Patent Document

BACKGROUND OF THE INVENTION 
     The present invention relates to an iris image pickup apparatus and an iris authentication apparatus for guiding the position of an eye in picking up an iris image used for personal authentication, and in particular to an iris image pickup apparatus and an iris authentication apparatus which can perform high-speed iris authentication by reducing the number of retries of iris image pickup. 
       FIG. 8A  is a front view of a conventional iris authentication apparatus.  FIG. 8B  is a sectional view of  FIG. 8A  taken along the line B—B.  FIG. 8C  is an enlarged view of a sight line guiding unit shown in  FIG. 8A  at a time of image-pickup of an iris. The iris authentication apparatus is provided with a pickup window  1  for transmitting a near infrared light on its front and an iris image pickup camera (not shown) is arranged on its rear. Near infrared light transmitting windows  2 ,  3  are arranged on both sides of the pickup window  1 . Near infrared light illuminating apparatuses (not shown) are provided behind the near infrared light transmitting windows  2 ,  3 . 
     A sight line guiding unit for iris image pickup  4  is provided above the pickup window  1 . The sight line guiding unit for iris image pickup  4  has an LED group  6  arranged in a predetermined shape on the bottom  5   a  of a recess  5  surrounded by right/left walls  5 L,  5 R approximately 1.5 cm in length and upper/lower walls  5 U,  5 D. In the shown example, the LED group  6  is arranged in the shape of a rectangular frame. The sight line guiding unit for iris image pickup  4  includes, on its periphery, a reporting LED  7  for indicating the progress of iris authentication and an instructing LED  8  for prompting a person to be authenticated to move forward/backward. 
     When a person to be authenticated stands to the left against the pickup window  1 , the person to be authenticated sees the left frame  6 L of the rectangular frame of the LED group  6  in a thinner shape than it is actually is, or cannot see the left frame  6 L, as obstructed by the left wall  5 L. When the person to be authenticated stands to the right against the pickup window  1 , the right frame  6 R of the rectangular frame is obstructed by the right wall  5 R. The person to be authenticated moves to a position where he/she sees the right/left frame  6 R,  6 L of the rectangular frame without partially or totally hidden, in order to stand facing toward the pickup window  1 . 
     Similarly, when a tall person comes too close to the iris authentication apparatus, the upper frame  6 U of the rectangular frame is partially hidden by the upper wall  5 U. When a short person comes too close to the iris authentication apparatus, the lower frame  6 D of the rectangular frame is partially hidden by the lower wall  5 D. Thus the person to be authenticated can make fore-and-aft adjustment. For the fore-and-aft adjustment, in case the image of a person shot is not in a predetermined size, a controller turns on the instructing LED  8  to instruct forward or backward movement of the person to be authenticated, as well as the indicator on the sight line guiding unit for iris image pickup  4 . 
     In case an iris image is shot on the iris authentication apparatus, a reporting LED  7  is turned on to report the progress of authentication in order for the person to be authenticated to recognize that image-pickup is under way. The person to be authenticated watches the indicator to know that image-pickup is under way or image-pickup is completed and authentication is under way. 
     The sight line guiding unit for iris image pickup  4  mentioned earlier can guide a person to be authenticated to a standing position where an iris image optimum for authentication can be shot. However, when the reporting LED  7  or instructing LED  8  comes on while the person to be authenticated is watching the LED group  6  in the recess  5 , the person to be authenticated naturally turns toward the reporting LED  7  or instructing LED  8 , thus the position of an eye of the person is dislocated from the initial position. This makes it impossible to pick up an iris image thus requiring retried iris image pickup. Several retries takes tame in authentication of an iris which gives the person to be authenticated an unpleasant feeling. 
     SUMMARY OF THE INVENTION 
     The object of the invention is to provide iris image pickup apparatus and iris authentication apparatus which can reduce the number of retries of iris image pickup to boost iris authentication. 
     An iris image pickup apparatus to attain the object is characterized in that the apparatus comprises image pickup means for shooting the iris of a person to be authenticated, indicator means provided just above the image pickup means for guiding the person to be authenticated to the standing position of the person to be authenticated as well as showing the progress of authentication of the person to be authenticated, and control means for controlling the indicator means. With this configuration, a person to be authenticated knows the progress of authentication without diverting his/her line of sight and a favorable iris image is obtained. 
     Preferably, the iris image pickup apparatus is characterized in that the indicator means comprises an LED group arranged radially. With this configuration, it is possible to show the progress of authentication by using radial indicator means in clockwise or counterclockwise direction thus allowing intuitive reporting of the progress. 
     Preferably, the iris image pickup apparatus is characterized in that the indicator means is arranged at the bottom of a recess sinking in the direction of the line of sight of the person to be authenticated. With this configuration, indicator means on the bottom is hidden by way of the walls around the recess when the person to be authenticated is dislocated from the optimum position. It is thus possible to guide the person to be authenticated to the optimum position. 
     Preferably, the iris image pickup apparatus is characterized in that the indicator means comprises right/left bar-shaped indicator sections respectively provided in a position adjacent the right/left walls which form the recess and a central bar-shaped indicator section provided in the center of the right/left bar-shaped indicator sections. With this configuration, a person to be authenticated can correct his/her position toward the center by recognizing that the right/left bar-shaped indicator sections are hidden by the right/left walls. 
     Preferably, the iris image pickup apparatus is characterized in that the length of each of the right/left bar-shaped indicator sections is equal to that of the central bar-shaped indicator section. With this configuration, a person to be authenticated knowing that the three bar-shaped indicator sections are equal in length easily finds that his/her position is wrong when he/she recognizes that the length is unequal between these indicator sections with a bar-shaped indicator section hidden by a wall around the recess. 
     Preferably, the iris image pickup apparatus is characterized in that the length of the central bar-shaped indicator section is longer than that of each of the right/left bar-shaped indicator sections. With this configuration, a person to be authenticated knowing that the length of the central bar-shaped indicator section is longer than that of the right/left bar-shaped indicator sections easily finds that his/her position is wrong when he/she recognizes that the length is equal between these indicator sections with a bar-shaped indicator section hidden by an upper/lower wall. 
     Preferably, the iris image pickup apparatus is characterized in that concave sections aligned with the central bar-shaped indicator section are engraved on the upper/lower walls forming the recess. With this configuration, in case the position of a person to be authenticated is too close to the sight line guiding unit for iris image pickup, the length of the central bar-shaped indicator section exceeds the length of the right/left bar-shaped indicator section. Thus the person to be authenticated easily finds that his/her position is wrong. 
     An iris authentication apparatus to attain the object is characterized in that the apparatus comprises iris image pickup apparatus of the aforementioned configuration. With this configuration, the time when a person to be authenticated waits for completion of authentication is shortened thus reducing the workload on the person to be authenticated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of an outer panel to cover iris authentication apparatus according to an embodiment of the invention; 
         FIG. 2  is a front view of iris authentication apparatus according to an embodiment of the invention; 
         FIG. 3  is an enlarged view of a sight line guiding unit for iris image pickup according to the first embodiment of the invention; 
         FIG. 4  is an indication transition diagram of the sight line guiding unit for iris image pickup  40  according to the first embodiment of the invention; 
         FIG. 5  explains the progress of authentication in the first embodiment of the invention; 
         FIGS. 6A and 6B  explain the sight line guiding unit for iris image pickup according to the second embodiment of the invention; 
         FIGS. 7A and 7B  explain the sight line guiding unit for iris image pickup according to the third embodiment of the invention; and 
         FIGS. 8A to 8C  explain a conventional sight line guiding unit for iris image pickup. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Preferred embodiments of the invention will be described referring to drawings. 
       FIG. 2  is a front view of iris authentication apparatus according to the present invention. Iris authentication apparatus  10  according to the present invention includes a longitudinal fixed table  11 . Iris lighting fixtures  12 ,  13  are attached on the left and right ends of the longitudinal fixed table  11 . Each iris lighting fixture  12 ,  13  includes a condensing lens for condensing and irradiating a near infrared light onto an iris and pan motors for lighting  12   a ,  13   a  and tilt motors for lighting  12   b ,  13   b  in order to orient the illuminating light in the direction of the iris. 
     Lighting fixtures for wide angle cameras  14 ,  15  are attached on the fixed table  11  in the inner direction of each iris lighting fixture (at the center direction of the fixed table  11 ). The lighting fixtures  14 ,  15  are also configured as an aggregation of a large number of light emitting diodes. The lighting fixtures  14 ,  15  are secured to the fixed table and no condensing lenses are provided, because they have only to illuminate a wide range evenly with a near infrared light (no panning or tilt operation is required). 
     A support plate  16  is elected on the fixed table  11  in the inner direction of the lighting fixture  14  (in the center direction of the fixed table  11 ). A support plate  17  is elected on the fixed table  11  in the inner direction of the lighting fixture  15  (in the center direction of the fixed table  11 ). A tilt table  20  is attached between both support plates  16 ,  17 . 
     The tilt table  20  includes axes  20   a ,  20   b  on the left and right respectively. Each axis  20   a ,  20   b  is respectively supported rotatably on the support plates  16 ,  17 . One axis  20   a  is directly coupled to the rotation axis of the motor for tilt  21  attached to the support plate  16 . The tilt table  20  is driven to rotate in the direction of an arrow A. A damper  29  is attached to the other axis  20   b.    
     The tilt table  20  includes a telephotographic camera (narrow angle camera)  22 , a mirror for panning  23 , a range finder (range sensor)  24 , a wide angle camera  25 , and a motor for panning  26 . A telephotographic camera  22  is arranged on the support plate  17  of the tilt table  20  so that the light axis may be coaxial with the rotation axis of the tilt table  20 . The mirror for panning  23  is arranged in front of the telephotographic camera  22 . A light reflected on the mirror for panning  23  impinges on the telephotographic camera  22 . The mirror for panning  23  is rotatable about the axis perpendicular to the light axis of the telephotographic camera  22 , that is, in the direction of an arrow B. 
     The motor for panning  26  for rotating the mirror for panning  23  in the direction of the arrow B is attached to the support plate  16  of the tilt table  20  and drives the mirror for panning  23  to rotate via the link mechanism  27 . The range finder  24 , interlocked with the mirror for panning  23 , is driven in the direction of the arrow B and irradiates an infrared light onto an object face to face thus allowing high-accuracy ranging. The range finder  24  is also driven to rotate by the motor for panning  26  via the link mechanism. 
     The wide angle camera  25  is arranged between the mirror for panning  23  and the motor for panning  26  and its light axis is provided at an intersection with the rotation axis of the tilt table  20 . This eliminates the vertical parallax between the wide angle camera  25  and the telephotographic camera  22 . 
     A controller  30  is arranged on the fixed table  11 . The controller  30  controls the operation of the light-emitting diodes of the iris lighting fixtures  12 ,  13 , pan motors for lighting  12   a ,  13   a , tilt motors for lighting  12   b ,  13   b , light-emitting diodes of the lighting fixtures for wide angle cameras  14 ,  15 , motor for tilt  21  of the tilt table  20 , motor for panning  26 , wide angle camera  25 , telephotographic camera  22 , and range finder  24 , as well as performs lighting control of the LEDs on the sight line guiding unit mentioned later. The controller  30  compares an iris image shot by a telephotographic camera with the dictionary data (iris image data of registered persons) acquired from an iris image database (not shown) for authentication. 
     Embodiment 1 
       FIG. 1  is a front view of an outer panel to cover the iris authentication apparatus described referring to  FIG. 2 . On the outer panel  31 , in the center front thereof, a pickup window  32  transmitting a near infrared light and cutting off a visible light is provided. On the right and left of the pickup window  32 , windows for lighting  33 ,  34  which transmits a near infrared light are provided. An illuminating light from the right/left lighting fixtures for wide angle cameras  14 ,  15  or iris lighting fixtures  12 ,  13  illuminates the face and iris of a person to be authenticated through the windows  33 ,  34 . The reflected light (near infrared light) of the illuminating light impinges on the pickup lens of the wide angle camera  25  through the pickup window  32  and is reflected on the mirror for panning  23  then impinges on the pickup lens of the telephotographic camera  22 . 
     Substantially above the pickup window  32 , a sight line guiding unit for iris image pickup  40 , according to the first embodiment of the invention, is provided. The sight line guiding unit for iris image pickup  40  includes a rectangular recess  41  provided on the outer panel  31  and three LEDs for decision  42 ,  43 ,  44  arranged on the left to the recess  41  as shown in  FIG. 3 . By providing the sight line guiding unit for iris image pickup  40  substantially above the pickup window  32 , it is possible to pick up the iris image of a person to be authenticated without the iris hidden by eyelashes. 
     The LED for decision  42  indicates “OK” meaning that the authentication result of a person to be authenticated has coincided with the iris of a registered person (person authorized to enter the room). The LED for decision  43  indicates “NG” meaning that the authentication result of a person to be authenticated has not coincided with the iris of a registered person. The LED  44  indicates “Wait” meaning that authentication is under way through another camera in the system. These LED indicators for decision reports information not overlapping the timing of iris image pickup to a person to be authenticated. These LEDs are not illuminated in a time zone when the face or iris of a person to be authenticated is shot. 
       FIG. 3  is an enlarged view of an LED group provided on the bottom of the recess  41  of the sight line guiding unit for iris image pickup  40 . Individual LEDs are not shown. In this embodiment, a left vertical bar LED group (bar-shaped indicator)  45  arranged in the shape of a vertical bar close to the left wall  41 L forming the recess  41 , a right vertical bar LED group (bar-shaped indicator)  46  arranged in the shape of a vertical bar close to the right wall  41 R forming the recess  41 , and a radial LED group  47  arranged radially in the center between the left vertical bar LED group  45  and a right vertical bar LED group  46 . 
     The radial LED group  47  includes an LED  47   m  arranged in the center and six LED groups  47   a ,  47   b ,  47   c ,  47   d ,  47   e ,  47   f  arranged radially about the LED  47   m . The LED group  47   a  and the LED group  47   d  are provided in parallel with the right/left vertical bar LED groups  45 ,  46  and altogether constitute a bar-shaped indicator section. The length from the upper end of the LED group  47   a  to the lower end of the LED group  47   d  is equal to the length from the upper end to the lower end of the LED group  45 ,  46 . 
     The LEDs constituting the sight line guiding unit for iris image pickup  40  of the aforementioned configuration are connected to the controller  30  shown in  FIG. 2 . Lighting, shut-off and blinking of the LEDs are controlled by the controller  30 . The decision LEDs  42 ,  43 ,  44  are also connected to the controller  30 . Lighting of the LEDs  42 ,  43 ,  44  is controlled by the controller  30 . 
       FIG. 4  is an LED lighting state transition diagram of sight line guiding unit for iris image pickup  40  according to this embodiment. For example, the iris authentication apparatus in  FIG. 1  is provided at the entrance of a room where only an authorized person is allowed to enter. A person wishing to enter the room stands before the iris authentication apparatus. 
     Indication in Mode 1 shown in  FIG. 4 , or a state where the central  47   m  alone is turned on and the other LEDs are turned off, shows a standby state. An infrared light is irradiated in the front direction from the range finder  24  shown in FIG.  1 . When the range finder  24  detects a reflected light, the controller  30  recognizes that a person to be authenticated is in front and makes a transition to the indication of Mode 2. 
     In Mode 2, the right/left bar LED groups  45 ,  46 , the central LED  47   m , and the upper/lower radial LED groups  47   a ,  47   b  are turned on. A person to be authenticated, watching the LED groups thus lit, chooses to stand in a position where the width of the right/left bar LED group  45 ,  46  looks the same. Thus the person to be authenticated is right in front of the pickup window  32 . The person to be authenticated can see the upper/lower radial LED groups  47   a ,  47   b  in the center so that it is easier to check the center position than the conventional unit shown in  FIG. 8 . 
     The person to be authenticated stands in the optimum position in the fore-and-aft direction when he/she stands in a position where he/she sees the three vertical bars (right/left LED groups  45 ,  46  and central LED groups  47   a ,  47   d ) in the center of the recess  41  without upper/lower ends of the bars hidden. The controller  30 , in case it has determined that an image of a person is not shot within the size of a predetermined range by the wide angle camera, instructs the person to be authenticated to move forward or backward so that the image of the person will be a size within the predetermined range. 
     Mode 3 shows an instruction to move forward. In the shown example, an upward arrow is indicated. That is, the central LED  47   m , LED groups  47   c ,  47   d ,  47   e  are turned on and the LED group  47   a  corresponding to the tip of the arrow is blinking. 
     Mode 3′ shows an instruction to move backward. In the shown example, a downward arrow is indicated. That is, the central LED  47   m , LED groups  47   a ,  47   b ,  47   f  are turned on and the LED group  47   d  corresponding to the tip of the arrow is blinking. Modes 3 and 3′ are used only when necessary. Otherwise, execution makes a transition to Mode 4. 
     In Mode 4 or subsequent modes, the progress of iris authentication is shown using the radial LED groups  47   a ,  47   b ,  47   c ,  47   d ,  47   e ,  47   f . In this embodiment, the progress of iris authentication is shown in three stages, “picking up a face image,” “picking up an eye image,” and “comparing.” 
     In Mode 4, “picking up a face image” is reported by turning on the central LED  47   m  and the radial LED group  47   a  and causing the LED group  47   b  to blink. While this reporting is under way, the controller  30  turns on the lighting fixture for wide angle cameras  14  or  15  and uses the wide angle camera  25  to take the face picture of a person to be authenticated. 
     When the face picture is shot, execution makes a transition to Mode 5. The LED group  47   b  blinking in Mode 4 is now lit and the next LED group  47   c  is blinking. Mode 5 means the end of face image-pickup and start of eye image-pickup. Based on Mode 5, the controller  30  uses the pattern matching technique to obtain the position of the right eye of the person to be authenticated from the face image, calculate the coordinates of the right eye obtained, orient the illuminating direction of the iris lighting fixture  12  or  13  toward the coordinates of the eye position, adjust the orientation of the motor for tilt  21  and the mirror for panning  23  then orient the image-pickup direction of the telephotographic camera  22  toward the coordinates of the eye position. 
     In Mode 6, the LED group  47   c  blinking in Mode 5 is now lit and the next LED group  47   d  is blinking. Mode 6 means that an eye image is being shot. Based on Mode 6, the controller  30  uses the telephotographic camera  22  to pick up an enlarged image of the right eye. 
     When the enlarged image of the right eye is shot, execution makes a transition to Mode 7. In Mode 7, the LED group  47   d  blinking in Mode 6 is now lit and the next LED  47   e  is blinking. Mode 7 means the end of pickup of the enlarged image of the right eye and start of authentication (comparison). 
     Based on Mode 7, the controller  30  cuts out an iris image from the enlarged image of the right eye shot. Then the controller compares the iris image with the registered iris image of the right eye of each person authorized to enter the room. When this comparison is complete, execution enter Mode 8 which is the same standby state as Mode 1. 
     In case it has determined that the iris image is blurred and is not appropriate for authentication, the controller  30  executes the auto-focus processing to pick up an iris image again or returns to Mode 4 to start with taking a face picture. In case it has determined that an image of the right eye is not appropriate for authentication, the controller  30  starts with taking a face picture, acquires an iris image of the left eye, then compares the resulting image with registered left eye iris images. The controller does not determine that the person to be authenticated is not a registered person via a single authentication process but repeats the pickup-and-comparison process as many as the preset number of retries, until it finally determines that the iris image does not pass the authentication and turns on the LED  43 . 
     It is possible to reduce the wait time of a person to be authenticated by reducing the number of retries thus reducing the number of image-pickup times until the person to be authenticated is determined as a registered person and the LED  42  is turned on. In this embodiment, the LEDs  42 ,  43 ,  44  provided outside the recess  41  are not lit and the LED groups in the recess  41  alone are lit from the start of image-pickup to the end of authentication of image-pickup. Thus it is possible to fix the sight line of the person to be authenticated within the recess  41 . This shortens the time to determination of the person to be authenticated as a registered person thus reducing the workload of the person to be authenticated. 
     Embodiment 2 
       FIG. 6A  is a front view of sight line guiding unit for iris image pickup  50  according to the second embodiment of the invention. The sight line guiding unit for iris image pickup  50  differs from the sight line guiding unit for iris image pickup  40  according to the first embodiment in that concave sections  51   a ,  51   b  are provided in the center of each of the upper wall  51 U and the lower wall  51 D among the walls forming the recess  51 . The concave sections  51   a ,  51   b  are provided to align with the radial LED groups  47   a ,  47   d.    
     With this configuration, when a tall person to be authenticated comes too close to the sight line guiding unit for iris image pickup  50 , the upper end of each of the right/left bar LED groups  45 ,  46  is hidden by the upper wall  51 U as shown in  FIG. 6B . On the other hand, the central radial LED group  47   a  is seen in its entirety because the concave section  51  is provided. The person to be authenticated finds that the length of the LED group  45 ,  46  is not equal to the length from the upper end of the LED group  47   a  to the lower end of the LED group  47   d . Thus the person to be authenticated easily knows that he/she is too close to the iris authentication apparatus. 
     Embodiment 3 
       FIG. 7A  is a front view of sight line guiding unit for iris image pickup  60  according to the third embodiment of the invention. The sight line guiding unit for iris image pickup  60  differs from the sight line guiding unit for iris image pickup  40  according to the first embodiment in that the length from the upper end of the LED group  47   a  to the lower end of the LED group  47   d  is longer than the length of the right/left LED group  45 ,  46 . 
     In case a tall person to be authenticated knowing the difference in the length in advance comes too close to a sight line guiding unit for iris image pickup, he/she sees the upper end of the central LED group  47   a  and the right/left bar LED group  45 ,  46  at the same level as shown in  FIG. 7B . In this case also, the person to be authenticated easily knows that he/she is too close to the iris authentication apparatus. 
     While iris authentication apparatus where a controller  30  for performing authentication (comparison) of iris images is integrally mounted on the iris image pickup apparatus for iris images pickup has been taken as an example in the aforementioned embodiments, the embodiments can be applied to iris authentication apparatus where a processor for performing authentication is provided separately from iris image pickup apparatus and where the processor receives iris image data acquired by the iris image pickup apparatus and a processor for authentication performs authentication. 
     While the LEDs for decision  42 ,  43 ,  44  are provided outside the recess  41  in the aforementioned embodiments, states of the LED group  47  maybe used without providing the LEDs for decision  42 ,  43 ,  44 . In this case, absence of external indicators provides a simpler appearance and fixes the line of sight of a person to be authenticated to the inside of the recess  41 , which is a favorable configuration. 
     According to the invention, it is possible to provide iris image pickup apparatus and iris authentication apparatus which can fix the line of sight of a person to be authenticated while the iris image of the person to be authenticated is being shot and which can reduce the iris image pickup times to shorten the processing time to completion of authentication.

Technology Category: 3