Face Recognition Device

Abstract

It is difficult to make the difference in security strength between an operation that prioritizes security and an operation that prioritizes convenience more pronounced. [Solution] The device comprises a first authentication unit that performs first authentication on a facial image to be authenticated based on a threshold value, a second authentication unit that performs second authentication using an authentication method other than facial authentication, a detection unit that detects whether the second authentication unit is being used, a threshold change unit that sets the threshold to a higher value when the second authentication unit is being used compared to when it is not being used, and an identity authentication unit that uses the set threshold value to perform identity authentication based on the result of the first authentication when the second authentication unit is not being used, and to perform identity authentication based on the result of the first authentication and the result of the second authentication when the second authentication unit is being used.

Description

[Technical field]

[0001] The present invention relates to a face recognition device, a face recognition method, and a program. [Background technology]

[0002] Conventionally, in various systems such as entrance / exit monitoring systems and attendance management systems, face recognition is used to authenticate the identity of users passing through gates, etc. In addition, in such systems, face recognition devices that perform personal authentication by combining face recognition with other authentication methods have been proposed or put into practical use.

[0003] For example, Patent Document 1 describes a face authentication device that uses face authentication and authentication by a PIN in combination. In the face authentication device described in Patent Document 1, a PIN is first input by a user and compared with a registered PIN. If all digits of the PIN are correctly input, the personal authentication is deemed successful without face authentication. If not even one digit of the PIN is input, or if only a predetermined number of digits or less are input correctly, the personal authentication is deemed unsuccessful without face authentication. In other cases, face authentication is performed, and the success or failure of the personal authentication is determined according to the result of face authentication. At that time, a threshold value for face authentication is set according to the number of digits of the correctly input PIN. Specifically, the more digits of the PIN are correctly input, that is, the higher the security strength is achieved by the PIN authentication method, the smaller the threshold value for face authentication is, making it easier to accept the person.

[0004] Combining two or more different types of authentication information, such as the facial recognition and PIN authentication mentioned above, is called two-factor authentication or multi-factor authentication. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2008-158627 A Summary of the Invention [Problem to be solved by the invention]

[0006] In a face recognition device that uses face recognition in combination with another authentication method, it is also possible to select whether or not to use the other authentication method. If the other authentication method is not used, personal authentication is performed based only on the result of face recognition, so security strength is reduced but convenience is increased. On the other hand, if the other authentication method is used, personal authentication is performed based on the result of face recognition and the result of the other authentication method, so convenience is reduced but security strength is increased.

[0007] In this way, in a face recognition device that can switch between an operation that prioritizes security and an operation that prioritizes convenience by selecting whether or not to use other authentication methods, it is desirable to make the difference in security strength between the two operations more noticeable. In other words, it is desirable to increase the difference in security strength between the operation that prioritizes security and the operation that prioritizes convenience. However, it is difficult to realize such an operation mode by simply selecting whether or not to use other authentication methods.

[0008] An object of the present invention is to provide a face recognition device that solves the above-mentioned problems. [Means for solving the problem]

[0009] A face recognition device according to one aspect of the present invention comprises: a first authentication unit that performs a first authentication on a face image to be authenticated based on a threshold value; a second authentication unit that performs a second authentication by an authentication method other than face authentication; A detection unit that detects whether the second authentication unit is used; a threshold change unit that sets the threshold to a larger value when the second authentication unit is used than when the second authentication unit is not used; The authentication unit includes an authentication unit that uses the set threshold value to perform identity authentication based on the result of the first authentication when the second authentication unit is not used, and performs identity authentication based on the result of the first authentication and the result of the second authentication when the second authentication unit is used.

[0010] A face recognition method according to another aspect of the present invention includes: Detect whether or not a second authentication method other than face recognition is used, a threshold value in a first authentication for performing authentication of a face image to be authenticated based on a threshold value is set to a larger value when the second authentication is used compared with a case where the second authentication is not used; Using the threshold value after being set, if the second authentication is not used, personal authentication is performed based on the result of the first authentication, and if the second authentication is used, personal authentication is performed based on the result of the first authentication and the result of the second authentication.

[0011] A program according to another aspect of the present invention includes: Computer, a first authentication unit that performs a first authentication on a face image to be authenticated based on a threshold value; a second authentication unit that performs a second authentication by an authentication method other than face authentication; A detection unit that detects whether the second authentication unit is used; a threshold change unit that sets the threshold to a larger value when the second authentication unit is used than when the second authentication unit is not used; an authentication unit that performs authentication based on a result of the first authentication using the set threshold value when the second authentication unit is not used, and performs authentication based on a result of the first authentication and a result of the second authentication when the second authentication unit is used; and make it function. Effect of the Invention

[0012] By having the above-described configuration, the present invention makes it possible to make the difference in security strength between two operations in a face recognition device that can be switched between an operation that emphasizes security and, conversely, an operation that emphasizes convenience, more pronounced by selecting whether or not to use other authentication methods. [Brief description of the drawings]

[0013] [Figure 1] 1 is a block diagram of a face recognition device according to a first embodiment of the present invention. [Diagram 2] 1 is a schematic diagram of an entrance / exit management system including a face recognition device according to a first embodiment of the present invention. [Diagram 3] 4 is a flowchart showing an outline of the operation of the face recognition device according to the first embodiment of the present invention. [Figure 4] 4 is a flowchart showing an outline of the operation of the face recognition device according to the first embodiment of the present invention. [Diagram 5] FIG. 2 is a conceptual diagram showing a combination of face image authentication and IC card authentication in the first embodiment of the present invention, and a security strength determined by a matching threshold value used in the face image authentication. [Figure 6] 10 is a flowchart showing an example of the operation of a threshold value changing unit in a face authentication device according to a second embodiment of the present invention. [Figure 7] FIG. 11 is a diagram showing an example of a matching threshold setting screen displayed by a threshold changing unit in the face authentication device according to the second embodiment of the present invention. [Figure 8] FIG. 11 is a block diagram of a face recognition device according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Next, an embodiment of the present invention will be described in detail with reference to the drawings. [First embodiment] Fig. 1 is a block diagram of a face authentication device 100 according to a first embodiment of the present invention. Fig. 2 is a schematic diagram of an entrance / exit management system including the face authentication device 100 according to this embodiment. Referring to Fig. 1, the face authentication device 100 according to this embodiment is composed of an interface unit 111 with a camera unit 141, an interface unit 112 with an IC card reader 144, an interface unit 113 with a gate device 142, a communication interface unit 114, an operation input unit 115, a screen display unit 116, a storage unit 120, and an arithmetic processing unit 130.

[0015] The interface unit 111 is configured to transmit and receive signals to and from a camera unit 141 that captures an image of a face of a person to be authenticated. The transmission and reception of signals may be wired or wireless. As shown in FIG. 2, the camera unit 141 is set at a position and angle of view that allows it to capture an image of a face of a user 143 passing through a gate device 142. The camera unit 141 is an imaging device made of a CCD (Charge Coupled Device) element, a CMOS (Complementary Metal-oxide Semiconductor) element, or the like that outputs image data obtained by capturing an image of a face of a person to be matched to the arithmetic processing unit 130 via the interface unit 111. The image data captured by the camera unit 141 is, for example, a black and white grayscale image with 256 gradations, but may also be a color image.

[0016] The interface unit 112 is configured to transmit and receive signals to and from the IC card reader 144. The transmission and reception of signals may be wired or wireless. As shown in FIG. 2, the IC card reader 144 is attached near the gate device 142. When passing through the gate device 142, when a user 143 brings an IC card 145 held by the user 143 close, the IC card reader 144 is configured to read information stored in the IC card 145 in a non-contact manner and output the information to the calculation processing unit 130 through the interface unit 112. The IC card 145 stores information including a user ID and authentication information.

[0017] The interface unit 113 is configured to transmit and receive signals such as the result of personal authentication between the gate device 142 and the gate device 142. The transmission and reception of signals may be wired or wireless. The gate device 142 performs a predetermined operation according to the received result of personal authentication. Various predetermined operations are possible. For example, the gate device 142 automatically performs an operation of opening and closing a door attached to the gate device 142 according to the result of personal authentication. Alternatively, the gate device 142 is provided with a gate bar that can be opened and closed manually, and unlocks the gate bar for a certain period of time only when the personal authentication is successful. Alternatively, the gate device 142 outputs a visual or acoustic message indicating whether or not the person can pass from an alarm attached to the gate device 142 according to the result of personal authentication. The gate device 142 may be a stationary type or a portable type that can be moved. The gate device 142 may be a device independent of the face authentication device 100, or may be a device integrated with the face authentication device 100.

[0018] The communication interface unit 114 is a communication device that performs data communication with an external device such as a terminal, etc. The communication method may be either wired or wireless.

[0019] The operation input unit 115 is an input device such as a keyboard or numeric keypad, and is configured to detect an operator's operation and output it to the arithmetic processing unit 130 .

[0020] The screen display unit 116 is a screen display device such as an LCD (Liquid Crystal Display) or a PDP (Plasma Display Panel). The screen display unit 116 is configured to display various information such as the collation result on the screen in response to an instruction from the arithmetic processing unit 130.

[0021] The storage unit 120 is a storage device such as a hard disk, a memory, etc. The storage unit 120 is configured to store processing information and programs 121 required for various processes performed by the arithmetic processing unit 130.

[0022] The program 121 is read into the arithmetic processing unit 130 and executed to realize various processing units. The program 121 is read in advance from an external device (not shown) or a storage medium (not shown) via a data input / output function such as the communication interface unit 114, and is stored in the storage unit 120.

[0023] The main processing information stored in the storage unit 120 includes reference face image data 122, a matching threshold value 123, reference card data 124, and data 125 on whether or not IC card authentication is used.

[0024] The reference face image data 122 is data in which a face image serving as a reference for use in face matching is associated with a user ID. The reference face image data 122 may be associated with a user ID and at least one face image of a person having the user ID as a reference face image. Alternatively, the reference face image data 122 may be associated with a user ID and a facial feature amount extracted from the face image of the person having the user ID as reference face information. Here, the facial feature amount is a numerical value indicating the features of each part of a face image for recognizing the positional relationship and shape of each part constituting a face, such as the eyes, nose, mouth, eyebrows, etc., and is used when performing a similarity judgment between images, etc.

[0025] The matching threshold 123 is a threshold used when performing face matching. In this embodiment, the matching threshold 123 is common to all user IDs. If the matching threshold is increased, the acceptance rate of other users decreases and security increases.

[0026] The reference card data 124 is data that associates authentication information serving as a reference for use in IC card authentication with a user ID. In the reference card data 124, information that is associated with a user ID and that is to be compared with authentication information stored in the IC card 145 having that user ID is recorded as reference authentication information.

[0027] The IC card authentication use / non-use data 125 is data indicating whether or not IC card authentication is used. For example, the IC card authentication use / non-use data 125 is set to a value of 1 when IC card authentication is used, and is reset to a value of 0 when IC card authentication is not used.

[0028] The arithmetic processing unit 130 is an arithmetic processing device having a microprocessor such as an MPU and its peripheral circuits. The arithmetic processing unit 130 is configured to read and execute a program 121 from the storage unit 120, thereby implementing various processing units by having the above hardware and the program 121 work together. The processing units implemented by the arithmetic processing unit 130 include an input unit 131, a face image acquisition unit 132, a matching unit 133, an IC card authentication use / non-use detection unit 134, a threshold change unit 135, an IC card information acquisition unit 136, an IC card authentication unit 137, an individual authentication unit 138, and an output unit 139.

[0029] The input unit 131 is configured to input the reference face image data 122 and the reference card data 124 from the outside via the communication interface unit 114 or the operation input unit 115 , and store them in the storage unit 120 .

[0030] The face image acquisition unit 132 is configured to input image data of a person to be matched, captured by the camera unit 141, through the interface unit 111, and acquire (detect) a face image of the person to be matched from the image data. The face image acquisition unit 132 acquires a face image present in the image data by matching a template showing a general outline of a person's face with the image data. Various known face detection algorithms other than template matching may be used. The face image acquisition unit 132 is configured to transmit the acquired face image to the matching unit 133.

[0031] The matching unit 133 is configured to read out the reference face image data 122 and the matching threshold value 123 from the storage unit 120, calculate the similarity between the reference face image included in the reference face image data 122 and the face image to be matched acquired by the face image acquisition unit 132 for each user ID, and determine whether the face image to be matched matches any of the reference face images of user IDs included in the reference face image data 152 or does not match any of the reference face images based on the result of comparing the calculated similarity for each user ID with the matching threshold value 123. As an example of the similarity, a cross-correlation coefficient between face images can be used. In this case, the similarity is large when both face images include face parts of the same person, and is small when both face images include face parts of different people. As the similarity between face images, a known similarity calculation technique other than the cross-correlation coefficient can be used. For example, the matching unit 133 may be configured to extract facial features from the acquired facial image to be matched, match the reference facial features included in the reference facial image data 122 with the facial features extracted from the facial image to be matched, and calculate the similarity between the reference facial image and the facial image to be matched.

[0032] The matching unit 133 is configured to generate an authentication result of face authentication failure when there is no reference face image of a user ID whose similarity with the face image to be matched acquired by the face image acquisition unit 132 is equal to or greater than the matching threshold value 123. The matching unit 133 is configured to generate an authentication result of face authentication success including the user ID with the highest similarity when there is one or more reference face images whose similarity with the face image to be matched acquired by the face image acquisition unit 162 is equal to or greater than the matching threshold value 123. The matching unit 133 is further configured to transmit the authentication result to the identity authentication unit 138.

[0033] The IC card authentication use / non-use detection unit 134 is configured to detect whether IC card authentication is being used. The IC card authentication use / non-use detection unit 134 is configured to detect whether IC card authentication is being used before starting operation of the face authentication device 100. The IC card authentication use / non-use detection unit 134 is also configured to detect whether IC card authentication is being used during operation of the face authentication device 100.

[0034] The IC card authentication use / non-use detection unit 134 detects that the IC card authentication is in use when it receives a command from the administrator via the communication interface unit 114 or the operation input unit 115 to use the IC card authentication. Conversely, the IC card authentication use / non-use detection unit 134 detects that the IC card authentication is not in use when it receives a command from the administrator to not use the IC card authentication. However, the method of detecting the use / non-use of the IC card authentication is not limited to this. For example, the IC card authentication use / non-use detection unit 134 may be configured to check whether the interface unit 112 with the IC card reader 144 is attached to the arithmetic processing unit 130, and detect that the IC card authentication is in use if it is attached, and that the IC card authentication is not in use if it is not attached. The IC card authentication use / non-use detection unit 134 is also configured to update the IC card authentication use / non-use data 125 stored in the storage unit 120 according to the detected use / non-use of the IC card authentication. Furthermore, the IC card authentication use / non-use detection unit 134 is configured to notify the threshold value change unit 135 when the IC card authentication use / non-use data 125 is set or changed.

[0035] The threshold change unit 135 is configured to read the IC card authentication use data 125 from the storage unit 120 when notified by the IC card authentication use detection unit 134, determine the value of the matching threshold 123 according to the data, and store the determined matching threshold 123 in the storage unit 120. Specifically, the threshold change unit 135 determines the matching threshold 123 so that it is larger when IC card authentication is used than when it is not used. In this embodiment, when IC card authentication is used, the threshold change unit 135 sets the matching threshold 123 to a value TH larger than a predetermined value T0, thereby reducing the false acceptance rate and increasing security strength. On the other hand, when IC card authentication is not used, the threshold change unit 135 sets the matching threshold 123 to a value TL smaller than a predetermined value T0, thereby reducing the false rejection rate and increasing convenience.

[0036] The IC card information acquiring unit 136 is configured to input the stored information of the IC card 145 read by the IC card reader 144 through the interface unit 112. The IC card information acquiring unit 136 is configured to transmit the acquired stored information of the IC card 145 to the IC card authentication unit 137.

[0037] The IC card authentication unit 137 is configured to read out the reference card data 124 from the storage unit 120, compare the reference authentication information included in the reference card data 124 with the stored information of the IC card 145 acquired by the IC card information acquisition unit 136, and perform IC card authentication based on the result of the comparison. For example, the IC card authentication unit 137 extracts a user ID and authentication information from the stored information of the IC card 145, compares the extracted authentication information with the reference authentication information included in the reference card data 124 having the same user ID as the extracted user ID, and determines that the authentication is successful if they match, and that the authentication is unsuccessful if they do not match. However, the authentication method is not limited to this, and any known IC card authentication technology can be used. The IC card authentication unit 137 is also configured to transmit the authentication result including the user ID that has been successfully authenticated to the personal authentication unit 138.

[0038] The personal authentication unit 138 is configured to perform personal authentication based on the authentication result of the collation unit 133, the authentication result of the IC card authentication unit 137, and the IC card authentication use / non-use data 125. Specifically, the personal authentication unit 138 reads the IC card authentication use / non-use data 125 from the storage unit 120 and judges whether or not the IC card authentication is to be used. Then, when the IC card authentication use / non-use data 125 indicates that the IC card authentication is to be used, the personal authentication unit 138 derives the result of personal authentication based on the authentication result of the collation unit 133 and the authentication result of the IC card authentication unit 137. That is, when both the authentication result of the collation unit 133 and the authentication result of the IC card authentication unit 137 indicate successful authentication and the successfully authenticated user IDs are the same in both cases, the personal authentication unit 138 judges that the personal authentication is successful. On the other hand, the personal authentication unit 138 judges that the personal authentication has failed if at least one of the authentication results of the collation unit 133 and the IC card authentication unit 137 is unsuccessful, or if both are successful but the successfully authenticated user IDs are different from each other. When the IC card authentication usage data 125 indicates that IC card authentication is not used, the personal authentication unit 138 derives the result of personal authentication based on the authentication result of the collation unit 133 without using the authentication result of the IC card authentication unit 137. That is, if the authentication result of the collation unit 133 is successful, the personal authentication unit 138 judges that the personal authentication has succeeded, and if the authentication result of the collation unit 133 is unsuccessful, the personal authentication unit 138 judges that the personal authentication has failed. The personal authentication unit 138 is configured to transmit the result of personal authentication including the successfully authenticated user ID to the output unit 139.

[0039] The output unit 139 is configured to transmit the result of personal authentication generated by the personal authentication unit 138 to the gate device 142 through the interface unit 113. The output unit 139 may also display the result of personal authentication generated by the personal authentication unit 138 on the screen display unit 116 and / or transmit the result to an external device through the communication interface unit 114.

[0040] FIG. 3 is a flowchart showing an overview of the operation of the face authentication device 100. Referring to FIG. 3, first, the input unit 131 of the face authentication device 100 inputs reference face image data 122 from the outside and stores it in the storage unit 120 (step S1). Next, the input unit 131 inputs reference card data 124 from the outside and stores it in the storage unit 120 (step S2). Next, the IC card authentication availability detection unit 134 of the face authentication device 100 detects the availability of IC card authentication based on a command input from the communication interface unit 114 or the operation input unit 115, and sets IC card authentication availability data 125 based on the detection result (step S3). That is, when a command indicating that IC card authentication is to be used is input, the IC card authentication availability detection unit 134 sets the value of the IC card authentication availability data 125 to 1, and when a command indicating that IC card authentication is not to be used is input, the above value is reset to 0. Next, the threshold value changing unit 135 of the face authentication device 100 sets a matching threshold value 123 having a value corresponding to the IC card authentication availability data 125 in the storage unit 120 (step S4). That is, the threshold value changing unit 135 sets the matching threshold value 123 with a value TH when IC card authentication is used, and sets the matching threshold value 123 with a value TL (<TH) when IC card authentication is not used. The processing of steps S1 to S4 above is a preparation process for starting the operation of face authentication, and may be omitted if it has been performed once. Note that, as will be described later with reference to FIG. 4, the availability of IC card authentication can be changed during operation.

[0041] During operation, the following operations are performed. First, the face image acquisition unit 132 of the face authentication device 100 inputs the image data obtained by imaging the object to be matched from the camera unit 141, and acquires the face image of the object to be matched from the image data (step S5). Next, the matching unit 133 of the face authentication device 100 calculates the similarity between each reference face image included in the reference face image data 122 and the face image of the object to be matched acquired by the face image acquisition unit 132, and compares it with the matching threshold value 123 to perform face authentication (step S6).

[0042] Next, the IC card information acquisition unit 136 of the face authentication device 100 reads the IC card authentication use / non-use data 125 from the storage unit 120, and checks the setting state of whether or not the IC card authentication is usable (step S7). If the value of the IC card authentication use / non-use data 125 is 1, the IC card information acquisition unit 136 determines that the IC card authentication is usable, and if the value is 0, that the IC card authentication is not usable.

[0043] When the IC card information acquisition unit 136 determines that the IC card authentication is available, it acquires the stored information read by the IC card reader 144 from the IC card 145 of the user 143 passing through the gate device 142 (step S8). Next, the IC card authentication unit 137 of the face authentication device 100 performs IC card authentication by comparing the reference authentication information included in the reference card data 124 with the stored information of the IC card 145 acquired by the IC card information acquisition unit 136 (step S9). Next, the personal authentication unit 138 of the face authentication device 100 derives the result of personal authentication based on the result of the face authentication performed in step S6 and the result of the IC card authentication performed in step S9 (step S10). On the other hand, when it is determined that the IC card authentication is unavailable, the personal authentication unit 138 does not perform IC card authentication, and derives the result of personal authentication based on the result of the face authentication performed in step S6 (step S11).

[0044] Next, the output unit 139 of the face authentication device 100 outputs the result of the personal authentication to the gate device 142 through the interface unit 113 (step S12). Then, the face authentication device 100 returns to step S5 and repeats the same process as described above.

[0045] Furthermore, the face authentication device 100 is configured to execute the process shown in Fig. 4 in parallel with the process shown in Fig. 3. Referring to Fig. 4, if the value of IC card authentication use / non-use data 125 stored in the storage unit 120 is 1, that is, if IC card authentication is being used (YES in step S21), the IC card authentication use / non-use detection unit 134 of the face authentication device 100 monitors whether a command to the effect that IC card authentication will not be used is input from the user via the communication interface unit 114 or the operation input unit 115 (step S22). Then, when a command to the effect that IC card authentication will not be used is input, the IC card authentication use / non-use detection unit 134 changes the value of the IC card authentication use / non-use data 125 stored in the storage unit 120 to 0 (step S23 Next, the threshold change unit 135 of the face authentication device 100 changes the value of the matching threshold 123 stored in the storage unit 120 to TL (step S24 Then, the face recognition device 100 returns to the process of step S21.

[0046] On the other hand, if the value of the IC card authentication use data 125 stored in the storage unit 120 is 0, that is, if the IC card authentication is not being used (NO in step S21), the IC card authentication use detection unit 134 monitors whether a command to use the IC card authentication is input from the user through the communication interface unit 114 or the operation input unit 115 (step S25). Then, when a command to use the IC card authentication is input, the IC card authentication use detection unit 134 changes the value of the IC card authentication use data 125 stored in the storage unit 120 to 1 (step S26). Next, the threshold change unit 135 of the face authentication device 100 changes the value of the matching threshold 123 stored in the storage unit 120 to TH (step S27). Then, the face authentication device 100 returns to the process of step S21.

[0047] As described above, in the face authentication device 100 according to this embodiment, when face authentication and IC card authentication are used in combination to perform personal authentication, the matching threshold 123 used in face authentication is set to TH, which is larger than the reference value T0, and the security strength is higher (the security strength at this time is SL6). On the other hand, in the face authentication device 100 according to this embodiment, when personal authentication is performed based on the face authentication result without using IC card authentication, the matching threshold 123 used in face authentication is set to TL, which is smaller than the reference value T0, and the security strength is lower (the security strength at this time is SL1). As a result, the difference in security strength (SL6-SL1) between the case where IC card authentication is used and the case where it is not used in the face authentication device 100 can be made more noticeable.

[0048] In contrast, if the matching threshold 123 used for face authentication is fixed regardless of whether IC card authentication is used, for example fixed at T0, the security strength when performing identity authentication by face authentication without using IC card authentication will be higher than SL1 (the security strength in this case is SL2), and the security strength when performing identity authentication by combining face authentication and IC card authentication will be lower than SL6 (the security strength in this case is SL5). Therefore, the obtained security strength difference (SL5-SL2) will be smaller than the above security strength difference (SL6-SL1).

[0049] Furthermore, if the idea of ​​Patent Document 1 that the higher the security strength achieved by an authentication method other than face authentication, the smaller the threshold for face authentication is applied, TL is used for the matching threshold 123 when IC card authentication is used, and TH is used for the matching threshold 123 when IC card authentication is not used. In this case, the security strength when performing identity authentication by face authentication without using IC card authentication becomes higher than SL2 (the security strength at this time is SL3), and the security strength when performing identity authentication by combining face authentication and IC card authentication becomes lower than SL5 (the security strength at this time is SL4). Therefore, the obtained security strength difference (SL4-SL3) becomes smaller than the above security strength difference (SL5-SL2).

[0050] Fig. 5 is a conceptual diagram of the security strength determined by the combination of face authentication and IC card authentication, and the matching threshold used in face authentication. In Fig. 5, SL1 to SL6 represent the security strengths according to the following combinations. SL1: Personal authentication using face recognition alone with matching threshold TL SL2: Personal authentication using face recognition alone with matching threshold T0 SL3: Personal authentication using face recognition alone with matching threshold TH SL4: Personal authentication using face recognition with matching threshold TL and IC card authentication SL5: Personal authentication using face recognition with matching threshold T0 and IC card authentication SL6: Personal authentication using face recognition with matching threshold TH and IC card authentication Here, TH>T0>TL.

[0051] Thus, according to this embodiment, by selecting whether or not to use IC card authentication, the face recognition device 100 can be switched between an operation that emphasizes security and the opposite, an operation that emphasizes convenience, making the difference in security strength between the two operations more pronounced.

[0052] [Second embodiment] Next, a second embodiment of the present invention will be described. The face authentication device 200 according to this embodiment differs from the first embodiment in that the threshold change unit 135 is configured to change the value of the matching threshold 123 in response to a request from a user. Other configurations and operations are the same as those of the first embodiment.

[0053] 6 is a flowchart showing an example of the process of threshold change unit 135 that changes the matching threshold in response to a request from a user. For example, when a command requesting a change of the matching threshold is input from operation input unit 115, threshold change unit 135 starts the process shown in FIG.

[0054] The threshold change unit 135 first displays a matching threshold setting screen on the screen display unit 116 (step S31). Fig. 7 shows an example of the matching threshold setting screen. The matching threshold setting screen in this example has a radio button for selecting whether or not to use IC card authentication, a slide bar for specifying the matching threshold value, an OK button, and a cancel button.

[0055] Next, threshold change unit 135 receives input from the user as to whether or not IC card authentication is to be used (step S32). On the comparison threshold setting screen of FIG. 7, the user uses a radio button to specify whether or not IC card authentication is to be used. Next, threshold change unit 135 receives input of the comparison threshold from the user (step S33). On the comparison threshold setting screen of FIG. 7, the user moves the position of the slider on the slide bar to the left or right to specify the comparison threshold. Next, when the OK button is clicked, threshold change unit 135 executes the processing from step S34 onward in FIG. 6. When the Cancel button is clicked, the processing in FIG. 6 ends.

[0056] In step S34, the threshold change unit 135 judges whether or not to use IC card authentication based on the state of the radio button. Next, if the IC card authentication is not to be used (NO in step S34), the threshold change unit 135 updates the matching threshold 123 in the storage unit 120 with the matching threshold value corresponding to the knob position of the slide bar, and also updates the usage / non-usage data 125 of IC card authentication to a non-usage state (step S35). If the IC card authentication is to be used (YES in step S34), the threshold change unit 135 judges whether or not the value corresponding to the knob position of the slide bar is greater than a predetermined value T0 (step S36). Then, if it is greater than the predetermined value T0, the threshold change unit 135 updates the matching threshold 123 in the storage unit 120 with the matching threshold value corresponding to the knob position of the slide bar, and also updates the usage / non-usage data 125 of IC card authentication to a usage state (step S35).

[0057] On the other hand, if the value according to the knob position of the slide bar is not greater than the predetermined value T0 (NO in step S36), the threshold change unit 135 rejects the change and sets the value to the predetermined value T0. Greater thanA message prompting the user to input a matching threshold is displayed on the screen display unit 116 (step S37). Then, the threshold change unit 135 returns to step S33 and accepts re-input of the matching threshold.

[0058] In this manner, in this embodiment, before changing the value of the matching threshold 123 in response to a user request, the threshold change unit 135 checks whether IC card authentication is being used and whether the changed value of the matching threshold 123 is greater than a predetermined value, and rejects the request if IC card authentication is being used but the changed value of the matching threshold is not greater than the predetermined value. This makes it possible to prevent a decrease in security when IC card authentication is being used.

[0059] 6, the threshold change unit 135 changes the matching threshold to the value specified by the user when IC card authentication is not used, but it may be configured to check whether the value specified by the user is smaller than a predetermined value T0 and reject the request if it is not smaller. This makes it possible to prevent the security strength from becoming too high when IC card authentication is used.

[0060] In each of the above-described embodiments, IC card authentication is used as an authentication method other than face authentication, but password authentication or the like may be used as an authentication method other than face authentication. Moreover, it is not limited to two-factor authentication, and multi-factor authentication may be used. Moreover, multi-stage authentication such as two-step authentication may be used. In that case, the authentication method other than face authentication may be iris authentication, fingerprint authentication, or the like.

[0061] In addition, in each of the above embodiments, the matching threshold used for face authentication is common to all user IDs, but the matching threshold may be configured to be set for each user.

[0062] [Third embodiment] Next, a third embodiment of the present invention will be described. Fig. 8 is a block diagram of a face recognition device 300 according to this embodiment. Referring to Fig. 8, the face recognition device 300 includes a first authentication unit 301, a second authentication unit 302, a detection unit 303, a personal authentication unit 304, and a threshold change unit 305.

[0063] The first authentication unit 301 is configured to perform the first authentication for the face image of the authentication target based on a threshold value. The first authentication unit 301 can be configured similarly to the collation unit 133 in FIG. 1, but is not limited thereto. The second authentication unit 302 is configured to perform the second authentication by an authentication method other than face authentication. The second authentication unit 302 can be configured similarly to the IC card authentication unit 137 in FIG. 1, but is not limited thereto. The detection unit 303 is configured to detect whether the second authentication unit 302 is used. The detection unit 303 can be configured similarly to the IC card authentication use / non-use detection unit 134 in FIG. 1, but is not limited thereto. The threshold change unit 305 is configured to set the threshold value to a value larger when the second authentication unit 302 is used than when the second authentication unit 302 is not used. The threshold change unit 305 can be configured similarly to the threshold change unit 135 in FIG. 1, but is not limited thereto. The personal authentication unit 304 is configured to use the above-mentioned set threshold value to perform personal authentication based on the result of the first authentication when the second authentication unit 302 is not used, and to perform personal authentication based on the results of the first authentication and the second authentication when the second authentication unit 302 is used. The personal authentication unit 304 can be configured similarly to the personal authentication unit 138 in Fig. 1, but is not limited thereto.

[0064] The face authentication device 300 according to this embodiment configured as described above operates as follows. That is, the detection unit 303 detects whether or not the second authentication by an authentication method other than face authentication is used. The threshold change unit 305 sets a larger value for the threshold in the first authentication, which performs authentication of the face image of the authentication target based on a threshold, when the second authentication is used compared to when it is not used. The personal authentication unit 138 uses the set threshold to perform personal authentication based on the result of the first authentication when the second authentication is not used, and performs personal authentication based on the result of the first authentication and the result of the second authentication when the second authentication is used.

[0065] In this way, according to the present embodiment, by selecting whether or not to use another authentication method, the face recognition device can be switched between an operation that prioritizes security and an operation that prioritizes convenience, and the performance difference between the two operations can be made more noticeable. This is because the threshold change unit sets the threshold to a larger value when the second authentication unit is used than when it is not used.

[0066] Although the present invention has been described with reference to the above-mentioned embodiments, the present invention is not limited to the above-mentioned embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

[0067] For example, in the first embodiment, in order to increase the difference in security strength, when IC card authentication is used, the matching threshold 123 is set to a value TH larger than a predetermined value T0 to increase the security strength, and on the other hand, when IC card authentication is not used, the matching threshold 123 is set to a value TL smaller than a predetermined value T0 to decrease the security strength. However, the basis of the present invention is to increase the matching threshold 123 when authentication other than face authentication is used compared to when it is not used. Therefore, when IC card authentication is not used, the matching threshold 123 may be set to the same value as T0. Alternatively, face authentication includes walk-through face authentication that enables face authentication while walking without stopping in front of a camera, and triggered face authentication that executes face authentication by stopping in front of a gate and touching the screen, etc. as a trigger. Therefore, as a setting value of the matching threshold 123 when IC card authentication is not used, in the case of triggered face authentication, the matching threshold 123 may be set to T0, and in the case of walk-through face authentication that prioritizes convenience, the matching threshold 123 may be set to TL.

[0068] In the first embodiment, when IC card authentication is used, face authentication is performed independently of IC card authentication. However, when IC card authentication is used, face authentication may be performed using the authentication result of IC card authentication. Specifically, when IC card authentication is used, IC card authentication is performed first, and then face authentication is performed using the result of IC card authentication. Then, in face authentication, the similarity between a reference face image registered in the reference face image data 122 corresponding to a user ID successfully authenticated by IC card authentication and a face image to be matched is calculated, and both faces are matched. By matching the face of an individual identified by IC card authentication with the face to be matched in this way, the processing amount of face authentication when IC card authentication is used can be reduced, and the authentication accuracy can be improved. [Industrial Applicability]

[0069] The present invention can be used in entry / exit monitoring systems, attendance management systems, and the like, and is particularly suitable for automatically correcting thresholds used for matching appropriately without burdening users, thereby improving convenience and safety.

[0070] A part or all of the above-described embodiments can be described as, but is not limited to, the following supplementary notes. [Appendix 1] a first authentication unit that performs a first authentication on a face image to be authenticated based on a threshold value; a second authentication unit that performs a second authentication by an authentication method other than face authentication; A detection unit that detects whether the second authentication unit is used; a threshold change unit that sets the threshold to a larger value when the second authentication unit is used than when the second authentication unit is not used; and an authentication unit that performs authentication based on a result of the first authentication using the set threshold value when the second authentication unit is not used, and performs authentication based on a result of the first authentication and a result of the second authentication when the second authentication unit is used. Facial recognition device. [Appendix 2] before changing the value of the threshold in response to a request from a user, the threshold change unit checks whether the second authentication unit is used and whether the changed value of the threshold is greater than a predetermined value, and rejects the request if the second authentication unit is used and the changed value of the threshold is not greater than the predetermined value. 2. A facial recognition device as described in claim 1. [Appendix 3] The detection unit performs the detection based on a command from a user specifying whether or not to use the second authentication unit. 3. A facial recognition device according to claim 1 or 2. [Appendix 4] the detection unit performs the detection based on the presence or absence of an interface unit for acquiring authentication information to be used in the second authentication unit from the authentication target. 4. A face recognition device according to any one of claims 1 to 3. [Appendix 5] the threshold change unit sets the threshold to be greater than a predetermined value when the second authentication unit is used. 5. A face recognition device according to any one of claims 1 to 4. [Appendix 6] Detect whether or not a second authentication method other than face recognition is used, a threshold value in a first authentication for performing authentication of a face image to be authenticated based on a threshold value is set to a larger value when the second authentication is used compared with a case where the second authentication is not used; using the set threshold value, when the second authentication is not used, to perform personal authentication based on a result of the first authentication, and when the second authentication is used, to perform personal authentication based on the result of the first authentication and the result of the second authentication. Face recognition method. [Appendix 7] In setting the threshold, before changing the value of the threshold in response to a request from a user, it is checked whether the second authentication is used and whether the changed value of the threshold is greater than a predetermined value, and if the second authentication is used and the changed value of the threshold is not greater than the predetermined value, the request is rejected. 7. The facial recognition method according to claim 6. [Appendix 8] the detection of whether the second authentication is used is performed based on a command from a user specifying whether the second authentication is used; 8. The face recognition method according to claim 6 or 7. [Appendix 9] The detection of whether the second authentication is used is performed based on the presence or absence of an interface unit for acquiring authentication information used in the second authentication from the authentication target. A face recognition method according to any one of appendix 6 to 8. [Appendix 10] In setting the threshold value, the threshold value is set to be greater than a predetermined value when the second authentication is used. A face recognition method according to any one of appendix 5 to 9. [Appendix 11] Computer, a first authentication unit that performs a first authentication on a face image to be authenticated based on a threshold value; a second authentication unit that performs a second authentication by an authentication method other than face authentication; A detection unit that detects whether the second authentication unit is used; a threshold change unit that sets the threshold to a larger value when the second authentication unit is used than when the second authentication unit is not used; an authentication unit that performs authentication based on a result of the first authentication using the set threshold value when the second authentication unit is not used, and performs authentication based on a result of the first authentication and a result of the second authentication when the second authentication unit is used; A program to make it function as such. [Appendix 12] In the first authentication, a facial feature amount extracted from the facial image to be authenticated is compared with a facial feature amount extracted from a reference facial image for each registered user, and a similarity between the facial image and the reference facial image is calculated. A face recognition device, a face recognition method, and a program according to any one of appendix 1 to 11. [Appendix 13] When the second authentication is used, a value larger than a predetermined value is set as the threshold value. A face recognition device, a face recognition method, and a program according to any one of appendix 1 to 12. [Appendix 14] When the second authentication is not used, the threshold is set to a value equal to or smaller than a predetermined value. A face recognition device, a face recognition method, and a program according to any one of appendix 1 to 13. [Appendix 15] In the first authentication, when the second authentication is used, the first authentication is performed by calculating a similarity between a face image to be authenticated and a reference face image of a registered user authenticated by the second authentication and comparing the calculated similarity with a threshold value. A face recognition device, a face recognition method, and a program according to any one of appendix 1 to 14. [Explanation of symbols]

[0071] 100…Facial recognition device 111...Interface section 112...Interface section 113...Interface section 114...Communication interface section 115...Operation input section 116...Screen display section 120...Storage section 121…Program 122...Reference face image data 123…Matching threshold 124...Standard card data 125...Data on whether IC card authentication is used 130...Computation processing unit 131...Input section 132...Facial image acquisition unit 133…Collation section 134...IC card authentication use detection unit 135...Threshold change unit 136…IC card information acquisition unit 137…IC card authentication section 138…Personal authentication section 139...Output section 141…Camera section 142...Gate device 143…User 144...IC card reader 145…IC card 200…Facial recognition device 300…Facial recognition device 301...First authentication section 302...Second authentication section 303…Detection section 304…Personal authentication section 305...Threshold change unit

Claims

1. a first authentication unit that performs a first authentication by comparing a similarity between a face image of a target to be authenticated and a pre-stored reference face image with a threshold value, thereby authenticating the target to be authenticated through face authentication; a second authentication unit that performs a second authentication to authenticate the authentication target by an authentication method other than face authentication; an individual authentication unit which determines that the individual authentication is successful if the result of the first authentication is authentication success when the second authentication unit is not used, and which determines that the individual authentication is successful if the result of both the second authentication and the result of the first authentication are authentication success when the second authentication unit is used, In a case where the second authentication unit is not used, a threshold value when the first authentication is performed by triggered face authentication is set so that a false acceptance rate is lower than a threshold value when the first authentication is performed by walk-through face authentication. Information processing device.

2. The threshold used in the first authentication performed when the second authentication unit is used is set so that a false acceptance rate is lower than the threshold used in the first authentication performed when the second authentication unit is not used. The information processing device according to claim 1 .

3. The second authentication unit performs the second authentication by comparing the specified authentication information with reference authentication information having the same user ID as the specified user ID.

3. The information processing device according to claim 1 or 2.

4. a first authentication unit that performs a first authentication by comparing a similarity between a face image of a target to be authenticated and a pre-stored reference face image with a threshold value, thereby authenticating the target to be authenticated through face authentication; a second authentication unit that performs a second authentication to authenticate the authentication target by an authentication method other than face authentication; an individual authentication unit which determines that the individual authentication is successful if the result of the first authentication is authentication success when the second authentication unit is not used, and which determines that the individual authentication is successful if the result of both the second authentication and the result of the first authentication are authentication success when the second authentication unit is used, the first authentication unit sets the threshold value used for the first authentication so that a false acceptance rate is lower when the second authentication unit is used than when the second authentication unit is not used; The second authentication unit performs the second authentication by comparing the specified authentication information with reference authentication information having the same user ID as the specified user ID. Information processing device.

5. the threshold value used in the first authentication when the second authentication unit is used is set so that a false acceptance rate is lower than a predetermined value; The information processing device according to claim 1 .

6. In a case where a second authentication for authenticating an authentication target by an authentication method other than face authentication is not used, a first authentication for authenticating the authentication target by comparing a similarity between a face image of the authentication target and a pre-stored reference face image with a threshold is performed, and if the result of the first authentication is successful, the personal authentication is successful; When the second authentication is used, the first authentication and the second authentication are performed, and if both the result of the first authentication and the result of the second authentication are authentication success, the personal authentication is considered to be successful; When the second authentication is not used, the threshold value when the first authentication is performed by triggered face authentication is set so that the false acceptance rate is lower than the threshold value when the first authentication is performed by walk-through face authentication. Face recognition method.

7. Computer, a first authentication unit that performs a first authentication by comparing a similarity between a face image of a target to be authenticated and a pre-stored reference face image with a threshold value, thereby authenticating the target to be authenticated through face authentication; a second authentication unit that performs a second authentication to authenticate the authentication target by an authentication method other than face authentication; an individual authentication unit that determines the individual authentication to be successful if the result of the first authentication is authentication success when the second authentication unit is not used, and determines the individual authentication to be successful if the result of both the second authentication and the result of the first authentication are authentication success when the second authentication unit is used; A program for causing the device to function as a When the second authentication unit is not used, the threshold value when the first authentication is performed by triggered face authentication is set so that the false acceptance rate is lower than the threshold value when the first authentication is performed by walk-through face authentication. program.

8. a first authentication unit that performs a first authentication by comparing a similarity between a face image of a target to be authenticated and a pre-stored reference face image with a threshold value, thereby authenticating the target to be authenticated through face authentication; a second authentication unit that performs a second authentication to authenticate the authentication target by an authentication method other than face authentication; an individual authentication unit which determines that the individual authentication is successful if the result of the first authentication is authentication success when the second authentication unit is not used, and which determines that the individual authentication is successful if the result of both the second authentication and the result of the first authentication are authentication success when the second authentication unit is used, In a case where the second authentication unit is not used, a threshold value when the first authentication is performed by triggered face authentication is set so that a false acceptance rate is lower than a threshold value when the first authentication is performed by walk-through face authentication. Information processing system.

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