Authentication device, system, method, and program

Abstract

The present invention makes it possible to reduce a probability of authentication failure without increasing the number of times of collation. A face image acquisition means (21) acquires a face image of a person to be authenticated. An authentication means (22) performs a first authentication of collating the face image of the person to be authenticated with a registered image of a registrant. When the first authentication is successful, the authentication means (22) stores the face image of the person to be authenticated in a face information storage unit (23) as face information successful in the authentication for the registrant. When the first authentication fails, the authentication means (22) performs a second authentication of collating the face of the person to be authenticated with the face information successful in the authentication and stored in the face information storage unit (23).

Description

[Technical Field]

[0001] The present disclosure relates to authentication devices, systems, methods, and computer-readable media. [Background technology]

[0002] As a related technique, Patent Document 1 discloses an authentication device. The authentication device described in Patent Document 1 acquires, from an imaging device, a plurality of consecutive images in chronological order, each of which shows a subject. The authentication device compares each of the plurality of images with a registered image and determines whether each image matches the registered image. If the number of consecutive matches is equal to or exceeds a set number, the authentication device associates the images that were not determined to match with the registered image and registers them.

[0003] For example, a photographing device continuously photographs person A and acquires face image data of person A in chronological order. An authentication device obtains N pieces of face image data of person A from the photographing device, where N is an arbitrary natural number. The authentication device compares each of the N pieces of face image data with a master (registered image) of person A. If the features of each piece of face image data from N-2 to N, which are consecutive in chronological order, match the features of the master of person A, the authentication device authenticates that the photographed person is person A.

[0004] If the features of each piece of facial image data from N-2 to N match the features of person A's master, there is a high possibility that the person appearing in the facial image data before N-3 is also person A, even if authentication failed at an earlier time. The authentication device calculates the match rate between each piece of facial image data before N-3 and the facial image data of N-2. Of the facial image data that failed authentication, the authentication device additionally registers facial image data with a match rate equal to or greater than a threshold value in the master for person A. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-169776 Summary of the Invention [Problem to be solved by the invention]

[0006] In Patent Document 1, the authentication device additionally registers, among facial image data for which authentication has failed, facial image data that has a high matching rate with facial image data for which authentication has succeeded, as registered images. By increasing the number of registered images, Patent Document 1 can reduce the probability of authentication failure and improve the authentication rate. However, Patent Document 1 routinely uses multiple registered images for each person to be authenticated. This increases the number of matching processes in authentication, and lengthens the time required for authentication.

[0007] In view of the above circumstances, the present disclosure aims to provide an authentication device, system, method, and computer-readable medium that can reduce the probability of authentication failure without increasing the number of matching attempts. [Means for solving the problem]

[0008] To achieve the above object, the present disclosure provides, as a first aspect, an authentication device. The authentication device includes a facial image acquisition means for acquiring a facial image of the person to be authenticated from a captured image acquired by an imaging device that captures the person to be authenticated, and an authentication means for performing a first authentication by comparing the acquired facial image of the person to be authenticated or features extracted from the facial image with a registered image of a registrant or features extracted from the registered image. If the first authentication is successful, the authentication means stores the facial image of the person to be authenticated or the features extracted from the facial image in a facial information storage unit as facial information of the registrant that has been successfully authenticated. If the first authentication is unsuccessful, the authentication means performs a second authentication by comparing the facial image of the person to be authenticated or the features extracted from the facial image with the facial information that has been successfully authenticated and is stored in the facial information storage unit.

[0009] The present disclosure provides, as a second aspect, an authentication system. The authentication system includes an imaging device that captures an image of a person to be authenticated, and an authentication device that acquires the captured image from the imaging device and authenticates the person to be authenticated. The authentication device includes a facial image acquisition means that acquires a facial image of the person to be authenticated from the captured image, and an authentication means that performs a first authentication by comparing the acquired facial image of the person to be authenticated or features extracted from the facial image with a registered image of a registrant or features extracted from the registered image. If the first authentication is successful, the authentication means stores the facial image of the person to be authenticated or the features extracted from the facial image in a facial information storage unit as facial information of the registrant that has been successfully authenticated. If the first authentication is unsuccessful, the authentication means performs a second authentication, which includes comparing the facial image of the person to be authenticated or the features extracted from the facial image with the facial information that has been successfully authenticated and is stored in the facial information storage unit.

[0010] The present disclosure provides, as a third aspect, an authentication method, which includes: acquiring a face image of a person to be authenticated from a captured image acquired from an imaging device that captures an image of the person to be authenticated; performing first authentication by comparing the acquired face image of the person to be authenticated or feature amounts extracted from the face image with a registered image of a registrant or feature amounts extracted from the registered image; determining whether the first authentication is successful; if it is determined that the first authentication is successful, storing the face image of the person to be authenticated or the feature amounts extracted from the face image in a face information storage unit as face information of the registrant that has been successfully authenticated; and, if it is determined that the first authentication has failed, performing second authentication by comparing the face image of the person to be authenticated or the feature amounts extracted from the face image with the face information that has been successfully authenticated and that is stored in the face information storage unit.

[0011] In a fourth aspect, the present disclosure provides a computer-readable medium storing a program for causing a computer to execute a process including acquiring a facial image of a person to be authenticated from a captured image acquired from an imaging device that captures the person to be authenticated, performing first authentication by comparing the acquired facial image of the person to be authenticated or feature amounts extracted from the facial image with a registered image of a registrant or feature amounts extracted from the registered image, determining whether the first authentication is successful, storing the facial image of the person to be authenticated or feature amounts extracted from the facial image in a face information storage unit as face information of the registrant that has been successfully authenticated, and performing second authentication by comparing the facial image of the person to be authenticated or feature amounts extracted from the facial image with the face information that has been successfully authenticated and that is stored in the face information storage unit, if it is determined that the first authentication has been unsuccessful. [Effects of the Invention]

[0012] The authentication device, system, method, and computer-readable medium according to the present disclosure can reduce the probability of authentication failure without increasing the number of times of matching. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a block diagram illustrating a schematic of an authentication system according to the present disclosure. [Figure 2] FIG. 1 is a block diagram illustrating an authentication system according to an embodiment of the present disclosure. [Figure 3] FIG. 4 is a diagram showing an example of face information stored in a face information storage unit. [Figure 4] 10 is a flowchart showing an operation procedure in the authentication device. [Figure 5] FIG. 1 is a schematic diagram illustrating a first face authentication. [Figure 6] FIG. 10 is a schematic diagram illustrating a second face authentication method. [Figure 7] FIG. 2 is a block diagram showing an example of the hardware configuration of an authentication device. DETAILED DESCRIPTION OF THE INVENTION

[0014] Prior to describing embodiments of the present disclosure, an overview of the present disclosure will be described. Fig. 1 schematically shows an authentication system according to the present disclosure. The authentication system 10 includes an authentication device 20 and an imaging device 30. The imaging device 30 captures an image of a person to be authenticated. The authentication device 20 acquires the captured image from the imaging device 30 and authenticates the person to be authenticated.

[0015] The authentication device 20 has a facial image acquisition means 21 and an authentication means 22. The facial image acquisition means 21 acquires a facial image of the person to be authenticated from an image captured by the imaging device 30. The authentication means 22 performs a first authentication and compares the facial image of the person to be authenticated with a registered image of a registrant. In the first authentication, the authentication means 22 may compare a feature extracted from the facial image of the person to be authenticated with a feature extracted from the registered image of the registrant.

[0016] If the first authentication is successful, the authentication means 22 stores the facial image or feature amounts extracted from the facial image of the person to be authenticated in the facial information storage unit 23 as facial information of the registrant that has been successfully authenticated. If the first authentication is unsuccessful, the authentication means 22 performs the second authentication. In the second authentication, the authentication means 22 compares the facial image or feature amounts of the person to be authenticated with the facial image or feature amounts that have been successfully authenticated and are stored in the facial information storage unit 23.

[0017] In the present disclosure, the authentication means 22 stores a facial image or feature amount of a person to be authenticated who has been successfully authenticated in the first authentication in the facial information storage unit 23. If the first authentication fails, the authentication means 22 acquires, from the facial information storage unit 23, a facial image or feature amount of a person to be authenticated who has been successfully authenticated in the past, and compares the facial image or feature amount of the person to be authenticated with the facial image or feature amount acquired from the facial information storage unit 23. The facial image acquired from the facial information storage unit 23 is an image that has been successfully authenticated in the past and that was captured using the imaging device 30. By using such an image for comparison when the first authentication fails, the probability of authentication failure in the second authentication can be reduced. Furthermore, in the present disclosure, the facial image or feature amount stored in the facial information storage unit 23 when the first authentication fails is used. Therefore, compared to the case where an image or feature amount that has been successfully authenticated in the past is regularly used, the probability of authentication failure can be reduced while suppressing an increase in the number of comparisons.

[0018] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the following description and drawings have been omitted and simplified as appropriate for clarity of explanation. In addition, in the following drawings, the same or similar elements are designated by the same reference numerals, and duplicate explanations are omitted as necessary.

[0019] FIG. 2 shows an authentication system according to an embodiment of the present disclosure. The authentication system 100 includes an authentication device 110 and a camera 130. In the following, an example will be described in which the authentication system 100 is used for vehicle interior entry in a vehicle such as an automobile. The authentication system 100 is not limited to vehicle interior entry, and can be applied to authentication in various systems. The authentication system 100 corresponds to the authentication system 10 shown in FIG. 1.

[0020] The camera 130 photographs a person to be authenticated (a subject). In this embodiment, the camera 130 photographs a subject outdoors. The camera 130 photographs, for example, a person about to get into a vehicle. The vehicle is a moving body such as a passenger car, a taxi, or a van. The camera 130 is mounted on the vehicle, for example, and photographs the subject outside the vehicle from inside the vehicle. The camera 130 may also be installed outside the vehicle and photograph the subject approaching the vehicle. Note that the number of cameras 130 in the authentication system 100 is not limited to one. The authentication system 100 may have multiple cameras 130. The camera 130 corresponds to the imaging device 30 shown in FIG. 1.

[0021] The authentication device 110 is a device that acquires an image of a subject from a camera 130 and performs authentication using the acquired image. The authentication device 110 is mounted on, for example, a vehicle. The authentication device 110 has an image acquisition unit 111, a face detection unit 112, a face information storage unit 113, and a matching unit 114. The authentication device 110 is configured as a device that includes, for example, one or more processors and one or more memories. At least a part of the function of each unit in the authentication device 110 can be realized by the processor performing processing in accordance with a program read from the memory. The authentication device 110 corresponds to the authentication device 20 shown in FIG. 1.

[0022] The image acquisition unit 111 acquires video (images) captured by the camera 130. The image acquisition unit 111 sequentially acquires the latest image data captured by the camera 130. The face detection unit 112 detects a face area (face image) from the image data acquired by the image acquisition unit 111. The face detection unit 112 corresponds to the face image acquisition means 21 shown in FIG. 1.

[0023] The face information storage unit 113 stores face information of one or more users (registrants) to be authenticated. Each user registers his or her own face image in the authentication device 110. The face information storage unit 113 stores the registered face image as a master. A face image registered by a user is also called a registered image. In addition to or instead of the registered image, the face information storage unit 113 may store feature amounts extracted from the registered image as a master.

[0024] The face information storage unit 113 stores, for each user, a face image of a subject whose face authentication has been successful, in addition to a registered image. For example, when a subject has been identified as a certain user through successful face authentication, the face information storage unit 113 stores the face image detected by the face detection unit 112 as a face image whose face authentication has been successful in the past. For example, for each user, the face information storage unit 113 stores a face image whose face authentication has been successful in the most recent face authentication. The face image whose face authentication has been successful and is stored in the face information storage unit 113 is not limited to a face image whose face authentication has been successful in the most recent face authentication. For example, for each user, the face information storage unit 113 may store face images whose face authentication has been successful in multiple past face authentications.

[0025] It should be noted that the face information storage unit 113 does not necessarily have to be included in the authentication device 20. The face information storage unit 113 may be configured using, for example, a storage device connected to the authentication device 20 via a network. The face information storage unit 113 corresponds to the face information storage unit 23 shown in FIG. 1.

[0026] The matching unit 114 performs face authentication of the authentication target person using the face image detected by the face detection unit 112. The face authentication performed by the matching unit 114 includes first face authentication (first authentication) and second face authentication (second authentication). In the first face authentication, the matching unit 114 matches the face image detected by the face detection unit 112 with a registered image registered in the face information storage unit 113. In the first face authentication, the matching unit 114 acquires a registered image of each user from the face information storage unit 113. The matching unit 114 compares the face image detected by the face detection unit 112 with the acquired registered image of each user. For example, the matching unit 114 extracts facial features from the face image detected by the face detection unit 112 and compares the extracted features with features extracted from the registered image.

[0027] The matching unit 114 calculates a matching score indicating the degree of match or similarity between the subject's facial image and the registered image. In the following description, it is assumed that the higher the degree of match or similarity, the higher the matching score. The matching unit 114 calculates a matching score for each of one or more users. The matching unit 114 determines whether the first face authentication has been successful based on the matching score. For example, the matching unit 114 compares the matching score calculated for each user with a first threshold value, and determines whether the first face authentication has been successful based on the comparison result.

[0028] For example, the matching unit 114 determines that the first face authentication is successful when the matching score between the face image of the subject and the registered image of a certain user is equal to or greater than a first threshold. If the first face authentication is successful, the matching unit 114 identifies the subject as the registered user with the highest matching score. If the first face authentication is successful, the matching unit 114 stores the face image detected by the face detection unit 112 in the face information storage unit 113 as the face image for which face authentication was successful. If the face information storage unit 113 already stores a face image for which face authentication was successful, it may overwrite the face image for which face authentication was successful with the face image for which face authentication was successful in the latest face authentication. The matching unit 114 may store features extracted from the face image in the face information storage unit 113 instead of or in addition to the face image.

[0029] If the matching score is smaller than the first threshold, the matching unit 114 determines that the first face authentication has failed. In this case, the matching unit 114 performs second face authentication using a face image that has been successfully authenticated and is stored in the face information storage unit 113. In the second face authentication, the matching unit 114 acquires, from the face information storage unit 113, a face image or its feature amount that has been successfully authenticated in the past. The matching unit 114 compares the face image or its feature amount of the subject with each of one or more registered images or their feature amounts of users, and the acquired face images or their feature amounts that have been successfully authenticated in the past.

[0030] In the second face authentication, the matching unit 114 acquires face images that have been successfully authenticated from the face information storage unit 113 based on the matching score of each user in the first face authentication. For example, the matching unit 114 identifies a user who had a high matching score in the first face authentication, and acquires face images of the identified user that have been successfully authenticated in the past from the face information storage unit 113. In the second face authentication, the matching unit 114 temporarily adds the acquired face images that have been successfully authenticated in the past to the enrolled images, and compares the enrolled images and the face images that have been successfully authenticated in the past with the face image of the subject.

[0031] In the second face authentication, the matching unit 114 calculates a matching score for each user to be matched. The method for calculating the matching score in the second face authentication may be the same as the method for calculating the matching score in the first face authentication. The matching unit 114 determines whether the second face authentication is successful or not based on the calculated matching score. The matching unit 114 determines that the second face authentication is successful when the matching score with a registered image of any user or a face image that has been successfully authenticated in the past is equal to or greater than a first threshold. The matching unit 114 corresponds to the authentication means 22 shown in FIG. 1.

[0032] The authentication device 110 outputs the authentication result to a device (not shown) such as an ECU (Electronic Control Unit) that controls the vehicle. If the test subject is authenticated as a pre-registered user, the ECU unlocks the vehicle door and allows the user to get into the vehicle. If the test subject is not authenticated as a pre-registered user, the ECU does not unlock the vehicle door.

[0033] FIG. 3 shows an example of face information stored in face information storage unit 113. In FIG. 3, user ID (Identifier) ​​indicates an ID for identifying each user. For each user, face information storage unit 113 stores a registration image and a face image for which face authentication has been successful in the past. The registration image may be an image taken using camera 130, or may be an image taken using an imaging device different from camera 130. In contrast, a face image for which face authentication has been successful in the past is an image taken by camera 130 when first face authentication was successful.

[0034] In the first face authentication, the matching unit 114 matches the face image detected by the face detection unit 112 with the registered image of each user registered in the face information storage unit 113. The matching unit 114 identifies, for example, the user ID corresponding to the registered image having the highest matching score with the face image detected by the face detection unit 112. If the matching score is equal to or greater than a first threshold value, the matching unit 114 determines that the first face authentication is successful. In this case, the matching unit 114 identifies the subject as the user identified by the identified user ID.

[0035] If the first face authentication fails, i.e., if the matching score is smaller than the first threshold value, the matching unit 114 performs second face authentication. In the second face authentication, the matching unit 114 acquires a face image that has been successfully authenticated in the past and that corresponds to the specified user ID from the face information storage unit 113. In the second face authentication, the matching unit 114 matches the face image detected by the face detection unit 112 with the registered image of each user and a face image that has been successfully authenticated in the past and that corresponds to the specified user ID.

[0036] In the second face authentication, the matching unit 114 identifies the user ID corresponding to the registered image with the highest matching score with the face image detected by the face detection unit 112 or the face image for which face authentication was successful in the past. If the matching score is equal to or greater than the first threshold, the matching unit 114 determines that the second face authentication was successful. In this case, the matching unit 114 identifies the subject as the user identified by the identified user ID.

[0037] Next, the operation procedure will be explained. Fig. 4 shows the operation procedure (authentication method) in authentication device 110. Image acquisition unit 111 acquires camera images from camera 130 (step S1). Image acquisition unit 111 periodically performs step S1 and acquires camera images in time series from camera 130, which captures moving images. Face detection unit 112 detects a face area from the camera images acquired by image acquisition unit 111 (step S2). Face detection unit 112 outputs an image of the face area (face image) detected in step S2 to matching unit 114.

[0038] The matching unit 114 performs first face authentication on the face image input from the face detection unit 112 (step S3). In the first face authentication, the matching unit 114 matches the face image input from the face detection unit 112 with each of the registered images registered in the face information storage unit 113. The matching unit 114 calculates a matching score between each registered image and the face image input from the face detection unit 112. The matching unit 114 determines whether the first face authentication is successful or not based on the calculated matching score (step S4). In step S4, the matching unit 114 compares the matching score calculated for each registered image with a first threshold value and determines whether the matching score is equal to or greater than the first threshold value.

[0039] If the matching score is equal to or greater than the first threshold, the matching unit 114 determines in step S4 that the first face authentication has been successful. If the matching unit 114 determines that the first face authentication has been successful, it stores the face image matched with the registered image in the face information storage unit 113 as a face image that has been successfully authenticated in the past (step S5). The matching unit 114 also outputs a message indicating that the face authentication has been successful (step S6). In step S6, the matching unit 114 also outputs the user ID corresponding to the registered image that has the highest matching score with the face image input from the face detection unit 112.

[0040] If the matching score is smaller than the first threshold value, the matching unit 114 determines in step S4 that the first face authentication has failed. In this case, the matching unit 114 acquires, from the face information storage unit 113, a face image that was successfully authenticated in the past face authentication (step S7). In step S7, the matching unit 114 acquires a face image that was successfully authenticated in the past, corresponding to the user with the highest matching score calculated in the first face authentication.

[0041] The matching unit 114 performs second face authentication on the face image input from the face detection unit 112 (step S8). In the second face authentication, the matching unit 114 matches the face image input from the face detection unit 112 with each registered image of each user and the face image acquired in step S7. The matching unit 114 calculates a matching score between the face image input from the face detection unit 112 and each registered image and the face image acquired in step S7.

[0042] The matching unit 114 determines whether the second face authentication has been successful based on the calculated matching score (step S9). In step S9, the matching unit 114 compares the matching score calculated for each registered image and the face image acquired in step S7 with a first threshold value, and determines whether the matching score is equal to or greater than the first threshold value. If the matching score is equal to or greater than the first threshold value, the matching unit 114 determines that the second face authentication has been successful. In that case, the matching unit 114 proceeds to step S6 and outputs a message indicating that the face authentication has been successful.

[0043] If the matching score is smaller than the first threshold value, the matching unit 114 determines that the second face authentication has failed in step S9. In this case, the matching unit 114 outputs a message indicating that the face authentication has failed (step S10). If the second face authentication has failed, the authentication device 110 may return to step S1 and start the face authentication again from the beginning.

[0044] The first and second face authentication will be explained below using specific examples. Fig. 5 shows a schematic diagram of the first face authentication. In Fig. 5, the authentication target image indicates the face image of the subject detected by the face detection unit 112. The three registered images indicate the registered images of users with user IDs: 001, 002, and 003 registered in the face information storage unit 113.

[0045] The matching unit 114 calculates the matching score between the authentication target image and each of the three registered images. In FIG. 5, it is assumed that the matching score between the authentication target image and the registered image of the user with user ID: 001 is 0.55. It is also assumed that the matching score between the authentication target image and the registered image of the user with user ID: 002 is 0.45. It is also assumed that the matching score between the authentication target image and the registered image of the user with user ID: 003 is 0.40. In this example, the matching score between the authentication target image and the registered image of the user with ID: 001 is the highest.

[0046] In the example of FIG. 5, the authentication score threshold (first threshold) for determining whether face authentication has been successful is assumed to be 0.6. The matching unit 114 determines whether the matching score is equal to or greater than the authentication score threshold. In this example, the matching scores of all registered images are smaller than the authentication score threshold. Therefore, the matching unit 114 determines that the first face authentication has failed.

[0047] If the matching score of the registered image of the user with user ID: 001 is equal to or greater than the authentication score threshold, the matching unit 114 determines that the first face authentication was successful and identifies the subject as the user with user ID: 001. In this case, the matching unit 114 stores the authentication target image matched with the registered image in the face information storage unit 113 as a face image of the user with user ID: 001 that was successfully authenticated in the past.

[0048] 6 schematically illustrates the second face authentication. If the first face authentication fails, the matching unit 114 acquires, from the face information storage unit 113, a face image that was successfully authenticated in the previous face authentication of the user with user ID: 001 who had the highest matching score in the first face authentication. In the second face authentication, the matching unit 114 calculates matching scores between the authentication target image acquired at the time the second face authentication is performed and each of the three registered images. The matching unit 114 also calculates matching scores between the authentication target image and the face image that was successfully authenticated in the previous face authentication of the user with user ID: 001.

[0049] In FIG. 6, it is assumed that the matching score between the authentication target image and the registered image of the user with user ID: 001 is 0.57. It is also assumed that the matching score between the authentication target image and the registered image of the user with user ID: 002 is 0.43. It is also assumed that the matching score between the authentication target image and the registered image of the user with user ID: 003 is 0.38. It is also assumed that the matching score between the authentication target image and the face image of the user with user ID: 001 that was successfully authenticated last time is 0.61. In this example, the matching score between the authentication target image and the face image of the user with user ID: 001 that was successfully authenticated last time exceeds the authentication score threshold. Therefore, in the second face authentication, the subject is identified as the user with user ID: 001.

[0050] When the authentication system 100 is used for vehicle interior entry, it is considered that the image captured by the camera 130 and the image captured as a registration image are captured in different environments. In particular, when the camera 130 captures an image of a subject outdoors, depending on the lighting environment around the camera 130, face authentication may fail even if the subject is a registered user.

[0051] In this embodiment, in the first face authentication, the matching unit 114 matches the face image of the subject with the registered image of each registered user. If the first face authentication is successful, the matching unit 114 stores the face image of the user captured using the camera 130 in the face information storage unit 113 as a face image for which face authentication has been successful. In this embodiment, the face information storage unit 113 stores, for each user, for example, the most recent face image for which face authentication has been successful. This face image is an image captured using the camera 130. If the first face authentication is unsuccessful, in the second face authentication, the matching unit 114 matches the face image of the subject with face images for which face authentication has been successful in the past, stored in the face information storage unit 113.

[0052] In this embodiment, in the second face authentication, the matching unit 114 temporarily adds face images that have been successfully authenticated in the past to the matching targets. In the second face authentication, the face image of the subject is matched with face images captured using the camera 130. In the second face authentication, face images captured using the same camera 130 are matched with each other, so the probability of successful face authentication is thought to be higher than in the first face authentication. If the face image of the subject were constantly matched with each user's registered image and face images that have been successfully authenticated in the past, the probability of successful authentication could be increased, but the number of matches would increase. In contrast, in this embodiment, if the first face authentication fails, face images that have been successfully authenticated in the past are temporarily used. Therefore, in this embodiment, the probability of authentication failure can be reduced while suppressing an increase in the number of matches, compared to when images that have been successfully authenticated in the past are constantly used.

[0053] In the above embodiment, an example was described in which a face image of a user with the highest matching score in the first face authentication, whose face was successfully authenticated in the past, is acquired. However, if the matching score is low, the probability that the subject is the user with the highest matching score is considered low. Therefore, when the difference between the matching score in the first face authentication and a first threshold value used to determine whether authentication is successful is equal to or less than a certain value, the matching unit 114 may acquire a face image of a user with the highest matching score, whose face was successfully authenticated in the past, and perform the second face authentication. In other words, the matching unit 114 may compare the maximum matching score in the first face authentication with a second threshold value smaller than the first threshold value, and when the matching score is equal to or greater than the second threshold value, acquire a face image of a user with the highest matching score, whose face was successfully authenticated in the past. When the maximum matching score is smaller than the second threshold value, the matching unit 114 may perform the first face authentication again without performing the second face authentication.

[0054] In the above embodiment, the matching unit 114 performs matching in the second face authentication with face images that have been successfully recognized in the past, in addition to the registered images that were matched in the first face authentication. However, registered images with a low matching score in the first face authentication are considered to be registered images of a different person from the subject, and are also considered to have a low matching score in the second face authentication. In the second face authentication, it is not necessary to match all registered images with the subject's face image. Registered images of users with low matching scores may be excluded from matching in the second face authentication. For example, the matching unit 114 compares the matching score calculated in the first face authentication with a third threshold value that is smaller than the first threshold value. The third threshold value may be different from or the same as the second threshold value. The third threshold value may be greater than or smaller than the second threshold value. In the second face authentication, the matching unit 114 may match registered images with a matching score equal to or greater than the third threshold value in the first face authentication with the subject's face image. In this case, the number of comparisons in the second face authentication can be reduced, thereby reducing the time required for the authentication process.

[0055] Next, the hardware configuration of the authentication device 110 will be described. Fig. 7 shows an example of the hardware configuration of the authentication device 110. The authentication device 110 has a processor (CPU: Central Processing Unit) 501, a ROM (read only memory) 502, and a RAM (random access memory) 503. In the authentication device 110, the processor 501, the ROM 502, and the RAM 503 are connected to each other via a bus 504. Although not shown, the authentication device 110 may include other circuits such as peripheral circuits, communication circuits, and interface circuits.

[0056] The ROM 502 is a non-volatile storage device. For example, a semiconductor storage device with a relatively small capacity, such as a flash memory, is used for the ROM 502. The ROM 502 stores the programs executed by the processor 501.

[0057] The program includes instructions (or software code) that, when loaded into a computer, cause the computer to perform one or more functions described in the embodiments. The program may be stored in a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, computer-readable media or tangible storage media include RAM, ROM, flash memory, solid-state drive (SSD) or other memory technologies, compact discs (CDs), digital versatile discs (DVDs), Blu-ray discs or other optical disc storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices. The program may also be transmitted on a transitory computer-readable medium or a communication medium. By way of example and not limitation, transitory computer-readable media or communication media include electrical, optical, acoustic, or other forms of propagated signals.

[0058] The RAM 503 is a volatile storage device. Various semiconductor memory devices such as a dynamic random access memory (DRAM) or a static random access memory (SRAM) are used for the RAM 503. The RAM 503 can be used as an internal buffer for temporarily storing data and the like.

[0059] The processor 501 loads the program stored in the ROM 502 into the RAM 503 and executes the program. When the CPU 501 executes the program, the functions of the various units in the authentication device 110 can be realized.

[0060] The authentication device 110 does not necessarily have to be a single device. The authentication device 110 may be configured using multiple physically separated devices. Furthermore, when the authentication device 110 is used for vehicle interior entry, not all functions of the authentication device 110 necessarily need to be installed in the vehicle. For example, each unit of the authentication device 110 may be located outside the vehicle. In this case, the authentication device 110 may acquire camera images from the camera 130 via a wireless communication network. The authentication device 110 may transmit the authentication result to the vehicle via the wireless communication network.

[0061] The above describes the embodiments of the present disclosure in detail, but the present disclosure is not limited to the above-described embodiments, and changes and modifications to the above-described embodiments that do not deviate from the spirit of the present disclosure are also included in the present disclosure.

[0062] For example, some or all of the above embodiments can be described as, but are not limited to, the following supplementary notes.

[0063] [Appendix 1] a facial image acquisition means for acquiring a facial image of the person to be authenticated from a captured image acquired by an imaging device that captures an image of the person to be authenticated; an authentication means for performing a first authentication by comparing the acquired face image of the person to be authenticated or a feature amount extracted from the face image with a registered image of a registrant or a feature amount extracted from the registered image, An authentication device in which, if the first authentication is successful, the authentication means stores a facial image of the person to be authenticated or features extracted from the facial image in a facial information storage unit as facial information of the registered person that has been successfully authenticated, and, if the first authentication is unsuccessful, performs a second authentication which includes comparing the facial image of the person to be authenticated or features extracted from the facial image with the facial information that has been successfully authenticated and is stored in the facial information storage unit.

[0064] [Appendix 2] The authentication device described in Appendix 1, wherein, in the first authentication, the authentication means compares the facial image of the person to be authenticated or features extracted from the facial image with each of the registered images of one or more of the registered persons or features extracted from each registered image.

[0065] [Appendix 3] The authentication device described in Appendix 2, wherein, in the first authentication, the authentication means calculates a matching score indicating the degree of match between the facial image of the person to be authenticated and the registered image for each of the one or more registered persons, compares the calculated authentication score with a first threshold value, and determines whether the first authentication is successful or not based on the result of the comparison.

[0066] [Appendix 4] The authentication device described in Appendix 3, wherein the authentication means determines that the first authentication is successful if the matching score of the registered person with the highest matching score is equal to or greater than the first threshold, and determines that the first authentication is unsuccessful if the matching score of the registered person with the highest matching score is smaller than the first threshold.

[0067] [Appendix 5] 5. The authentication device according to claim 4, wherein, if the first authentication is successful, the authentication means identifies the person to be authenticated as the registered person with the highest matching score.

[0068] [Appendix 6] The authentication device according to any one of appendices 3 to 5, wherein in the second authentication, the authentication means acquires the face information of the successfully authenticated person from the face information storage unit based on the authentication score of each registered person in the first authentication, and compares the acquired face information with a face image of the person to be authenticated or features extracted from the face image.

[0069] [Appendix 7] 7. The authentication device according to claim 6, wherein the authentication means acquires from the face information storage unit the face information of the registered person who had the highest matching score in the first authentication and who was successfully authenticated.

[0070] [Appendix 8] The authentication device described in Appendix 7, wherein, if the first authentication fails, the authentication means compares the matching score of the registrant with the highest matching score in the first authentication with a second threshold value that is smaller than the first threshold value, and if the matching score of the registrant with the highest matching score is equal to or greater than the second threshold value, obtains the face information that was successfully authenticated from the face information storage unit.

[0071] [Appendix 9] 9. The authentication device according to claim 8, wherein the authentication means retries the first authentication if the matching score of the registrant with the highest matching score is lower than the second threshold value.

[0072] [Appendix 10] The authentication device according to any one of Supplementary Notes 2 to 9, wherein in the second authentication, the authentication means compares the facial image of the person to be authenticated or features extracted from the facial image with each of the registered images of the one or more registered persons or features extracted from each registered image, and the facial information that has been successfully authenticated.

[0073] [Appendix 11] The authentication device according to any one of Supplementary Notes 3 to 9, wherein in the second authentication, the authentication means compares the facial image of the person to be authenticated or the features extracted from the facial image with the registered image or the features extracted from the registered image of a registrant among the one or more registrants whose matching score in the first authentication is equal to or greater than a third threshold value that is smaller than the first threshold value, and with the facial information that has been successfully authenticated.

[0074] [Appendix 12] 12. The authentication device according to claim 1, wherein the captured image is an image of a person to be authenticated who is outdoors.

[0075] [Appendix 13] an imaging device for capturing an image of a person to be authenticated; an authentication device that acquires a captured image from the imaging device and authenticates the person to be authenticated; The authentication device a facial image acquisition means for acquiring a facial image of the person to be authenticated from the captured image; and an authentication means for performing a first authentication by comparing the acquired face image of the person to be authenticated or a feature amount extracted from the face image with a registered image of a registered person or a feature amount extracted from the registered image, An authentication system in which, if the first authentication is successful, the authentication means stores a facial image of the person to be authenticated or features extracted from the facial image in a facial information storage unit as facial information of the registered person that has been successfully authenticated, and, if the first authentication is unsuccessful, performs a second authentication which includes comparing the facial image of the person to be authenticated or features extracted from the facial image with the facial information that has been successfully authenticated and is stored in the facial information storage unit.

[0076] [Appendix 14] The authentication system described in Appendix 13, wherein, in the first authentication, the authentication means compares the facial image of the person to be authenticated or features extracted from the facial image with each of the registered images of one or more of the registered persons or features extracted from each registered image.

[0077] [Appendix 15] The authentication system described in Appendix 14, wherein, in the first authentication, the authentication means calculates a matching score indicating the degree of match between the facial image of the person to be authenticated and the registered image for each of the one or more registered persons, compares the calculated authentication score with a first threshold value, and determines whether the first authentication is successful based on the result of the comparison.

[0078] [Appendix 16] The authentication system described in Appendix 14 or 15, wherein in the second authentication, the authentication means compares the facial image of the person to be authenticated or features extracted from the facial image with each of the registered images of the one or more registered persons or features extracted from each registered image, and the facial information that has been successfully authenticated.

[0079] [Appendix 17] acquiring a face image of the person to be authenticated from a captured image acquired by an imaging device that captures an image of the person to be authenticated; performing a first authentication in which the acquired face image of the person to be authenticated or the feature amount extracted from the face image is compared with a registered image of a registrant or the feature amount extracted from the registered image; determining whether the first authentication is successful; If it is determined that the first authentication is successful, a face image of the person to be authenticated or a feature amount extracted from the face image is stored in a face information storage unit as face information of the registrant that has been successfully authenticated; An authentication method comprising: when it is determined that the first authentication has failed, performing a second authentication, which includes comparing a facial image of the person to be authenticated or features extracted from the facial image with the facial information that has been successfully authenticated and is stored in the facial information storage unit.

[0080] [Appendix 18] acquiring a face image of the person to be authenticated from a captured image acquired by an imaging device that captures an image of the person to be authenticated; performing a first authentication in which the acquired face image of the person to be authenticated or the feature amount extracted from the face image is compared with a registered image of a registrant or the feature amount extracted from the registered image; determining whether the first authentication is successful; If it is determined that the first authentication is successful, a face image of the person to be authenticated or a feature amount extracted from the face image is stored in a face information storage unit as face information of the registrant that has been successfully authenticated; A non-transitory computer-readable medium that stores a program for causing a computer to perform a process including, if it is determined that the first authentication has failed, performing a second authentication, which includes comparing a facial image of the person to be authenticated or features extracted from the facial image with the facial information that has been successfully authenticated and is stored in the facial information storage unit. [Explanation of symbols]

[0081] 10: Authentication system 20: Authentication device 21: Facial image acquisition means 22: Authentication method 30: Imaging device 100: Authentication system 110: Authentication device 111: Image acquisition unit 112: Face detection unit 113: Face information memory unit 114: Matching section 130: Camera 501: Processor 502:ROM 503:RAM 504: Bus

Claims

1. a facial image acquisition means for acquiring a facial image of the person to be authenticated from a captured image acquired by an imaging device that captures an image of the person to be authenticated; an authentication means for performing a first authentication by comparing the acquired face image of the person to be authenticated or a feature amount extracted from the face image with a registered image of a registrant or a feature amount extracted from the registered image, An authentication device in which, if the first authentication is successful, the authentication means stores a facial image of the person to be authenticated or features extracted from the facial image in a facial information storage unit as facial information that has been successfully authenticated for the registered person, and, if the first authentication is unsuccessful, performs a second authentication which includes comparing the facial image of the person to be authenticated or the features extracted from the facial image with the facial information that has been successfully authenticated and is stored in the facial information storage unit.

2. 2. The authentication device according to claim 1, wherein the authentication means, in the first authentication, compares a facial image of the person to be authenticated or a feature extracted from the facial image with each of registered images of one or more of the registered persons or feature extracted from each registered image.

3. 3. The authentication device according to claim 2, wherein the authentication means calculates, for each of the one or more registered persons, a matching score indicating a degree of match between the facial image of the person to be authenticated and the registered image in the first authentication, compares the calculated matching score with a first threshold value, and determines whether the first authentication is successful or not based on the result of the comparison.

4. 4. The authentication device according to claim 3, wherein the authentication means determines that the first authentication has been successful if the matching score of the registered person with the highest matching score is equal to or greater than the first threshold value, and determines that the first authentication has been unsuccessful if the matching score of the registered person with the highest matching score is smaller than the first threshold value.

5. 5. The authentication device according to claim 3, wherein in the second authentication, the authentication means acquires the facial information of the successfully authenticated person from the facial information storage unit based on the matching score of each registered person in the first authentication, and compares the acquired facial information with a facial image of the person to be authenticated or features extracted from the facial image.

6. 6. The authentication device according to claim 3, wherein in the second authentication, the authentication means compares the facial image of the person to be authenticated or features extracted from the facial image with each of the registered images of the one or more registered persons or features extracted from each registered image, and the facial information that has been successfully authenticated.

7. 7. The authentication device according to claim 3, wherein in the second authentication, the authentication means compares a facial image of the person to be authenticated or features extracted from the facial image with a registered image or features extracted from the registered image of a registrant among the one or more registrants whose matching score in the first authentication is equal to or greater than a third threshold value that is smaller than the first threshold value, and with facial information that has been successfully authenticated.

8. an imaging device for capturing an image of a person to be authenticated; an authentication device that acquires a captured image from the imaging device and authenticates the person to be authenticated; The authentication device a facial image acquisition means for acquiring a facial image of the person to be authenticated from the captured image; and an authentication means for performing a first authentication by comparing the acquired face image of the person to be authenticated or a feature amount extracted from the face image with a registered image of a registered person or a feature amount extracted from the registered image, an authentication means for storing, in a face information storage unit, a face image of the person to be authenticated or features extracted from the face image as face information of the registered person that has been successfully authenticated, if the first authentication is successful; and, if the first authentication is unsuccessful, performing a second authentication that includes comparing the face image of the person to be authenticated or features extracted from the face image with the face information of the person that has been successfully authenticated and that is stored in the face information storage unit.

9. acquiring a face image of the person to be authenticated from a captured image acquired by an imaging device that captures an image of the person to be authenticated; performing a first authentication in which the acquired face image of the person to be authenticated or a feature amount extracted from the face image is compared with a registered image of a registrant or a feature amount extracted from the registered image; determining whether the first authentication is successful; If it is determined that the first authentication is successful, a face image of the person to be authenticated or a feature amount extracted from the face image is stored in a face information storage unit as face information of the registrant that has been successfully authenticated; An authentication method comprising: if it is determined that the first authentication has failed, performing a second authentication, which includes comparing a facial image of the person to be authenticated or features extracted from the facial image with the facial information that has been successfully authenticated and is stored in the facial information storage unit.

10. acquiring a face image of the person to be authenticated from a captured image acquired by an imaging device that captures an image of the person to be authenticated; performing a first authentication in which the acquired face image of the person to be authenticated or a feature amount extracted from the face image is compared with a registered image of a registrant or a feature amount extracted from the registered image; determining whether the first authentication is successful; If it is determined that the first authentication is successful, a face image of the person to be authenticated or a feature amount extracted from the face image is stored in a face information storage unit as face information of the registrant that has been successfully authenticated; A program for causing a computer to perform processing including, when it is determined that the first authentication has failed, performing a second authentication including comparing a facial image of the person to be authenticated or features extracted from the facial image with the facial information that has been successfully authenticated and is stored in the facial information storage unit.

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