JP6828972B2 - Iris data registration device, iris data registration method and iris data registration program - Google Patents

Description

The present invention relates to an iris data registration device, an iris data registration method, and an iris data registration program.

Conventionally, biometric authentication using iris data obtained by imaging an iris including a pupil has been used for entering a room classified by security level or for an electronic device such as a smartphone. In recent years, in order to improve authentication accuracy and speed up authentication speed, multiple iris data captured with different illuminances are registered in advance, and the registered iris data according to the illuminance at the time of authentication is selected and authenticated. The technique used for processing is also known.

Japanese Patent Application Laid-Open No. 2013-518319

However, since the imaging of iris data is affected by the imaging environment such as sunlight and illuminance, it takes a lot of time to register multiple iris data by changing the illuminance, which is convenient for the user. descend.

In one aspect, it is an object of the present invention to provide an iris data registration device, an iris data registration method, and an iris data registration program that can reduce the time required for registration of iris data used for authentication.

In the first proposal, the iris data registration device images the pupil by using the change in the size of the pupil, which changes depending on the illuminance, and the permissible range of misidentification in iris recognition using the iris data in which the pupil is imaged. It has a changing part that changes the illuminance at the time of imaging to a brightness brighter or darker than the illuminance at the start of imaging. The iris data registration device has a registration unit that registers the iris data obtained by imaging the pupil with the changed illuminance as registration data for the iris authentication.

According to one embodiment, the time required for registering the iris data used for authentication can be shortened.

FIG. 1 is a diagram illustrating a pupil to be authenticated. FIG. 2 is a diagram for explaining the pupil size for each illuminance around the eyes. FIG. 3 is a diagram for explaining the pupil size and the authentication rate. FIG. 4 is a diagram illustrating an authentication method using a plurality of registered data. FIG. 5 is a diagram illustrating registration data covering the entire area. FIG. 6 is a diagram illustrating an example of the electronic device according to the first embodiment. FIG. 7 is a diagram illustrating registration of iris data. FIG. 8 is a flowchart showing the flow of the iris data registration process. FIG. 9 is a diagram illustrating a comparison between the embodiment and the conventional registration data. FIG. 10 is a configuration diagram of a system having a registration device and an authentication device.

Hereinafter, examples of the iris data registration device, the iris data registration method, and the iris data registration program disclosed in the present application will be described in detail with reference to the drawings. In addition, each Example can be combined appropriately within a consistent range. Moreover, this embodiment does not limit the present invention.

[Explanation of pupils to be authenticated]
First, the pupil data obtained by imaging the pupil used for iris recognition will be described with reference to FIGS. 1 to 5. FIG. 1 is a diagram illustrating a pupil to be authenticated. In this embodiment, an example of an electronic device such as a smartphone will be described. Specifically, the user's iris data is captured and registered using the display of an electronic device, and the registered iris data is compared with the iris data captured at the time of authentication to perform iris authentication. It should be noted that the processing is not limited to electronic devices such as smartphones, and the same processing can be performed by a stationary authentication device or the like.

As shown in FIG. 1, the size of the pupil used for iris recognition (hereinafter, may be referred to as the pupil size) changes depending on the environment when the pupil is imaged. For example, the pupil size is 2 mm (millimeters), which is a common size outdoors in sunlight, 3 mm to 4 mm indoors, and 7 mm to 8 mm in the dark.

That is, the brighter the illuminance, the smaller the pupil size (the iris pattern grows), and the darker the illuminance, the larger the pupil size. Therefore, since the difference in pupil size between outdoors and in the dark is as much as 5 mm to 6 mm, there is a large difference in pupil size between the environment for registering iris data including the pupil and the environment for actual authentication. Often. For this reason, in electronic devices such as smartphones that are used both indoors and outdoors, it takes time to correct the iris pattern by the authentication engine, resulting in longer iris recognition and lower authentication accuracy. ..

Next, the relationship between the illuminance when imaging the pupil (hereinafter, may be referred to as the illuminance around the eyes) and the pupil size will be described. FIG. 2 is a diagram for explaining the pupil size for each illuminance around the eyes. Here, in order to eliminate external factors other than pupil size as much as possible, in an environment where the distance between the electronic device that performs iris recognition and the eye area (naked eye) is about 25 cm, the amount of artificial sun is adjusted for each eye illuminance. Measure the pupil size of.

FIG. 2 illustrates the relationship between the illuminance around the eyes (Lux) and the pupil size. The illuminance around the eyes is less than about 100 lux, which is an outdoor night or dark environment, 100 lux or more and less than 1000 lux, which is an indoor environment, and 1000 lux or more and less than 9000 lux, which is an outdoor cloudy or shaded environment. An outdoor sunny environment of 9000 lux or more was used.

The graphs (solid lines) shown by V1 to V6 shown in FIG. 2 show the change in the pupil size according to the environment, and show the change in the pupil size in the environment of each eye illuminance without looking at the display. Specifically, when the eye illuminance is 0 lux, the pupil size is V6, when the eye illuminance is 200 lux, the pupil size is V5, and when the eye illuminance is 500 lux, the pupil size is V4, and the eye illuminance is V4. When the eye illuminance is 1000 lux, the pupil size is V3, when the eye illuminance is 2000 lux, the pupil size is V2, and when the eye illuminance is 4000 lux or more, the pupil size is stable at V1.

The other graph (dotted line) shown in FIG. 2 shows the change in pupil size when the display is viewed under the environment of each eye illuminance. Specifically, when the eye illuminance is 0 lux, the pupil size is 3 × N1, when the eye illuminance is 200 lux, the pupil size is 2.5 × N1, and when the eye illuminance is 500 lux, the pupil size is 2. × N1, the pupil size is 1.8 × N1 when the eye illuminance is 1000 lux, the pupil size is 1.5 × N1 when the eye illuminance is 2000 lux, and N1 when the eye illuminance is 4000 lux or more. Stable at pupil size.

As can be seen from FIG. 2, the pupil becomes smaller and more stable depending on the brightness of the display. For example, at 0 lux eye illuminance, the pupil size decreases from V6 to 3 × N1 depending on the brightness of the display, and at 1000 lux eye illuminance, the pupil size decreases from V3 to 1.8 × N1 and 4000 lux or more. At the illuminance around the eyes, the pupil size decreases from V1 to N1. Further, in any state, when the illuminance exceeds a certain level, the pupil size becomes almost constant.

Subsequently, the registered iris data (hereinafter, may be referred to as registered data) and the iris data captured at the time of authentication (hereinafter, may be referred to as authentication data) are generated for each eye illumination. Then, verify the authentication rate when performing round-robin authentication. FIG. 3 is a diagram for explaining the pupil size and the authentication rate. FIG. 3 shows the diameter of the pupil at the illuminance at the time of registration of the iris data (hereinafter, may be referred to as registered illuminance) and the pupil at the illuminance at the time of iris recognition (hereinafter, may be referred to as certified illuminance). For each combination with the diameter, it indicates whether or not the success rate when iris recognition is performed multiple times is equal to or higher than a predetermined value. The combination indicated by 〇 in FIG. 3 has a high success rate (authentication rate), and the combination indicated by × has a low success rate (authentication rate).

For example, the registration data of "pupil diameter (2.5 x N1)" imaged at "illuminance (200 lux)" at the time of registration and "pupil diameter (V4)" imaged at "illuminance (500 lux)" at the time of authentication. When collated with the registered data of ", it indicates that the authentication rate is high. That is, when the difference in pupil size is "V4- (2.5 x N1)", the authentication rate is high. On the other hand, the registration data of "pupil diameter (2.5 x N1)" imaged at "illuminance (200 lux)" at the time of registration and "pupil diameter (V2)" imaged at "illuminance (2000 lux)" at the time of authentication. ) ”, It indicates that the authentication rate is low. That is, when the difference in pupil size is "V2- (2.5 x N1)", the authentication rate is low.

From the result of the authentication rate shown in FIG. 3, the amount of change in the pupil size at which the decrease in the authentication rate occurs is specified. That is, the difference between the pupil diameter at the registered illuminance and the pupil diameter at the certified illuminance, which satisfies the acceptable authentication rate, is specified. Specifically, it is specified how much the difference in pupil diameter is the acceptable authentication rate, and how large the difference is below the acceptable authentication rate. Here, it is specified that if the difference (difference in pupil size) between the pupil diameter at the registered illuminance and the pupil diameter at the certified illuminance is within "N2 (mm)", the certification rate is acceptable.

Here, an example using a plurality of commonly used registered data will be described. FIG. 4 is a diagram illustrating an authentication method using a plurality of registered data. As shown in FIG. 4, at least two registered data are required in order to cover the entire range of the eye illuminance at the time of authentication from 0 lux to 20000 lux. Normally, since the general illuminance around the eyes when imaging the registered data is around 200 lux, only one registered data having a pupil size of "2.8 x N1" is registered. However, since the pupil size is N2 or more smaller than "2.8 x N1" outdoors at 1000 lux or more, the authentication rate of the authentication process depends on the illuminance at the time of authentication only with the registered data of the pupil size "2.8 x N1". Makes a big difference. That is, when the authentication is performed in an environment of 1000 lux or more, the authentication rate is lowered.

For this reason, in general iris recognition, in order to cover an environment of 1000 lux or more, registration data imaged at 4000 lux in which the pupil size is "N1" is additionally registered. Then, from 0 lux to around 1000 lux, iris recognition is performed using the registered data having a pupil size of "2.8 x N1", and from around 1000 lux to around 20000 lux, the registered data having a pupil size of "N1" is performed. Perform iris recognition using. In this way, by adding the registration data captured outdoors, iris authentication covering all illuminance is executed. However, it is troublesome for a general user to set a fine illuminance and to image and register the pupil both indoors and outdoors. Therefore, in many cases, only the iris data captured indoors is registered, resulting in a decrease in the authentication rate.

Therefore, in this embodiment, registration data of the pupil size covering the entire region is generated and registered. That is, registration data in which the difference in pupil size is within "N2" is generated and registered regardless of the illuminance around the eyes at the time of authentication. FIG. 5 is a diagram illustrating registration data covering the entire area. In this embodiment, as shown in FIG. 5, the pupil size “N3” which is within N2 from the pupil size “3 × N1” at 0 lux and within N2 from the pupil size “N1” of 4000 lux or more is used as the registration data. Take an image. Hereinafter, each process or the like executed by the electronic device to image the pupil size “N3” as registered data will be described.

[Explanation of electronic devices]
FIG. 6 is a diagram illustrating an example of the electronic device according to the first embodiment. FIG. 6 shows the hardware configuration of the electronic device 10. As shown in FIG. 6, the electronic device 10 includes an RF (Radio Frequency) circuit 11, an image pickup device 12, a display device 13, a memory 14, and a processor 20. An authentication device or the like that does not have the RF circuit 11 can also be adopted.

Further, the electronic device 10 releases the "processing restriction" when the authentication based on the "iris data" is successful. The "processing restriction" is, for example, a restriction for shifting the display state of the display device 13 of the electronic device 10 from the standby screen state to the next screen state. It can also be applied to an authentication device that does not have the RF circuit 11.

The RF circuit 11 receives the radio signal transmitted from the communication device of the communication partner via the antenna 11a, and performs a predetermined wireless reception process (down-conversion, analog-digital conversion, etc.) on the received wireless signal. The obtained received signal is output to the processor 20. Further, the RF circuit 11 performs a predetermined wireless transmission process (digital-to-analog conversion, up-conversion, etc.) on the transmission signal received from the processor 20, and transmits the obtained wireless signal via the antenna 11a.

The image pickup apparatus 12 takes an image of an image pickup target, generates a captured image, and outputs the generated captured image to the processor 20. For example, the image pickup apparatus 12 has a normal camera (not shown), an infrared LED (not shown), and an IR camera (not shown) that utilize visible light.

The display device 13 is a display that displays a display image corresponding to the display data received from the processor 20 based on the control by the processor 20. In addition, the display device 13 has a backlight that controls the brightness of the display.

The processor 20 controls the overall processing of the electronic device 10. For example, the processor 20 controls communication processing, display processing, processing restriction processing, restriction release processing, authentication processing, and the like. Various processing functions realized by the processor 20 are realized by recording a program corresponding to each processing in the memory 14 and executing each program in the processor 20. Examples of the processor 20 include a CPU (Central Processing Unit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), and the like.

Further, the processor 20 executes the process of specifying the difference in pupil size "N2" and the process of specifying the illuminance at which the pupil size is "N2", which are described with reference to FIGS. 2 to 5. Specifically, the processor 20 receives the verification data shown in FIG. 3 from the administrator or another device, and identifies the difference "N2" in pupil size that can keep the authentication rate above a certain value. Further, the processor 20 specifies the pupil size "N3" that can keep the difference in pupil size within "N2" regardless of the illuminance. Further, the processor 20 specifies the illuminance (for example, 250 lux) at which the pupil size is "N3".

For example, the processor 20 is specified by using a table or the like in which the size of the pupil and the illuminance are associated with each other. This table can be generated in advance by measuring the size of the pupil by changing the illuminance in advance, or a generally known table or the like can be adopted. Further, the verification data shown in FIG. 3 can also be generated in advance, and a generally known table or the like can be adopted. Each of the above processes can be executed by another device. In that case, the other device notifies the electronic device 10 of the difference in illuminance and pupil size, and the electronic device 10 sends each information from the other device. get.

Next, one iris data registration process executed by the processor 20 and an authentication process using the registered iris data will be described. As described above, the registration process is preferably performed in an environment where the distance between the electronic device for iris recognition and the eye (naked eye) is about 25 cm in order to eliminate external factors other than the pupil size as much as possible. ..

(registration process)
The processor 20 executes the iris data registration process. For example, when the processor 20 receives the instruction to start the registration process, the processor 20 raises the brightness of the display from the default value specified in advance to the brightness at which the pupil size becomes the eye illuminance of "N3". In this way, the processor 20 captures the iris data including the pupil having a size of "N3". Then, the processor 20 registers the captured iris data as registration data for authentication in a predetermined storage unit such as a memory or a hard disk, and returns the brightness value of the display to the original brightness value.

FIG. 7 is a diagram illustrating registration of iris data. As shown in FIG. 7, when the processor 20 receives the operation of the registration process, the processor 20 displays the guidance on the display device 13 with the default luminance value. For example, the processor 20 displays a message such as "Register indoors to register an accurate iris. If you are wearing glasses, remove the glasses and register." Subsequently, the processor 20 displays an animation or the like explaining a method of registering the iris.

After that, the processor 20 displays an area for imaging the iris on the display device 13, and when the iris is detected in the area, the processor 20 changes the brightness value of the display device 13 to the brightness value for registering the iris. To do. Then, the processor 20 takes an image of the iris including the pupil in a state where the brightness value of the display device 13 is changed. After that, the processor 20 saves the captured iris data, returns the brightness value of the display device 13 to the original default value, and ends the registration process.

The brightness of the display is not limited to the control of increasing the brightness to the maximum value, and can be controlled to increase the brightness to a predetermined value specified in advance. For example, assuming that the illuminance around the eyes where the pupil size is "N3" changes depending on the gender, age, etc., the illuminance around the eyes where the pupil size is "N3" can be measured in advance according to the gender, age, and the like. Then, the processor 20 can also adjust the backlight of the display so as to obtain the measured eye illuminance according to the owner.

Further, the processor 20 changes the brightness value of the display to a predetermined value, images the iris, resets the brightness value of the display according to the size of the pupil included in the imaged iris data, and performs imaging again. You can also do it. For example, the processor 20 captures iris data in a state where the registered illuminance is changed by changing the brightness value of the display to a predetermined value. Then, when the size of the pupil is larger than "N3", the processor 20 increases the illuminance by further increasing the brightness value of the display and executes imaging again. On the other hand, when the size of the imaged pupil is smaller than "N3", the processor 20 can reduce the illuminance by further reducing the brightness value of the display and perform the image capturing again. In this way, the processor 20 can adjust the brightness value of the display and repeat the imaging of the iris data in which the pupil size is “N3”.

(Authentication processing)
The processor 20 executes an authentication process using the iris data. For example, when the processor 20 receives the instruction to start the authentication process, the processor 20 displays guidance in the same manner as the registration process. After that, the processor 20 maintains the brightness value of the display device 13 as the default value (set value), and uses the display device 13 to image the iris. Then, the processor 20 compares the captured iris data for authentication with the registered data registered in the above registration process, and if the coincidence point is equal to or greater than the threshold value and can be determined to be the same iris, authentication is permitted. To do. On the other hand, the processor 20 rejects the authentication when the coincidence point between the captured iris data for authentication and the registered data registered in the registration process is less than the threshold value and cannot be determined to be the same iris.

[Flow of registration process]
FIG. 8 is a flowchart showing the flow of the iris data registration process. As shown in FIG. 8, when the processor 20 receives the start operation of the registration process (S101: Yes), the processor 20 displays the guidance on the display (S102).

Subsequently, when the processor 20 detects the pupil on the display (S103: Yes), the processor 20 changes the brightness value of the display to the maximum value (S104). After that, the processor 20 images the pupil (S105).

Here, when the processor 20 cannot normally image the image (S106: No), the processor 20 images the pupil again. On the other hand, when the processor 20 can normally image (S106: Yes), the captured pupil is saved (S107), and the brightness value of the display is changed to the original value (S108).

[effect]
As described above, the electronic device 10 can adjust the illuminance around the eyes so that the pupil size is "N3". Further, the electronic device 10 can execute iris authentication with high authentication accuracy by registering one registration data having a pupil size of "N3", so that the time required for registering the iris data used for authentication is shortened. can do. Further, since the electronic device 10 can register the registration data having the pupil size of "N3", it is possible to maintain high authentication accuracy at each eye illuminance. Further, since the electronic device 10 does not hold a plurality of registered data, the memory capacity can be reduced.

FIG. 9 is a diagram illustrating a comparison between the embodiment and the conventional registration data. As shown in FIG. 9, conventionally, since the control of the brightness value is set to auto and the image of the registered data is executed with the default value, the registered data having the pupil size of “2.8 × N1” is registered. For this reason, the authentication rate has decreased in an environment where the illuminance around the eyes is bright.

On the other hand, in the case of the first embodiment, since the image of the registered data is executed by setting the maximum value of the luminance value, the registered data having the pupil size of "N3" can be registered. Therefore, the difference in pupil size of each eye illuminance can be kept within "N2", and the decrease in the authentication rate can be suppressed. That is, the electronic device 10 of the first embodiment controls the illuminance around the eyes at the time of registration in a brighter direction as compared with the conventional technique, and executes iris imaging for the registered data.

Although the examples of the present invention have been described so far, the present invention may be implemented in various different forms other than the above-described examples. Therefore, different embodiments will be described below.

[Pupil size]
In the above embodiment, an example in which the brightness value of the display is maximized in order to capture iris data having a pupil size of “N3” has been described, but the pupil size is not limited to this. The pupil size to be registered can be arbitrarily changed according to the tolerance of misidentification. For example, if a decrease in the authentication rate is acceptable in a very dark environment or a very bright environment, the difference in pupil size is not within "N2", and the difference in pupil size is changed to a longer value so that it can be registered. The pupil size to be used can be reduced from "N3".

[Illuminance adjustment]
In the above embodiment, an example in which the brightness value of the display is changed to change the illuminance around the eyes has been described, but the present invention is not limited to this. For example, the light included in the electronic device 10 may be adjusted, or the amount of light of the fluorescent lamp with wireless connection connected to the electronic device 10 by wireless communication may be adjusted.

[Separate housing]
In the above embodiment, the example in which the electronic device 10 performs both the registration process for registering the iris data and the authentication process for performing the authentication using the iris data has been described, but the present invention is not limited thereto. For example, each process may be realized in a separate housing, and a cloud system or the like may be adopted.

FIG. 10 is a configuration diagram of a system having a registration device and an authentication device. The registration device 100 shown in FIG. 10 executes the registration process, images the iris, generates registration data, and then saves the registration data in the management server 110 for each user. The authentication device 120 acquires the registration data of the corresponding user from the management server 110 and executes the above authentication process. It is also possible to save the registration data in the registration device 100 without using the management server 110.

[system]
Further, among the processes described in this embodiment, all or a part of the processes described as being automatically performed can be manually performed. Alternatively, all or part of the processing described as being performed manually can be automatically performed by a known method. In addition, the processing procedure, control procedure, specific name, and information including various data and parameters shown in the above document and drawings can be arbitrarily changed unless otherwise specified.

Further, each component of each of the illustrated devices is a functional concept, and does not necessarily have to be physically configured as shown in the figure. That is, the specific form of distribution / integration of each device is not limited to the one shown in the figure. That is, all or a part thereof can be functionally or physically distributed / integrated in any unit according to various loads, usage conditions, and the like. Further, each processing function performed by each device may be realized by a CPU and a program analyzed and executed by the CPU, or may be realized as hardware by wired logic.

10 Electronic equipment 11 RF circuit 12 Imaging device 13 Display device 14 Memory 20 Processor

Claims (4)

Using the difference in the size of each pupil imaged at each illuminance, the tolerance at which the decrease in the authentication rate in iris recognition is equal to or less than a certain value is specified, and the size of the pupil at each illuminance is the tolerance. A specific part that specifies a reference value of 1 that falls within the range of
An illuminance for changing the illuminance when imaging the pupil from a predetermined illuminance specified in advance to an illuminance in which the size of the pupil becomes the reference value of 1 ;
An iris data registration device comprising a registration unit that registers one iris data obtained by imaging the pupil, which is the size of the reference value at the changed illuminance, as registration data for the iris authentication. Claim 1 is characterized in that the changing unit changes the brightness value of the display displaying the pupil to change the illuminance around the pupil to the illuminance at which the size of the pupil becomes the reference value of 1. The iris data registration device described in. The computer
Using the difference in the size of each pupil imaged at each illuminance, the tolerance at which the decrease in the authentication rate in iris recognition is equal to or less than a certain value is specified, and the size of the pupil at each illuminance is the tolerance. Identify a reference value of 1 that falls within the range of
The illuminance at the time of imaging the pupil is changed from the illuminance specified in advance to the illuminance in which the size of the pupil becomes the reference value of 1 .
A method for registering iris data, which comprises executing a process of registering the iris data of 1 obtained by imaging the pupil, which is the size of the reference value of 1 at the changed illuminance, as registration data for iris authentication. .. On the computer
Using the difference in the size of each pupil imaged at each illuminance, the tolerance at which the decrease in the authentication rate in iris recognition is equal to or less than a certain value is specified, and the size of the pupil at each illuminance is the tolerance. Identify a reference value of 1 that falls within the range of
The illuminance at the time of imaging the pupil is changed from the illuminance specified in advance to the illuminance in which the size of the pupil becomes the reference value of 1 .
An iris data registration program characterized by executing a process of registering the iris data of 1 obtained by imaging the pupil, which is the size of the reference value of 1 at the changed illuminance, as registration data for iris recognition. ..

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