JP3802892B2 - Iris authentication device - Google Patents

Description

  The present invention relates to an iris authentication device used in a security system or the like.

  There are various types of personal authentication devices used in security systems such as an entrance management system. Iris authentication is a kind of personal authentication based on biometrics. The iris around the pupil of the eye is an iris that works to adjust the amount of light that enters the pupil. Since the iris pattern varies from person to person and the geometric pattern does not change when stretched, the iris pattern can be used for personal authentication. Iris authentication has features such as higher authentication accuracy than other methods, and has already been put to practical use in many environments.

Various conventional iris authentication devices have been proposed (see, for example, Patent Document 1). In order to further improve the authentication accuracy of the iris authentication device, the configuration of the light source, filter, and optical system has been devised, and the detection accuracy of the iris has been improved. In the apparatus disclosed in Patent Document 1, a light emitting diode is used as a light source, and a light emitting diode having a wavelength capable of effectively capturing an image of a subject is used.
JP 2003-157431 A

However, the conventional techniques have the following problems.
The color of the iris is not common to everyone, and when there are many melanin granules present in the iris, it looks from brownish brown to brown, and when there are few melanin granules, it turns from gray to blue. Blacks and yellow races have more pigments and white races have less pigments. Also, if you have a disease that can't make melanin, the blood vessels behind the iris will appear red. In addition, because of individual differences, the accuracy of authentication for a person to be authenticated having an iris color that deviates from the wavelength of the light emitting diode is inferior, and in particular, people with various iris colors are to be authenticated. In the environment of use, there is a possibility that many errors will occur such as not authenticating the correct authenticated user who is a registrant, or conversely authenticating the authenticated user who is not the registrant. Rise.

  Accordingly, the present invention has been made to solve such problems, and an iris authentication apparatus having high authentication accuracy even in a use environment in which people having various iris colors are to be authenticated. The purpose is to provide.

  In order to achieve the above object, an iris authentication apparatus according to the present invention includes a light source unit including a plurality of light sources having different center wavelengths, a light source selection unit that selects one of the plurality of light sources, and the selected one. An imaging unit that captures an image of the iris of the person to be authenticated using a light source, and an authentication unit that authenticates the person to be authenticated based on the image captured by the imaging unit. Further, the authentication means includes an image selection means for selecting one image from images picked up by the image pickup means, an iris data detection means for detecting iris data from the image selected by the image selection means, The storage means for storing the authentication target's iris data detected by the iris data detection means in advance as registration data, the authentication target's iris data detected by the iris data detection means, and the storage means. Collation means for collating the registered data.

  The image selection means selects an image having the highest luminance peak of a certain feature point from among the plurality of iris images of the authentication target person, or has the highest luminance inclination angle near a certain feature point. A large image is selected, or an image that maximizes the level of a certain spatial frequency band is selected.

  The present invention can be realized not only as such an apparatus, but also as an iris authentication method or a program that causes a computer to function as means included in the iris authentication apparatus.

  According to the present invention, since a plurality of light emitting diodes having different center wavelengths are used as a light source, based on an image captured with light from a light emitting diode having a wavelength that allows the iris pattern of the person to be authenticated to be captured most clearly, Since the iris data that is the characteristic data of the person to be authenticated is detected, the detection accuracy of the iris pattern can be improved regardless of the color of the person to be authenticated. Therefore, the accuracy of authentication can be increased even in an environment used by a person to be authenticated having various iris colors.

  By using the iris authentication apparatus of the present invention for a security system for room entry management or the like, a security system with high authentication accuracy can be realized, and its practical value is extremely high.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 is an example of an external view of an iris authentication apparatus according to Embodiment 1 of the present invention. The iris authentication apparatus 10 includes a light source unit 1 that irradiates a subject's iris with a light source, an imaging unit 2 that captures an iris, a display unit 5 that displays a message or the like on a liquid crystal screen, and a user or administrator who uses a button for data An operation unit 6 for performing input and the like and an antenna 9 for performing communication with the main body system and the like are provided.

  FIG. 2 is a block diagram of the iris authentication apparatus according to Embodiment 1 of the present invention. The light source selection unit 11 outputs a control signal indicating which one of the light sources is turned on. The light source unit 1 includes light sources 1a, 1b, and 1c, which are light emitting diodes having different center wavelengths. When a control signal is input from the light source selection unit 11, the power source of each light source is controlled and designated 1 Only one light source is irradiated to the person to be authenticated, and the other light sources are not irradiated. The imaging unit 2 captures an iris with a CCD camera and outputs an image signal to the image selection unit 13. The image selection unit 13 receives the image signal from the imaging unit 2, determines an image optimal for authentication among the images by image processing, and outputs the image to the iris data detection unit 14. The iris data detection unit 14 performs processing for extracting iris data that is feature data of the iris based on the image input from the image selection unit 13, and outputs the extracted iris data to the matching unit 12. The collation unit 12 obtains the distance between the iris data and the registration data in order to compare the iris data input from the iris data detection unit 14 with the registration data input from the storage unit 7, and calculates the distance between the distance and the threshold value. It is determined whether or not to authenticate based on the size relationship, and the authentication result is transmitted to an external device such as the main system via the input / output interface unit 8. The display unit 5 displays a message or the like to the administrator or the person to be authenticated based on the signal from the control unit 4. The operation unit 6 outputs an input by a push button operated by an administrator or a person to be authenticated to the control unit 4. The storage unit 7 receives and stores various data such as administrator setting data and iris data for registration of the authenticated person as write signals from the control unit 4, and also by read signals from the control unit 4. The stored data is output to the control unit 4.

  FIG. 3 is a diagram for explaining a method of generating iris data from the iris. Iris data is encoded as binary data indicating the density of the iris pattern (radius pattern drawn radially) in each of a plurality of regions that are pre-divided into radial and rotational directions in polar coordinates with the origin at the center of the iris. It has been done.

  FIG. 4 is a diagram illustrating an example of the relationship between the wavelength of each light source and the light emission intensity. A light emitting diode is used as the light source, and each light emitting diode has a different center wavelength at which the light emission intensity peaks. Therefore, by preparing a plurality of light emitting diodes having different characteristics as light sources, the iris pattern can be clearly imaged by any one of the light emitting diodes, regardless of the color of the iris of the person to be authenticated.

  FIG. 5 is a flowchart showing a registration operation procedure in the iris authentication apparatus according to Embodiment 1 of the present invention. First, the iris is imaged using only the light source 1a (for example, a light source for oriental people whose iris is brown) and recorded as an image Pa (S1). Next, an iris is imaged using only the light source 1b (for example, a light source for Westerners whose iris is blue) and recorded as an image Pb (S2). Furthermore, an iris is imaged using only the light source 1c (for example, a light source for people with a thin iris color) and recorded as an image Pc (S3). Among these three images Pa, Pb, and Pc, an image most suitable for authentication is determined and set as an image P (S4). The method for determining the optimality of the image is to select an image that captures the iris of the person to be authenticated most clearly by using a method such as adopting an image P having the highest luminance peak at a certain feature point. can do. Next, iris data D of the image P is obtained by image processing (S5). Finally, the obtained iris data D is recorded as registration data R (S6).

  FIG. 6 is a flowchart showing an authentication operation procedure in the iris authentication apparatus according to Embodiment 1 of the present invention. First, an iris is imaged using only the light source 1a (brown) and recorded as an image Pa (S11). Next, an iris is imaged using only the light source 1b (blue) and recorded as an image Pb (S12). Furthermore, an iris is imaged using only the light source 1c (special) and recorded as an image Pc (S13). Among these three images Pa, Pb, and Pc, an optimum image is determined and set as an image P (S14). The optimum image determination method is the same as the method described in the description of FIG. Next, iris data D of the image P is obtained by image processing (S15). The iris data D is compared with the registration data R stored in the storage unit (S16). Specifically, a method such as calculating the Hamming distance between two data is taken. If the distance between the iris data D and the registration data R is smaller than the threshold (YES in S17), the person to be authenticated is authenticated as a registrant (S18). Otherwise (NO in S17), authentication is performed. No (S19). Thereafter, the determination data as to whether or not to authenticate is transmitted to an external device such as the main system through the input / output interface.

  As described above, according to the iris authentication apparatus in the first embodiment of the present invention, it is possible to realize an iris authentication apparatus with high authentication accuracy even when used in an environment where the iris color of the person to be authenticated is various. Can do.

(Embodiment 2)
In the second embodiment of the present invention, the administrator sets the light emission order of each light source in accordance with the use environment, and the authentication work is completed at that point if the authentication with the captured image is established. FIG. 7 is a diagram showing a setting example of the light emission order of each light source in the iris authentication apparatus according to Embodiment 2 of the present invention. The light source 1a (brown) is an oriental light source whose iris is brown. The light source 1b (blue) is a light source for westerners whose iris is blue. The light source 1c (special) is a light source for a person with a thin iris color. For example, when the setting number 1 is selected, the light source 1a (brown) emits light first, then the light source 1b (blue), and finally the light source 1c (special) emits light, thereby imaging the iris. When setting number 3 is selected, the light source 1b (blue) emits light first, then the light source 1a (brown), and finally the light source 1c (special) emits light. If authentication with an image is established, the authentication operation is terminated at that time, and imaging with the remaining light sources is not performed. Therefore, if the setting number 1 is selected in an installation place where the person to be authenticated is often an Oriental person, and if the setting number 3 is selected in an installation place in which the person to be authenticated is often a Western person, the authentication time is reduced. It can be shortened and is very useful.

  FIG. 8 is a flowchart showing an authentication operation procedure in the iris authentication apparatus according to Embodiment 2 of the present invention. First, as shown in FIG. 7, the light emission order of the light sources is determined according to the setting number set by the administrator (S31). The first light source in the light emission order is set to 1x (S32). Next, the iris is imaged using only the light source 1x and recorded as an image Px (S33), iris data Dx of the image Px is obtained by image processing (S34), and the iris data Dx is compared with the registration data R (S35). ). If the hamming distance between the iris data Dx and the registration data R is smaller than the threshold (YES in S36), the person to be authenticated is authenticated as a registrant and the process ends (S40). If not (NO in S36), it is determined whether or not the current light source 1x is the last light source (S37). If it is not the last light source (NO in S37), the light source corresponding to the next order in the table is set to 1x. (S38) The iris is imaged again using only the light source 1x and recorded as an image Px (S33). On the other hand, if the current light source 1x is the last light source (YES in S37), authentication is not performed (S39). Thereafter, the determination data as to whether or not to authenticate is transmitted to an external device such as the main system through the input / output interface.

  As described above, according to the iris authentication device in the embodiment of the present invention, it is possible to realize an iris authentication device with high authentication accuracy even when used in an environment where the iris color of the person to be authenticated is various. it can.

  As mentioned above, although the iris authentication apparatus etc. which concern on this invention were demonstrated based on embodiment, this invention is not limited to these embodiment. In the embodiment of the present invention, a light emitting diode having a center frequency in the visible light region is used as a light source. However, for example, a light emitting diode other than an infrared light emitting diode or a light emitting diode may be used.

  In addition to the method described in the first embodiment, the method for selecting the image that captures the iris of the person to be authenticated most clearly from the plurality of images is that the inclination angle of the luminance of the image near a certain feature point is There is a way to select the largest one.

  Further, when the density of the captured image is analyzed by spatial frequency analysis, a space corresponding to an iris pattern in an image captured using a light source that best matches the iris color of the person to be authenticated among a plurality of images. The level of the frequency band is maximized, and the image captured using a light source that does not match is blurred. Therefore, the level of the spatial frequency band corresponding to the iris pattern decreases. Of course, a method of selecting an image having a maximum level in a spatial frequency band range corresponding to an iris pattern from a plurality of images may be adopted.

  The iris authentication apparatus and the iris authentication method according to the present invention have an effect that the authentication accuracy is high even when used in an environment where the iris color of the person to be authenticated is various, and is used in an entrance management security system or the like. This is useful as an iris authentication device.

It is an example of the external view of the iris authentication apparatus which concerns on Embodiment 1 of this invention. It is a block diagram of the iris authentication apparatus which concerns on Embodiment 1 of this invention. It is a figure for demonstrating the method to produce | generate iris data from an iris. It is a figure which shows the example of the relationship between the wavelength of each light source, and emitted light intensity. It is a flowchart which shows the registration operation | movement procedure in the iris authentication device which concerns on Embodiment 1 of this invention. It is a flowchart which shows the authentication operation | movement procedure in the iris authentication device which concerns on Embodiment 1 of this invention. It is a figure which shows the example of a setting of the light emission order of the light source in the iris authentication apparatus which concerns on Embodiment 1 of this invention. It is a flowchart which shows the authentication operation | movement procedure in the iris authentication device which concerns on Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source part 1a, 1b, 1c Light source 2 Imaging part 4 Control part 5 Display part 6 Operation part 7 Memory | storage part 8 Input / output interface part 9 Antenna 10 Iris authentication apparatus 11 Light source selection part 12 Collation part 13 Image selection part 14 Iris pattern detection Part 20 Iris

Claims (9)

An iris authentication device for detecting and authenticating an iris pattern of a person to be authenticated,
Light source means comprising a plurality of light sources having different center wavelengths;
Light source selection means for selecting one of the plurality of light sources;
An imaging means for capturing an image of the iris of the person to be authenticated using the selected light source;
Authentication means for authenticating the person to be authenticated based on an image picked up by the image pickup means;
The authentication means includes
An image selecting means for selecting one image from which the iris of the person to be authenticated is most clearly taken out of images picked up by the image pickup means;
Iris data detection means for detecting iris data from the image selected by the image selection means;
Storage means for previously storing iris data of the person to be authenticated detected by the iris data detection means as registration data;
A collation unit that collates the iris data of the person to be authenticated detected by the iris data detection unit and the registration data stored in the storage unit;
An iris authentication device characterized by that. Wherein the image selection means, a plurality of the out of the person to be authenticated iris image, an iris authentication device according to claim 1, wherein the peak intensity of a feature point to select the highest image. 2. The iris authentication apparatus according to claim 1, wherein the image selection unit selects an image having the largest brightness inclination angle near a certain feature point from a plurality of iris images of the authentication subject. . Wherein the image selection means, a plurality of the out of the person to be authenticated iris image, an iris authentication device according to claim 1, wherein the level of a spatial frequency band and selects an image to be maximized. An iris authentication method in an iris authentication device for detecting and authenticating an iris pattern of a person to be authenticated,
The iris authentication apparatus includes light source means including a plurality of light sources having different center wavelengths,
The iris authentication method includes:
A light source selection step of selecting one of the plurality of light sources;
An imaging step of capturing an image of the iris of the person to be authenticated using the light source selected in the light source selection step;
An authentication step of authenticating the person to be authenticated based on the image captured in the imaging step,
The authentication step includes
An image selection step of selecting one image in which the iris of the person to be authenticated is most clearly taken out of the images captured in the imaging step;
An iris data detection step of detecting iris data from the image selected in the image selection step;
A storage step for storing the iris data of the authenticated person detected in the iris data detection step as registered data in advance;
An iris authentication method comprising: a collation step of collating the iris data of the person to be authenticated detected in the iris data detection step with the registration data stored in the storage step . The iris authentication method according to claim 5 , wherein the image selection step selects an image having a highest luminance peak at a certain feature point from a plurality of iris images of the person to be authenticated. 6. The iris authentication method according to claim 5 , wherein the image selection step selects an image having the largest brightness inclination angle near a certain feature point from a plurality of iris images of the authentication subject. . The iris authentication method according to claim 5 , wherein the image selection step selects an image having a maximum level in a certain spatial frequency band from a plurality of iris images of the person to be authenticated. A program for an iris authentication device for detecting and authenticating an iris pattern of a person to be authenticated,
A program that causes a computer to function as means included in the iris authentication apparatus according to any one of claims 1 to 4 .

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