored in the second image storage unit 8. Compare (S7).

  In step S7, if there is no difference in the degree of focus between the first image information 51 and the second image information 52 (S8), it is considered that the subject 41 is not yet present at the predetermined position. Then, returning to step S1 (S9), the first image information 51 is taken again.

  In step S7, if there is a difference in the degree of focus between the first image information 51 and the second image information 52, the subject 41 is considered to be present at a predetermined position from the biometric determination device 15. By extracting the difference between the image information 51 and the second image information 52 (S10), the subject area including the subject 41 can be extracted.

  Next, the biometric determination unit 11 determines the degree of focus between the second image information 52 stored in the second image storage unit 8 and the third image information 53 stored in the third image storage unit 9. Compare (S11).

  In step S11, when there is no difference in focus degree between the second image information 52 and the third image information 53, or when there is no substantial difference (S12), the subject 41 is impersonated. Therefore, the living body determination unit 11 causes the alarm generation unit 13 to generate an alarm (S14).

  On the other hand, if there is a difference in focus between the second image information 52 and the third image information 53 in step S11, the subject 41 is regarded as a living body and the image information is used. The authentication processing unit 71 performs authentication processing (S20). If necessary, the result of the authentication processing performed by the authentication processing unit 71 is displayed on the display unit 12, and the processing is terminated.

  The present invention does not limit the authentication process to be performed by the authentication processing unit. However, as an authentication method using a face, a feature point of a face is extracted and its position is registered in advance. It is possible to appropriately use a known technique such as a technique for performing authentication in comparison with the above, and as an authentication process using an iris pattern of a subject, for example, an iris authentication method as disclosed in Japanese Patent No. 3307936 Can be used.

  As described above, if the authentication device 70 according to the second embodiment of the present invention is used, the authentication process can be performed on the image of the subject 41 that has been previously determined to be a living body by the living body determination unit 11, so that more security is provided. It is possible to realize a highly reliable authentication device.

  According to the biometric device, the authentication device using the biometric device, and the biometric method according to the present invention, the aperture of the aperture is adjusted, images with different apertures of the aperture are photographed, and the images are compared. Since it is possible to prevent impersonation with a simple configuration, an authentication device that performs personal authentication using biometric information such as an image of the face or eye of the person to be authenticated, particularly the person to be authenticated This is useful as an authentication device having a living body discrimination function for discriminating whether or not it is a living body.

The block diagram which shows the structure of the biometric discrimination apparatus in the 1st Embodiment of this invention. The figure which shows the basic principle of the function of the to-be-photographed object extraction part or the biometric discrimination | determination part of the biometric discrimination apparatus in the 1st Embodiment of this invention. The figure which shows the difference in the object depth by the difference in the aperture degree of the lens in the 1st Embodiment of this invention. The figure for demonstrating the operation | movement principle of the to-be-extracted object extraction part of the biometric discrimination apparatus in the 1st Embodiment of this invention, and a biometric discrimination part. The figure which shows an example of the image information image | photographed by the biometric discrimination apparatus in the 1st Embodiment of this invention. The figure for demonstrating the other operation | movement principle of the to-be-extracted part and the biometric discrimination | determination part of the biometric discrimination apparatus in the 1st Embodiment of this invention. The figure which shows the other example of the image information image | photographed by the biometric discrimination apparatus in the 1st Embodiment of this invention. The flowchart which shows the operation | movement step of the biometric discrimination apparatus in the 1st Embodiment of this invention. The figure for demonstrating the effect of the biometric discrimination apparatus in the 1st Embodiment of this invention The block diagram which shows the structure of the authentication apparatus in the 2nd Embodiment of this invention. The flowchart explaining the operation | movement step of the authentication apparatus in the 2nd Embodiment of this invention.

Explanation of symbols

1 Aperture 2,32 Lens 3,33 Imaging unit (imaging device)
DESCRIPTION OF SYMBOLS 4 Diaphragm adjustment part 5 Synchronization signal generation part 6 Distribution part 7 1st image storage part 8 2nd image storage part 9 3rd image storage part 10 Subject extraction part 11 Living body discrimination | determination part 12 Display part 13 Alarm generation part 15 Living body Discriminating device 31 Object 41 Subject 42 Person other than subject 51, 61 First image information 52, 62 Second image information 53, 63 Third image information 60 Photo 70 Authentication device 71 Authentication processing unit

Claims (12)

An aperture,
An aperture adjuster for adjusting the aperture of the aperture,
A shooting section for shooting the subject;
Biological discrimination for discriminating whether or not the subject is a living body by comparing a plurality of images with different opening degrees of the subject photographed by the photographing unit with the opening degree varied by the opening degree adjusting unit And a living body discrimination device. The said living body discrimination | determination part discriminate | determines whether the said to-be-photographed object is a biological body based on the difference in the focus degree in the several image from which the said opening degree each differs in the said to-be-photographed object. Biological discrimination device. The said living body discrimination | determination part discriminate | determines that the said to-be-photographed object is not a biological body when the focus degree of the some image from which the said opening degree each differs in said subject is substantially equal. Biological discrimination device. The said biometric discrimination | determination part calculates the focus degree in the some image from which the said opening degree differs each of the said object based on the coefficient at the time of performing a DCT process, The Claim 2 or Claim 3 characterized by the above-mentioned. Biological discrimination device. 5. The biometric discrimination unit calculates the degree of focus in each of the plurality of images with different apertures of the subject by integrating coefficient values of predetermined frequencies when DCT processing is performed. Biological discrimination device. The living body discrimination according to any one of claims 1 to 5, further comprising a subject extraction unit that extracts an image of a subject region from a plurality of images having different opening degrees of the subject. apparatus. The living body determination apparatus according to claim 6, wherein the living body determination unit determines whether or not the subject is a living body using an image of the subject area. The photographing unit photographs three images having different opening degrees,
The subject extraction unit uses the first image having the smallest opening degree and the second image having the larger opening degree than the first image among the three images having different opening degrees. Perform processing to extract the subject,
The living body determination unit determines whether or not the subject is a living body using the second image and a third image having a larger opening degree than the second image. Item 8. The living body discrimination device according to item 6 or 7. The living body discrimination apparatus according to any one of claims 1 to 8, wherein the aperture section includes a liquid crystal shutter. The living body discrimination apparatus according to claim 9, wherein the opening degree adjustment unit includes a light amount adjustment unit that adjusts the light amount so that a light amount of light passing through the liquid crystal shutter is constant. The living body discrimination device according to any one of claims 1 to 10,
An authentication apparatus comprising: an authentication processing unit that performs an authentication process of the subject using an image in which the subject is determined to be a living body by the biometric determination unit. A first step of taking a first image of a subject with a first aperture opening;
A second step of taking a second image of the subject with a second aperture opening larger than the first aperture opening;
A third step of taking a third image of the subject with a third aperture opening degree greater than the second aperture opening degree;
A fourth step of calculating a degree of focus of each of the first image and the second image;
A fifth step of extracting a subject area having a high degree of focus from the first image and the second image by comparing the degree of focus;
A sixth step of calculating a degree of focus of each of the second image and the third image;
And a seventh step of determining whether or not the subject is a living body by comparing the degree of focus.

Images