JP2003308524A - Access control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an access control system that authenticates a principal with high precision and improves security by acquiring a face image close to a registered face image in the authentication processing. <P>SOLUTION: In access control, when a camera 2 images a user who desires access, an imaging processing part 5 compares the imaging state of a face image detected by a face detection part 4 and imaging state data registered in advance in a storage part 1, and controls imaging conditions of the camera 2 and an illuminator 3 to approximate a registered imaging state before the user imaging, so that a face image close to a registered one is acquired for principal authentication. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an access control system for authenticating a person based on face image recognition processing and controlling whether or not to permit access of a user, and in particular, realizes highly accurate person authentication. Technology for improving security.

[0002]

2. Description of the Related Art In general, access control checks whether a user has an authority to use a resource in a system, so that the resource is used within the authority of the user. Control. A conventional access control system is, for example, a user's property,
It is realized by secret information or biometrics alone or in combination. Specifically, there is a method using a physical key, a card, or the like as access control by a property. Further, as a method of access control using secret information, there is a method using a personal identification number or the like. Further, as an access control by biometrics, there is a method using a fingerprint, an iris, a face and the like.

In the conventional access control system, in order to improve the security, it is necessary to combine a plurality of various methods as described above, but the convenience may be impaired accordingly. Therefore, in order to improve security without impairing convenience as much as possible, for example, in the technology disclosed in Japanese Patent Laid-Open No. 2000-67188, information stored in an IC card or the like and a face image captured by a camera or the like are used. There has been proposed a method of authenticating a user by combining them.

[0004]

By the way, in the conventional access control system as described above, when the identity of the user who is trying to access is authenticated, the face image of the user is taken in the photographing environment (fluorescent lamp, sun, etc.) at that time. The user is illuminated so that a camera or the like can capture an image regardless of the light, background, etc.). However, the face image required for personal authentication is close to the face image captured at the time of registration, and there is a problem that a good face image cannot always be obtained even when illuminated.

The present invention has been made by paying attention to the above point, and the personal authentication is performed by setting the image capturing condition for the personal authentication based on the registration information regarding the image capturing state stored in advance at the time of user registration. It is an object of the present invention to provide an access control system with high accuracy and improved security.

[0006]

Therefore, according to the invention of claim 1, personal authentication is performed based on the recognition processing of the face image obtained by capturing the image of the user who desires access, and the result of the personal authentication is obtained. In an access control system that controls whether or not to permit access by the user according to the above, the imaging state that changes according to the imaging condition is detected from the face image of the user, and the detection result and the previously registered imaging state are related. The imaging condition of the user's face image is controlled so that the detection result approaches the registration information by comparing with the registration information, and the recognition process is executed based on the face image captured under the optimal imaging condition to identify the person. It is configured to perform authentication.

In such a configuration, the image pickup state is detected from the face image obtained by picking up the image of the user, and the image pickup condition is controlled so that the detection result is the state closest to the image pickup state at the time of registration. The personal authentication is performed based on the face image in the image pickup state closest to that at the time of registration. As a result, more reliable personal authentication can be performed as compared with the conventional system, so that it is possible to improve security.

[0008] Specifically, as in claim 2, a storage unit that stores at least the registration information regarding the facial features of the user, the registration information regarding the imaging state, and the registration information regarding the access right in advance, and the user who desires to access. An image pickup means for picking up a face image by picking up the image, and an image pickup state of the user's face image based on the face image obtained by the image pickup means, and the detected image pickup state and the image pickup state stored in the storage means. Image pickup condition control means for controlling the image pickup condition at the time of the user image pickup by the image pickup means and outputting a control completion signal when the image pickup condition becomes optimum so that the detection result approaches the registered information. And the face image of the user at the time when the control completion signal is output and the registration information relating to the facial features stored in the storage unit are collated to authenticate whether or not the user is the person. Authentication determination means for determining whether or not to permit access by the user according to the authentication result and registration information regarding the access right stored in the storage means; and for the user according to the determination result of the authentication determination means. It may be configured by including access control means for controlling access.

In such a structure, the face of the user who desires access is imaged by the image pickup means. The image capturing condition control unit detects the image capturing state of the face image of the user based on the face image obtained by the image capturing unit, compares it with the registration information regarding the image capturing state stored in the storage unit, and based on the comparison result, the image capturing condition. Is controlled so that the face image in the imaging state closest to the registered imaging state is captured. The authentication determination means collates the face image closest to the registration time obtained by the imaging means under the control of the imaging condition control means with each piece of registration information in the storage means, and performs authentication processing and access right as to whether or not the user is the user himself. The determination process of is executed. The access control means controls the access of the user according to the processing result of the authentication judging means.

Further, as described in claim 3, it is preferable that the storage means stores in advance the registration information relating to the imaging condition of the face image of the user at the time of registration. in this case,
According to another aspect of the present invention, the image capturing condition control unit sets the image capturing condition based on the registration information regarding the image capturing condition stored in the storage unit, and then detects the image capturing state and the image capturing state stored in the storage unit. It is advisable to compare the registration information with the registration information, and control the imaging condition at the time of the user imaging by the imaging unit so that the detection result approaches the registration information.

In such a structure, the image pickup control means first
The image pickup device is set to the same image pickup condition as the registration information of the image pickup condition stored in the storage device. The imaging condition is detected from the face image of the user obtained in this state, and the imaging condition is controlled so that the detection result approaches the registration information regarding the imaging condition stored in the storage means. As a result, it becomes possible to quickly acquire a face image close to the image pickup state at the time of registration.

The registration information relating to the image pickup state may be the brightness information of the face image of the user as in claim 5, or the grayscale information of the face image of the user as in claim 6. The imaging condition to be controlled may include the control of the illumination that illuminates the user at the time of imaging as in claim 7.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an access control system according to an embodiment of the present invention. In FIG. 1, the access control system includes, for example, a storage unit 1 serving as a storage unit, a camera 2 serving as an imaging unit, a lighting device 3, and a face detection unit 4, and an imaging processing unit 5 serving as an imaging condition control unit. A personal authentication unit 6 and an access right determination unit 7 as an authentication determination unit, and an access control unit 8 as an access control unit are configured.

The storage unit 1 stores registration information relating to the features of the user's face (hereinafter referred to as registered face data) and registration information relating to the imaging state of the face image at the time of registration of the user (hereinafter referred to as "following face data").
Registered imaging status data), registration information regarding the imaging conditions of the face image at the time of user registration (hereinafter referred to as registered imaging condition data), and registration information regarding access rights granted to the user (hereinafter referred to as access). It is a general information storage medium in which personal registration data including the authorization data) is stored in advance. As a specific configuration of the storage unit 1, for example, as shown in FIG. 2, a plurality of users A, B,
The memory 10 having a required capacity in which the individual registration data for C, ... Are collectively stored may be used. In this case, each registration data stored in the memory 10 is read by the imaging processing unit 5, the personal authentication unit 6, and the access right determination unit 7. Further, as shown in FIG. 3, for example, each user is allowed to carry a portable storage medium such as the non-contact IC card 11 in which the above personal registration data is stored, and the non-contact IC card 11 or the like is stored. It is also possible to read the personal registration data by bringing it closer to the card reading unit 12 provided on the system side. In this case, the personal registration data read by the card reading unit 12 is sent to the imaging processing unit 5, the personal authentication unit 6, and the access right determination unit 7. The storage means in the present invention is not limited to the above specific example, and a known information storage medium capable of storing personal registration data can be used.

As the registered face data, for example, a face image previously acquired for personal authentication may be used as the registered data as it is. Further, for example, it is possible to calculate the facial feature amount based on the face image for personal authentication and use the calculation result as the registration data. The above-mentioned facial feature quantity is a numerical representation of the facial features of the user who can distinguish between the person and the other person. For example, facial components (eyes, nose, mouth, eyebrows, etc.)
Is a numerical representation of the shape and the mutual arrangement relationship.

The registered image pickup state data is information in which the image pickup state of the face image of the user used for registration is registered as data for personal authentication. The information indicating the imaging state is, for example, a value obtained by digitizing the brightness (average of gradation) in a predetermined area of the face by a known image processing technique. It should be noted that, in addition to the brightness, light and shade or the like may be used. The registered image capturing condition data is data in which image capturing conditions for capturing the face image of the user used for registration are registered as data for personal authentication. Specifically, the setting conditions (gain, aperture, shutter speed, position, orientation, etc.) of the camera when the user is imaged at the time of registration and the setting conditions of the lighting device at that time (strength, ON / O).
FF, orientation, position, etc.).

The access right data is information on the usage right given to the rightful owner, and is information indicating the range in which the use of resources in the system is permitted.
Specifically, for example, when it is used for access control at a door or the like, the identification information or the like about the room permitted to enter becomes the access right data. When used for access control at a ticket gate of a station, for example, well-known commuter pass data corresponds to access right data. The access right data in the present invention is not limited to the above specific example, and can be set appropriately according to the required access control.

The camera 2 can mainly capture the face of the user who desires access, and outputs the acquired image to the face detection unit 4. The camera 2 may have a function (for example, auto focus) for appropriately capturing an image inside the image capturing area. The illumination device 3 is provided so that the user can be illuminated in order to capture a face image that is not affected by the surrounding environment (fluorescent light, sunlight, background, etc.) when the user captures an image.

The face detecting section 4 is, for example, as shown in FIG.
The video from the camera 2 is processed as a continuous image, and the user's face detection process is executed from each image. Then, when the face of the user is detected, the face image is cut out and the face image is sent to the imaging processing unit 5 and the personal identification unit 6, respectively. As shown in FIG. 1, the image pickup processing unit 5 includes an image pickup state data calculation unit 5A, an image pickup state data comparison unit 5B, a control amount calculation unit 5, and an image pickup condition control unit 5D. The imaging state data calculation unit 5A has a predetermined face predetermined area in each face image continuously sent from the face detection unit 4, for example, an area surrounded by a broken line in FIG. 5A or 5B. Brightness (or shading) is calculated, and the numerical data is output to the imaging state data comparison unit 5B as the imaging state data of the user. The imaging state data comparison unit 5B compares the numerical value data of the brightness (or the light and shade) sent from the imaging state calculation unit 5A with the registered imaging state data stored from the storage unit 1 and stored at the time of registration, and controls the comparison result. It is output to the amount calculation unit 5D. The control amount calculation unit 5B takes in the registered imaging condition data from the storage unit 1, calculates the control amount based on the data, and acquires the imaging condition control unit 5B.
Output to D. In addition, the control amount is calculated based on the comparison result sent from the imaging state data comparison unit 5B and output to the imaging condition control unit 5D. The imaging condition control unit 5D controls the camera 2 and the lighting device 3 to control the imaging condition based on the control amount sent from the control amount calculation unit 5C.

The personal identification section 6 collates the face image sent from the face detection section 4 with the registered face data stored in the storage section 1, and the image is picked up by the camera 2 based on the scale of the collation result. Authentication is performed as to whether the user's face matches the user's face registered in the storage unit 1, and the authentication result is output to the access right determination unit 7. Specifically, when the face image acquired in advance for personal authentication is registered as it is as the registered face data, the face authentication processing in the personal authentication unit 6 is performed as shown in FIG. Enlargement / reduction processing is performed on the face image from the detection unit 4, and the size is made equal to the registered face data (a plurality of face images are shown in the figure, but one face image may be used). Next, the face image and registered face data are collated and the difference between them is calculated to obtain the degree of similarity between both face images. It is assumed that this similarity is higher as the difference is smaller. Then, if the calculated similarity exceeds a preset threshold value, it is determined that the face image and the registered face data match, and the user is authenticated as the user.

Further, when the face feature amount calculated based on the face image for personal authentication is registered as the registered face data, for example, as shown in FIG. The facial feature amount calculating means 6A of the personal identification section 6 calculates the facial feature amount based on the above, and the facial feature amount and the facial feature amount shown as the registered face data are collated by the face characteristic amount collating means 6B to calculate the similarity. Ask for. Then, the facial feature amount authentication unit 6C determines whether or not the calculated similarity exceeds a preset threshold,
If the degree of similarity exceeds the threshold, the user is authenticated as the user.

The access right decision unit 7 decides whether or not to permit the user's access based on each authentication result in the personal identification unit 6 and the access right data stored in the storage unit 1, and The determination result is output to the access control unit 8. The determination process in the access right determination unit 7 is, for example, full when the authentication result in the person authentication unit 6 is YES, depending on the usage right indicated in the access right data from the storage unit 1. It is determined whether access is possible, partial access is possible or not, and a signal indicating the determination result is transmitted to the access control unit 8.

The access control unit 8 permits the required access to the user who is determined to have the legitimate access right at the same time as being authenticated according to the result of the judgment by the access right judging unit 7. However, access control is performed to deny access to other users. FIG. 8 shows an example of the configuration of the registration device 20 for registering the above-mentioned registration information.

The registration device 20 includes a camera 21 and a lighting device 2.
2, a face detection unit 23, an imaging condition data acquisition unit 24, an imaging state data calculation unit 25, an image processing unit 26, and an access right input unit 27. In order to register information by the registration device 20, first, the face of the user to be registered is captured by the camera 2
Image at 1. At this time, when a shadow appears on the face, the lighting device 22 illuminates the face to remove the shadow, and the like, so that the influence of the surrounding environment at the time of imaging is minimized. Camera 21
The image obtained in step 3 is sent to the face detection section 23, and the face detection processing is performed in the same manner as the face detection section 4. When the face detection unit 23 detects a face, the face detection unit 23 sends a face detection completion signal to the imaging condition data acquisition unit 24, and sends the cut face image to the imaging state data calculation unit 25 and the image processing unit 26. As a result, the imaging condition data acquisition unit 24 outputs the setting data of the lighting device 22 and the camera 21 at that time to the storage unit 1 as the registration information regarding the imaging condition and stores the registration data. Further, the image capturing state data calculating unit 25, like the image capturing state data calculating unit 5A, calculates the values of the brightness and the light and shade of a predetermined area of the face image and stores them in the storage unit 1 as registration information regarding the image capturing state. The image processing unit 26 creates the above-mentioned registered face data based on the sent face image and stores it in the storage unit 1. Further, the operator operates the access right input unit 27 to input the access right data of the user to be registered so that the access right data is stored in the storage unit 1.

Next, the user registration operation and the user authentication operation in the access control system of this embodiment will be described with reference to the flowcharts of FIGS. 9 to 11. First, the user registration operation will be described. User registration is performed, for example, as shown in the flowchart of FIG.
In step 1 (indicated by S1 in the drawing, the same applies hereinafter), it is determined whether or not a portion corresponding to the user's face is detected in the images continuously sent from the camera 21, and the face portion is detected. Is detected, a face detection completion signal is output to the imaging condition data acquisition unit 24, and the setting states of the camera 21 and the lighting device 22 at that time are registered in the storage unit 1 as imaging condition data.

Further, in step 3, the face image is cut out and the image pickup state data calculating section 25 and the image processing section 26 are extracted.
Are output respectively. The imaging state data calculation unit 25 and the image processing unit 26 each determine whether or not a face image is input as in step 4. Then, if it is determined that the face image is input, the imaging state data calculation unit 25 calculates the imaging state data and the storage unit 1 as in step 5.
Register with. Also, as in step 6, the image processing unit 26
Creates registration face data and registers it in the storage unit 1. In step 7, it is determined whether or not the access right data is input by the operator, and if it is input, the access right data input in step 8 is registered in the storage unit 1.

In the flow chart of FIG. 9, the respective operations are shown as steps 1 to 8 in sequence.
3 is processed in parallel when the determination in step 1 is YES, and steps 5 and 6 are also Y in step 4.
It is processed in parallel by the ES determination. Further, steps 7 and 8 are processed in parallel with steps 1 to 6.

Next, the personal authentication operation will be described. When the access control by the present access control system is started, the imaging processing unit 5 reads the registered imaging condition data from the storage unit 1 in step 11, and the control amount calculation unit 5C reads the registered imaging condition data read in step 12 from the control amount calculation unit 5C. The control amount is determined, and the camera 2 and the illumination device 3 are set by the image capturing condition control unit 5D so that they are the same as the image capturing conditions at the time of registration. After that, the user who desires access is imaged by the camera 2 and the image is sent to the face detection unit 4.

In step 13, it is judged by the face detecting section 4 whether or not a portion corresponding to the face of the user is detected in the images continuously sent from the camera 2, and when the face portion is detected. In step 14, the face image is cut out and output to the imaging state data calculation unit 5A. In step 15, the imaging state data calculation unit 5A determines whether or not a face image is input, and if a face image is input, step 1
6, the image pickup state data (luminance, shade, etc.) in a predetermined area of the face as shown in FIGS. 5A and 5B is calculated and output to the image pickup state data comparison unit 5B.

In step 17, the registered image pickup state data is read from the storage unit 1 in the image pickup state data comparison unit 5B, compared with the calculated image pickup state data, and the comparison result is output to the control amount calculation unit 5C. In step 18, the control amount calculation unit 5C calculates the control amount according to the comparison result, and in step 19, it is determined whether the calculated control amount is within a predetermined range.
If the control amount is not within the predetermined range, the process proceeds to step 20, the camera 2 and the lighting device 3 are controlled according to the control amount, and the process returns to step 13. Then, in step 18, the determination is YE.
The operations of steps 20 and 13 to 18 are repeated until S is reached. When the control amount is within the predetermined range including 0 and the determination is YES, the process proceeds to step 21, and the image capturing condition control unit 5D outputs a control completion signal to the face detection unit 4.

In step 22, the face detection unit 4 which has received the control completion signal outputs the face image at that time to the personal identification unit 6. When the face image is output to the personal identification unit 6, the face image input in step 23 of FIG. 11 and the registered face data stored in the storage unit 1 are collated. At this time, when the storage unit 1 uses the memory 10 as shown in FIG. 2, the registered face data of a plurality of users A, B, C, ... The personal identification unit 6 sequentially reads the images, and the matching process with the face image is executed.
Further, the storage unit 1 has a non-contact IC as shown in FIG.
In the case of the card 11 and the card information reading unit 12, the non-contact I presented by the user captured by the camera 1
The registered face data included in the personal registration data transmitted from the C card and received by the card information reading unit 12 is sent to the person authenticating unit 6 and the matching process with the face image is executed.
Then, in step 24, it is determined whether the similarity indicating the result of the collation exceeds the threshold value and the collation coincidence is determined. When the collation coincidence is discriminated, the process proceeds to step 25, and the authentication result in the person authenticating unit 6 is A signal indicating yes is output to the access right determination unit 6.

In step 26, the access right judging section 7 judges whether or not an output signal indicating that the authentication result is YES is inputted from the person authenticating section 6. If the authentication result is yes, the process proceeds to step 27, the access right to the user is determined according to the access right data stored in the storage unit 1, and the signal indicating the determination result is accessed in step 28. It is output to the control unit 8. Then, in step 29, the access control unit 8 controls access to the user.

As described above, according to the access control system of the present embodiment, when the user's face image is registered, the image capturing state is also registered at the same time, and the user is authenticated based on the registered image capturing state data. Since the face image is captured by setting the image capturing condition by using the image capturing condition, it is possible to perform the authentication process based on the face image close to the time of registration. As a result, it is possible to perform highly accurate personal authentication, and it is possible to improve the security of the access control system.

Further, in the present embodiment, at the time of image pickup of a user who desires access by registering the image pickup condition at the time of registration, after presetting the camera 2 and the illuminating device 3 by the registered image pickup condition data, based on the image pickup state. Since the image pickup condition is finely adjusted by the above, the face image for authentication can be acquired at high speed, and the processing speed of personal authentication becomes high. Although the imaging conditions of the camera and the lighting device are registered at the time of registration in the above-described embodiment, if the imaging conditions of the camera and the lighting device are set to be the same on the registration side and the authentication side, the imaging condition The registration of can be omitted.

[0035]

As described above, according to the access control system of the present invention, the personal authentication is performed based on the face image captured by reproducing the image capturing condition substantially similar to that at the time of user registration. Therefore, it is possible to perform personal authentication with a face image that is extremely close to the registered face image. This allows
It is possible to improve the security of the access control system.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of an access control system according to the present invention.

FIG. 2 is a diagram showing a specific configuration example of a storage unit of the above embodiment.

FIG. 3 is a diagram showing another specific configuration example of the storage unit of the above embodiment.

FIG. 4 is a diagram for explaining specific processing in the face detection unit of the above embodiment.

FIG. 5 is a diagram for explaining an example of calculating imaging state data according to the above embodiment.

FIG. 6 is a diagram for explaining a specific process of an identity authentication unit of the above embodiment.

FIG. 7 is a diagram for explaining another specific process of the personal authentication unit of the above embodiment.

FIG. 8 is a block diagram showing a configuration example of a registration device in the access control system of the above embodiment.

FIG. 9 is a flowchart showing an operation at the time of user registration in the above embodiment.

FIG. 10 is a flowchart showing an operation during personal authentication according to the above embodiment.

FIG. 11 is a flowchart showing an operation at the time of person authentication following FIG.

[Explanation of symbols]

1 memory 2 camera 3 lighting equipment 4 Face detector 5 Image processing unit 6 Personal Authentication Department 7 Access right judgment part 8 Access control section

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kiyoshi Yanagisawa             1836 Otani, Omiya, Kuki City, Saitama Prefecture             This signal Kuki office F-term (reference) 5B047 AA23 CA30 CB18                 5B057 BA02 CA12 CA16 DB02 DC01                       DC36                 5L096 BA18 CA02 FA00 JA11

Claims (7)

[Claims] 1. A personal authentication is performed based on a recognition process of a face image obtained by capturing an image of a user who desires access, and whether or not to permit access of the user according to the result of the personal authentication. In the controlled access control system, an imaging state that changes according to the imaging conditions is detected from the face image of the user, and the detection result is compared with registration information relating to the imaging state registered in advance, and the detection result is the registration information. The access control system is characterized in that the image pickup condition of the face image of the user is controlled so as to approach the user, and the recognition process is executed based on the face image picked up under the optimum image pickup condition to perform personal authentication. 2. A storage unit for pre-storing at least registration information regarding facial features of a user, registration information regarding an imaging state, and registration information regarding an access right, and imaging for obtaining a face image by imaging a user who desires access. Means for detecting the image pickup state of the face image of the user based on the face image obtained by the image pickup means, comparing the detected image pickup state with registered information on the image pickup state stored in the storage means, and detecting An image pickup condition control unit that controls the image pickup condition when the user takes an image by the image pickup unit and outputs a control completion signal when the image pickup condition is optimized, and the control completion signal is output. When the user's face image and the registered information about the facial features stored in the storage unit are collated, it is authenticated whether the user is the person in question, and the authentication result and the memory Authentication determination means for determining whether or not to permit access by the user according to the registration information relating to the access right stored in the access control means, and access control means for controlling access by the user according to the determination result of the authentication determination means. The access control system according to claim 1, further comprising: 3. The access control system according to claim 2, wherein the storage means has a configuration in which registration information relating to image pickup conditions of the face image of the user at the time of registration is stored in advance. 4. The image pickup condition control means sets an image pickup condition based on registration information relating to the image pickup condition stored in the storage means, and then registers the detected image pickup state and the image pickup state stored in the storage means. 4. The access control system according to claim 3, wherein the access control system is configured to compare information and to control an image capturing condition when the user captures an image by the image capturing unit so that a detection result approaches the registered information. 5. The access control system according to claim 1, wherein the registration information relating to the image pickup state is luminance information of a face image of a user. 6. The access control system according to claim 1, wherein the registration information relating to the image pickup state is grayscale information of a face image of a user. 7. The access control system according to claim 1, wherein the imaging condition to be controlled includes control of illumination for illuminating a user during imaging.