JP2007037617A - Illumination apparatus and ocular image input unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illumination apparatus and an ocular image input unit which keep the illuminance of a subject constant regardless of the surrounding environment and distance to the subject and which input a clear image with constant brightness without increasing electric power consumption necessary for illumination. <P>SOLUTION: The illumination apparatus comprises an illumination section for radiating illumination light to a region of the subject including the eyes, a measurement section for measuring the distance between the illumination section and the subject, and a light modulation section for modulating the illumination angle of the illumination light radiated from the illumination section in accordance with the distance between the illumination section and the subject measured by the measurement section. The light modulation section has, for example, a concave lens 302 and a convex lens 303. By adjusting the distance between the concave lens 302 and the convex lens 303, the illumination angle of the light radiated from the illumination section is modulated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an eye image input device for biometric discrimination / authentication and an illumination device that may be used in the eye image input device.

  In recent years, as a method of personal authentication at the time of access in devices that require high security such as entry / exit management devices and information devices storing important information such as personal information, human fingerprints, irises, fundus blood vessels, facial Various authentication methods using so-called biometric information unique to a subject, such as features, blood vessel patterns such as arms and hands, have been put into practical use.

  As one of them, an authentication method using the difference in eyelid pattern of the iris portion of the eye (hereinafter, this authentication method is referred to as “iris authentication method”) has been proposed and put into practical use.

  In this iris authentication method, the eye of the subject and its surroundings are illuminated with near-infrared illumination or the like, and an image of an area including the eye of the subject (hereinafter referred to as “eye image”) is captured using a camera. Then, an iris region is extracted from the obtained eye image, and authentication information encoded so that the difference in the eyelid pattern of the iris portion is expressed as numerical information is created, and this authentication information is registered in advance as authentication information ( Hereinafter, it is compared with “registered authentication information”). As a result of the comparison and collation, when it is determined that they match each other, the subject is authenticated as a person who has been registered in advance (see, for example, Patent Document 1). In addition, since the iris image can obtain the clearest image in the near-infrared wavelength region, many of the devices that capture the eye image used at this time have a visible light cut filter attached to the lens.

  This iris authentication method has been widely put into practical use as an authentication method in places where high reliability such as a low identity rejection rate and a low acceptance rate for others and high security is required, and has demonstrated excellent effects.

  On the other hand, in an authentication apparatus that performs personal authentication by the iris authentication method as described above, an eye image that can be authenticated by the authentication apparatus, that is, an eye image in which the iris of the subject is clearly captured at an appropriate position and in an appropriate size is obtained. Must be incorporated into the authentication device.

  For that purpose, it is required to irradiate an appropriate amount of illumination to the peripheral region of the eye centered on the iris of the subject. For example, if the amount of light applied to the peripheral region of the eye centering on the iris of the subject is small, clear image information cannot be acquired with sufficient contrast, and conversely if too much light is applied, so-called halation is caused. As a result, a phenomenon occurs in which light irregularly reflected on a CCD (Charge Coupled Device) surface causes image formation to blur, so that clear image information cannot be acquired.

Therefore, in order to irradiate an appropriate amount of illumination to the peripheral region of the eye centered on the iris of the subject, for example, a method of controlling the output of the light source according to the distance from the light source to the subject has been proposed (for example, patents) Reference 2).
Japanese Patent No. 3307936 JP 2001-358987 A

  According to the above-described conventional technology, the distance from the camera to the subject is measured using the distance measuring unit capable of measuring the distance to the object, and the illumination unit capable of changing the illumination intensity of the illumination light. By changing the illumination intensity based on the measured distance, the illuminance in the region including the subject's eyes can be kept constant. However, in the above-described conventional technology, there is a problem that the illumination intensity must be increased as the distance to the subject increases, and the power consumption in the illumination unit increases.

  The present invention has been made in view of such problems, and it is an object of the present invention to provide an illumination device and an eye image input device that can maintain a constant illuminance in a region including an eye of a subject without changing illumination intensity. And

  An illumination device according to the present invention includes an illumination unit that irradiates illumination light to a region including the subject's eyes, a measurement unit that measures a distance from the illumination unit to the subject, and an illumination unit that irradiates the illumination unit according to the distance. A light control unit is provided that changes the illumination angle of light to make the illuminance of a region including the eye of the subject constant.

  With this configuration, the amount of light applied to the region including the subject's eyes is adjusted according to the distance from the illumination unit measured by the measurement unit to the subject, and the power consumption in the region including the subject's eyes is increased without increasing power consumption. The illuminance can be kept constant.

  Moreover, the light control part is good also as a structure provided with the lens part. According to this configuration, it is possible to maintain a constant illuminance in a region including the subject's eyes by using a lens that is a general-purpose and easily available general component.

  In addition, the lens unit includes a plurality of lenses, and further includes a lens control unit that moves all or part of the plurality of lenses according to the distance from the illumination unit measured by the measurement unit to the subject. It is good also as a structure which made all or one part movable. According to this configuration, the lens unit is configured by a plurality of lenses that are general and easily available general parts, and all or a part of the plurality of lenses is moved according to the distance from the illumination unit to the subject. With this simple configuration, the illuminance in the region including the subject's eyes can be maintained constant.

  Moreover, the light control part is good also as a structure provided with the concave mirror. According to this configuration, the illuminance in the region including the eye of the subject can be maintained constant by the concave mirror, which is a general-purpose and easily available general part.

  Moreover, it is good also as a structure which changed the space | interval of an illumination part and a concave mirror by making any one or both of an illumination part and a concave mirror movable. According to this configuration, the dimming unit is configured by the concave mirror that is a general and easily available general part, and the distance between the lighting unit and the concave mirror is changed according to the distance from the lighting unit to the subject. With the configuration, the illuminance in the region including the subject's eyes can be kept constant.

  The eye image input device of the present invention is characterized by including the above-described illumination device of the present invention.

  According to this configuration, the illuminance in the area including the subject's eyes can be constantly maintained, and a clear eye image can be input with constant brightness regardless of the distance to the subject.

  Further, the illumination method of the present invention is an illumination method by an illumination device including a dimming unit having a plurality of lenses and an illumination unit that irradiates illumination light, and measuring a distance from the illumination unit to a subject; Calculating a moving amount of the lens for making the illuminance of the area including the eye of the subject substantially constant based on the measured distance, moving the lens based on the calculated moving amount, and Irradiating illumination light to a region including the eye.

  According to this method, in an illuminating device including a dimming unit having a plurality of lenses and an illuminating unit that irradiates illumination light, irradiation that irradiates a region including the eye of the subject according to the distance from the illuminating unit to the subject It is possible to maintain a constant illuminance in an area including the subject's eyes without adjusting the amount of light and increasing the power consumption.

  Further, the illumination method of the present invention is an illumination method by an illumination device including a light control unit having a concave mirror and an illumination unit that irradiates illumination light, the step of measuring the distance from the illumination unit to the subject, and the measurement Calculating an interval between the illumination unit and the concave mirror to make the illuminance of the region including the eye of the subject substantially constant based on the determined distance, and setting the interval between the illumination unit and the concave mirror to the calculated interval And a step of irradiating illumination light to a region including the eye of the subject.

  According to this method, in an illuminating device including a dimming unit having a concave mirror and an illuminating unit that illuminates illuminating light, the amount of irradiation light that irradiates an area including the eye of the subject according to the distance from the illuminating unit to the subject It is possible to keep the illuminance constant in the region including the subject's eyes without adjusting and increasing the power consumption.

  According to the present invention, a clear eye image is input with a constant brightness, maintaining a constant illuminance on the subject regardless of the surrounding environment and the distance to the subject, and without increasing the power consumption required for illumination. It is possible to provide an illumination device and an eye image input device that can be used.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
The iris authentication apparatus 100 which is Embodiment 1 of this invention is demonstrated using FIG. FIG. 1 is a diagram showing an overview of the usage status of the iris authentication apparatus 100 according to the first embodiment of the present invention.

  The iris authentication apparatus 100 shown in FIG. 1 includes a camera 201, an illumination unit 210, and a distance measuring unit 202. The iris authentication apparatus 100 includes other parts, but those not directly related to the description here are not shown, and some of them are shown in FIG.

  The camera 201 captures an image of an area including the eye of the subject 134, that is, an eye image, and inputs eye image data to be authenticated by the iris authentication apparatus 100. The camera 201 includes a camera lens unit 126, and the eye image data of the subject 134 is input through the camera lens unit 126. The camera lens unit 126 includes a mechanism for adjusting the focus. Known mechanisms such as autofocus can be applied to this mechanism.

  The camera 201 or the camera lens unit 126 transmits light having a specific wavelength, for example, near-infrared light among reflected light reflected by the subject, and cuts light having other wavelengths. A configuration having a filter is desirable.

  The distance measuring unit 202 measures the distance from the iris authentication device 100 to the subject 134. More precisely, the distance from the camera lens unit 126 of the iris authentication apparatus 100 to the eye position 132 of the subject 134 is measured. This measured distance is used for illumination of the subject 134 by the illumination unit 210 (to be described later), focus adjustment in the camera lens unit 126, and the like.

  As shown in FIG. 1, the distance measuring unit 202 irradiates, for example, a distance measuring light beam 122 toward the subject 134, receives the distance measuring light beam 122 reflected by the subject 134, and the light is reflected on the subject 134. The distance to the subject 134 can be measured by detecting the time for reciprocating between and the phase difference between the irradiated light and the reflected light. Alternatively, the distance measuring light beam 122 is not necessarily limited to the light beam, and may be electromagnetic waves other than visible light such as directional sound waves or ultrasonic waves. The distance measuring unit 202 may measure the distance to the subject 134 based on a so-called triangulation principle, or measure the distance to the subject 134 by other methods such as a distance measuring method using ultrasonic waves. It doesn't matter.

  The illumination unit 210 irradiates the illumination light beam 124 to the eye position 132 of the subject 134 so that the camera 201 can acquire an eye image of the subject 134 with sufficient brightness. The illumination unit 210 also includes a lens unit 233, and the lens unit 233 adjusts the spread angle of the illumination light beam 124. The adjustment of the spread angle of the illumination light beam 124 is performed using the lens unit 233 of the illumination unit 210 based on the distance information to the subject 134 measured by the distance measurement unit 202. By adjusting the spread angle of the illumination light beam 124, the illuminance at the eye position 132 of the subject 134 can always be kept constant. These will be described in more detail with reference to FIG.

  FIG. 2 is a schematic configuration diagram of the iris authentication device 100 according to the first embodiment of the present invention.

  As shown in FIG. 2, the iris authentication apparatus 100 is photographed by the photographing unit 204 that photographs an eye image of the subject 134, the illumination unit 210 that irradiates the illumination light beam 124 to the eye position 132 of the subject 134, and the photographing unit 204. And an authentication unit 250 that authenticates the eye image of the subject 134. The iris authentication apparatus 100 also includes other parts, but the description is omitted because it is not directly related to the present invention.

  The photographing unit 204 includes a camera 201, a distance measuring unit 202, and an AF control unit 203 that is an automatic focus control unit.

  The camera 201 captures an image of an area including the eye of the subject 134, acquires eye image data to be authenticated by the iris authentication apparatus 100, and sends the eye image data to the authentication unit 250. The camera 201 includes a camera lens unit 126, and the eye image data of the subject 134 is input through the camera lens unit 126. The camera lens unit 126 has a function of adjusting the focus. This focus adjustment is based on the distance from the camera lens unit 126 of the iris authentication apparatus 100 measured by the distance measuring unit 202 to the eye position 132 of the subject 134. , AF controller 203 performs.

  The illumination unit 210 includes a light source unit 234, a lens unit 233, a lens control unit 232, and an illumination control unit 211.

  The light source unit 234 is a light source that emits directional light that is the basis of the irradiation light beam 124 and is preferably close to a point light source, but is not necessarily limited to a point light source, and may have some emission area or emission volume. It may be a light source having Examples of the light source include a light emitting diode (LED) that emits near-infrared light.

  The lens unit 233 is configured by a concave lens, a convex lens, or a combination thereof, and all or a part of these lenses are configured to be movable in the optical axis direction.

  The distance data from the camera lens unit 126 of the iris authentication apparatus 100 measured by the distance measuring unit 202 of the imaging unit 204 to the eye position 132 of the subject 134 is input to the illumination control unit 211 of the illumination unit 210, and the illumination control unit 211 Based on this data, the extent of the illumination light beam 124 that should be irradiated with the light beam emitted from the light source unit 234 is calculated, and the illumination light beam 124 having such a spread is irradiated. Calculates the position where the lens of the lens unit 233 should be arranged, and sends the lens position information to the lens control unit 232. The lens control unit 232 receives the lens position information from the illumination control unit 211 and performs control so that the lens of the lens unit 233 is arranged at a designated position based on the lens position information.

  As a result, the light emitted from the light source unit 234 is applied to the eye position 132 of the subject 134 as an illumination light beam 124 having an appropriate spread. The appropriate spread angle of the illumination light beam 124 and the lens position at that time are most closely related to the essence of the present invention, and will be described in detail later.

  The authentication unit 250 inputs the eye image data photographed by the photographing unit 204 and authenticates whether or not the eye image data belongs to the valid subject 134.

  The authentication unit 250 includes a preprocessing unit 251, an iris position detection unit 252, an iris image acquisition unit 253, an iris information registration unit 254, an iris information database 255, an iris authentication processing unit 256, and an authentication result output unit 257. The authentication unit 250 has other parts, but the description is omitted because it is not directly related to the essence of the present invention.

  The pre-processing unit 251 extracts an image signal component from the electrical signal input from the camera 201, performs image quality adjustment on contrast, focus, and the like, performs necessary processing such as gain adjustment, and then sends the iris position detection unit 252 with it. Output.

  The iris position detection unit 252 detects the position of the pupil from the eye image data received from the preprocessing unit 251, and detects the position of the iris based on the detected position of the pupil. As a method for detecting the position of the pupil from the image data and a method for detecting the position of the iris, there are generally known methods such as a method using template matching or a method using circular integration (Japanese Patent Publication No. 8-504979). Technology can be used. The iris position detection unit 252 appropriately detects the iris position only when the position of the detected pupil is at the center of the entire eye image and can be detected stably for a certain time (for example, about 0.5 seconds). It can also be determined that the position has been detected.

  The iris image acquisition unit 253 receives information indicating that the iris position has been detected from the iris position detection unit 252 and information indicating the position, and acquires iris image data based on the position information. The acquisition of the iris image data can be executed by, for example, cutting out a specific range from the image data that has been preprocessed by the preprocessing unit 251 based on information indicated by the iris position data.

  The iris image data acquired by the iris image acquisition unit 253 is sent to the iris information registration unit 254. The iris information registration unit 254 sends the iris image data to the iris authentication processing unit 256, and at the same time, registration to the iris information database 255 is performed. . This is because the iris image data authenticated by the iris authentication device 100 is stored in a database together with other various data and used in the iris authentication processing in the iris authentication processing unit 256. This is because information relating to a large amount of iris image data performed is accumulated and used for later authentication to improve the accuracy of iris authentication.

  The iris authentication processing unit 256 receives the iris image data from the iris information registration unit 254 and authenticates the iris image data. The authentication of the iris image data is performed by cutting out only the image of the iris region from the received iris image data, creating authentication information based on the iris pattern of the iris part, and the registration authentication information registered in the iris information database 255 in advance. The created authentication information is compared and checked, and it is determined whether or not the subject 134 is a registrant by determining whether or not they match each other. The determination as to whether or not they match is made with a certain limit threshold set, and the determination result is registered in the iris information database 255 for use in improving the accuracy of subsequent determinations.

  The iris information database 255 is a recording device that records information by combining magnetic principles, optical principles, other physicochemical principles, or a combination thereof, such as an HDD (Hard Disk Drive), a DVD (Digital Versatile Disk), or For example, iris image data is stored together with authentication data and other related data in various known recording devices such as a recording device using various semiconductor memories represented by RAM (Random Access Memory).

  The authentication result output unit 257 outputs the result of the iris authentication performed by the iris authentication processing unit 256, that is, the determination result of whether or not the subject 134 is a valid registrant. The output form may be displayed on some visible display device, sent out as an electronic signal or information to other devices, devices, systems, or the like, or may be performed in combination.

  Note that the authentication unit 250 and the preprocessing unit 251, the iris position detection unit 252, the iris image acquisition unit 253, the iris information registration unit 254, the iris information database 255, the iris authentication processing unit 256, and the authentication result output unit Regarding the functions of 257 and other parts, for example, a method known so far as described in Patent Document 1 can also be realized.

  Next, based on the distance data from the camera lens unit 126 of the iris authentication apparatus 100 to the eye position 132 of the subject 134 measured by the distance measuring unit 202 of the photographing unit 204, the illumination control unit 211 emits light from the light source unit 234. The spread of the luminous flux as the illumination luminous flux 124 to be irradiated is obtained, the lens arrangement of the lens unit 233 for irradiating the illumination luminous flux 124 having such a spread is determined, and lens position information thereof An embodiment in which control is performed so that the lens of the lens unit 233 is arranged at a designated position based on the above will be described in detail with reference to FIGS.

  3 corresponds to the light source 301 constituting the light source unit 234 of the illumination unit 210, the concave lens 302 and the convex lens 303 constituting the lens unit 233, and the eye position 305 of the subject 134 (corresponding to the eye position 132 of the subject 134 in FIG. 1). It is the schematic which shows an example of the positional relationship with this. FIG. 4 is an enlarged view showing the positional relationship between the light source 301 and the concave lens 302 and the convex lens 303 constituting the lens unit 233 in more detail. As shown in FIGS. 3 and 4, the light emitted from the light source 301 and passed through the concave lens 302 and the convex lens 303 is irradiated to the eye of the subject 134 through the light path 304.

  5 corresponds to the light source 301 constituting the light source unit 234 of the illumination unit 210, the concave lens 302 and the convex lens 303 constituting the lens unit 233, and the eye position 505 of the subject 134 (corresponding to the eye position 132 of the subject 134 in FIG. 1). 6 is a schematic diagram showing another example of the positional relationship between the concave lens 302 and the convex lens 303 constituting the lens unit 233 in FIG. FIG. Further, as shown in FIGS. 5 and 6, the light emitted from the light source 301 and passing through the concave lens 302 and the convex lens 303 is irradiated to the eye of the subject 134 through the light path 504.

  3 is different from FIG. 5 in that the eye position 305 of the subject 134 and the eye position 505 of the subject 134 are different from each other in the distance from the iris authentication apparatus 100.

  When the eye position 305 of the subject 134 and the eye position 505 of the subject 134 are different in whether they are closer or farther from the iris authentication apparatus 100, the same illumination light beam 124 is always directed toward the eye position 132 of the subject 134. The amount of illumination light actually received by the region including the eye of the subject 134 varies depending on the distance from the iris authentication apparatus 100 to the subject 134, and the eye image captured by the camera 201 is too bright image data. Or the image data becomes too dark, and it is difficult to obtain clear eye image data for authentication.

  Therefore, in the embodiment of the present invention, as shown in an example in FIG. 3, when the eye position 305 of the subject 134 is closer, that is, when the distance L381 between the convex lens 303 and the eye position 305 of the subject 134 is smaller, illumination is performed. The irradiation angle R388 of the light beam 124 is made larger. Thus, it is possible to adjust so that the overexposure caused by the closer eye position 305 of the subject 134 is offset and the clearest eye image data for authentication can be acquired.

  On the other hand, as shown in an example in FIG. 5, when the eye position 505 of the subject 134 is further away, that is, when the distance L581 between the convex lens 303 and the eye position 505 of the subject 134 is larger, the irradiation angle of the illumination light beam 124. Let R588 be smaller. Thus, the underexposure caused by the eye position 505 of the subject 134 being farther away can be offset, and adjustment can be performed so that the clearest eye image data for authentication can be acquired.

  In FIG. 4, when the eye position 305 of the subject 134 is closer, that is, when the distance L381 between the convex lens 303 and the eye position 305 of the subject 134 is smaller, the irradiation angle R388 of the illumination light beam 124 is larger. Therefore, a specific arrangement, that is, a positional relationship, of the light source 301, the concave lens 302, and the convex lens 303 is shown.

  As is well known, when light enters a substance other than air, such as quartz glass, the light is refracted from an incident angle according to the refractive index of the quartz glass. This refractive index is determined by the difference between the traveling speed of light in air and the traveling speed of light in quartz glass. When light exits from quartz glass into the air, it is refracted with a refractive index opposite to that at the time of incidence. The irradiation angle does not change just by moving in parallel.

  However, if the surface of the quartz glass is curved, the refraction angle changes depending on whether light enters or exits the quartz glass. Also changes. This is the principle of the lens.

  Further, as is well known, a lens having a thicker central portion than a peripheral portion is called a convex lens, and when the light beam passes through the convex lens, it is refracted in the direction toward the center of the lens. On the other hand, a lens having a thinner central portion than a peripheral portion is called a concave lens, and refracts away from the center of the lens when a light beam passes through the concave lens. This refraction angle is determined by the refractive index of the material constituting the lens, for example, quartz glass, the curvature of both surfaces of the lens, and the angle at which the light ray enters the lens.

  Therefore, by using a combination of the convex lens and the concave lens, a light beam (for example, an illumination light beam 124 shown in FIG. 1) emitted from a light source (preferably a point light source is not necessarily limited to a point light source). It can be controlled to be an arbitrary angle (for example, R388 shown in FIGS. 3 and 4 and R588 shown in FIGS. 5 and 6). In the following description, the light source is assumed to be a point light source for simplicity.

  For example, as shown in FIG. 3, assuming that the eye position 305 of the subject 134 is relatively close (L381 is relatively small), the amount of irradiation light tends to be relatively large, so the irradiation angle (R388) Unless the value is made relatively large, the irradiation light quantity is kept constant, and a clear image with constant brightness cannot be obtained. Therefore, by narrowing the distance (L383) between the concave lens 302 and the convex lens 303, the irradiation angle (R388) can be increased accordingly. An enlarged view of this state is shown in FIG. Specifically, for example, the refractive indexes of the concave lens 302 and the convex lens 303 are both assumed to be 1.5, and the curvature of the surface of the lens is assumed to be 1/100 for both the concave lens 302 and the convex lens 303 on both sides of the lens. Assuming that the irradiation angle (half width) from the point light source is ± 10 deg, the distance from the light source 301 to the concave lens 302 (L385) is 15 mm, and the distance from the concave lens 302 to the convex lens 303 (L383) is 2.5 mm. Then, the irradiation angle after passing through the concave lens 302 and the convex lens 303 is 18 deg (± 9 deg) according to the simulation result. However, both the concave lens 302 and the convex lens 303 are simulated on the assumption that the lens diameter is 30 mm and the thickness of the central portion is 5 mm.

  On the other hand, for example, as shown in FIG. 5, assuming that the eye position 505 of the subject 134 is relatively far (L581 is relatively large), the irradiation light amount per unit area, that is, the illuminance is the eye position with a constant light source. It tends to decrease according to 505. In order to solve this, the illumination angle (R588) is decreased according to the interval between the illumination unit 210 and the eye position 505, so that the illuminance at the eye position 505 can be maintained constant. Brightness images can be acquired. Specifically, the irradiation angle (R588) can be made relatively small by making the distance (L583) between the concave lens 302 and the convex lens 303 relatively large. An enlarged view of this state is shown in FIG. Specifically, as in FIGS. 3 and 4, for example, the refractive indices of the concave lens 302 and the convex lens 303 are both assumed to be 1.5, and the curvature of the lens surface is determined for both the concave lens 302 and the convex lens 303. It is assumed that both surfaces are the same and 1/100, the irradiation angle (half width) from the point light source is assumed to be ± 10 deg, and the distance (L385) from the light source 301 to the concave lens 302 is assumed to be 15 mm.

  3 and 4, assuming that the distance (L583) from the concave lens 302 to the convex lens 303 is 37.0 mm, the irradiation angle after passing through the concave lens 302 and the convex lens 303 is based on the simulation results. 10 deg (± 5 deg). However, in both the concave lens 302 and the convex lens 303, the simulation is performed in the same manner as in FIGS. 3 and 4, assuming that the diameter of the lens is 30 mm and the thickness of the central portion is 5 mm.

  As described above, the light irradiation angle becomes 18 deg when the distance between the concave lens 302 and the convex lens 303 is set to 2.5 mm while the other conditions are the same, and the light is emitted when the distance between the concave lens 302 and the convex lens 303 is set to 37.0 mm. The irradiation angle is 10 deg. For example, when the interval between the concave lens 302 and the convex lens 303 is set to an arbitrary length between 2.5 mm and 37.0 mm, the light irradiation angle can be set within the range of 18 deg to 10 deg. .

  The outline is shown in FIG. FIG. 7 is a diagram showing an outline of the relationship among the distance to the eye of the subject 134, the angle of irradiation light, and the interval between the concave lens and the convex lens. FIG. 7 shows a case corresponding to FIGS. 3 to 6 as an example.

For example, it is assumed that the distance (L381) to the eye of the subject 134 is X ₁ mm (X ₁ <X ₂ ), which is a relatively short distance. The distance (L381) from the subject 134 to the eye corresponds to the distance from the camera 201 to the eye position 132 of the subject 134 in FIG. 1, and is measured by the distance measuring unit 202.

When a relatively small value (L381 = X ₁ mm) is obtained as the distance to the eye of the subject 134, “the distance to the subject's eye and the angle of the irradiation light” shown in the first quadrant of the graph shown in FIG. About 18 deg can be read as the angle (R388) of the irradiation light corresponding to the distance to the eye of the subject 134 (L381 = X ₁ mm). This “graph representing the relationship between the distance to the eye of the subject 134 and the angle of the irradiation light” can be obtained by theoretical calculation or computer simulation.

  Next, when the angle of irradiation light (R388 = 18 deg) is obtained, the “graph showing the relationship between the angle of irradiation light and the interval between the concave lens and the convex lens” shown in the second quadrant of the graph shown in FIG. 7 is used. The distance (L383) between the concave lens 302 and the convex lens 303 corresponding to the angle of irradiation light (R388 = 18 deg) can be read as 2.5 mm. This “graph showing the relationship between the angle of irradiation light and the interval between the concave lens and the convex lens” can also be obtained by theoretical calculation or computer simulation.

Similarly, for example, it is assumed that the distance (L581) to the eye of the subject 134 is X ₂ mm (X ₂ > X ₁ ), which is a relatively long distance. The distance to the eye of the subject 134 (L581) also corresponds to the distance from the camera 201 to the eye position 132 of the subject 134 in FIG. 1, and is measured by the distance measuring unit 202.

When a relatively large value (L581 = X ₂ mm) is obtained as the distance to the eye of the subject 134, “the distance to the subject's eye and the angle of the irradiation light” shown in the first quadrant of the graph shown in FIG. 10 degrees can be read as the angle (R588) of the irradiation light corresponding to the distance to the eye of the subject 134 (L581 = X ₂ mm). This “graph representing the relationship between the distance to the subject's eye and the angle of the irradiation light” can be obtained by theoretical calculation or computer simulation.

  Next, when the angle of irradiation light (R588 = 10 deg) is obtained, the “graph showing the relationship between the angle of irradiation light and the interval between the concave lens and the convex lens” shown in the second quadrant of the graph shown in FIG. 7 is used. 37.0 mm can be read as the distance (L583) between the concave lens 302 and the convex lens 303 corresponding to the angle of irradiation light (R588 = 10 deg). This “graph representing the relationship between the angle of irradiation light and the interval between the concave lens and the convex lens” can also be obtained by theoretical calculation or computer simulation.

In the above description, only the cases where “L381 = X ₁ mm” and “L581 = X ₂ mm” are described as the distance from the camera 201 measured by the distance measuring unit 202 to the eye position 132 of the subject 134. Since this is the same in the case of, detailed description is omitted. In this way, even if the distance from the camera 201 measured by the distance measuring unit 202 to the eye position 132 of the subject 134 is an arbitrary length, the illuminance of the illumination light beam 124 always at the eye position 132 of the subject 134 Can be kept constant and a clear eye image can always be acquired for iris authentication.

  Note that the functions of the pre-processing unit 251, iris position detection unit 252, iris image acquisition unit 253, iris information registration unit 254, iris authentication processing unit 256, and authentication result output unit 257 that constitute the authentication unit 250 are each hardware. Alternatively, each function may be described so as to be realized by software and executed by an arithmetic device or the like. When the respective functions are realized by software, the authentication unit 250 can be configured using a computer loaded with a program for realizing each functional block described above in an arithmetic device.

(Embodiment 2)
Next, an iris authentication apparatus 800 according to the second embodiment of the present invention will be described in detail with reference to FIG. The iris authentication apparatus 800 according to the second embodiment of the present invention is similar to the iris authentication apparatus 100 according to the first embodiment in many respects, and therefore, different parts will be mainly described.

  FIG. 8 is a schematic configuration diagram of an iris authentication device 800 according to the second embodiment of the present invention.

  As illustrated in FIG. 8, the iris authentication apparatus 800 includes a photographing unit 804 that captures an eye image of the subject 134, an illumination unit 810, and an authentication unit 850.

  The imaging unit 804 includes a camera 801, a distance measuring unit 802, and an AF control unit 803. The camera 801, the distance measuring unit 802, and the AF control unit 803 have substantially the same functions as those of the first embodiment of the present invention.

  The authentication unit 850 receives the eye image data captured by the image capturing unit 804 and authenticates whether the eye image data belongs to the valid subject 134. The authentication unit 850 includes a pre-processing unit 851, an iris position detection unit 852, an iris image acquisition unit 853, an iris information registration unit 854, an iris information database 855, an iris authentication processing unit 856, and an authentication result output unit 857. Also, the authentication unit 850 has substantially the same function as that of the first embodiment of the present invention.

  The illumination unit 810 includes a light source unit 834, a mirror unit 833, a light source control unit 832, and an illumination control unit 811.

  The light source unit 834 is a light source that emits directional light that is the basis of the irradiation light beam 124 and is preferably close to a point light source, but a complete point light source is impossible and is not necessarily limited to a point light source. Alternatively, the light source may have a certain light emission area or light emission volume. These are the same as in the first embodiment of the present invention.

  However, in the first embodiment of the present invention, the light source unit 234 is fixed and does not change, but in the second embodiment of the present invention, the position of the light source unit 834 is changed by the control by the light source control unit 832. To do. This will be described in more detail later.

  The mirror unit 833 replaces the lens unit 233 according to the first embodiment of the present invention. The most significant difference between the iris authentication device 800 according to the second embodiment of the present invention and the iris authentication device 100 according to the first embodiment is as follows. Instead of the lens portion 233, a mirror portion 833 is provided.

  The mirror part 833 is, for example, a concave mirror whose cross section is indicated by a parabola, and for example, a parabola having a shape represented by the equation Y = 0.0011 × X × X is used. Can do. However, the parabola is not necessarily limited to the shape represented by the above formula, and the concave mirror is not necessarily limited to the parabola in cross section. For example, a concave mirror having a circular cross section or some other shape may be used. And the concave mirror which comprises this mirror part 833 is being fixed, and does not move.

  In the iris authentication device 800 according to the second embodiment of the present invention, the distance data from the camera lens unit 126 of the iris authentication device 800 to the eye position 132 of the subject 134 measured by the distance measuring unit 802 of the photographing unit 804 is the illumination unit. Based on this data, the illumination control unit 811 inputs a light beam emitted from the light source unit 834 and calculates how wide the illumination light beam 124 should be irradiated. In order to irradiate the illumination light beam 124 having such a spread, the position of the light source of the light source unit 834 with respect to the concave mirror of the mirror unit 833 is obtained by calculation, and the light source position Information is sent to the light source controller 832. The light source control unit 832 receives the light source position information from the illumination control unit 811 and performs control so that the light source of the light source unit 834 is arranged at a designated position based on the light source position information.

  As a result, the light emitted from the light source unit 834 is applied to the eye position 132 of the subject 134 as an illumination light beam 124 having an appropriate spread. The appropriate spread angle of the illumination light beam 124 and the light source position at that time are most closely related to the essence of the present invention, and will be described in more detail.

  9 shows a light source 341 that constitutes the light source unit 834 of the illumination unit 810, a concave mirror 342 that constitutes the mirror unit 833, and an eye position 345 of the subject 134 (corresponding to the eye position 132 of the subject 134 in FIG. 1). It is the schematic which shows an example of positional relationship. As shown in FIG. 9, the light emitted from the light source 341 and reflected by the concave mirror 342 is irradiated to the eye of the subject 134 through the light path 344.

  10 shows a light source 341 constituting the light source unit 834 of the illumination unit 810, a concave mirror 342 constituting the mirror unit 833, and an eye position 555 of the subject 134 (corresponding to the eye position 132 of the subject 134 in FIG. 1). It is the schematic which shows the other example of positional relationship. As shown in FIG. 10, the light emitted from the light source 341 and reflected by the concave mirror 342 is irradiated to the eye of the subject 134 through the light path 554.

  Here, FIG. 9 differs from FIG. 10 in that the eye position 345 of the subject 134 and the eye position 555 of the subject 134 are different depending on whether they are closer or farther from the iris authentication apparatus 800. .

  When the eye position 345 of the subject 134 and the eye position 555 of the subject 134 are different in whether they are closer or farther from the iris authentication apparatus 800, the same illumination light beam 124 is always directed toward the eye position 132 of the subject 134. The amount of illumination light actually received by the eye of the subject 134 varies depending on the distance from the iris authentication apparatus 800 to the subject 134, and the iris image captured by the camera 801 becomes image data that is too bright. Thus, the image data becomes too dark, and it is difficult to obtain clear eye image data for authentication. This is the same as in the first embodiment of the present invention.

  Therefore, in the second embodiment of the present invention, as in the first embodiment, as shown in FIG. 9, the eye position 345 of the subject 134 is closer, that is, the concave mirror 342 and the eye position 345 of the subject 134 are closer to each other. When the distance L391 is smaller, the irradiation angle R398 of the illumination light beam 124 is made larger. As a result, it is possible to eliminate the overexposure due to the eye position 345 of the subject 134 being closer, and to adjust so that the clearest eye image data for authentication can be acquired. For this purpose, the light source 341 is brought closer to the concave mirror 342, and the distance L393 between the light source 341 and the concave mirror 342 is made smaller. For example, the distance L393 between the light source 341 and the apex of the parabola that forms the cross section of the concave mirror 342 can be set to 20 mm.

  Conversely, as shown in an example in FIG. 10, when the eye position 555 of the subject 134 is further away, that is, when the distance L591 between the concave mirror 342 and the eye position 555 of the subject 134 is larger, the irradiation angle of the illumination beam 124. Let R598 be smaller. As a result, it is possible to eliminate the underexposure due to the eye position 555 of the subject 134 being farther away, and to adjust so that the clearest eye image data for authentication can be acquired. For this purpose, the light source 341 is further away from the concave mirror 342, and the distance L593 between the light source 341 and the concave mirror 342 is increased. For example, the distance L593 between the light source 341 and the apex of the parabola that forms the cross section of the concave mirror 342 can be set to 25 mm.

  The method of measuring the distance to the eye position of the subject 134, obtaining the exposure degree from the value, and setting the light source position to adjust so that the clearest eye image data for authentication can be acquired as shown in the above example However, since it is substantially the same as Embodiment 1 of this invention, detailed description is abbreviate | omitted.

  In this way, even if the distance from the camera 801 to the eye position 132 of the subject 134 measured by the distance measuring unit 802 is an arbitrary length, the illuminance of the illumination light beam 124 always at the eye position 132 of the subject 134 It is possible to always obtain a clear eye image for iris authentication.

  In the second embodiment of the present invention, the configuration in which the concave mirror of the mirror unit 833 is fixed and the light source of the light source unit 834 is movable has been described. However, the configuration is not necessarily limited to this, and the distance between the light source and the concave mirror is adjusted by fixing the light source of the light source unit 834 and allowing the concave mirror of the mirror unit 833 to move, whereby light is emitted from the light source. It may be adjusted so that the illuminated light irradiates the eye position 132 of the subject 134 as an illumination light beam 124 having an appropriate spread.

  Alternatively, in another embodiment, the light emitted from the light source has an appropriate spread by fixing both the light source of the light source unit 834 and the concave mirror of the mirror unit 833 and changing the shape of the reflecting surface of the concave mirror. You may adjust so that the eye position 132 of the to-be-photographed object 134 may be irradiated as the illumination light beam 124.

  In still another embodiment, the light beam 124 for illumination in which the light emitted from the light source has an appropriate spread is obtained by combining the configurations described in the first embodiment, the second embodiment, or the other embodiments. It may be adjusted so that the eye position 132 of the subject 134 is irradiated.

  Further, the functions of the pre-processing unit 851, iris position detection unit 852, iris image acquisition unit 853, iris information registration unit 854, iris authentication processing unit 856, and authentication result output unit 857 constituting the authentication unit 850 are respectively hardware. Alternatively, each function may be described so as to be realized by software and executed by an arithmetic device or the like. When each function is realized by software, the authentication unit 850 can be configured by using a computer in which a program for realizing each functional block described above is loaded into an arithmetic device.

  According to the illumination device and the eye image input device according to the present invention, it is possible to maintain the illuminance in the region including the subject's eyes constant regardless of the surrounding environment and the distance to the subject, and to increase the power consumption necessary for illumination. In addition, an illumination device and an eye image input device that can input a clear eye image with a constant brightness can be provided, and industrial applicability is extremely large.

The figure which shows the general view of the use condition of the iris authentication apparatus which is Embodiment 1 of this invention. Schematic configuration diagram of the iris authentication device Schematic showing an example of a positional relationship among a light source, a concave lens, a convex lens, and an eye position of a subject Figure showing the positional relationship among the light source, concave lens, and convex lens in more detail. Schematic showing another example of the positional relationship between the light source, the concave lens, the convex lens, and the eye position of the subject Figure showing the positional relationship among the light source, concave lens, and convex lens in more detail. The figure which shows the outline of the relationship between the distance to a subject's eye, the angle of irradiation light, and the space | interval of a concave lens and a convex lens Schematic configuration diagram of an iris authentication apparatus according to Embodiment 2 of the present invention Schematic showing an example of the positional relationship between the light source, the concave mirror, and the eye position of the subject Schematic showing another example of the positional relationship between the light source, the concave mirror, and the eye position of the subject

Explanation of symbols

100,800 Iris authentication device 122 Distance measuring beam 124 Illuminating beam 126 Camera lens unit 132,305,345,505,555 Eye position (subject) 134 Subject 201,801 Camera 202,802 Distance measuring unit 203,803 AF Control unit 204,804 Imaging unit 210,810 Illumination unit 211,811 Illumination control unit 232 Lens control unit 233 Lens unit 234,834 Light source unit 250,850 Authentication unit 251,851 Preprocessing unit 252,852 Iris position detection unit 253 853 Iris image acquisition unit 254,854 Iris information registration unit 255,855 Iris information database 256,856 Iris authentication processing unit 257,857 Authentication result output unit 301,341 Light source 302 Concave lens 303 Convex lens 304,344,504,554 Light path 34 Concave mirror 832 light source control unit 833 mirror

Claims (8)

An illumination unit that emits illumination light to a region including the subject's eyes;
A measurement unit for measuring a distance from the illumination unit to the subject;
An illuminating device comprising: a light adjusting unit that changes an irradiation angle of light emitted from the illuminating unit in accordance with the distance to make the illuminance of a region including the eye of the subject constant. The lighting device according to claim 1, wherein the light control unit includes a lens unit. The lens unit includes a plurality of lenses.
A lens control unit that moves all or part of the plurality of lenses according to the distance from the illumination unit to the subject measured by the measurement unit;
The lighting device according to claim 2, wherein all or some of the plurality of lenses are movable. The lighting device according to any one of claims 1 to 3, wherein the light control unit includes a concave mirror. The lighting device according to claim 4, wherein either one or both of the illumination unit and the concave mirror is movable to change a distance between the illumination unit and the concave mirror. An eye image input device comprising the illumination device according to any one of claims 1 to 5. An illumination method using an illumination device including a light control unit having a plurality of lenses and an illumination unit that irradiates illumination light,
Measuring a distance from the illumination unit to a subject;
Calculating a movement amount of the lens for making the illuminance of the region including the eye of the subject substantially constant based on the measured distance;
Moving the lens based on the calculated amount of movement;
Irradiating illumination light to a region including the eye of the subject. An illumination method with an illumination device comprising a light control unit having a concave mirror and an illumination unit for illuminating illumination light,
Measuring a distance from the illumination unit to a subject;
Calculating an interval between the illumination unit and the concave mirror for making the illuminance of the region including the eye of the subject substantially constant based on the measured distance;
Setting the distance between the illumination unit and the concave mirror to a calculated distance;
Irradiating illumination light to a region including the eye of the subject.

Images