KR102601100B1 - User authentication apparatus and user authentication method - Google Patents

Abstract

A user authentication device and user authentication method are disclosed. The user authentication device includes a card reader that acquires a registered facial image stored in the card when the card is recognized, a camera that acquires a first query facial image at a first viewpoint including a facial area of the user, and a first query facial image. It includes a processor that determines a user authentication result based on the user authentication result and generates a control signal according to the user authentication result. If the user authentication result based on the registered face image and the first query face image is determined to be successful, the processor stores the first query face image in the storage device, and the camera detects the second query face at a second time point after the first time point. When acquiring an image, a user authentication result is determined based on at least one face image stored in the storage device and the second query face image.

Description

User authentication device and user authentication method {USER AUTHENTICATION APPARATUS AND USER AUTHENTICATION METHOD}

The explanation below is about user authentication technology based on face authentication.

At the entrances of facilities that require security, including important facilities, a user authentication system is generally installed to verify the identity of the person entering and control the user's access according to access authority. In these user authentication systems, access cards are widely used as a means to verify the user's access authority, and access control systems using biometric authentication have also been developed to increase security.

In the case of using an access card, there is a risk that the access card may be lost or not returned, or that an unauthorized third party may acquire or steal the access card and gain access to the facility. In addition, the access control system that uses biometric information such as face, fingerprint, and iris can overcome the problems of using the access card described above, but there is a false rejection rate and the false recognition rate increases as the number of users increases. There is a limit to the increased cost of implementing a control system. Additionally, a lot of money is spent on storing and managing the user's unique biometric information, and there are concerns about biometric information being hacked.

Research and development on user authentication technology that can effectively solve the above problems is required.

A user authentication device according to an embodiment includes: a card reader that obtains a registered face image stored in the card when the card is recognized; A camera that acquires a first query face image at a first time including the user's face area; and a processor that determines a user authentication result based on the first query face image and generates a control signal according to the user authentication result, wherein the processor determines a user authentication result based on the registered face image and the first query face image. If the user authentication result is determined to be successful, the first query face image is stored in the storage device, and if the camera acquires a second query face image at a second time point after the first time point, the first query face image is stored in the storage device. A user authentication result may be determined based on at least one stored face image and the second query face image, and at least one face image stored in the storage device may include the first query face image.

When a user authentication result based on the second query face image is determined, the processor may control to delete the second query face image.

The processor may control to delete all facial images stored in the storage device at a preset time after the second time.

When a validity period designated for each user expires, the processor may control the user's face image whose validity period has expired to be deleted from the storage device.

If authentication of the user's departure from work is successful, the processor may control the storage device to delete the user's first query face image.

When a user attempts to authenticate attendance using the card, the processor acquires the registered face image through the card reader, acquires a first query face image of the user through the camera, and acquires the registered face image. Based on the image and the first query face image, it may be determined whether the user's attendance authentication is successful.

The storage device stores a face image of at least one user who succeeded in attendance authentication on the current day, and the face image of the at least one user is each acquired by the camera when attendance authentication is successful. It may correspond to the user's first query face image.

A user authentication method according to an embodiment includes, when a card is recognized by a card reader, obtaining a registered face image stored in the card; determining, via a camera, a user authentication result based on the first query facial image of the user; If the user authentication result based on the registered face image and the first query face image is determined to be successful, storing the first query face image in a storage device; and when the camera acquires a second query face image at a second time point after the first time point, determining a user authentication result based on at least one face image stored in the storage device and the second query face image. and at least one face image stored in the storage device may include the first query face image.

1 is a diagram for explaining the outline of a user authentication system according to an embodiment.
FIG. 2 is a diagram illustrating the configuration of a user authentication system including a user authentication device according to an embodiment.
Figure 3 is a diagram for explaining the operation of a user authentication device according to an embodiment.
FIG. 4 is a diagram illustrating a case in which a query face image is stored in a storage device or a query face image is deleted from a storage device, according to an embodiment.
Figures 5A and 5B are flowcharts for explaining the operation of a user authentication method according to an embodiment.

Hereinafter, embodiments will be described in detail with reference to the attached drawings. However, various changes can be made to the embodiments, so the scope of the patent application is not limited or limited by these embodiments. It should be understood that all changes, equivalents, or substitutes for the embodiments are included in the scope of rights.

The terms used in the examples are for descriptive purposes only and should not be construed as limiting. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by a person of ordinary skill in the technical field to which the embodiments belong. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and unless explicitly defined in the present application, should not be interpreted in an ideal or excessively formal sense. No.

In addition, when describing with reference to the accompanying drawings, identical components will be assigned the same reference numerals regardless of the reference numerals, and overlapping descriptions thereof will be omitted. In describing the embodiments, if it is determined that detailed descriptions of related known technologies may unnecessarily obscure the gist of the embodiments, the detailed descriptions are omitted.

1 is a diagram for explaining the outline of a user authentication system according to an embodiment.

Referring to FIG. 1, the user 110 may attempt user authentication through the user authentication device 130. In this specification, the user 110 may refer to a person who wishes to attempt user authentication with the user authentication device 130 and may also be referred to as a person to be authenticated. The user 110 can recognize a card in the user authentication device 130 for user authentication, and the user authentication device 130 can perform a user authentication process when the card is recognized. The user authentication process is a liveness test process that distinguishes whether the test subject is a real living object (genuine object) or a fake object (fake object such as paper, photo, digital device, model, etc.) and the authentication result based on the facial image. It may include a face authentication process that determines .

In one embodiment, the user authentication process may include determining whether the card is valid. When the card is recognized, the user authentication device 130 may receive card information from the card and determine whether the card is a valid card based on the received card information (eg, card identification information, etc.). If the user authentication device 130 determines that the card is a valid card, it continues to perform the user authentication process of the liveness check process and the face authentication process. If it determines that the card is not a valid card, the user authentication device 130 stops the user authentication process and performs the user authentication process. Access to (110) can be blocked.

In this specification, the card may be a security card 120 in which the registered face image of the user 110 is stored. The security card 120 may be, for example, a biometric ID card in which a registered face image is compressed or encrypted and stored. Since the security card 120 stores the registered face image, it provides the advantage that existing issued security cards can be used interchangeably even if the face authentication algorithm is changed in another system.

Depending on the embodiment, information such as name, email address, unique identification code, private key, public key, certificate, and personal data may be further encrypted and stored in the security card 120. The user 110 may attempt user authentication with the user authentication device 130 using the security card 120, and the user authentication device 130 uses the encrypted registered face image obtained from the security card 120. User authentication can be performed using a query face image obtained by photographing the face of the user 110. At this time, the user authentication device 130 may acquire at least one of a color image and an infrared image of the face 160 of the user 110 as a query face image through the image acquisition unit 140. The user authentication device 130 performs a liveness check on the user 110 through an infrared image and/or color image, based on the registered facial image and the color image and/or infrared image obtained from the security card 120. This allows user authentication to be performed. Liveness inspection can effectively block misrecognition caused by spoofing attacks using models, photos, or display devices, and thus improve the accuracy of user authentication.

When the user 110 tags the security card 120 to the card reader 150 of the user authentication device 130, the biometric information (e.g., registered facial image) stored in the security card 120 is stored in the card reader 150. It can be transmitted to the user authentication device 130 through . The card reader 150 may include a communication unit (not shown) capable of performing a short-range wireless communication function. The user authentication device 130 acquires a query face image about the face 160 of the user 110 through the image acquisition unit 140, and performs image analysis in real time to obtain the query face image from the security card 120. The user authentication result may be determined by comparing facial features shown in the registered facial image and the query facial image (color image and/or infrared image).

In one embodiment, user authentication using the security card 120 described above may be performed only once within a certain period of time (eg, one day). For example, user authentication using the security card 120 may be performed when the user 110 is certified for attendance or enters the facility for the first time within a certain period of time. After that, user authentication may be performed based on the query face image acquired by the image acquisition unit 140 without using the security card 120. When user authentication using the security card 120 is initially successful, the user authentication device 130 may store the first query face image used to use the user authentication result. Afterwards, the user authentication device 130 may perform user authentication using the stored first query face image as a registered face image. After user authentication using the security card 120 is successful, the user 110 receives the second query face image obtained through the image acquisition unit 140 without having to attempt user authentication using the security card 120. You can attempt user authentication with . If user authentication using the security card 120 is successful initially, the user may then submit a query face image without the need to tag his/her security card 120 to the card reader 150 every time he/she attempts user authentication. Successful user authentication can be expected just by using user authentication.

According to the user authentication device 130 and user authentication method proposed in this specification, the disadvantages of the method using only the security card 120 and the disadvantages of the method using only biometrics are effectively overcome at the same time, resulting in higher accuracy and more convenient user experience. Implementation of authentication technology becomes possible.

Hereinafter, the user authentication device 130 and the user authentication method performed by the user authentication device 130 will be described in more detail.

FIG. 2 is a diagram illustrating the configuration of a user authentication system including a user authentication device according to an embodiment.

Referring to FIG. 2, the user authentication system includes a security card 120 and a user authentication device 130. The security card 120 may include a registered face image of the user corresponding to the security card 120. Depending on the embodiment, the security card 120 may further include information about personal information or a unique identification code related to the user. Data stored in the security card 120 may be stored in encrypted form.

In one embodiment, the security card 120 may be a smart card type card capable of short-distance communication. The security card 120 can be used as a user authentication tool to transmit encrypted and stored information to the user authentication device 130 when a user authentication event initially occurs. The security card 120 may include a storage element such as a microchip 220, an antenna 210 connected to the microchip 220, and a memory that stores registered facial images and other related information. The security card 120 can communicate with an external device having a short-range wireless communication function through the antenna 210, and the data stored in the security card 120 is transmitted to the outside of the security card 120 through the antenna 210. can be sent to

In this specification, the form of the security card 120 is not limited by what is described in the drawings or embodiments, and may be implemented in various forms. For example, if it includes an antenna that can perform close-range communication and a chip that stores specific data, it can be used as the security card 120.

The user authentication device 130 according to one embodiment may include a light source 230, an infrared camera 250, a color camera 240, a card reader 150, a processor 260, and a storage device 270. . Depending on the embodiment, the user authentication device 130 may further include a proximity sensor (not shown) and/or a plurality of special function keys 282, 284, 286, and 288. For example, the special function keys 282, 284, 286, and 288 may be function keys for starting authentication of the user's departure from work, attendance, outside work, and return, respectively. If the user selects the special function key 282 corresponding to attendance and attempts user authentication, and user authentication is successful, the user may be processed as having attended work when user authentication is successful. If the user selects the special function key 284 corresponding to leaving work and attempts user authentication and user authentication succeeds, the user may be processed as having left work when user authentication is successful.

The occurrence of a user authentication event by the user authentication device 130 may occur, for example, when the security card 120 is tagged with the card reader 150 or when the infrared camera 250 or the color camera 240 is used in the face area. This may be done when detection is made, or when it is detected that an object has approached the user authentication device 130 through a proximity sensor. When a user authentication event occurs, a series of user authentication processes including a liveness check process and/or a face authentication process are performed.

In one embodiment, the light source 230 may include an infrared light source that emits infrared light toward the user. The infrared camera 250 can acquire an infrared image including the user's face area. The color camera 240 can acquire a color image including the user's face area. When a card such as the security card 120 is recognized, the card reader 150 may obtain the registered face image stored in the security card 120. The acquired registered face image, infrared image, and/or color image may be temporarily stored in the storage device 270. The storage device 270 includes storage elements that can store data, such as memory and storage.

The processor 260 controls the overall operation of the user authentication device 130. The processor 260 can transmit and receive control and processing data of each component of the user authentication device 130, and execute operations depending on user authentication success or user authentication failure depending on the user's access authority.

For example, the processor 260 may determine a user authentication result based on at least one of a registered face image, an infrared image, and a color image obtained from the security card 120, and generate a control signal according to the user authentication result. there is. In one embodiment, the processor 260 may perform a liveness check on the user based on the acquired infrared image. The processor 260 may determine that the liveness check result is successful if the liveness check result determines that the user is a real object. In this case, the processor 260 may perform face authentication to determine the face authentication result. If the liveness check result determines that the user is a fake object, the processor 260 determines that the liveness check result is a failure, determines that the final result of user authentication is failed, and blocks the user's access or restricts entry. You can control it.

In one embodiment, when processor 260 determines that the liveness check result is successful, the processor 260 provides information about the facial area appearing in the query facial image in the color image and/or infrared image and the facial area appearing in the registered facial image obtained from the card. The face authentication result can be determined based on the information.

If the liveness test result is determined to be successful, the processor 260 extracts the first facial feature from the registered facial image acquired through the card reader 150, and the color image and infrared images acquired through the color camera 240. The second facial feature may be extracted from the query face image including at least one of the infrared images acquired through the camera 250. In one embodiment, the processor 260 extracts and analyzes facial feature points from a registered face image obtained from a card to determine a first facial feature, and extracts and analyzes facial feature points from a query face image to determine a second facial feature. can be decided.

The processor 260 may compare the first facial feature and the second facial feature and determine a facial authentication result based on the comparison result between the first facial feature and the second facial feature. For example, the processor 260 may calculate the similarity between the first facial feature and the second facial feature, and if the calculated similarity is greater than or equal to a threshold value, the processor 260 may determine that the face authentication result is successful. If the similarity is less than the threshold, the face authentication result may be determined to have failed. After the face authentication result is determined, the processor 260 may control the registered face image of the security card 120 acquired during the user authentication process to be deleted from the storage device 270 .

The user authentication system does not store biometric information for face authentication in the user authentication device 130 or another external server, but rather uses biometric information such as a registered face image stored in the security card 120 owned by the user. Since it operates in a one-time use manner in the user authentication device 130, it is free from hacking of biometric information and provides the effect of lowering the management cost of personal information and the cost of establishing an authentication system. Additionally, in the user authentication system, biometric information stored in the security card 120 is compared with information obtained from an actual person attempting user authentication in front of the user authentication device 130, so even if the security card 120 is lost, a third party Since fraudulent use of the security card 120 is impossible, the user authentication system provides excellent security.

Meanwhile, the user authentication process based on the security card 120 described above can only be performed initially within a specific period, and thereafter, the color camera 240 or the infrared camera 250 is used without using the security card 120. The face authentication result may be determined based on the query face image acquired by the camera. For example, when attempting user authentication for the first time, such as when authenticating for attendance during the day, the security card 120 is required for successful user authentication, but thereafter, user authentication can be determined to be successful even without the security card 120. . This will be explained in detail below with reference to Figure 3.

Figure 3 is a diagram for explaining the operation of a user authentication device according to an embodiment.

In the embodiment of FIG. 3, it will be explained as an example that the user 160 performs authentication, such as attendance and departure, through a user authentication device.

When a user comes to work on the same day and attempts attendance authentication, the security card 120 may be used. In this case, when the user 160 attempts to authenticate attendance using the security card 120, the processor 260 acquires the registered face image stored in the security card 120 through the card reader 150, and color The first query face image of the user 160 may be obtained through the camera 240 and/or the infrared camera 250. The processor 260 may determine whether attendance authentication of the user 160 is successful based on the registered face image and the first query face image.

More specifically, the user authentication device may first monitor whether access to the security card 120 is recognized by the card reader 150 and a user authentication event occurs. When access to a card such as the security card 120 is recognized, the card reader 150 can obtain card information stored in the card. The user authentication device may check whether the corresponding security card 120 is an authorized security card 120 based on the obtained card information. If the security card 120 is an authorized security card 120, a user authentication event occurs, and the card reader 150 can acquire the registered face image stored in the security card 120 through short-distance wireless communication. . The registered face image may be decoded by the processor 260 and temporarily stored in the storage device 270.

The processor 260 may analyze the registered facial image obtained from the security card 120 and extract the first facial feature corresponding to the first biometric information. For example, the first facial feature may include facial feature point information. The processor 260 may temporarily store information about the extracted first facial feature in the storage device 270 .

The processor 260 may activate the light source 230, the color camera 240, and the infrared camera 250 to capture the face of the user holding the security card 120. The light source 230 may emit infrared rays toward the user's face 160, and the infrared camera 250 may receive the reflected light returned when the infrared rays emitted from the light source 230 are reflected on the user's face 160, thereby allowing the user to use the infrared rays. An infrared image showing the face area can be obtained. The color camera 240 can photograph the user's face 160 and obtain a color image showing the face area. The camera of the color camera 240 and/or the infrared camera 250 captures a first query facial image (the color image and/or the infrared image) at a first time including the facial area of the user 160. obtain.

In one embodiment, processor 260 may perform a liveness check based on the acquired infrared image and/or color image. The liveness test is a test to distinguish between a real person's face and a fake face reproduced through photos, models, videos, etc. If it is determined that the face is not a real person's face, the liveness test result is determined to be a failure, and the real person's face is determined to be a failure. If it is determined to be a human face, the liveness test result may be determined to be successful.

If the liveness check result is determined to be a failure, the next step may not be progressed and the user authentication result may be ultimately determined to have failed. Conversely, if the liveness test result is determined to be successful, the face authentication procedure can be operated.

When the face authentication procedure operates, the processor 260 may determine a user authentication result based on the first query face image and generate a control signal according to the user authentication result. The processor 260 may extract a second facial feature corresponding to the second biometric information from the first query facial image. The second facial feature may include facial feature point information extracted from the first query face image. The processor 260 detects the user's face area in the first query face image and generates facial feature points (e.g., feature points located in areas such as eyes, nose, mouth corner, eyebrows, etc.) from the detected face area. 2 It can be extracted as facial features. The processor 260 may temporarily store information about the extracted second facial feature in the storage device 270 .

The processor 260 may compare the first facial feature and the second facial feature to calculate the degree of similarity between the two facial features. The processor 260 may determine that face authentication is successful if the calculated similarity satisfies a specific condition (e.g., is greater than or equal to a threshold value), and may determine that face authentication has failed if the calculated similarity does not satisfy the condition.

The processor 260 may transmit user authentication result information according to the user authentication result or perform a corresponding action according to successful user authentication. For example, if the liveness test result is determined to be failed or the face authentication result is determined to be failed, user authentication is ultimately determined to have failed, and the processor 260 performs a control operation to block access to the gate 310. can do. If both the liveness test result and the face authentication result are determined to be successful, the user authentication is finally determined to be successful, and the processor 260 allows access to the gate 310 to open the gate, and the user 160 Control operations such as saving attendance records can be performed.

If the user authentication result based on the registered face image of the security card 120 and the first query face image is determined to be successful, the processor 260 may store the first query face image of the user 160 in the storage device 270. there is. The stored first query face image can be used as a face image registered during the day. The storage device 270 may store a face image of at least one user who has successfully completed attendance authentication on the same day or the current day. At least one user's face image stored in the storage device 270 corresponds to each user's first query face image acquired by the camera when attendance authentication is successful.

When the user authentication process including the liveness check and/or the face authentication process is completed, the processor 260 may control the registered face image obtained from the security card 120 to be deleted from the storage device 270 . The user authentication device does not need to have a separate database to store biometric information of registered users, and thus can fundamentally prevent the risk of biometric information being hacked.

After user authentication for attendance authentication is successful, the user 160 may attempt user authentication again with the user authentication device in order to enter the facility. In this case, the user 160 may attempt user authentication without the security card 120. When the camera of the color camera 240 and/or the infrared camera 250 acquires a second query facial image at a second time point after the first time point, the processor 260 stores each user stored in the storage device 270. The user authentication result may be determined based on the first query face image and the corresponding second query face image. In this way, user convenience can be improved by enabling user authentication without the security card 120 after attendance authentication is successful. The first time point and the second time point may be specific times within a day or specific times within a predefined validity period.

The processor 260 compares the facial features between the first query face image and the second query face image of at least one user who succeeded in authentication for attendance on the current date (or the same day), and searches each first query stored in the storage device 270. The similarity between the face image and the second query face image may be calculated, and if there is a first query face image whose similarity is greater than or equal to a threshold value, it may be determined that user authentication is successful. In this way, in user authentication attempted after successful attendance authentication, the facial images to be compared for user authentication are limited to the facial images of users who attended work on the current date, so the calculation amount can be reduced and the error rate can be lowered. Additionally, since the latest facial image taken on the current date is used as the facial image to be compared, the accuracy of user authentication can be increased. Since the face of the user 160 gradually changes over time after the registered face image stored in the security card 120 is captured, the registered face image stored in the security card 120 is that of the current user 160. It does not fully reflect the appearance of the face. By using the latest face image taken on the current date as the object of comparison for user authentication as above, errors that may occur due to facial changes over time can be greatly reduced, and the accuracy of user authentication will be improved accordingly. You can.

When user authentication based on the second query face image is completed, the processor 260 may control the deletion of the second query face image used in the user authentication process. Accordingly, after the user authentication result is determined, the second query face image does not remain in the user authentication device. That is, only the first query face image of the user captured during attendance authentication is temporarily stored in the storage device 270. Afterwards, the query face images taken in the middle are deleted after user authentication is completed.

If the authentication of the user 160 leaving work is successful, the processor 260 may control the deletion of the first query face image of the user 160 stored in the storage device 270 . Alternatively, the processor 260 may control to delete all face images (first query face images) stored in the storage device 270 at a preset time point after the first time point and the second time point. For example, the processor 260 may control to delete all face images stored in the storage device 270 at midnight, when the current date ends, or at a preset specific point in time. As another example, a validity period may be specified for each user, and in this case, the processor 260 controls the storage device 270 to delete the face image of the user whose validity period has expired when the validity period specified for each user expires. You can. When the validity period for each user expires, the facial images of the users whose validity period has expired may be sequentially deleted from the storage device 270. The validity period can be defined as a predefined length of time, starting from, for example, the time when the user successfully authenticates for attendance or the time when the user successfully authenticates for the first time that day. Following this process, there is no need to store and manage biometric data of users registered in the user authentication system, and problems that may arise due to leakage of biometric information can be prevented in advance.

FIG. 4 is a diagram illustrating a case in which a query face image is stored in a storage device or a query face image is deleted from a storage device, according to an embodiment.

Referring to case (A) in FIG. 4 , the storage device 270 may store first query face images 410 and 412 of users who successfully authenticated their first user within a specific period of time. For example, the first query face images 410 and 412 may correspond to first query face images obtained through attendance authentication of users who successfully authenticated attendance within the same day. If the user succeeds in user authentication for attendance authentication based on the security card and the first query face image 420 on the same day, the first query face image 420 may be temporarily stored in the storage device 270. there is.

(B) Referring to the case, when a user who succeeds in attendance authentication subsequently attempts user authentication, a second query face image 430 for the user is obtained, and a second query face image (430) is obtained without using a security card. The user authentication result is determined based on 430). If the user attempts user authentication and does not tag the security card, the user authentication device acquires a second query face image 430 for the user and stores the acquired second query face image 430 and the storage device 270. The similarity of facial features is calculated between each of the stored first query face images 410, 412, and 420, and if there is a similarity that satisfies a predetermined condition, it may be determined that user authentication is successful. For example, if there is a similarity greater than a threshold value, it may be determined that a predetermined condition is satisfied. If there is no similarity that satisfies the predetermined condition, the user authentication device may determine that user authentication has failed. Regardless of whether user authentication is successful, the user authentication device does not store the second query face image 430 used for user authentication in the storage device 270.

Referring to the case (C), if the user succeeds in leaving work authentication, the user authentication device controls the user's first query face image 420 stored in the storage device 270 to be deleted from the storage device 270. You can. Accordingly, after work leave authentication is successful, the user's face image does not remain in the user authentication device. Meanwhile, the user authentication device may control deletion of all first query face images 410, 412, and 420 stored in the storage device 270 when a preset time or condition is achieved.

Figures 5A and 5B are flowcharts for explaining the operation of a user authentication method according to an embodiment. The user authentication method may be performed by the user authentication device described herein.

FIG. 5A is a flowchart illustrating a user authentication process performed when authenticating attendance according to an embodiment. Referring to FIG. 5A, in step 510, the user authentication device may wait for a card, such as a security card, to access the card reader. The card reader of the user authentication device may be waiting while broadcasting a request signal to obtain security card information.

At step 515, the user authentication device monitors whether the card has been recognized. As a result of monitoring, if the card is not recognized, the user authentication device returns to step 510 and continues to wait. In one embodiment, when a user approaches a security card to a card reader of a user authentication device, the card reader capable of performing short-range wireless communication can check whether the security card is authorized. For example, the user authentication device can confirm whether the security card is an authorized card by verifying the issuing code or unique identification code stored in the security card. If it is confirmed that the card is unauthorized, the user authentication device returns to the standby state in step 510.

If the card is recognized as an authorized card, a user authentication event occurs, and the user authentication device obtains information stored in the card through a card reader in step 520. The user authentication device may, for example, obtain information about the registered face image or unique identification code stored in the card through a card reader. The user authentication device can decode and temporarily store information about the acquired registered face image or unique identification code.

In step 530, the user authentication device may acquire a first query facial image at a first viewpoint including the user's face area through a camera.

In step 535, the user authentication device may determine a user authentication result based on the registered face image obtained from the card and the first query face image obtained through the camera. The user authentication device may determine whether the user's attendance authentication is successful according to the user authentication result. In one embodiment, the user authentication device may extract the first facial feature from the registered facial image and the second facial feature from the first query facial image. The user authentication device may determine similarity by comparing the first facial feature and the second facial feature, and determine a facial authentication result based on the comparison result between the first facial feature and the second facial feature. In one embodiment, the user authentication device may perform face authentication by comparing feature points indicated by each of the first facial feature and the second facial feature to determine whether the face belongs to the same user. If the face authentication result is successful, the user authentication device may perform processing operations corresponding to user authentication success. If the face authentication result is a failure, the user authentication device may perform processing operations corresponding to the user authentication failure, such as blocking or not allowing the user's access. Depending on the embodiment, a liveness check process may be performed along with the face authentication process.

In step 540, it is determined whether the user authentication result is successful. If the user authentication result based on the registered face image and the first query face image is determined to be successful, the user authentication device determines the first query face image in step 545. can be stored on a storage device. The user authentication device deletes the registered face image used in the user authentication process so that it does not remain in the user authentication device or other devices.

FIG. 5B is a flowchart illustrating a user authentication process performed after attendance authentication is successful according to an embodiment. Referring to FIG. 5B, in step 550, the camera of the user authentication device acquires a second query face image at a second viewpoint after the first viewpoint. When the camera detects the user's face area or detects that the user has approached the user authentication device through a proximity sensor, a user authentication event may occur, the camera may be activated, and a second query face image may be obtained.

In step 555, the user authentication device determines a user authentication result based on at least one face image and the second query face image stored in the storage device. Here, at least one face image stored in the storage device may include the first query face image obtained in step 530. In one embodiment, the storage device stores a facial image of at least one user who succeeded in attendance authentication on the current date (same day), and the stored facial image of at least one user is obtained by a camera when attendance authentication is successful. It may correspond to the first query face image of each user.

In step 560, when the user authentication result is determined, the user authentication device may delete the second query face image obtained in step 550 for user authentication.

In step 560, the user authentication device determines whether the preset condition is satisfied. If the preset condition is satisfied, in step 570, the user authentication device may delete the first query face image stored in the storage device. there is. For example, if authentication of the user leaving work is successful, the user authentication device may delete the user's first query face image from the storage device. As another example, the user authentication device may delete all face images stored in the storage device when a preset time point (eg, midnight) occurs after the first time point and the second time point. As another example, when the validity period specified for each user expires, the user authentication device may delete the face image of the user whose validity period has expired from the storage device. The validity period may be determined based on when the user first successfully authenticates within the day. For example, the validity period may be determined as 12 hours from the time of first successful authentication.

The device described above may be implemented with hardware components, software components, and/or a combination of hardware components and software components. For example, devices and components described in embodiments may include, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), etc. , may be implemented using one or more general-purpose or special-purpose computers, such as a programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions. A processing device may execute an operating system (OS) and one or more software applications that run on the operating system. Additionally, a processing device may access, store, manipulate, process, and generate data in response to the execution of software. For ease of understanding, a single processing device may be described as being used; however, those skilled in the art will understand that a processing device includes multiple processing elements and/or multiple types of processing elements. It can be seen that it may include. For example, a processing device may include a plurality of processors or one processor and one controller. Additionally, other processing configurations, such as parallel processors, are possible.

The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc., singly or in combination. Program instructions recorded on the medium may be specially designed and configured for the embodiment or may be known and available to those skilled in the art of computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floptical disks. -Includes optical media (magneto-optical media) and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, etc. Examples of program instructions include machine language code, such as that produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter, etc. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

As described above, although the embodiments have been described with limited examples and drawings, various modifications and variations can be made by those skilled in the art from the above description. For example, the described techniques are performed in a different order than the described method, and/or components of the described system, structure, device, circuit, etc. are combined or combined in a different form than the described method, or other components are used. Alternatively, appropriate results may be achieved even if substituted or substituted by an equivalent.

Therefore, other implementations, other embodiments and equivalents of the claims also fall within the scope of the following claims.

Claims (14)

In the user authentication device,
A card reader that obtains the registered face image stored in the card when the card is recognized;
A camera that acquires a first query face image at a first time including the user's face area; and
A processor that determines a user authentication result based on the first query face image and generates a control signal according to the user authentication result,
The processor,
When the user authentication result based on the registered face image and the first query face image is determined to be successful, the user's attendance authentication is determined to be successful, and the first query face image is stored in a storage device, and the registered face delete the image,
When the camera acquires a second query face image at a second time point after the first time point, at least one face image stored in the storage device and the second query face image are displayed without a user authentication process using the card. Based on this, determine the user authentication result,
When a user authentication result is determined based on the second query face image, deleting the second query face image,
If the user's exit from work authentication is successful, control to delete the user's first query face image from the storage device,
At least one face image stored in the storage device includes a first query face image of each user obtained by the camera when each user is successfully authenticated for attendance on the current day,
User authentication device. delete According to paragraph 1,
The processor,
Control to delete all facial images stored in the storage device at a preset time after the second time, or
A user authentication device that controls to delete from the storage device the face image of a user whose validity period has expired when a validity period specified for each user expires. delete delete delete According to paragraph 1,
The first time point and the second time point are specific times within a day or specific times within a predefined validity period. In a user authentication method performed by a user authentication device,
When the card is recognized by the card reader, obtaining a registered face image stored in the card;
Obtaining a first query face image at a first time including a face area of the user through a camera;
determining a user authentication result based on the first query face image;
If the user authentication result based on the registered face image and the first query face image is determined to be successful, storing the first query face image in a storage device;
When the camera acquires a second query face image at a second time point after the first time point, at least one face image stored in the storage device and the second query face image are displayed without a user authentication process using the card. determining a user authentication result based on;
When a user authentication result based on the second query face image is determined, deleting the second query face image; and
When authentication of the user leaving work is successful, deleting the first query face image of the user from the storage device,
At least one face image stored in the storage device includes a first query face image of each user acquired by the camera when each user is successfully authenticated for attendance on the current day,
The user authentication device determines that attendance authentication of the user is successful when the user authentication result based on the registered face image and the first query face image is determined to be successful, and deletes the registered face image.
User authentication method. delete According to clause 8,
Delete all face images stored in the storage device at a preset time after the first time and the second time, or store the face image of the user whose validity period has expired when the validity period specified for each user expires. Steps to delete from device
A user authentication method further comprising: delete delete delete A computer-readable recording medium recording a program for performing the method of claim 8.

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