JP7679971B2 - Face Recognition Device - Google Patents

Description

The present invention relates to a face recognition device, a face recognition method, and a program.

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

For example, Patent Document 1 describes a face authentication device that combines face authentication and authentication by a PIN. In the face authentication device described in Patent Document 1, a PIN is first input by the user and compared with a registered PIN. If all digits of the PIN are correctly input, face authentication is not performed and identity authentication is deemed successful. If no digit of the PIN is input, or if only a predetermined number of digits or less are input correctly, face authentication is not performed and identity authentication is deemed unsuccessful. In other cases, face authentication is performed and identity authentication is judged to be successful or unsuccessful 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 achieved by the PIN authentication method, the smaller the threshold value for face authentication is, making it easier to accept the identity of the person.

The combination of two or more different types of authentication information, such as facial recognition and PIN authentication, is called two-factor authentication or multi-factor authentication.

JP 2008-158627 A

In a face recognition device that uses face recognition in conjunction with other authentication methods, it is also possible to make it possible to select whether or not to use the other authentication methods. If the other authentication methods are not used, personal authentication is performed based only on the results of face recognition, which reduces security but increases convenience. On the other hand, if the other authentication methods are used, personal authentication is performed based on the results of face recognition and the results of the other authentication methods, which reduces convenience but increases security.

In this way, in a face recognition device that can switch between security-oriented operation and convenience-oriented operation 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 pronounced. In other words, it is desirable to increase the difference in security strength between operations that emphasize security and operations that emphasize convenience. However, it is difficult to achieve such an operation mode by simply selecting whether or not to use other authentication methods.

The object of the present invention is to provide a face recognition device that solves the above-mentioned problems.

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 being 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 device 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.

A face recognition method according to another aspect of the present invention includes:
Detecting whether 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.

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 being 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.

By having the above-mentioned configuration, the present invention can make the difference in security strength between two operations in a face recognition device that can be switched between security-oriented operation and, conversely, convenience-oriented operation, more prominent by selecting whether or not to use other authentication methods.

1 is a block diagram of a face recognition device according to a first embodiment of the present invention. 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. 4 is a flowchart showing an outline of the operation of the face authentication device according to the first embodiment of the present invention. 4 is a flowchart showing an outline of the operation of the face authentication device according to the first embodiment of the present invention. 4 is a conceptual diagram showing a combination of face image authentication and IC card authentication according to the first embodiment of the present invention, and a security strength determined by a matching threshold value used in the face image authentication. FIG. 10 is a flowchart showing an example of an operation of a threshold value changing unit in a face authentication device according to a second embodiment of the present invention. 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. FIG. 11 is a block diagram of a face recognition device according to a third embodiment of the present invention.

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.

The interface unit 111 is configured to transmit and receive signals to and from the camera unit 141, which captures an image of the face of the 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 the face of a user 143 passing through the gate device 142. The camera unit 141 is an imaging device made of a CCD (Charge Coupled Device) element or a CMOS (Complementary Metal-Oxide Semiconductor) element that outputs image data obtained by capturing an image of the face of the 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.

The interface unit 112 is configured to send and receive signals to and from the IC card reader 144. The signal may be sent or received either wired or wirelessly. 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 he or she possesses close to the IC card reader 144, 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 via the interface unit 112. The IC card 145 stores information including a user ID and authentication information.

The interface unit 113 is configured to send and receive signals such as the result of personal authentication between the gate device 142 and the gate device 142. The signal may be sent or received either wired or wirelessly. The gate device 142 performs a predetermined operation according to the received result of personal authentication. There are various possible predetermined operations. For example, the gate device 142 automatically opens and closes a door attached to the gate device 142 according to the result of personal authentication. Alternatively, the gate device 142 has 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.

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

The operation input unit 115 is an input device such as a keyboard or numeric keypad, and is configured to detect the operator's operations and output them to the calculation processing unit 130.

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 matching results on the screen in response to instructions from the calculation processing unit 130.

The storage unit 120 is a storage device such as a hard disk or memory. The storage unit 120 is configured to store processing information and programs 121 required for various processes performed by the calculation processing unit 130.

The program 121 is read into the calculation 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.

The main processing information stored in the memory unit 120 includes reference face image data 122, matching threshold value 123, reference card data 124, and data on whether IC card authentication is used 125.

The reference face image data 122 is data that associates a face image that serves as a reference for use in face matching with a user ID. The reference face image data 122 may be associated with a user ID and associated with at least one face image of a person having that user ID as a reference face image. Alternatively, the reference face image data 122 may be associated with a user ID and associated with facial features extracted from the face image of a person having that user ID as reference face information. Here, the facial features are numerical values that indicate the features of each part of a face image for recognizing the positional relationship and shape of each part that constitutes the face, such as the eyes, nose, mouth, eyebrows, etc., and are used when making a judgment of similarity between images, etc.

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. Increasing the matching threshold reduces the rate of false acceptance and increases security.

The reference card data 124 is data that associates a user ID with authentication information that serves as a reference used when performing IC card authentication. 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 that has that user ID is recorded as reference authentication information.

The IC card authentication usage data 125 is data indicating whether or not IC card authentication is used. For example, the IC card authentication usage 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.

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 the program 121 from the memory 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.

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

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

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 the 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, the cross-correlation coefficient between the face images can be used. In that case, the similarity is large when both face images include the face parts of the same person, and the similarity is small when both face images include the face parts of different people. As the similarity between the 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 face image to be matched, match the reference face features included in the reference face image data 122 with the facial features extracted from the face image to be matched, and calculate the similarity between the reference face image and the face image to be matched.

The matching unit 133 is also 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 123. The matching unit 133 is also 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 123. The matching unit 133 is also configured to transmit the authentication result to the identity authentication unit 138.

The IC card authentication usage detection unit 134 is configured to detect whether IC card authentication is being used. The IC card authentication usage detection unit 134 is configured to detect whether IC card authentication is being used before the face authentication device 100 starts operating. The IC card authentication usage detection unit 134 is also configured to detect whether IC card authentication is being used while the face authentication device 100 is operating.

The IC card authentication use/non-use detection unit 134 detects that 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 IC card authentication. Conversely, the IC card authentication use/non-use detection unit 134 detects that IC card authentication is not in use when it receives a command from the administrator to not use IC card authentication. However, the method of detecting whether IC card authentication is in use 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 calculation processing unit 130, and if it is attached, it is in a state in which IC card authentication is in use, and if it is not attached, it is in a state in which IC card authentication is not in use. 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 IC card authentication. Furthermore, the IC card authentication use/non-use detection unit 134 is configured to notify the threshold change unit 135 when the IC card authentication use/non-use data 125 is set or changed.

When the threshold change unit 135 receives a notification from the IC card authentication use/non-use detection unit 134, the threshold change unit 135 is configured to read the IC card authentication use/non-use data 125 from the storage unit 120, 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.

The IC card information acquisition 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 acquisition unit 136 is configured to transmit the acquired stored information of the IC card 145 to the IC card authentication unit 137.

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 contained in the reference card data 124 with the storage 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 storage information of the IC card 145, compares the extracted authentication information with the reference authentication information contained in the reference card data 124 having the same user ID as the extracted user ID, and determines that authentication is successful if they match, and that 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.

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 IC card authentication is to be used. Then, when the IC card authentication use/non-use data 125 indicates that 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, if 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 user IDs that have been successfully authenticated are the same in both cases, the personal authentication unit 138 judges that the personal authentication has been successful. On the other hand, if at least one of the authentication results of the comparison unit 133 and the IC card authentication unit 137 is unsuccessful, or if both are successful but the successfully authenticated user IDs are different, the personal authentication unit 138 determines that the personal authentication has failed. If 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 comparison unit 133 without using the authentication result of the IC card authentication unit 137. That is, if the authentication result of the comparison unit 133 is successful, the personal authentication unit 138 determines that the personal authentication has succeeded, and if the authentication result of the comparison unit 133 is unsuccessful, the personal authentication unit 138 determines that the personal authentication has failed. The personal authentication unit 138 is configured to transmit the result of personal authentication, including the user ID for which the personal authentication has succeeded, to the output unit 139.

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

3 is a flowchart showing an outline 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 the reference face image data 122 from the outside and stores it in the storage unit 120 (step S1). Next, the input unit 131 inputs the reference card data 124 from the outside and stores it in the storage unit 120 (step S2). Next, the IC card authentication use/non-use detection unit 134 of the face authentication device 100 detects whether or not IC card authentication is used based on a command input from the communication interface unit 114 or the operation input unit 115, and sets the IC card authentication use/non-use data 125 based on the detection result (step S3). That is, when a command to use IC card authentication is input, the IC card authentication use/non-use detection unit 134 sets the value of the IC card authentication use/non-use data 125 to 1, and when a command to not use IC card authentication is input, the IC card authentication use/non-use detection unit 134 resets the value to 0. Next, the threshold change unit 135 of the face authentication device 100 sets the matching threshold 123, which has a value corresponding to the IC card authentication use/non-use data 125, in the storage unit 120 (step S4). That is, the threshold change unit 135 sets the matching threshold 123 to a value TH when IC card authentication is used, and sets the matching threshold 123 to a value TL (<TH) when IC card authentication is not used. The above steps S1 to S4 are preparation processes for starting the operation of face authentication, and may be omitted if they have been performed once. Note that, as will be described later with reference to FIG. 4, the use or non-use of IC card authentication can be changed during operation.

During operation, the following operations are performed. First, the face image acquisition unit 132 of the face recognition device 100 inputs image data obtained by capturing an image of the target for matching from the camera unit 141, and acquires the face image of the target for matching from the image data (step S5). Next, the matching unit 133 of the face recognition device 100 performs face recognition by calculating the similarity between each reference face image included in the reference face image data 122 and the face image of the target for matching acquired by the face image acquisition unit 132, and comparing it with the matching threshold value 123 (step S6).

Next, the IC card information acquisition unit 136 of the face recognition device 100 reads the IC card authentication use/non-use data 125 from the memory unit 120 and checks the setting state of whether or not the IC card authentication can be used (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 can be used, and if the value is 0, it determines that the IC card authentication cannot be used.

If the IC card information acquisition unit 136 determines that 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, if it is determined that 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).

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

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 the IC card authentication use data 125 stored in the storage unit 120 is 1, that is, if the IC card authentication is being used (YES in step S21), the IC card authentication use detection unit 134 of the face authentication device 100 monitors whether a command to not use the IC card authentication is input from the user through the communication interface unit 114 or the operation input unit 115 (step S22). Then, when the command to not 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 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 authentication device 100 returns to the process of step S21.

On the other hand, if the value of the IC card authentication usage data 125 stored in the memory unit 120 is 0, that is, if IC card authentication is not being used (NO in step S21), the IC card authentication usage detection unit 134 monitors whether a command to use 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 IC card authentication is input, the IC card authentication usage detection unit 134 changes the value of the IC card authentication usage data 125 stored in the memory unit 120 to 1 (step S26). Next, the threshold change unit 135 of the face recognition device 100 changes the value of the matching threshold 123 stored in the memory unit 120 to TH (step S27). Then, the face recognition device 100 returns to the process of step S21.

As described above, in the face recognition device 100 according to this embodiment, when face recognition and IC card authentication are used in combination to perform identity authentication, the matching threshold 123 used for face recognition 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 recognition device 100 according to this embodiment, when identity authentication is performed based on the face recognition result without using IC card authentication, the matching threshold 123 used for face recognition 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 when IC card authentication is used and when it is not used in the face recognition device 100 can be made more noticeable.

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 identity authentication is performed by face authentication without IC card authentication will be higher than SL1 (the security strength in this case will be SL2), and the security strength when identity authentication is performed using both face authentication and IC card authentication will be lower than SL6 (the security strength in this case will be SL5). Therefore, the resulting security strength difference (SL5-SL2) will be smaller than the above security strength difference (SL6-SL1).

In addition, if the idea of Patent Document 1 that the higher the security strength achieved by an authentication method other than facial authentication, the smaller the threshold for facial authentication is, 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 authenticating the individual by facial authentication without using IC card authentication is even higher than SL2 (the security strength in this case is SL3), and the security strength when authenticating the individual by using both facial authentication and IC card authentication is even lower than SL5 (the security strength in this case is SL4). Therefore, the obtained security strength difference (SL4-SL3) is even smaller than the above security strength difference (SL5-SL2).

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

In this way, 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 an operation that emphasizes convenience, making the difference in security strength between the two operations more pronounced.

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.

Figure 6 is a flowchart showing an example of the processing of the threshold change unit 135 that changes the matching threshold in accordance with a request from a user. For example, when a command requesting a change in the matching threshold is input from the operation input unit 115, the threshold change unit 135 starts the processing shown in Figure 6.

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.

Then, the 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 matching threshold setting screen in FIG. 7, the user uses a radio button to specify whether or not IC card authentication is to be used. Next, the threshold change unit 135 receives input of the matching threshold from the user (step S33). On the matching threshold setting screen in FIG. 7, the user moves the position of the slider on the slide bar to the left or right to specify the matching threshold. Next, when the OK button is clicked, the 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.

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

On the other hand, if the value according to the position of the slider is not greater than the predetermined value T0 (NO in step S36), the threshold change unit 135 rejects the change and displays a message on the screen display unit 116 prompting the user to input a matching threshold greater than the predetermined value T0 (step S37).Then, the threshold change unit 135 returns to step S33 and accepts re-input of the matching threshold.

In this manner, in this embodiment, before changing the value of the matching threshold 123 in response to a request from a user, 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 strength when IC card authentication is being used.

In FIG. 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 also 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.

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

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.

[Third embodiment]
Next, a third embodiment of the present invention will be described. Fig. 8 is a block diagram of a face authentication device 300 according to this embodiment. Referring to Fig. 8, the face authentication 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.

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 matching 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 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 larger value when the second authentication unit 302 is used than when it 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 result of the first authentication and the result of the second authentication when the second authentication unit 302 is used. The personal authentication unit 304 can be configured in the same way as the personal authentication unit 138 in FIG. 1, but is not limited thereto.

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 using an authentication method other than face authentication is being used. The threshold change unit 305 sets the threshold in the first authentication, which performs authentication of the face image of the authentication target based on a threshold, to a larger value when the second authentication is used compared to when it is not used. The personal authentication unit 138 uses the above-mentioned 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.

As described above, according to this embodiment, by selecting whether or not to use another authentication method, the face recognition device can be switched between an operation that emphasizes security and an operation that emphasizes convenience, making the performance difference between the two operations more noticeable. This is because the threshold change unit sets the threshold to a larger value when the second authentication unit is used compared to when it is not used.

The present invention has been described above with reference to the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments. Various modifications that can be understood by a person skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

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, there are walk-through face authentication, which enables face authentication while walking without stopping in front of the camera, and triggered face authentication, which executes face authentication triggered by stopping in front of a gate and touching the screen, etc. Therefore, as the 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, which prioritizes convenience, the matching threshold 123 may be set to TL.

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 the reference face image registered in the reference face image data 122 corresponding to the user ID successfully authenticated by IC card authentication and the face image to be matched is calculated, and the two 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.

The present invention can be used in systems such as entrance and exit monitoring systems and attendance management systems, and is particularly suited to improving convenience and safety by automatically correcting the thresholds used for matching without placing a burden on users.

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 being 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 identity authentication unit that uses the set threshold value to perform identity authentication based on a 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.
[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 being 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 being used and the changed value of the threshold is not greater than the predetermined value.
2. A face 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. The face 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]
Detecting whether 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 face authentication method according to claim 6.
[Appendix 8]
the detection of whether or not the second authentication is used is performed based on a command from a user specifying whether or not the second authentication is used;
8. The face authentication 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;
9. A face authentication method according to any one of claims 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.
10. A face authentication method according to any one of claims 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 being 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 of the authentication target is compared with a facial feature amount extracted from a reference facial image of 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 appendixes 1 to 11.
[Appendix 13]
In setting the threshold value, a value larger than a predetermined value is set to the threshold value when the second authentication is used.
A face recognition device, a face recognition method, and a program according to any one of appendices 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 appendixes 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 appendices 1 to 14.

100...Facial authentication device 111...Interface unit 112...Interface unit 113...Interface unit 114...Communication interface unit 115...Operation input unit 116...Screen display unit 120...Memory unit 121...Program 122...Reference facial image data 123...Matching threshold 124...Reference card data 125...IC card authentication use/non-use data 130...Calculation processing unit 131...Input unit 132...Facial image acquisition unit 133...Matching unit 134...IC card authentication use detection unit 135...Threshold change unit 136...IC card information acquisition unit 137...IC card authentication unit 138...Personal authentication unit 139...Output unit 141...Camera unit 142...Gate device 143...User 144...IC card reader 145...IC card 200...Facial authentication device 300...Facial authentication device 301...First authentication unit 302...Second authentication unit 303...Detection unit 304...Personal authentication unit 305...Threshold change unit

Claims (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,
When the second authentication unit is not used, a threshold value when the first authentication is performed by triggered face authentication is set so that the false acceptance rate is lower than a threshold value when the first authentication is performed by walk-through face authentication. 2. The information processing device according to claim 1, wherein the threshold used for the first authentication performed when the second authentication unit is used is set so as to have a lower false acceptance rate than the threshold used for the first authentication performed when the second authentication unit is not used. The information processing apparatus according to claim 1 , wherein the second authentication unit performs the second authentication by comparing the identified authentication information with reference authentication information having the same user ID as the identified user ID. 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 information processing device, wherein the second authentication unit performs the second authentication by comparing the identified authentication information with reference authentication information having the same user ID as the identified user ID. 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 . 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;
A face recognition method in which, when the second authentication is not used, a threshold value when the first authentication is performed using triggered face recognition is set so that the false acceptance rate is lower than the threshold value when the first authentication is performed using walk-through face recognition. 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
A program for setting a threshold value when the first authentication is performed using triggered face authentication so that the false acceptance rate is lower than a threshold value when the first authentication is performed using walk-through face authentication when the second authentication unit is not used. 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,
An information processing system characterized in that, when the second authentication unit is not used, a threshold value when the first authentication is performed using triggered face authentication is set so that the acceptance rate of other people is lower than a threshold value when the first authentication is performed using walk-through face authentication.

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