JP7510800B2 - Authentication Device - Google Patents

Description

An embodiment of the present invention relates to an authentication device.

Conventionally, authentication systems for identifying an individual have included authentication using media such as cards, and biometric authentication, which require personal information such as ID authentication data and facial image data for biometric matching to be registered on a server. However, shared facilities such as shared offices are used by an unspecified number of people, making it difficult to ensure security when storing personal information.

Patent Publication 2019-080182

The problem that this invention aims to solve is to provide an authentication device that reduces the security risk to personal information that is pre-registered for authentication purposes.

In order to solve the above problem, the authentication device of this embodiment has an acquisition unit, a memory, and a control unit. The acquisition unit acquires a first face image that is an image of a user's face or a second face image that is a face image with a lower resolution than the first face image, and an auxiliary image that is an image including at least elements of the user other than the face. The memory registers the first face image, the second face image, and the auxiliary image as authentication images to be registered for authentication. The control unit performs a process of registering the second face image and the auxiliary image in the memory as authentication images when an authentication condition for storing the memory in the memory for a predetermined period is input .

FIG. 1 is a block diagram showing a hardware configuration of an image forming apparatus according to an embodiment. 4A to 4C are conceptual diagrams of a face image and an auxiliary image according to the embodiment. FIG. 1 is a front view of an image forming apparatus according to an embodiment. FIG. 2 is a block diagram showing the configuration of an authentication processing unit of the image forming apparatus according to the embodiment. FIG. 2 is a diagram showing an image capturing area captured by an image capturing unit of the image forming apparatus according to the embodiment. 6 is a flowchart showing a registration process of an authentication image by a control unit according to the embodiment. 13 is an example of a display that enables input of a start operation for user authentication and authentication conditions. 6 is a flowchart showing an authentication process by a control unit according to the embodiment. 13 is an example of a display on an operation panel when authentication has failed according to the embodiment. 10 is a flowchart showing an authentication process by a control unit according to a first modified example. FIG. 11 is a block diagram showing the configuration of an image forming apparatus and a server according to a second modified example. FIG. 13 is a block diagram showing a hardware configuration of an image forming apparatus according to a third modified example. FIG. 13 is a block diagram showing a configuration of an authentication processing unit of an image forming apparatus according to a third modified example. 13 is a flowchart showing a registration process of an authentication image by a control unit according to a third modified example. 13 is a flowchart showing an authentication process by a control unit according to a third modified example.

The authentication device of the present invention is an authentication device that controls a controlled device and is capable of authenticating a user using a low-resolution face image (hereinafter, the second face image) input from a camera and an auxiliary image associated with the second face image. This eliminates the need to register a high-resolution face image (hereinafter, the first face image) in memory as an authentication image, thereby reducing security risks to personal information. Furthermore, authentication accuracy can be improved by additionally using general identification information such as the characteristics of the user's belongings as an auxiliary image for authentication.

Below, the form for implementing the invention will be explained with reference to the drawings.

When authentication and registration using a facial image is required to use a conference room or equipment in a shared office used for a certain period of time, for example, the authentication device enables authentication and registration using a second facial image and an auxiliary image associated with the second facial image. To achieve this, the authentication device has a control unit 10, memory 12, an imaging unit 14, and an authentication processing unit 11. In the embodiment, a laser print type MFP will be used as an example of an image forming device 1 equipped with an authentication device.

The image forming device 1 shown in FIG. 1 has a control unit 10, an authentication processing unit 11, a memory 12, a communication I/F 13, an imaging unit 14, an operation panel 15, a reading unit 16, and a printing unit 17.

The control unit 10 controls whether or not functions of the image forming device 1 can be used, such as scanning a document using the reading unit 16, printing an image using the printing unit 17, and transferring data to a fax or PC via the network 20 using the communication I/F 13, based on the determination of the user authentication process by the authentication processing unit 11.

The control unit 10 is responsible for controlling the image forming apparatus 1, which is an apparatus having an authentication device. The authentication processing unit 11 performs matching using an authentication image and a verification image to perform authentication processing of a user. The memory 12 is a storage area where the authentication image is written and read. The communication I/F 13 is an interface for connecting the image forming apparatus 1 to a network. The imaging unit 14 captures a facial image and an auxiliary image of the user. The operation panel 15 is a touch panel that allows operation input to the image forming apparatus 1. The reading unit 16 is a scanner that scans an original document. The printing unit 17 is a mechanism that prints an image on paper.

The control unit 10 has an authentication condition determination unit 104 that determines the authentication conditions.

As shown in FIG. 4, the authentication processing unit 11 has an authentication area detection unit 111, a feature extraction unit 112, and a matching unit 113. The authentication area detection unit 111 detects an area where authentication processing is performed (authentication area) from the captured face image and auxiliary image. The feature extraction unit 112 detects features that quantitatively represent the features of the image from within the detected authentication area. The matching unit 113 matches the features of the authentication image and the verification image to determine whether the users in the images match, and performs authentication.

A facial image is an image of the user's face. An auxiliary image is an image of elements other than the user's face. Figure 2 shows an image of a facial image and auxiliary image in this embodiment.

The authentication image is a facial image and auxiliary image captured during the authentication image registration process and registered in memory 12, and is an image that is compared with the verification image during the authentication process. The verification image is a facial image and auxiliary image captured during the authentication process and is an image that is compared with the authentication image during the authentication process.

There are two types of authentication conditions that are linked when registering an authentication image. In this embodiment, the first authentication condition is long-term registration, and the second authentication condition is short-term registration. Long-term registration stores the authentication image in memory 12 without specifying the period for which the authentication image is to be registered. Short-term registration stores the authentication image in memory 12 for a predetermined period. Figure 2 shows an example of an authentication image stored in memory 12 depending on the authentication condition, with Figure 2(a) showing the case of long-term registration, which is the first authentication condition, and Figure 2(b) showing the case of short-term registration, which is the second authentication condition.

As shown in FIG. 2(a), in the case of long-term registration, a first face image is registered as an authentication image. Also, as shown in FIG. 2(b), in the case of short-term registration, a second face image is registered as an authentication image, and an auxiliary image is registered in association with the second image.

Note that the authentication conditions do not necessarily determine the period for which the authentication image is to be retained in memory 12. For example, if there is no need to delete the authentication image in a short period of time, but you do not want to register a high-resolution face photo, you can register it under the first authentication condition shown in FIG. 2(b).

This section explains the flow of the authentication process when the authentication condition is short-term registration.

When a user performs authentication processing for short-term registration to use the functions of the image forming device 1, the imaging unit 14 captures a second face image of the user and sends it to the authentication processing unit 11 as a verification image (verification face image) of the face image. The authentication processing unit 11 compares the verification face image with an authentication image (authentication face image) of a face image previously registered in memory 12 by a registration process, and determines consistency. If it is determined that consistency is achieved, the imaging unit 14 captures an auxiliary image of the user and sends it to the authentication processing unit 11 as a verification image (verification auxiliary image) of the auxiliary image. The authentication processing unit 11 compares the verification auxiliary image with an authentication image (authentication auxiliary image) of an auxiliary image previously registered in memory 12 by a registration process, and determines consistency. If it is determined that consistency is achieved, the control unit 10 authenticates the user.

Each part is explained in detail below.

The control unit 10 has a processor 101, a ROM 102, a RAM 103, and an authentication condition determination unit 104. The processor 101 includes an arithmetic circuit that executes a program for controlling the image forming device 1. The ROM 102 is composed of a non-volatile memory. The ROM 102 stores programs and data for controlling the image forming device 1. The RAM 103 is composed of a volatile memory. The RAM 103 temporarily holds data for controlling the image forming device 1.

The authentication condition determination unit 104 determines whether the input authentication conditions are short-term registration or long-term registration during the user authentication process and the process of registering an authentication image. The operation panel 15 is used to input the authentication conditions. The authentication conditions may also be input from a PC or the like from outside the image forming device 1 via the network 20.

The memory 12 is a so-called storage device, and is composed of a non-volatile memory. Programs and data are input and output to and from the memory 12 by the control unit 10. The memory 12 is composed of a storage device such as an HDD or SSD.

The communication I/F 13 is an interface for communicating with a server or other external devices via the network 20. The connection to the network 20 may be either a wired connection or a wireless connection.

The imaging unit 14 is, for example, a camera. The imaging unit 14 captures an image of an area including the user's face and other elements of the user, and obtains a face image and an auxiliary image. The imaging unit 14 is provided in a position where it can capture an image of the user's face and other elements of the user, such as personal belongings (clothes, glasses, accessories, etc.). There is no limit to the number of imaging units 14 that can be provided. In addition, the imaging units 14 do not need to be integrated into the image forming device 1, and may be an external device having a communication function that can send and receive data with the image forming device 1 via the communication I/F 13.

The facial image captured by the imaging unit 14 is an image from which feature quantities described below can be extracted from the user's face, and the auxiliary image may be any image from which feature quantities other than the user's face can be extracted, for example, feature quantities are extracted from the user's belongings. The auxiliary image may also be, for example, an image of only the user's feet.

In the embodiment, as shown in FIG. 3, for example, two cameras are provided near the operation panel 15: a low-resolution camera 141 that captures the second face image and a high-resolution camera 142 that captures the first face image. Furthermore, the cameras 141 and 142 can zoom in and out, and a single camera can capture the user's face and upper body. As shown in FIG. 5, the cameras 141 and 142 capture an area at angle a including the user's face by zooming in, and an area at angle b including the user's upper body by zooming out. Note that the auxiliary image may be captured by either the camera 141 or the camera 142, but it is preferable to capture the auxiliary image by the low-resolution camera 141 if the user's face appears more clearly in the auxiliary image than in the second face image.

The operation panel 15 is a display that displays predetermined information and is a user interface that accepts user input operations via a touch panel. Physical keys may also be used for input operations.

The reading unit 16 is a scanner that scans, for example, an original document fed by an ADF (automatic document feeder) or an original document placed on a platen glass, and reads the original document. Image data of the read original document is stored in the memory 12 and sent to an external device, or an image is formed on paper by the printing unit 17.

The printing unit 17 includes, for example, a toner cartridge that contains toner, a photosensitive drum that electrically attaches toner using an electrostatic latent image written based on image data, a circular transfer belt that electrically attaches toner from the photosensitive drum, and a transfer roller that heat-fuse the toner attached to the transfer belt onto the paper. The printing unit 17 forms an image on the paper using the above configuration.

The authentication processing unit 11 authenticates the user based on the verification image captured by the imaging unit 14 and the authentication image registered in the memory 12. As shown in FIG. 4, the authentication processing unit 11 has an authentication area extraction unit 111, a feature extraction unit 112, and a matching unit 113.

The authentication area detection unit 111 detects the face area of the facial image and a specified area of the auxiliary image as the area of the image where authentication processing is performed (authentication area).

As a method for detecting a face region, for example, a template image of an average face preregistered in memory 12 is moved over the authentication image or verification image to find a correlation value, and the region that gives the highest correlation value is detected as the face region. As a method for detecting an authentication region of an auxiliary image, for example, if the upper body of a user is to be the authentication region, a template image of the upper body of an average person preregistered in memory 12 is moved over the verification image or authentication image to find a correlation value, and the region that gives the highest correlation value is detected as the authentication region of the auxiliary image.

The feature extraction unit 112 detects features from within the authentication area detected by the authentication area detection unit 111. The features are data that indicate the features within the authentication area of the image, and are used by the matching unit 113 to match the authentication image with the verification image.

The features of a face image are, for example, the position and shape of the face outline and facial features (eyes, nose, mouth, etc.). The face outline and facial features are detected, for example, from the difference in brightness within the face area. Feature points are placed at specific positions that are characteristic of the detected face outline and facial features, and the feature values are extracted based on the distance and positional relationship of the feature points.

Feature quantities of the auxiliary image include, for example, the color of the clothes, the shape of the glasses, the hairstyle of the user, etc. For example, the method of extracting the color of the clothes, which is a feature quantity of the auxiliary image, may be set in advance to extract the color of a specified position in the authentication area. This allows the color of a specified position in the authentication area of the detected upper body to be extracted. Feature quantities of the shape of the glasses and the hairstyle of the user may be extracted by further analyzing the light and dark around the detected eyes and the entire face, and placing feature points at specified characteristic positions.

The color of the clothes is shown as an example of a feature of the auxiliary image, but the color of the object may change depending on the environment when the image is captured (such as the color of the lighting or reflected light from nearby objects). For this reason, a light may be attached near the imaging unit 14, and the image may be captured in an environment where the amount of light is constant.

The matching unit 113 calculates the similarity using the features of the authentication image and the verification image obtained from the feature extraction unit 112, and compares it with a predetermined reference value to determine the consistency of the images.

We will briefly explain the process by which the authentication processing unit 11 compares the authentication image with the verification image.

As shown in FIG. 4, first, a verification image is captured by the imaging unit 14 based on the determination of the authentication condition determination unit 104, and the verification image is sent to the authentication area detection unit 111. The authentication area detection unit 111 detects an authentication area, which is an area for authentication processing, from the sent verification image (for example, if it is a face image, it detects the face area). Next, the feature extraction unit 112 extracts predetermined features from the authentication area detected by the authentication area detection unit 111, and sends them to the matching unit 113.

In the memory 12, an authentication image is registered in advance by a registration process, and based on the judgment of the authentication condition judgment unit 104, an authentication image with the corresponding authentication condition is sent to the authentication area detection unit 111. As with the verification image, the authentication area of the authentication image is detected by the authentication area detection unit 111, and a specific feature of the authentication area is extracted by the feature extraction unit 112 and sent to the matching unit 113. The matching unit 113 calculates a similarity indicating the similarity between the authentication image and the verification image using the respective feature amounts, and judges consistency by comparing the calculated similarity with a specific threshold value for authentication. In other words, it judges whether the users in the images match. The judgment result of the matching unit 113 is sent to the control unit 10. The control unit 10 performs a specific control based on the judgment result and the program.

In addition, in the embodiment, when multiple authentication images are registered in memory 12, all authentication images based on the authentication conditions registered in memory 12 are compared with the verification image until the comparison unit 113 determines that the authentication image and the verification image match the user or features shown in the verification image. If the comparison unit 113 determines that the authentication image and the verification image do not match the user or features shown in the verification image, the control unit 10 does not allow authentication of the user.

Also, an ID number may be assigned to the authentication image and registered in memory 12, and the user may retrieve the authentication image corresponding to the ID number from memory 12 using, for example, an ID card, and have authentication performed by authentication processing unit 11. This eliminates the need for authentication processing unit 11 to compare the verification image with all authentication images registered in memory 12, thereby shortening the time required for authentication judgment.

The feature extraction method and authentication method described above are not limited to these, and any form of authentication method using a second face image and an auxiliary image is acceptable.

The registration and authentication processes of this embodiment are described in detail below.

The authentication image registration process is explained with reference to Figure 6.

Figure 6 is a flowchart showing the authentication image registration process performed by the control unit 10 of the image forming device 1 according to the embodiment.

First, to authenticate a user, it is necessary to register user information for authentication in advance. Therefore, an authentication image is registered as user information for authentication by a registration process. The user performs an operation input to perform the registration process on the image forming device 1.

The image forming device 1 accepts the input of authentication conditions for the authentication image to be registered (ACT201). The user inputs to the image forming device 1 whether the authentication image to be registered is a short-term registration or a long-term registration as an authentication condition. The image forming device 1 accepts the input of authentication conditions from, for example, the operation panel 15. In the embodiment, short-term registration is assumed to be a case where the image forming device 1 is used for only one day. The control unit 10 may be configured to perform a process of deleting an authentication image registered as a short-term registration after a certain period of time has elapsed (for example, 24 hours have elapsed since the authentication image was registered). The authentication condition acceptance process (ACT201) may also be input at the stage where the user performs an operation to perform the registration process. For example, as shown in FIG. 7(a), the operation panel 15 may display "User registration (in the case of long-term registration)" or "User registration (in the case of short-term registration)," and the operation to start the registration process and the authentication conditions can be input at the same time.

When the authentication conditions are input and the authentication condition determination unit 104 determines that the authentication conditions are short-term registration (ACT 202, YES), a second face image of the user is captured by the low-resolution camera 141, which is the imaging unit 14 (ACT 203).

The captured second facial image is registered in memory 12 as an authentication facial image (ACT 204).

When the low-resolution authentication face image is registered in memory 12, the imaging unit 14 captures an image of the user's upper body and obtains an auxiliary image (ACT 205).

The captured auxiliary image is associated with the second face image and registered in the memory 12 as an authentication auxiliary image (ACT 206). The control unit 10 then ends the authentication image registration process.

On the other hand, if the input authentication conditions are determined to be long-term registration (ACT 202, NO), a first facial image of the user is captured by the high-resolution camera 142, which is the imaging unit 14 (ACT 207).

The captured first face image is registered in the memory 12 as an authentication face image (ACT 208). The control unit 10 then ends the authentication image registration process.

By using a low-resolution image of the face, the amount of personal information in the authentication face image registered in the storage area can be reduced.

The auxiliary image can increase the accuracy of authentication by using general identification information, such as clothing that is valid only on that day, as an additional authentication image, thereby reducing the probability of authentication errors.

The user authentication process is explained with reference to Figure 8.

Figure 8 is a flowchart showing the authentication process performed by the control unit 10 of the image forming device 1 according to the embodiment.

To use the functions of the image forming device 1, the user must be authenticated through authentication processing. First, the user performs operational input to the image forming device 1 to perform the authentication processing.

The image forming device 1 accepts the input of authentication conditions (ACT301). The user inputs whether short-term registration or long-term registration as the authentication condition to the image forming device 1. The image forming device 1 accepts the input of authentication conditions from, for example, the operation panel 15. The authentication condition acceptance process (ACT301) may also be input at the stage where the user performs an operation to perform the authentication process. For example, as shown in FIG. 7(b), "User authentication (in the case of long-term registration)" or "User authentication (in the case of short-term registration)" may be displayed on the operation panel 15, making it possible to input the operation to start the authentication process and the authentication conditions at the same time.

When the authentication conditions are input and the authentication condition determination unit 104 determines that the authentication conditions are short-term registration (ACT 302, YES), a second face image of the user is captured by the low-resolution camera 141, which is the imaging unit 14. The captured second face image is sent to the authentication processing unit 11 as a verification face image (ACT 303).

Next, the control unit 10 reads out a low-resolution authentication face image from the memory 12 based on the authentication conditions. The read out low-resolution authentication face image is sent to the authentication processing unit 11 (ACT 304).

When the verification face image and authentication face image are sent, the authentication processing unit 11 performs matching using the verification face image and authentication face image (ACT 305).

If the authentication processing unit 11 determines that the authentication face image and the verification face image are consistent (ACT 306, YES), the imaging unit 14 captures an image of the user's upper body. The captured auxiliary image is sent to the authentication processing unit as a verification image (verification auxiliary image) (ACT 307).

Next, the control unit 10 reads out an authentication assistant image associated with the authentication face image from the memory 12. The read out authentication assistant image is sent to the authentication processing unit (ACT 308).

When the verification face image and authentication face image are sent, the authentication processing unit 11 performs matching using the verification auxiliary image and authentication auxiliary image (ACT 309).

If the authentication processing unit 11 determines that the characteristics of the authentication auxiliary image and the verification auxiliary image match (ACT 310, YES), the image forming device 1 authenticates the user (ACT 311). At this time, a notification that authentication has been completed may be displayed on the operation panel 15.

On the other hand, if the input authentication conditions are determined to be long-term registration (ACT 302, NO), a first facial image of the user is captured by the high-resolution camera 142, which is the imaging unit 14. The captured first facial image is sent to the authentication processing unit 11 as a verification image (verification facial image) (ACT 312).

Next, the control unit 10 reads out a high-resolution authentication face image from the memory 12 based on the authentication conditions. The read out high-resolution authentication face image is sent to the authentication processing unit 11 (ACT 313).

When the verification face image and the authentication face image are sent, the authentication processing unit 11 performs matching using the authentication face image and the verification face image (ACT 314).

If the authentication processing unit 11 determines that the authentication face image and the verification face image are consistent (ACT 315, YES), the image forming device 1 completes the authentication of the user (ACT 316). At this time, a notification that authentication has been completed may be displayed on the operation panel 15.

In addition, if the authentication processing unit 11 determines that the authentication image and the verification image are not consistent (ACT 306, ACT 310, ACT 315, NO), the control unit 10 displays a notification on the operation panel 15 that authentication was not possible, and ends the authentication process (ACT 317).

In the image forming device 1 of the embodiment, for example, the color of the user's clothing is used as a feature of the auxiliary image, so there is a high possibility that authentication will be rejected if the authentication process is performed while wearing clothes different from those used at the time of authentication registration. Therefore, if authentication is rejected, a notification may be displayed on the operation panel 15 urging the user to perform the authentication process while wearing the clothes used at the time of registration (see FIG. 9).

According to the above-described embodiment, the image forming device 1 can authenticate a user based on the second facial image and the auxiliary image. This eliminates the need to register a first facial photo that contains a large amount of personal information, for example, when registering an authentication image to be used for a short period of time, and reduces the security risk of personal information. In addition, the auxiliary image can be used as an authentication image by additionally using general identification information such as clothing that is valid only at the time of authentication, thereby improving authentication accuracy and reducing the risk of authentication errors.

As a first modified example, the authentication condition acceptance process (Figure 8, ACT301) may be omitted in the user authentication process. The first modified example differs from the authentication process of the embodiment in that the first modified example does not accept input of authentication conditions and performs authentication using the first face image as a verification image, and if authentication is not successful, performs authentication using the second face image and the auxiliary image as verification images.

The authentication process for the first variant will be explained using FIG. 10.

ACT401, ACT402, ACT403, ACT406, ACT407, ACT408, ACT409, ACT410, ACT411, ACT412, ACT413, and ACT414 in FIG. 10 are the same processes as ACT312, ACT313, ACT314, ACT303, ACT304, ACT305, ACT306, ACT307, ACT308, ACT309, ACT310, and ACT311 in FIG. 8, so detailed explanations will be omitted.

In the first variant, when a user performs an operation input to start the authentication process, a first face image is captured by the imaging unit 14 and sent to the authentication processing unit 11 as a verification face image (ACT 401). Then, an authentication face image is sent from the memory 12 to the authentication processing unit 11 (ACT 402), and the verification face image and the authentication face image are compared (ACT 403). If the comparison proves consistent with the user appearing in the image (ACT 404, YES), the image forming device 1 completes the authentication of the user (ACT 405).

On the other hand, if the verification face image and the authentication face image are not consistent with each other (ACT 404, NO), the imaging unit 14 captures a second face image and sends it to the authentication processing unit 11 as the verification face image (ACT 406). Then, the authentication face image is sent from the memory 12 to the authentication processing device 11 (ACT 407), and the verification face image and the authentication face image are compared (ACT 408).

If the verification face image and the authentication face image are matched to confirm the match of the user in the image (ACT 409, YES), an auxiliary image is captured by the imaging unit 14 and sent to the authentication processing unit 11 as the verification auxiliary image (ACT 410). The authentication auxiliary image is then sent from the memory 12 to the authentication processing device 11 (ACT 411), and the verification auxiliary image and the authentication auxiliary image are matched (ACT 412). If the matching confirms the match of specific elements in the images (ACT 413, YES), the image forming device 1 completes the authentication of the user (ACT 414).

If consistency is not achieved by comparing the verification image and authentication image of the second face image or auxiliary image (ACT 409, ACT 413, NO), the image forming device 1 does not authenticate the user (ACT 415).

This allows authentication to be performed without entering authentication conditions.

As a second modified example, as shown in FIG. 11, the image forming device 1 is connected to the server 6 via a communication I/F 13, and the server 6 may have, instead of the image forming device 1, an authentication processing unit 11 that performs matching using an authentication image and a verification image, and a memory 12 that registers the authentication image sent from the image forming device 1. In this case, the server 6 performs matching using the authentication image registered in the memory 12 of the server 6 and the verification image sent from the image forming device 1, and sends the matching result to the image forming device 1. The image forming device 1 authenticates the user based on the judgment result of the authentication processing unit 11 of the server 6.

As a result, the authentication image can be registered in the memory 12 of the server 6 and the authentication image can be compared with the verification image on the server 6, which does not put a strain on the storage capacity of the image forming device 1. Furthermore, the authentication image can be shared between multiple image forming devices 1 and other information processing devices (such as PCs) connected to the server 6.

The third variant will be described.

As shown in Fig. 12, the image forming device 1 according to the third modified example has a configuration in which a resolution conversion unit 18 is added to the image forming device 1 according to the embodiment (see Fig. 1). Also, as shown in Fig. 13, compared to the embodiment (see Fig. 4), the image sent from the imaging unit 14 to the authentication processing unit 11 and memory 12 may be configured to pass through the resolution conversion unit 18.

The resolution conversion unit 18 can reduce the resolution of the image captured by the imaging unit 14. This eliminates the need to capture images with different resolutions using the low-resolution camera 141 and the high-resolution camera 142 of the embodiment, and one camera with zoom-in/zoom-out functionality can suffice. Alternatively, by using two cameras for face images and auxiliary images, the camera's zoom-in/zoom-out functionality can be eliminated, reducing manufacturing costs.

In the third modified example, camera 141 is an imaging unit 14 for a face image, and is capable of capturing a face image of the user. Camera 142 is an imaging unit 14 for an auxiliary image, and is capable of capturing an auxiliary image of the user. Note that cameras 141 and 142 do not have a zoom-in/zoom-out function. In the third modified example, cameras 141 and 142 are installed in the same positions as in the embodiment.

The rest of the components are configured the same as in the embodiment, so the explanation will be omitted.

The authentication image registration process in the third variant will be described with reference to FIG. 14.

ACT501, ACT505, ACT506, ACT507, and ACT508 shown in FIG. 14 in the third modified example are the same processes as ACT201, ACT204, ACT205, ACT206, and ACT208 shown in FIG. 6 in the embodiment.

First, the user performs an operation input to perform the registration process on the image forming device 1. The image forming device 1 accepts the input of the authentication conditions for the authentication image to be registered (ACT501). As in the embodiment, the authentication condition acceptance process (ACT501) may be input at the stage where the user performs an operation input to perform the registration process.

When the authentication conditions are input, a first facial image of the user is captured by the facial image camera 141, which is the imaging unit 14 (ACT 502).

When the first face image is captured, if the authentication condition is short-term registration (ACT 503, YES), the resolution conversion unit 18 reduces the resolution of the first face image captured by the camera 141 (ACT 504).

Then, the second face image obtained by subjecting the first face image to a low-resolution process (ACT 504) is registered in memory 12 as an authentication face image (ACT 505).

When the low-resolution authentication face image is registered in memory 12, the imaging unit 14 captures an image of the user's upper body and obtains an auxiliary image (ACT 506).

The captured auxiliary image is associated with the second face image registered as the authentication face image, and is registered in the memory 12 as the authentication auxiliary image (ACT 507). After that, the control unit 10 ends the authentication image registration process.

On the other hand, when the first face image is captured and the authentication condition is long-term registration (ACT 503, NO), the resolution conversion unit 18 does not perform a low-resolution process, and the captured first face image is registered in the memory as an authentication face image (ACT 508). After that, the control unit 10 ends the registration process of the authentication image.

The authentication process in the third variant will be described with reference to FIG. 15.

Compared to the authentication process according to the first modified example, the authentication process according to the third modified example has changed the low-resolution verification face image acquisition process (Figure 10, ACT 406) to a low-resolution verification face image process (Figure 15, ACT 606).

ACT601, ACT602, ACT603, ACT604, ACT605, ACT607, ACT608, ACT609, ACT610, ACT611, ACT612, ACT613, ACT614, and ACT615 in FIG. 15 in the third modified example are the same processes as ACT401, ACT402, ACT403, ACT404, ACT405, ACT407, ACT408, ACT409, ACT410, ACT411, ACT412, ACT413, ACT414, and ACT415 in FIG. 10 in the first modified example. Therefore, the description of these will be omitted.

The difference between the authentication process in the first variant is that two verification face images with different resolutions can be obtained by capturing an image once.

If it is determined that there is no consistency in the matching between the authentication face image and the verification face image using the first face image (ACT 604, NO), the resolution conversion unit 18 reduces the resolution of the first face image captured by the imaging unit 14 in ACT 601 to generate a second face image. After that, the second face image is sent to the authentication processing unit 11 as a verification face image (ACT 606).

The authentication device of the present invention has been described using an image forming device 1 as an example embodiment, but to register personal information for authentication, it is sufficient to have a control unit 10 that controls the device itself, an imaging unit 14 that captures a face image and an auxiliary image, and a memory 12 that stores the authentication image. Furthermore, to authenticate a user, an authentication method that additionally has an authentication processing unit 11 that can perform matching using an authentication image and a verification image is sufficient. For example, as a device for managing entry and exit installed in a conference room of a shared office, the authentication device of the present invention may control the opening and closing function of a door for entering and exiting (opening and closing of a lock installed on the door, or automatic opening and closing of the door) depending on whether or not the user has been authenticated.

Although embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims.

1: Image forming apparatus 10: Control unit 11: Authentication processing unit 12: Memory 14: Imaging unit 18: Resolution conversion unit 104: Authentication condition determination unit 111: Authentication area detection unit 112: Feature extraction unit 113: Collation unit ACT504, ACT606: Resolution reduction processing

Claims (6)

an acquisition unit that acquires a first face image that is an image of a user's face or a second face image that is a face image having a lower resolution than the first face image, and an auxiliary image that is an image including at least an element of the user other than the face;
a memory for registering the first face image, the second face image, and the auxiliary image as authentication images to be registered for authentication;
a control unit that performs a process of registering the second face image and the auxiliary image as the authentication image in the memory when an authentication condition for storing the authentication image in the memory for a predetermined period is input ;
An authentication device having the above configuration. the acquisition unit includes an imaging unit that acquires the first face image and the auxiliary image;
a resolution conversion unit that reduces a resolution of the first facial image and converts the first facial image into the second facial image;
The authentication device according to claim 1 , further comprising: The acquisition unit includes a first imaging unit configured to acquire the first face image;
a second imaging unit that captures the second face image;
The authentication device according to claim 1 , further comprising: an authentication processing unit that performs authentication processing based on the second face image and the auxiliary image as the authentication image registered in the memory, and the second face image and the auxiliary image as a verification image formed of an image further acquired by the acquisition unit;
4. The authentication device according to claim 1, further comprising: an authentication condition determination unit that determines two authentication conditions;
a control unit that performs a process of registering the first face image in the memory as the authentication image, or registering the second face image and the auxiliary image in the memory as the authentication images, based on a determination by the authentication condition determination unit;
5. The authentication device according to claim 1, further comprising: an authentication processing unit that performs authentication processing based on the first face image registered in the memory as the authentication image and the first face image as a verification image formed from an image further acquired by the acquisition unit based on a determination of the authentication condition determination unit, or performs authentication processing based on the second face image and the auxiliary image registered in the memory as the authentication image and the second face image and the auxiliary image as the verification image formed from an image further acquired by the acquisition unit;
6. The authentication device according to claim 5, further comprising:

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