Patent Publication Number: US-2009220128-A1

Title: Authentication device, authentication method and authentication program

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2008-050947, filed Feb. 29, 2008, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     1. Field 
     The present invention relates to an authentication method for a person, and more particularly to an authentication method for a person&#39;s face. 
     2. Description of the Related Art 
     In using a computer system, it is important to correctly authenticate the user who uses the computer system. Nowadays, the biometrics techniques with biometrical information have been employed to enhance the authentication accuracy. One method is a face authentication method that collates the features of the user&#39;s face. In the face authentication method, the user can apply it without a feeling of reluctance, because the user only needs to stand before the camera, though the authentication accuracy may depend on the position or angle of the face. 
     Therefore, a method for displaying an index for aligning both eyes of the user subjected to face authentication on the screen has been proposed (refer to JP-A-2003-317100). 
     In making the face authentication for the user, the authentication accuracy may be often varied depending on the position or angle of the face reflected on the camera. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       A general architecture that implements the various feature of the invention will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the invention and not to limit the scope of the invention. 
         FIG. 1  is an exemplary view showing one example of an authentication device according to an embodiment of the present invention. 
         FIG. 2  is an exemplary block diagram showing one example of the authentication device according to the embodiment. 
         FIG. 3  is an exemplary functional block diagram showing one example of the authentication device according to the embodiment. 
         FIG. 4  is an exemplary view showing an example of guide image according to the embodiment. 
         FIG. 5  is an exemplary view showing an example of image synthesis according to the embodiment. 
         FIG. 6  is an exemplary flowchart showing one example of operation flow of the authentication device according to the embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments according to the invention will be described hereinafter with reference to the accompanying drawings. In general, according to one embodiment of the invention, there is provided an authentication apparatus for authenticating an authentication target of a user&#39;s face includes: a display configured to display an image to authentication target; a camera arranged in the vicinity of the display to take an image of the authentication target; an assist unit configured to output a guide image instructing a user a direction in which to turn in accordance with an attribute of the authenticating; and an image synthesis unit configured to synthesize the image taken by the camera and the guide image output from the assist unit to display a synthesized image on the display. 
     According to another aspect of the present invention, there is provided an authentication method for authenticating an authentication target of a user&#39;s face including: selecting a guide image instructing a user a direction in which to turn in accordance with an attribute of the authenticating; acquiring a face image of the authentication target; generating a synthesized image from the face image and the selected guide image; and displaying the synthesized image to a user. 
     According to another aspect of the present invention, there is provided a computer readable storage medium that stores a software program causing a computer system to perform an authentication process for authenticating an authentication target of a user&#39;s face, the process including: selecting a guide image instructing a user a direction in which to turn in accordance with an attribute of the authenticating; acquiring a face image of the authentication target; generating a synthesized image from the face image and the selected guide image; and displaying the synthesized image to a user. 
     Embodiment 
       FIG. 1  is a view showing one example of an authentication device according to an embodiment of the present invention. In  FIG. 1 , a PC  100 , a display  101 , a keyboard  102 , a mouse  103  and a camera  104  are shown. 
     The PC  100  is a portable personal computer such as a notebook personal computer. 
     The display  101  is a display unit mounted on the PC  100 . For example, it is an LCD (Liquid Crystal Display) in which the PC  100  displays information to the user. 
     The keyboard  102  is an input unit built into the PC  100 . The user of the PC  100  can give any instruction by keying on the keyboard  102 . 
     The mouse  103  is an input unit for moving a mouse cursor displayed on the screen of the PC  100  according to the user&#39;s intention. Such input unit is used to point to a predetermined position on the screen and also called a pointing device. Further, it comprises some buttons used for instructing the PC  100  to start a predetermined operation. 
     The camera  104  is provided on the top of the display  101 , and laid to photograph a video of the user who manipulates the PC  100 . The camera  104  has a function of converting the video in an opening direction into an electronic signal of image data. 
       FIG. 2  is a block diagram showing one example of the authentication device according to the embodiment. In  FIG. 2 , a CPU  200 , a main memory  201 , a bus controller  202 , an HDD  203 , an input/output controller  204  and a USB controller  205  are shown. 
     The CPU  200  is a central processing unit (Central Processing Unit) for controlling the overall information apparatus  100 . Also, it has a function of executing a program to perform a predetermined processing according to the program. 
     The main memory  201  is composed of a semiconductor memory, and used as a storage area of program and data when the CPU  200  performs a program. 
     The bus controller  202  has a function of controlling a bus for conveying information between the components of the information apparatus  100 . An instruction from the CPU  200  reads or writes data from or into the main memory  201  via the bus, or gives an instruction to another apparatus. 
     The HDD  203  is a mass storage unit composed of a magnetic disk unit (Hard Disk Drive), for example. It stores an application performed by the CPU  200  or data required during execution, which is passed via the bus controller  202  to the CPU  200 , as needed. 
     The input/output controller  204  has a function of providing the interface with the CPU  200 , the HDD  203 , and various kinds of input/output units such as the display unit  101  and the keyboard  102 . 
     The USB controller  205  is a control unit for connecting the apparatus having the interface conforming to the USB (Universal Serial Bus) standards. Various apparatuses conforming to the USB standards have appeared, and can be freely connected or disconnected even while the information apparatus  100  is operating with a PnP (Plug and Play) technology. In this embodiment, it is employed to connect the mouse  103  and the camera  104 . 
       FIG. 3  is a functional block diagram showing one example of the authentication device according to the embodiment. In  FIG. 3 , a camera image acquisition part  300 , a face authentication engine  301 , a database  302 , a face authentication support part  303 , an image synthesis part  304  and a video output par  305  are shown. 
     The camera image acquisition part  300  has a function of acquiring a video captured by the camera  104  as image data. For example, the driver software of the camera  104  corresponds to this. 
     The face authentication engine  301  has a function of inputting a face image of the user acquired by the camera video acquisition part  300  and specifying the person with the face. Several methods for identifying the specific person from the face image are known, but not described here in detail. Generally, to specify the specific person from the face image, the face image is photographed in advance, and the feature points contained therein are extracted. In the authentication, a process for extracting the feature points of the face image photographed by the camera, and collating them with the feature points stored beforehand is performed. 
     In the face authentication, when the user faces sideways, has a shade due to the influence of illumination, or unsteadily move, they are all noise, possibly degrading the face authentication accuracy. At this time, the accuracy of face authentication can be improved by storing beforehand the feature points extracted from the face images in plural directions, not the feature points of the face image in only one direction such as facing forward, and collating them with the face images oriented in respective directions. 
     The database  302  is the database of the HDD  203 , for example, storing the guide image. The guide image as used herein refers to the image representing to which direction the user has the face turned in the face authentication. The guide image is superimposed on the camera image photographed by the camera  104  and displayed on the display  101 . The details of the guide image will be described later. 
     The face authentication support part  303  has a function of supporting the face authentication operation, or acquiring the guide image for instructing the user in front of the camera  104  to turn the face right from the database  302 , when it is desired to make the face authentication using the face image turning right, for example. Further, it instructs the face authentication engine  301  to make the authentication for the acquired camera image, using the feature points of the face turning right. When there are guide images in plural directions and the feature points of the face images oriented in plural directions, the instructions for acquiring the guide image and authentication may be repeated for respective directions. With this constitution, the comparison with the feature points of plural face images can be made for one user, whereby the face recognition ratio is improved. 
     The image synthesis part  304  has a function of synthesizing the camera image acquired by the camera image acquisition part  300  and the guide image acquired by the face authentication support part  303 , if any, to generate one image, 
     The video output part  305  has a function of outputting the composite image generated by the image synthesis part  304  to display it on the display  101 . For example, a display driver or a GUI (Graphical User Interface) corresponds to this. 
       FIG. 4  is a view showing an example of the guide image according to the embodiment. A face image  400  is an example of the image in which an illustration of the person facing right is drawn, and instructs the user, while seeing this image, to make a confirmation in front of the camera  104  so that the user may be reflected in the same orientation or at the same position of the illustration of the image as this image. Similarly, a face image  401  instructs the user to face front toward the camera  104 . In addition to the instruction of this case, other instructions for turning the face such as up or down, right or left, or diagonal or inclined direction may be prepared, as needed. Or the guide image for instructing the user to put on or off the glasses or furnishings, or the guide image representing the instruction for coming closer to or leaving away from the camera may be prepared. With this configuration, the user seeing this guide image can easily understand intuitively which direction to turn the face. 
       FIG. 5  is a view showing an example of image synthesis according to the embodiment. At the time of face authentication, it is supposed that if there is a camera image  500  captured by the camera  104 , the face authentication support part  303  acquires a guide image  501  representing facing forward from the database  302  to make the face authentication in the forward direction. The image synthesis part  304  receives the camera image  500  acquired by the camera image acquisition part  300  and the guide image  501  acquired by the face authentication support part  303 , and outputs a synthesized image  502  to the video output part  305  to display it on the display  101 . 
     Since the guide image  501  is synthesized with the camera image  500  and displayed on the display  101 , the use can easily know to which direction to turn the face while seeing the display  101 , or how much to come closer to the camera  104  by making the comparison with the size of the guide image  501 . 
     During face authentication, the user continues to face in the direction toward the camera  104  laid on the top of the display  101 , and can easily confirm the motion of his or her own. 
       FIG. 6  is a flowchart showing one example of operation flow of the authentication device according to the embodiment. 
     First of all, it is judged whether or not the face authentication engine  301  is during face authentication (step S 01 ). 
     If the face authentication engine  301  is during face authentication (Yes), it is judged whether or not the face authentication support part  303  makes the face authentication using the feature points of the face image of the user with the attribute of facing forward (step S 02 ). 
     If the face authentication is made using the face image with the attribute of facing forward (Yes), the face authentication support part  303  acquires the guide image representing facing forward from the database  302  (step S 03 ). After acquisition, the image synthesis part  304  synthesizes the camera image acquired by the camera image acquisition part  300  with the guide image, and the video output part  305  displays the composite image on the display  101  (step S 04 ). 
     If the face authentication with the attribute of facing forward is not made at step S 02  (No), it is judged whether or not the face authentication involves the attribute of facing right (step S 05 ). 
     If the face authentication involves the attribute of facing right (Yes), the guide image representing facing right is acquired from the database  302  (step S 06 ), and the composite image is displayed on the display  101  (step S 04 ). 
     If the face authentication does not involve the attribute of facing right (No), the guide image representing facing left is acquired (step S 07 ), judging that the face authentication involves another attribute of facing left, and the composite image is displayed (step S 04 ). 
     With this configuration, in the face authentication, it is possible to support the user with an instruction accompanying motion to the position or orientation of the user&#39;s face to be reflected without averting the light of sight from the camera. 
     The invention is by no means limited to the above embodiment, but may be embodied in other forms by varying the components without departing from the spirit or scope of the invention at the practical stage. Also, various inventions may be formed by making appropriate combinations of plural components as disclosed in the above embodiment. For example, some of the components may be deleted from all the components as shown in the embodiment. Further, the components in different embodiments may be appropriately combined. 
     As described with reference to the embodiment, there is provided an authentication device, an authentication method and an authentication program that can support the user with an instruction accompanying motion to the position or orientation of the user&#39;s face to be reflected without averting the line of sight from the camera in trying to enhance the authentication accuracy using the face images oriented in plural directions. 
     It is possible to provide an authentication device, an authentication method and an authentication program that can support the user with an instruction accompanying motion for instructing the position or orientation of the user&#39;s face to be reflected without averting the line of sight from the camera in making the face authentication.