US-12620259-B2 - Face authentication apparatus

Abstract

A face authentication apparatus includes a face image acquisition unit that acquires, as a first face image, a face image of a user who moves from a first area to a second area via a gate provided between the first area and the second area, a collation unit that performs face authentication, a flow rate measurement unit that measures a flow rate of users who move from the first area to the second area via the gate and a flow rate of users who move from the second area to the first area via the gate, and a security level determination unit that determines the security level of the first area and the security level of the second area on the basis of the flow rates measured.

Inventors

• Taketo Kochi
• Kenji Saito

Assignees

• NEC CORPORATION

Dates

Publication Date

20260505

Application Date

20240621

Priority Date

20180112

Claims (20)

1. 1 . A face authentication apparatus comprising: a memory containing program instructions; and a processor coupled to the memory, wherein the processor is configured to execute the program instructions to: acquire, as a first face image, a face image of a person who moves from a first area to a second area via a gate provided between the first area and the second area, and acquire, as a second face image, a face image of a person who moves from the second area to the first area via the gate; perform first face authentication for the first face image based on a first threshold; perform second face authentication for the second face image based on a second threshold; determine a security level of the first area and a security level of the second area based on at least one of a number of times of success in the first face authentication and a number of times of success in the second face authentication; and change the first threshold and the second threshold according to the determined security level of the first area and the determined security level of the second area, wherein: the second face authentication is further performed on the second face image by calculating similarity between the second face image and a reference face image for each registered person and comparing the similarity with the second threshold, and the second threshold is changed in an increasing or decreasing direction that is opposite to the increasing or decreasing direction of changing the first threshold.
2. 2 . The face authentication apparatus according to claim 1 , wherein the determination of the security level is changed when a predetermined date and time arrives.
3. 3 . The face authentication apparatus according to claim 1 , wherein the determination of the security level is changed when at least one of the number of times of success in the first face authentication and the number of times of success in the second face authentication reaches a certain number of times.
4. 4 . The face authentication apparatus according to claim 1 , wherein the determination of the security level includes determining the security level of the first area and the security level of the second area according to a security level determination rule set in advance, based on the measured number of times of success in the first face authentication and the measured number of times of success in the second face authentication.
5. 5 . The face authentication apparatus according to claim 4 , wherein the security level determination rule includes a condition section that describes a condition to be satisfied by the measured number of times of success in the first face authentication or the measured number of times of success in the second face authentication, and a conclusion section that describes a security level of the first area and a security level of the second area when the condition is satisfied.
6. 6 . The face authentication apparatus according to claim 5 , wherein: the condition section describes as the condition that there is a difference between a first rate of persons who moved from the first area to the second area and a second rate of persons who moved from the second area to the first area, and the conclusion section describes on which of a downstream side and an upstream side having a larger flow rate in a designated time period, the security level is set to be higher.
7. 7 . The face authentication apparatus according to claim 1 , wherein the change of the first threshold includes changing the first threshold when the security level of the second area is determined to be higher than the security level of the first area and when the security level of the second area is determined to be lower than the security level of the first area.
8. 8 . The face authentication apparatus according to claim 1 , wherein the change of the first threshold includes changing the first threshold to be larger than a predetermined value when the security level of the second area is determined to be higher than the security level of the first area, and changing the first threshold to be smaller than the predetermined value when the security level of the second area is determined to lower than the security level of the first area.
9. 9 . The face authentication apparatus according to claim 1 , wherein: the first face authentication is further performed on the first face image by calculating similarity between the first face image and the reference face image for each registered person and comparing the similarity with the first threshold, and the first threshold is changed in an increasing or decreasing direction that is opposite to the increasing or decreasing direction of changing the second threshold.
10. 10 . The face authentication apparatus according to claim 1 , wherein: the first face image is captured by a first camera fixed at a first position and a first angle of a first view capable of capturing a first image of a first face of a first person moving from the first area to the second area through the gate, and the second face image is captured by a second camera fixed at a second position and a second angle of a second view capable of capturing a second image of a second face of a second person moving from the second area to the first area through the gate.
11. 11 . The face authentication apparatus according to claim 1 , wherein, when the first threshold and the second threshold are changed, the changed first threshold and the second threshold are maintained until the first threshold and the second threshold are initialized.
12. 12 . A face authentication method comprising: acquiring, as a first face image, a face image of a person who moves from a first area to a second area via a gate provided between the first area and the second area, and acquiring, as a second face image, a face image of a person who moves from the second area to the first area via the gate; performing first face authentication for the first face image based on a first threshold; performing second face authentication for the second face image based on a second threshold; determining a security level of the first area and a security level of the second area based on at least one of a number of times of success in the first face authentication and a number of times of success in the second face authentication; change the first threshold and the second threshold according to the determined security level of the first area and the determined security level of the second area; wherein: the second face authentication is further performed on the second face image by calculating similarity between the second face image and a reference face image for each registered person and comparing the similarity with the second threshold, and the second threshold is changed in an increasing or decreasing direction that is opposite to the increasing or decreasing direction of changing the first threshold.
13. 13 . The face authentication method according to claim 12 , wherein the determining of the security level includes changing when a predetermined date and time arrives.
14. 14 . The face authentication method according to claim 12 , wherein the determining of the security level includes changing when at least one of the number of times of success in the first face authentication and the number of times of success in the second face authentication reaches a certain number of times.
15. 15 . The face authentication method according to claim 12 , wherein the determining of the security level includes determining the security level of the first area and the security level of the second area according to a security level determination rule set in advance, based on the measured number of times of success in the first face authentication and the measured number of times of success in the second face authentication.
16. 16 . The face authentication method according to claim 15 , wherein the security level determination rule includes a condition section that describes a condition to be satisfied by the measured number of times of success in the first face authentication or the measured number of times of success in the second face authentication, and a conclusion section that describes a security level of the first area and a security level of the second area when the condition is satisfied.
17. 17 . The face authentication method according to claim 16 , wherein: the condition section describes as the condition that there is a difference between a first rate of persons who moved from the first area to the second area and a second rate of persons who moved from the second area to the first area, and the conclusion section describes on which of a downstream side and an upstream side having a larger flow rate in a designated time period, the security level is set to be higher.
18. 18 . The face authentication method according to claim 12 , wherein the changing of the first threshold includes changing the first threshold when the security level of the second area is determined to be higher than the security level of the first area and when the security level of the second area is determined to be lower than the security level of the first area.
19. 19 . The face authentication method according to claim 12 , wherein the changing of the first threshold includes: changing the first threshold to be larger than a predetermined value when the security level of the second area is determined to be higher than the security level of the first area, and changing the first threshold to be smaller than the predetermined value when the security level of the second area is determined to lower than the security level of the first area.
20. 20 . A non-transitory computer-readable medium storing a program comprising instructions for causing a computer to perform processes to: acquiring, as a first face image, a face image of a person who moves from a first area to a second area via a gate provided between the first area and the second area, and acquiring, as a second face image, a face image of a person who moves from the second area to the first area via the gate; performing first face authentication for the first face image based on a first threshold; performing second face authentication for the second face image based on a second threshold; determining a security level of the first area and a security level of the second area based on at least one of a number of times of success in the first face authentication and a number of times of success in the second face authentication; change the first threshold and the second threshold according to the determined security level of the first area and the determined security level of the second area; wherein: the second face authentication is further performed on the second face image by calculating similarity between the second face image and a reference face image for each registered person and comparing the similarity with the second threshold, and the second threshold is changed in an increasing or decreasing direction that is opposite to the increasing or decreasing direction of changing the first threshold.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a continuation of U.S. patent application Ser. No. 17/848,594 filed on Jun. 24, 2022, which is a continuation of U.S. patent application Ser. No. 16/961,310 filed on Jul. 10, 2020, which issued as U.S. Pat. No. 11,403,873, which is a National Stage Entry of international application PCT/JP2018/047063 filed on Dec. 20, 2018, which claims the benefit of priority from Japanese Patent Application No. 2018-003229 filed on Jan. 12, 2018, the disclosures of all of which are incorporated in their entirety by reference herein. TECHNICAL FIELD The present invention relates to a face authentication apparatus, a face authentication method, and a recording medium. BACKGROUND ART Conventionally, in various systems such as an access monitoring system and an attendance management system, personal authentication by means of face authentication is performed on a user who passes through a gate or the like. For example, Patent Literatures 1 and 2 each disclose a face authentication apparatus that performs face authentication by acquiring a face image of a person who passes through a gate provided at an entrance of a collective housing or an office building, calculating similarity between the face image and a reference face image of a previously registered person, and comparing it with a threshold. Further, in the face authentication apparatus of this type, a configuration of automatically changing a threshold to be used for collation is employed. For example, in Patent Literature 1, a threshold to be used for collation of a person who passes through a gate is automatically changed based on a previously set reference time such as an average time to go home and the current time. In Patent Literature 2, the number of persons who pass through a gate is measured, and when the number of persons is large, a small threshold is set. Patent Literature 1: JP 2009-3659 APatent Literature 2: JP 2007-156541 A SUMMARY In a system for face authentication of a user who passes through a gate, generally, an administrator determines the security levels of both sides of the gate and sets a threshold for face authentication on the basis of the determination result. Specifically, like an entry gate of an office building or an event site, in the case of performing face authentication on users who enter the inside having a high security level from the outside having a low security level, a collation threshold is set to be relatively larger so as to lower the false acceptance rate to place emphasis on security. On the other hand, like an exit gate of an office building or an event site, in the case of performing face authentication on users who go out from the inside having a high security level to the outside having a low security level, a collation threshold is set to be relatively smaller so as to lower the false rejection rate to place emphasis on convenience. However, if the security levels of both sides of a gate are determined manually, a burden on the administrator increases. An exemplary object of the present invention is to provide a face authentication apparatus that solves the aforementioned problem. A face authentication apparatus according to one aspect of the present invention includes a face image acquisition unit that acquires, as a first face image, a face image of a user who moves from a first area to a second area via a gate provided between the first area and the second area,a collation unit that performs face authentication on the first face image,a flow rate measurement unit that measures a flow rate of users who move from the first area to the second area via the gate and a flow rate of users who move from the second area to the first area via the gate, anda security level determination unit that determines a security level of the first area and a security level of the second area on the basis of the flow rates measured. A face authentication method according to another aspect of the present invention includes acquiring, as a first face image, a face image of a user who moves from a first area to a second area via a gate provided between the first area and the second area,performing face authentication on the first face image,measuring a flow rate of users who move from the first area to the second area via the gate and a flow rate of users who move from the second area to the first area via the gate, anddetermining a security level of the first area and a security level of the second area on the basis of the flow rates measured. A computer-readable medium according to another aspect of the present invention is a medium storing a program for causing a computer to function as: a face image acquisition unit that acquires, as a first face image, a face image of a user who moves from a first area to a second area via a gate provided between the first area and the second area,a collation unit that performs face authentication on the first face image,a flow rate measur