JP2000210271A - Iris imaging system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an iris imaging system which can execute iris-imaging for accurate recognition of an individual. SOLUTION: This iris imaging system calculates the diameter of the pupil part 8 from iris image signals obtained by imaging the iris of a subject. When the diameter is larger than a prescribed value, the display luminance of a display 2 to display based on the iris signals is decreased once and then increased to forcibly make the diameter of the pupil part smaller and the diameter of the pupil part 8 is still smaller then the prescribed value, the iris imaging signals obtained by the above-mentioned imaging are outputted outside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an iris photographing apparatus for photographing an iris (iris) of a human eye.

[0002]

2. Description of the Related Art In recent years, attention has been paid to a security system that performs personal recognition using an iris pattern of a human eye. In such a security system, first, the subject is illuminated with eyes and photographed, and a portion corresponding to an iris is extracted from an image signal of the eye obtained by the photographing. next,
An image signal corresponding to the iris is subjected to feature extraction processing using a Gabor filter or the like to obtain an iris pattern. Next, iris registration or iris collation is executed using the iris pattern.

[0003] First, in iris registration, a label (registrant name, I name) is added to the iris pattern of the subject obtained as described above.
(D number, date, etc.) are stored in the storage device. On the other hand, in the iris verification, an iris pattern substantially identical to the iris pattern of the subject obtained as described above is searched from the storage device. Here, when substantially the same iris is retrieved from the storage device, the label attached to the iris pattern is read out from the storage device to obtain the name of the subject and the personal information such as the ID number. Get it.

As described above, in the above-mentioned security system, personal recognition is performed based on an iris pattern obtained by photographing a human eye. Therefore, as an iris photographing device for photographing iris,
It is desired that a photographing that can perform such individual recognition with high accuracy is possible.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an iris photographing apparatus capable of photographing an iris capable of accurately performing individual recognition.

[0006]

SUMMARY OF THE INVENTION An iris photographing apparatus according to the present invention comprises: a camera for photographing an iris to obtain an iris image signal; a display device for displaying an image based on the iris image signal; Means for determining the size of the pupil portion based on the pupil portion; brightness adjustment means for temporarily decreasing the display brightness of the display device and then increasing the display brightness when the size of the pupil portion is larger than a predetermined value; Means for externally outputting the iris image signal when the size is smaller than a predetermined value.

[0007]

According to the present invention, when the diameter of the subject's pupil determined from the photographed iris image signal is larger than a predetermined value, the display brightness of a display device for displaying an image based on the iris image signal is displayed. The diameter of the pupil portion is forcibly reduced by decreasing the pupil portion once and then increasing the iris image signal obtained as described above only when the diameter of the pupil portion is smaller than a predetermined value. Since the iris image is configured to be externally output, an iris image larger than a predetermined area is always externally output, and an iris pattern with high recognition accuracy can be generated.

[0008]

FIG. 1 is a diagram showing the configuration of an iris photographing apparatus according to the present invention. In FIG. 1, an illumination unit 4 illuminates an iris 6 of a subject's eye with illumination light for imaging. The illumination unit 4 is configured by arranging a plurality of LED elements 4a having a peak component in the near infrared region in a matrix. The iris image reflected from the iris part 6 of the subject's eye by the illumination light from the illumination unit 4 is led out to the half mirror 1 via the protective glass 7.

The half mirror 1 reflects an iris image derived through the protective glass 7 and guides the iris image to an imaging lens (not shown) of the camera 3, while also displaying a display device such as a liquid crystal display device. The display image displayed on the second display surface 2a is transmitted and led out to the protective glass 7. The half mirror 1 is a so-called hot mirror that has characteristics as shown in FIG. 2, that is, transmits visible light and reflects 90% or more of light in the near infrared wavelength region (750 nm or more).
Therefore, the iris image containing a large portion of the near infrared wavelength region,
The image is guided to the photographing lens of the camera 3 as a bright image.

The photographing lens of the camera 3 condenses the iris image reflected by the half mirror 1 on a light receiving surface of an image sensor (not shown) of the camera 3. The image sensor generates an image signal corresponding to the iris image formed on the light receiving surface, and uses the generated image signal as an iris image signal _IV, as an iris photographing control circuit 10, a display device driving circuit 12, and a transmitting circuit 1.
3 to each.

The transmission circuit 13 includes an iris photographing control circuit 1
In response to the transmission start command signal TX supplied from 0, one frame of the iris image signal _IV obtained by photographing with the camera 3 at that time is transmitted as a transmission iris image signal to an iris recognition device (not shown). I do. The iris recognition device extracts a portion corresponding to the iris from the iris image signal _IV , performs a feature extraction process using a Gabor filter or the like, obtains an iris pattern, and registers the iris pattern or compares the iris pattern with the registered iris pattern. I do.

On the other hand, the display device drive circuit 12 drives the display device 2 to display an image based on the iris image signal _IV supplied from the camera 3 on the display surface 2a. In addition, the display device driving circuit 12 responds to the backlight on / off control signal L _ON supplied from the iris photographing control circuit 10 to control the backlight 2b of the display device 2.
Is turned on or off. For example, when the backlight on / off control signal L _{ON of} the logical level “0” is supplied, the display device driving circuit 12 turns off the backlight 2b, and the backlight on / off control signal L _{ON of the} logical level “1”. Is supplied, the backlight 2b is turned on. At this time, when the backlight 2b is turned on, an image corresponding to the iris image signal _IV is displayed on the display surface 2a, and the displayed image passes through the half mirror 1 and the protective glass 7 and reaches the eyes of the subject. That is, the iris image of the subject taken by the camera 3 is displayed on the display surface 2a of the display device 2, and is transmitted through the half mirror 1 and the protective glass 7 and is again shown to the subject's eyes.
While monitoring the iris image displayed on the display surface 2a of the display device 2, the subject adjusts the position by moving his / her face so that the iris image is located at the center of the screen. When the position adjustment is completed, the subject depresses the switch 14 so as to transmit the iris image of the iris recognized by the position adjustment to the iris recognition device. The switch 14 transmits the transmission request signal T _RQ in response to the pressing operation.
And supplies it to the iris photographing control circuit 10.

The iris photographing control circuit 10 includes, for example, a ROM (Read Only Memory) in which a program for controlling operation during iris photographing is stored, and a CPU (Central) for executing iris photographing control in accordance with the program.
Processing Unit) and RAM (Random Access Memor)
y). Here, when the transmission request signal _TRQ is supplied from the switch 14, the iris imaging control circuit 1
0 is the main flow currently being executed.
Then, the process proceeds to the execution of the iris photographing control routine shown in FIG.

In FIG. 3, first, the CPU executes a pupil size calculation routine (step S1). In the pupil size calculation routine, first, a pupil image corresponding to the subject's pupil portion 8 is extracted from the iris image signal _IV supplied from the camera 3. Next, calculate the size of the pupil portion 8 based on the extracted pupil image (diameter), which is stored in the RAM as the pupil size P _S. After storing the pupil size P _S in RAM, CPU moves to the execution of step S2 described below goes through the pupil size calculation routine, whether the pupil size P _S is larger than a predetermined size R Is determined (step S2).

In step S2, the pupil size
P_SIs larger than the predetermined size R, C
The PU outputs a backlight on / off control signal of logic level "0".
No. L _ONAnd sends it to the display device drive circuit 12.
(Step S3). The display device drive circuit 12 is based on such a theory.
Backlight level on / off control signal L at logic level "0"_ONIn response
The backlight 2b of the display device 2 is turned off,
Reduce display brightness. Thus, the backlight 2b
Is turned off and the display brightness of the display device 2 decreases,
Reach the eyes of the subject via the mirror 1 and the protective glass 7
The pupil part 8 of the subject follows the
Size (diameter) of the iris part 6
Area is reduced. Next, the CPU sets the logic level “1”.
Backlight on / off control signal L_ONThe display device drive circuit
12 (step S4). Display device drive circuit 12
Is the backlight on / off control of the logical level "1".
Signal L_ONThe backlight 2b of the display device 2 again
The display is turned on to increase the display brightness. Display device 2
The backlight 2b changes from the unlit state to the lit state and is displayed.
When the display luminance increases, the half mirror 1 and the protective glass 7
As the amount of light reaching the subject's eyes also increases,
Accordingly, the size (diameter) of the pupil 8 of the subject becomes smaller,
The area of the iris part 6 increases by that amount.

After the end of step S4, the CPU
Returning to the execution of step S1 again, step S2
At up to pupil size P _S it is determined not to be larger than a predetermined size R, to repeatedly execute the operations as described above. Here, in such a step S2, the pupil size P _S is determined not to be larger than a predetermined size R,
The CPU sends a transmission start command signal TX to the transmission circuit 13.
Is transmitted (step S5). The transmission start command signal T
According to X, the transmission circuit 13 transmits a still image of one frame of the iris image signal _IV obtained by photographing with the camera 3 at that time to the iris recognition device (not shown) as a transmission iris image signal. . In other words, pupil size P _S is smaller than a predetermined size R, i.e., only when the area of the iris portion 6 is larger than a predetermined is to output the captured iris image to the iris recognition system.

After the end of step S5, the CPU
The process exits the iris photographing control routine as shown in FIG. 3 and returns to the execution of the main flow (not described). in this way,
In the iris photographing apparatus according to the present invention, in photographing the iris of the subject and outputting the photographed iris to the outside, first,
The size of the pupil 8 from the photographed subject's iris image
(Diameter). At this time, if the size of the pupil portion 8 is larger than the predetermined size R, the backlight 2b
Is turned off, the display luminance of the display device 2 is once reduced, and then the backlight 2b is turned on to increase the display luminance, whereby the pupil portion 8 of the subject's eye is increased.
Is forcibly reduced in size.
This operation is generally performed in view of the fact that the pupil of the human eye becomes smaller when the amount of light changes from a dark state to a bright state. According to such an operation, even if the size of the pupil portion 8 of the subject's eye is larger than the predetermined size R at the beginning of imaging, it can be forcibly reduced. Here, when the size of the pupil portion 8 is smaller than the predetermined size R, an iris image signal for one frame obtained by photographing at this time is externally output.

That is, the present invention focuses on the point that the smaller the diameter of the pupil of the subject's eye is, the larger the area of the iris is, and it is possible to generate an iris pattern with high recognition accuracy.
Only when the diameter of the photographed pupil is smaller than a predetermined value, the iris image signal obtained at this time is externally output. At this time, even if the diameter of the pupil of the subject's eye is larger than a predetermined value, the display brightness of the display device is temporarily reduced and then increased, thereby forcibly increasing the diameter of the pupil of the subject's eye. I try to make it smaller.

Therefore, according to the iris photographing apparatus of the present invention, only an iris image larger than a predetermined area can be always output to the outside (transmitted to the iris recognition apparatus). Will be possible. In the above embodiment, in order to forcibly reduce the pupil of the subject's eye, in steps S3 and S4,
The backlight 2b of the display device 2 is turned off and on to decrease and increase the display brightness of the display device 2, but the operation is not limited to this.

FIG. 4 is a diagram showing another example of the iris photographing control routine made in view of the above points. In FIG. 4, steps S1, S2 and S5 are described as follows.
The description is omitted because it is the same as that shown in FIG. In the iris photographing control routine shown in FIG.
When pupil size P _S in the step S2 is determined to be larger than a predetermined size R, CPU sends an image signal supply stop instruction to the display device driving circuit 12
(Step S3 '). In response to the image signal supply stop command, the display device driving circuit 12 stops supplying the image signal to the display device 2. As described above, when the supply of the image signal is stopped, the display surface 2a of the display device 2 is momentarily brought into a pure white screen state with only the backlight, and in response to this, the pupil of the subject's eye is reduced. Next, the CPU sends an image signal supply restart command to the display device drive circuit 12 (step S4 '). In response to the image signal supply restart instruction, the display device drive circuit 12 restarts the supply of the image signal to the display device 2 again.

As described above, even if the supply of the iris image signal to the display device 2 is temporarily stopped and then restarted, the size of the pupil 8 of the subject's eye can be reduced. Step S3 (S
In 3 ′) and S4 (S4 ′), the pupil of the subject's eye is forcibly changed to be small by largely changing the amount of light applied to the subject's eye. It is known that the light amount changes even with a slight change in light amount. In short, steps S3 (S3 ') and S4 (S4')
Then, the display luminance of the display device 2 may be changed to such an extent that the pupil of the subject's eyes changes in a direction in which the pupil becomes smaller.

Further, in the embodiment shown in FIG. 1, an example of the iris photographing device in which the camera 3 and the display device 2 are integrated is shown, but the display device 2 is a personal computer (hereinafter referred to as a personal computer). (Referred to as PC). FIG. 5 is a diagram showing a configuration of an iris photographing device made in view of such a point. still,
The configuration shown in FIG. 5 includes a notebook personal computer (hereinafter, referred to as a notebook PC) 20 having not only the display device 2 but also the function of the iris recognition device as described above.
The notebook PC 20 includes a camera 3, a half mirror 1, a transmission cable 70, and a PC card 80 attached to a display unit housing 30 of the notebook PC 20 by detachable clips or the like.

An illumination unit 4 is provided on the front surface of the camera 3. Further, a half mirror 1 is attached to the front surface so as to be rotatable in parallel with the front surface and around J in the figure. Here, the subject examines the screen 30a of the notebook PC 20 through the half mirror 1.
, An iris image of the eye of the subject is photographed by the camera 3, and an iris image signal obtained by the photographing is taken into the notebook PC 20 via the transmission cable 70 and the PC card 80. The notebook PC 20 has a screen 3
Ia window 50 as shown in FIG.
Is displayed, and the iris image of the subject captured as described above is displayed in the display frame. That is, the screen 30a of the notebook PC 20 and the iris window 50 have the same function as the display device 2 shown in FIG. At this time, the CPU of the notebook PC 20 may execute the iris photographing control routine and the operation of the iris recognition device shown in FIG.

In the above embodiment, the case where a liquid crystal display device is used as the display device 2 has been described. As the display device 2, any display device such as a cathode ray tube display, an electroluminescence display, or a plasma display is used. May be used.

[0025]

As described above, according to the present invention, the diameter of the pupil is obtained from the iris image signal obtained by photographing the iris of the subject, and when the pupil diameter is larger than a predetermined value,
The display brightness of the display device that performs display based on the iris image signal is reduced once and then increased, thereby forcibly reducing the diameter of the pupil, and when the diameter of the pupil is smaller than a predetermined value. As far as possible, the iris image signal obtained by the above photographing is externally output.

According to the iris photographing apparatus of the present invention, only the iris image signal containing the iris image larger than the predetermined area is externally output from the photographed iris image signals. A high iris pattern can be generated.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an iris photographing device according to the present invention.

FIG. 2 is a diagram showing reflection / transmission characteristics of the half mirror 1;

FIG. 3 is a diagram showing an iris photographing control routine.

FIG. 4 is a diagram showing another example of an iris photographing control routine.

FIG. 5 is a diagram showing a configuration when an iris photographing device according to the present invention is combined with a personal computer.

[Brief description of reference numerals]

 DESCRIPTION OF SYMBOLS 1 Half mirror 2 Display device 2b Backlight 3 Camera 10 Iris photography control circuit 13 Transmission circuit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4C038 VA07 VB04 VC05 5B043 AA09 BA04 CA10 DA05 EA07 EA15 FA03 GA02 HA02 5B047 AA23 AB04 BB06 CA12 CA19 CA23 CB12 CB25 DC09

Claims (3)

[Claims] A camera that captures an iris to obtain an iris image signal; a display device that displays an image based on the iris image signal; and a unit that determines a size of a pupil based on the iris image signal. Brightness adjusting means for temporarily decreasing the display brightness of the display device when the size of the pupil portion is larger than a predetermined value and then increasing the display brightness; and setting the iris when the size of the pupil portion is smaller than a predetermined value. Means for externally outputting an image signal. 2. The method according to claim 1, wherein the display device is a liquid crystal display device, and the brightness adjusting means turns off the backlight of the liquid crystal display device once when the size of the pupil portion is larger than a predetermined size, and then again. The iris photographing device according to claim 1, wherein the iris is lit. 3. A camera that captures an iris to obtain an iris image signal, a display device that performs image display based on the iris image signal, a unit that determines a size of a pupil based on the iris image signal, Means for temporarily stopping the supply of the iris image signal to the display device when the size of the pupil portion is larger than a predetermined value, and for supplying the iris image signal again, and when the size of the pupil portion is smaller than a predetermined value. Means for externally outputting the iris image signal.