JP2010267121A - Iris imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enlarge an area of an iris which is an authentication target when the iris is covered with an upper lashes or an upper eyelid, and to improve an authentication rate. <P>SOLUTION: An iris imaging device is configured with a camera 20 that takes an image of the iris of a user, and a sight line orientation section 30 that is provided at an upper side with respect to an optical axis of the camera, and the line of sight of the user is directed to the upper side with respect to the optical axis of the camera. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an iris photographing apparatus used for iris (iris) authentication, which is one of biometric authentication techniques.

  In principle, the iris authentication is performed by detecting an iris or a pupil from captured image data using a circle having a shape thereof, and extracting a characteristic portion necessary for the authentication from the detected iris. For this reason, in a general iris photographing apparatus, the shape of the iris of the image data is made as close to a circle as possible by matching the optical axis of the camera of the iris photographing apparatus with the user's line of sight.

  A conventional general iris photographing apparatus will be described with reference to FIG. FIG. 7 is a schematic diagram of a conventional iris photographing apparatus.

  The iris photographing apparatus 110 includes a camera 120 and a line-of-sight directing unit 130.

  The camera 120 captures the user's eyes 80 and outputs image data. The camera 120 includes, for example, an image sensor such as a charge coupled device (CCD) and a photographing lens.

  The line-of-sight directing means 130 is provided on a surface (hereinafter, referred to as “device front surface”) 110 a facing the user of the iris photographing apparatus 110. The line-of-sight directing means 130 is an instrument that causes the user to gaze at the time of photographing the iris. The line-of-sight directing means 130 is configured by a mirror, an LED, or the like.

  The iris photographing apparatus 110 is provided near the intersection (indicated by III in the figure) between the apparatus front surface 110a and the optical axis of the camera 120 (indicated by dotted line I in the figure). In this configuration, the user's line of sight (indicated by an arrow II in the figure) is made to coincide with the optical axis I of the camera 120 by causing the user to gaze at the line-of-sight directing means 130 during shooting.

  In order to improve user convenience, proposals have been made to enable iris authentication even when the user's line of sight and the optical axis of the camera do not match (for example, Patent Documents). 1). According to the technique disclosed in Patent Document 1, when the iris authentication apparatus includes a correction unit and the photographed iris has an elliptical shape, the iris is corrected into a circular shape. For this reason, the iris authentication can be performed even when photographing is performed in a state where the optical axis (I) of the camera and the line of sight (II) of the user do not match.

JP 2007-11667 A

  However, in the conventional iris photographing apparatus described with reference to FIG. 7, even if the optical axis of the camera and the line of sight of the user coincide with each other, for example, when the eyelashes are on the iris, the eyelash portion becomes a noise component. In some cases, the rejection rate increases.

  Further, depending on the algorithm for performing the iris authentication, not only the eyelashes themselves but also the portion where the iris between the eyelashes is exposed may be excluded from the authentication target area. In this case, as a result, the area of the iris to be authenticated decreases more than the area of the eyelash itself, leading to an increase in the rejection rate.

  In order to solve this problem, it is conceivable as one countermeasure to have the user open his eyes wide. However, this measure cannot solve the above-mentioned problem for users who cannot open their eyes wide or who have long eyelashes and are likely to suffer from iris.

  In addition, forcing the user to open his / her eyes means a decrease in convenience for the user.

  Therefore, the inventors of this application have conducted extensive research and found that when the user's line of sight is directed upward with respect to the optical axis of the camera, the rejection rate can be reduced and the authentication rate can be improved. . The reason for this will be described with reference to FIG.

  In general, the eyelashes 88 on the upper eyelid 84 (upper eyelashes) 88 are longer than the eyelashes 90 on the lower eyelid 86 (lower eyelashes) 90. Further, the upper eyelashes 88 may extend from the upper eyelid 84 so as to wind upward, and some people may extend so as to hang downward. On the other hand, the lower eyelash 90 mostly extends so as to hang downward from the lower eyelid 86, and rarely rolls upward.

  If the user's line of sight (II) coincides with the optical axis (I) of the camera due to the shape of the eyelashes, the iris 82 is covered with the upper eyelashes 88 particularly in the upper part thereof. As a result, the area S1 of the authentication target iris 82 is reduced (see FIG. 8A).

  On the other hand, when the user's line of sight (II) is directed upward with respect to the optical axis (I) of the camera, the influence of concealment of the iris 82 by the upper eyelash 88 is reduced, and therefore the area S2 of the iris 82 to be authenticated. Becomes larger (see FIG. 8B).

  Further, if the angle (elevation angle) of the optical axis (I) of the camera with respect to the user's line of sight (II) is 20 ° or less, the elevation angle is 0 °, that is, the user's line of sight is It has also been reported that there is almost no difference in performance compared to the case where the optical axis of the camera is coincident (for example, IRIS RECOGNITION STUDY 2006 (IRIS06) (http://www.authenti-corp.com/ Fig. 6-32 of iris06 / report / IRIS06_final_report_v1-0_20070901.pdf).

  In this way, if the user's line of sight is directed upward with respect to the optical axis of the camera, the rejection rate can be improved.

  The present invention has been made in view of the above-described problems, and the object of the present invention is to increase the area of the iris to be authenticated when the user's iris is covered with upper eyelashes or upper eyelids. Then, it is to provide an iris photographing apparatus that lowers the person rejection rate, that is, improves the authentication rate.

  In order to achieve the above-described object, an iris photographing apparatus according to the present invention includes a camera that photographs a user's iris, and line-of-sight directing means provided above the optical axis of the camera. .

  According to another preferred embodiment of the iris photographing apparatus of the present invention, the iris photographing device includes a camera for photographing the user's iris and a gaze directing means, and the gaze directing means with respect to the optical axis of the camera. The position in the vertical direction is variable, and the line-of-sight directing means can be disposed above the optical axis of the camera.

  According to another preferred embodiment of the iris photographing apparatus of the present invention, the iris photographing apparatus includes a camera for photographing the user's iris and a gaze direction directing unit, and the gaze direction directing unit has a plurality of positions in different vertical directions. The light emitting means is provided, and at least one light emitting means is provided on the upper side with respect to the optical axis of the camera, and at the time of photographing the iris, any one of the plurality of light emitting means emits light and serves as a line-of-sight directing means. .

  According to another preferred embodiment of the iris photographing apparatus of the present invention, the iris photographing apparatus includes a camera for photographing the user's iris and a line-of-sight directing means, and the camera is located on an arc centered on the iris photographing possible position. It is movable and the line-of-sight directing means can be arranged above the optical axis of the camera.

  In the implementation of the above-described iris photographing apparatus, preferably, an autofocus function is further provided with a distance measuring unit that measures the distance from the camera to the user, and the camera performs focus control using the measurement result in the distance measuring unit. It is preferable to provide an auto-zoom function for controlling the photographing magnification using the measurement result.

  Further, in the implementation of the above-described iris photographing apparatus, preferably, an iris dictionary storing the iris data of both eyes of the registrant and eye image cutout means for obtaining the iris data of both eyes from the image data photographed by the camera. It is good to further include.

  According to the iris photographing apparatus of the present invention, when the user's line of sight is directed upward with respect to the optical axis of the camera, the influence of the concealment of the iris by the upper eyelash is reduced, so that the area of the iris to be authenticated is large. As a result, the rejection rate can be reduced and the authentication rate can be improved.

  Further, when the vertical direction position of the line-of-sight directing means with respect to the optical axis of the camera is variable and the line-of-sight directing means can be arranged on the upper side with respect to the optical axis of the camera, the iris by the upper eyelash or the upper eyelid It is possible to shoot in an appropriate state according to the size of the concealment effect, which leads to further improvement of the authentication rate.

  In addition, the iris photographing apparatus further includes a distance measuring unit that measures the distance from the camera to the user, and the camera performs focusing control using a measurement result in the distance measuring unit, and a measurement result. If an auto-zoom function that controls the shooting magnification using is provided, the shootable range is expanded and the convenience for the user is improved.

  Further, if an iris dictionary storing iris data of both eyes of the registrant and eye image cutout means for acquiring iris data of both eyes from image data taken by the camera are further provided, authentication with one eye cannot be performed. In this case, since the data of the other eye can be used as it is, it is not necessary to perform the imaging process again, and the time for authentication can be shortened.

It is a schematic diagram of the iris imaging device of 1st Embodiment. It is a block diagram of the iris imaging device of a 1st embodiment. It is a block diagram of the iris imaging device of a 2nd embodiment. It is a block diagram of the iris imaging device of a 3rd embodiment. It is the schematic diagram and block diagram of the iris imaging device of 4th Embodiment. It is the schematic diagram and block diagram of the iris imaging device of 5th Embodiment. It is a schematic diagram of the prior art example of an iris imaging device. It is a schematic diagram explaining the relationship between the optical axis of a camera, and a user's eyes | visual_axis.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the arrangement relationship of each component is merely schematically shown to the extent that the present invention can be understood. In the following, a preferred configuration example of the present invention will be described. However, numerical conditions and the like are merely preferred examples. Therefore, the present invention is not limited to the following embodiments, and many changes or modifications that can achieve the effects of the present invention can be made without departing from the scope of the configuration of the present invention.

(First embodiment)
With reference to FIG.1 and FIG.2, the iris imaging device of 1st Embodiment is demonstrated. FIG. 1 is a schematic diagram of an iris photographing apparatus showing a relationship between a user's line of sight and an optical axis of a camera included in the iris photographing apparatus. FIG. 2 is a block diagram of the iris photographing apparatus.

  The iris photographing apparatus 10 includes a camera 20, a distance measuring unit 22, an illumination unit 24, a line-of-sight directing unit 30, a control unit 40, and an iris database (DB) 70. The controller 40 includes, for example, a central processing unit (CPU) and storage means such as a ROM (Read Only Memory) and a RAM (Random Access Memory). When the control unit 40 executes the program stored in the storage unit, the distance determining unit 50, the imaging control unit 52, the image processing unit 54, the iris feature extracting unit 56, the iris collating unit 58 and the result are provided as functional units. The output means 60 is realized.

  The camera 20 shoots the user's eyes 80 including the iris in response to an instruction from the control unit 40, and outputs image data. The camera 20 includes, for example, an image sensor such as a charge coupled device (CCD) and a photographing lens. The image data output from the camera 20 is sent to the control unit 40.

  The distance measuring unit 22 measures the distance from the camera 20 to the user using, for example, the principle of three-point surveying using infrared light. The distance information measured by the distance measuring unit 22 is sent to the control unit 40.

  The illumination unit 24 irradiates the user with light having a luminance appropriate for photographing the iris. The irradiation of light to the user and the adjustment of the luminance of the irradiated light are performed in response to an instruction from the control unit 40. The illumination unit 24 is composed of, for example, a light emitting diode (LED), and the luminance is determined according to the magnitude of the current flowing through the LED.

  The line-of-sight directing means 30 is provided on a surface (hereinafter, referred to as “device front surface”) 10 a facing the user of the iris photographing apparatus 10. The line-of-sight directing means 30 is an instrument that causes the user to gaze at the time of photographing the iris. The line-of-sight directing means 30 is configured by a mirror, an LED, or the like.

  In the iris photographing apparatus 10 of this embodiment, the optical axis of the camera 20 is tilted at a predetermined angle vertically upward with respect to the horizontal direction, and the line-of-sight directing means 30 includes the optical axis of the camera 20 and the apparatus. It is provided above the intersection (indicated with III in the figure) with the front surface 10a.

  The distance determination unit 50 uses the distance information received from the distance measuring unit 22 to determine whether or not the distance between the camera 20 and the user is within the shootable range. When the distance between the camera 20 and the user is within the shootable range, the determination result is sent to the imaging control means 52.

  When receiving the determination result from the distance determination unit 50, the imaging control unit 52 controls the camera 20 and the illumination unit 24. Under the control of the imaging control unit 52, the camera 20 and the illumination unit 24 perform shooting while irradiating the user with light having appropriate luminance.

  The image processing means 54 has a function of cutting out the iris from the image data received from the camera 20. The image processing unit 54 sends the extracted iris information to the iris feature extraction unit 56.

  The iris feature extraction unit 56 extracts feature data (also referred to as iris data) used for matching from the iris information cut out by the image processing unit 54. The iris feature extraction means 56 sends the feature data of the user's iris to the iris collation means 58.

  The iris collating unit 58 compares the user's iris feature data received from the iris feature extracting unit 56 with the registrant's iris feature data read from the iris DB 70 to perform personal authentication. In the iris DB 70, the feature data of the registrant's iris is stored in advance so as to be readable. The result of the iris collation by the iris collating unit 58 is sent to the result output unit 60.

  The result output means 60 outputs the result of personal authentication by the iris collating means 58.

  In addition, since the iris authentication process performed by each function means of the control unit 40 is publicly known, detailed description thereof is omitted here.

  According to the configuration of the first embodiment, when a user who is in the camera's imageable range gazes at the line-of-sight directing means 30 when shooting an iris, the user's line of sight coincides with the optical axis of the camera. do not do. Further, when the user's line of sight is directed in the horizontal direction, the optical axis of the camera is inclined upward at a predetermined angle with respect to the horizontal direction, and the iris is photographed from the lower side. For this reason, since the influence of the concealment of the iris by the upper eyelash is reduced, the area of the iris to be authenticated is increased, and as a result, the rejection rate of the principal can be reduced and the authentication rate can be improved.

  In the first embodiment, an example in which the user's line of sight is horizontal and the optical axis of the camera is tilted at a predetermined angle is shown, but the present invention is not limited to this example. Considering the convenience of the user, it is preferable that the user's line of sight is horizontal, but the optical axis of the camera is horizontal and the user's line of sight is inclined upward at a predetermined angle with respect to the horizontal direction. good.

  Further, it is sufficient that the user gazes at the line-of-sight directing means 30 so that the line of sight is directed above the optical axis of the camera. The line-of-sight directing means 30 is not necessarily provided on the front surface 10a of the apparatus. May be.

  When the angle formed by the user's line of sight and the optical axis of the camera is increased, a means such as circular correction as disclosed in Patent Document 1 may be required. The authentication rate depends on not only the angle between the user's line of sight and the optical axis of the camera, but also the quality of the image, the algorithm used for authentication, the state of the user's eyelids and eyelashes, etc., but according to the report of IRIS06 For example, the angle formed by the user's line of sight and the optical axis of the camera can be about 20 degrees.

(Second Embodiment)
With reference to FIG. 3, the iris imaging device of 2nd Embodiment is demonstrated. FIG. 3 is a block diagram of the iris photographing apparatus.

  The iris photographing apparatus of the second embodiment is different in that the camera 21 is configured to have an autofocus function and an autozoom function, and that the control unit 42 further includes a zoom / focus change means 62. Since other configurations and functions are the same as those of the iris photographing apparatus according to the first embodiment described with reference to FIGS. 1 and 2, overlapping description is omitted.

  The zoom / focus change means 62 changes the photographing magnification using the distance measurement result obtained by the distance determination means 50. That is, even when the distance from the iris photographing device to the user is different, the area occupied by the iris in the image is maintained within a certain range.

  Information on the photographing magnification set by the zoom / focus changing means 62 is sent to the camera 21. The camera 21 has an auto zoom function, and performs shooting magnification control, for example, by moving the position of the zoom lens using the shooting magnification information. The camera 21 also has an autofocus function, and performs focusing control using information on the distance to the photographer and the photographing magnification.

  According to the configuration of the second embodiment, similarly to the configuration of the first embodiment, since the influence of the concealment of the iris by the upper eyelash is reduced, the area of the iris to be authenticated is increased, and as a result, the person rejection rate The authentication rate can be improved. In the configuration of the first embodiment, since the shooting magnification is not controlled, the distance from the camera to the user at the time of shooting is limited to a narrow range. On the other hand, according to the structure of 2nd Embodiment, it can image | photograph with a suitable magnification according to the distance from a camera to a user. As a result, the restriction on the position of the user at the time of iris photographing is relaxed, and the convenience for the user is improved.

(Third embodiment)
With reference to FIG. 4, the iris imaging device of 3rd Embodiment is demonstrated. FIG. 4 is a block diagram of the iris photographing apparatus.

  In the iris photographing apparatus according to the third embodiment, the control unit 44 further includes eye image clipping means 64 that obtains iris data of both eyes from the image data photographed by the camera 20, and the iris DB 72 stores the eyes of the registrant's eyes. The difference is that the iris data is stored. Since the other configuration is the same as that of the iris photographing apparatus according to the first embodiment described with reference to FIGS.

  The eye image cutout means 64 determines the positions of the right eye and the left eye from the image data. The eye image cutout unit 64 cuts out an image including one eye of the right eye and the left eye from the image data. The cut image data is sent to the image processing means 54.

  The collation process performed by each functional unit of the control unit 44 is performed in the same manner as in the first embodiment. The iris DB 72 stores iris data of the registrant's right eye and left eye, and when the eye image cutout means 64 cuts out an image including one eye (here, the right eye), the iris collating means. 58 collates with the registered iris data of the right eye.

  As a result of the collation, if the person can be recognized, the result output means 60 outputs the result and ends the iris authentication process. On the other hand, when the person cannot be recognized, the eye image cutout unit 64 cuts out an image including the left eye, which is the other eye, and sends the image to the image processing unit 54 to perform a matching process.

  According to the configuration of the third embodiment, similarly to the configuration of the first embodiment, since the influence of the concealment of the iris by the upper eyelash is reduced, the area of the iris to be authenticated is increased, and as a result, the person rejection rate The authentication rate can be improved. Further, according to the configuration of the third embodiment, when the authentication cannot be performed with one eye, the data of the other eye can be used as it is, so that the re-shooting process becomes unnecessary. As a result, the time for authentication can be shortened.

  Here, in addition to the configuration and function of the iris photographing apparatus of the first embodiment, an example in which both eyes can be photographed has been described, but the auto focus function and auto zoom function described in the second embodiment are further provided. It may be configured.

(Fourth embodiment)
In the iris photographing apparatus of each embodiment described above, the angle formed by the user's line of sight and the optical axis of the camera is constant, but the vertical position of the line-of-sight directing means with respect to the optical axis of the camera is variable. There may be. Hereinafter, a configuration example of the fourth embodiment in which the angle formed by the user's line of sight and the optical axis of the camera is variable will be described with reference to FIG. In addition, the description which overlaps with the iris imaging device of 1st Embodiment demonstrated with reference to FIG. 1 and 2 may be abbreviate | omitted.

  FIG. 5A is a schematic diagram of the user's line of sight and the iris photographing apparatus. FIG. 5B is a block diagram of the iris photographing apparatus.

  The iris imaging device 16 includes a line-of-sight directing unit 32 on the device front surface 16a. The line-of-sight directing unit 32 includes a plurality of light emitting units 33a, 33b, and 33c having different vertical positions. At least one of the plurality of light emitting means 33a, 33b, and 33c is provided on the upper side with respect to the optical axis I of the camera.

  The control unit 46 includes line-of-sight changing means 66. The line-of-sight changing unit 66 controls the plurality of light emitting units 33a, 33b, and 33c, and causes any one of the plurality of light emitting units 33a, 33b, and 33c to emit light. At the time of photographing the iris, the light emitting means emitting light among the plurality of light emitting means 33a, 33b and 33c functions as a line-of-sight directing means.

  According to this configuration, the position in the vertical direction of the line-of-sight directing means with respect to the optical axis of the camera is variable, and the line-of-sight directing means can be disposed on the upper side with respect to the optical axis of the camera. Also, if the vertical position of the line-of-sight directing means with respect to the optical axis of the camera is variable, it will be possible to shoot in an appropriate state depending on the effect of concealing the iris by the upper eyelashes and upper eyelids, and the person will be denied Leading to a further reduction in rate.

  Here, in addition to the configuration and function of the iris photographing apparatus of the first embodiment, the example in which the position of the line-of-sight directing means is variable has been described. However, the autofocus function and the autozoom function described in the second embodiment. Or a configuration provided with a function of cutting out images of both eyes described in the third embodiment, or a configuration provided with both.

(Fifth embodiment)
In the iris photographing apparatus of the fourth embodiment, the optical axis I of the camera is fixed, and the user's line of sight is variable. On the other hand, in the iris photographing apparatus of the fifth embodiment, the user's line of sight II is fixed and the optical axis I of the camera is variable.

  FIG. 6A is a schematic diagram of the user's line of sight and the iris photographing apparatus of the fifth embodiment. FIG. 6B is a block diagram of the iris photographing apparatus.

  The iris photographing device 18 includes camera moving means 28 for moving the camera 20 that photographs the user's iris. Further, the control unit 48 includes an optical axis changing unit 68.

  The camera moving means 28 is configured by, for example, an arc-shaped rail. In response to an instruction from the optical axis changing means 68, the camera 20 moves on the camera moving means 28 by any suitable well-known mechanism such as a motor. In this case, the arc of the camera moving means 28 is centered on a certain point (hereinafter referred to as a center point, indicated by IV in the figure) within the camera's imageable range, and when the camera moves, The optical axis I moves so as to pass through the center point. Further, the line-of-sight directing means 30 can be arranged on the upper side with respect to the optical axis I of the camera.

  According to the configuration of the fifth embodiment, in addition to the effect of the fourth embodiment, since the direction of the line of sight is fixed, there is no need for the user to move the line of sight, and the convenience is improved. can get.

  Here, in addition to the configuration and function of the iris photographing apparatus of the first embodiment, the example in which the position of the optical axis is variable has been described. However, the auto focus function and the auto zoom function described in the second embodiment are provided. You may make it the structure provided with the structure, the structure provided with the function which extracts each image of both eyes demonstrated in 3rd Embodiment, or both.

10, 16, 18, 110 Iris photographing device
20, 21, 120 Camera 22 Distance measuring unit 24 Illuminating unit 28 Camera moving means
30, 130 Gaze direction means
32 Line-of-sight directing section 33a, 33b, 33c Light emitting means
40, 42, 44, 46, 48 Control unit 50 Distance determination means 52 Imaging control means 54 Image processing means 56 Iris feature extraction means 58 Iris collation means 60 Result output means 62 Zoom / focus change means 64 Eye image cutout means 66 Gaze change Means 68 Optical axis changing means 70, 72 Iris DB
80 User's Eye 82 Iris 84 Upper Eyelid 86 Lower Eyelid 88 Upper Eyelash 90 Lower Eyelash

Claims (6)

A camera that captures the user's iris;
An iris photographing apparatus comprising: a line-of-sight directing means provided above the optical axis of the camera. A camera that captures the user's iris;
Eye gaze directing means,
Iris photography characterized in that the vertical position of the line-of-sight directing means with respect to the optical axis of the camera is variable, and the line-of-sight directing means can be arranged above the optical axis of the camera. apparatus. A camera that captures the user's iris;
A line-of-sight directing unit,
The line-of-sight directing unit includes a plurality of light emitting means having different vertical positions,
At least one of the light emitting means is provided above the optical axis of the camera,
At the time of photographing the iris, any one of the plurality of light emitting means emits light and serves as a line-of-sight directing means. A camera that captures the user's iris;
Eye gaze directing means,
The camera is movable on an arc centered at a position where an iris can be photographed;
An iris photographing apparatus characterized in that the line-of-sight directing means can be arranged above the optical axis of the camera. A distance measuring unit for measuring a distance from the camera to the user;
2. The camera according to claim 1, further comprising an autofocus function for performing focusing control using a measurement result obtained by the distance measuring unit, and an auto zoom function for performing photographing magnification control using the measurement result. The iris imaging device as described in any one of -4. An iris dictionary that stores iris data for both registrant eyes,
The iris photographing apparatus according to any one of claims 1 to 5, further comprising eye image cutout means for obtaining iris data of both eyes from image data photographed by the camera.

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