KR20090106790A - Iris scanning device and method - Google Patents

Abstract

PURPOSE: An iris scanning device and a method thereof are provided to obtain an image suitable for scanning an iris using an image sensor with a narrow angle lens. CONSTITUTION: An iris scanning device includes an illumination light source, a narrow angle image sensor and a distance calculating unit. The illumination light sources(205a,205b,205c,205d) illuminate an infrared ray toward eyes of a user. The narrow angle image sensors(204a,204b,204c,204d) photographs the eyes of the user illuminated by the illumination light source. The narrow angle image sensors are spaced to photograph the eyes of the user several times. The distance calculating units(207a,207b) calculate a distance to the eyes of the user from an image photographed by the narrow angle image sensors.

Description

Iris scanning device and method

The present invention relates to an iris recognition device and method.

More specifically, the present invention relates to an apparatus and a method for guiding a user to an operation region in an iris recognition system, and to measure a distance by applying a plurality of stereo cameras to both eyes of a person without using a separate distance measuring sensor. The present invention relates to an iris recognition device and method capable of more accurately measuring distance and acquiring an improved image.

In general, in the case of existing keys, access cards, etc., there is a lot of room for theft, loss, duplication, etc., so it is relatively low in security, must carry, and it is necessary to carry out labor such as memorizing password. There are many researches on personal identification technologies with higher security and convenience.

As one of them, biometric systems are gradually being commercialized, and biometrics can be identified by extracting biometric information (fingerprint, face, iris, cornea, hand shape, hand vein, voice, etc.) that are different for each person. In order to extract information for recognition by photographing a living body using a camera, a personal identification system using iris recognition is widely used.

As one of such biometric systems, an iris recognition system has been proposed.

The iris recognition system is a device that recognizes the identity of a person by recognizing the iris of a person entering and leaving. This iris recognition system is in the spotlight as a new security system because it is impossible to copy or forge an iris. The iris recognition system can be installed inside the door, wall, or independently to identify the identity of the person.

In the iris recognition system, when the user enters the proper distance from the iris recognition system, that is, the operating area, the image sensor initiates an operation to capture the user's eyes and compare the captured image with the iris image stored in the database. An iris recognition operation is performed.

However, since the user does not know where the operating area of the iris recognition system is, a technique for guiding the user into the operating area of the iris recognition system is required.

Conventionally, a distance sensor is used to guide the user into the operating area and the user is in the operating area using an indicator such as a lamp to measure the distance to the user and display the distance or indicate whether the user is at a suitable distance. The method of guiding the user to the operating area was used.

1 illustrates an example of an iris recognition system according to a conventional method.

In the conventional iris recognition system, the distance measuring sensor 11 is used to measure the distance to the user, and when the user enters the operating area, the user is informed by an indicator 12 such as an LED. However, when the distance measuring sensor 11 is used, since the face of the person is not flat and there is curvature, the accurate distance cannot be measured, and the sensitivity of the distance measuring sensor itself is low. This has the disadvantage of increasing.

In addition, as shown in FIG. 1, in the conventional method, one image sensor 13a and 13b is used to capture an image of one eye. Therefore, a wide angle view camera is used as an image sensor to satisfy various eye lengths (IPD: Inter Papillary Distance, 40mm to 90mm).

However, when a wide-angle camera is used, it is difficult to acquire an image (see High Quality, ISO / IEC 19794-6) having a large data throughput and a data amount suitable for iris recognition due to the large field of view.

In order to implement an improved iris recognition system, a more accurate distance measurement and a method of capturing an improved image are required.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an iris recognition device and method which can guide a user to a more accurate operating range.

An object of the present invention is to provide an iris recognition device and method capable of accurately measuring a distance to a user rather than a distance measuring sensor.

An object of the present invention is to provide an iris recognition apparatus and method that can obtain an image more suitable for iris recognition by using an image sensor equipped with a narrow angle lens.

An iris recognition device according to an embodiment of the present invention, the illumination light source for illuminating the infrared toward the user's eyes; A plurality of narrow-angle image sensors configured to photograph the eyes of the user illuminated by the illumination light source and are arranged to photograph each of the eyes of the user at a predetermined interval; And a distance calculator configured to calculate a distance from the image captured by the narrow-angle infrared image sensor to the eyes of the user.

Iris recognition method according to an embodiment of the present invention, the step of illuminating the infrared to the user's eyes; Photographing each eye of the user illuminated by the infrared rays with a plurality of narrow-angle infrared cameras spaced apart from each other by a predetermined distance; Calculating a distance from the eye images captured by the plurality of narrow-angle infrared cameras to the user's eyes; And performing iris recognition based on the captured image.

According to the present invention, by applying a plurality of image sensors to each eye of the user to measure the distance to the user's eyes it is possible to quickly and accurately guide the user to the operating region of the iris recognition device.

The present invention can obtain an iris image having a wider range and a larger amount of data while using a narrow angle image sensor with a reduced angle of view.

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

Figure 2 is an exploded view showing the configuration of the iris recognition device according to the present invention, a top view looking down the disassembled state of the iris recognition device.

As shown in FIG. 2, the iris recognition apparatus according to the present invention includes an illumination light source 205a, 205b, 205c, 205d and an illumination light source 205a, 205b, 205c, 205d that illuminate infrared rays toward a user's eyes. A plurality of narrow-angle image sensors 204a, 204b, 204c, and 204d arranged to capture a plurality of eyes of the user at a predetermined interval, and images captured by the narrow-angle infrared image sensor And distance calculation units 207a and 207b for calculating the distance from the eye to the user's eyes.

According to an embodiment, a sealed case (not shown) may be further included surrounding all of the components to block external light.

The illumination light sources 205a, 205b, 205c, and 205d emit infrared light toward the opening 209 of the iris recognition device and illuminate both eyes of the user. In FIG. 2, four of the two image sensors 204a, 204b, 204c, and 204d are arranged on the left and right sides of the image sensor, but the position and number thereof may vary according to embodiments.

Preferably, the illumination light sources 205a, 205b, 205c, and 205d may be infrared LEDs, and may be LED arrays in which a plurality of infrared LEDs are mounted on a substrate. It may also be preferably arranged to be symmetrical about the optical axis 208 for uniform illumination.

Narrow-angle infrared image sensors 204a, 204b, 204c and 204d capture images of both eyes of a person illuminated by the illumination light sources 205a, 205b, 205c and 205d, respectively.

Image sensors 204a and 204b photograph one eye, and image sensors 204c and 204d photograph the other eye. In some embodiments, a larger number of image sensors may be allocated to each eye for photographing. That is, depending on the embodiment, three or more image sensors may be used for each eye to cover a wider operating area.

On the other hand, the iris recognition device and method according to the present invention uses a narrow-angle infrared image sensor as the image sensor (204a, 204b, 204c, 204d). In the present invention, the narrow-angle infrared image sensor refers to an image sensor having 7 to 11 degrees that is an angle view of a lens (ie, a condenser lens) used. By using a narrow-angle image sensor, unlike conventional wide view image sensors, data throughput can be reduced, and images of a quality closer to 200 pixel / cm (see ISO / IEC 19794-6) suitable for iris recognition can be obtained. You can get it.

In FIG. 2, the image sensors 204a, 204b, 204c, and 204d are disposed on the same plane. However, in some embodiments, arrangement directions of the image sensors 204a, 204b, 204c, and 204d may be different.

Since a plurality of image sensors spaced by a predetermined distance per eye are allocated and photographed, the distance from the image sensor to the user's eyes can be measured without a distance sensor. The interval at which the image sensor is spaced apart may vary depending on the size and design of the iris recognition device.

That is, as shown in FIG. 3, the left eye 210 is photographed by two image sensors 204a and 204b spaced apart from each other by a predetermined distance, and the right eye 211 is similarly spaced by a predetermined distance. The image is captured by the sensors 204c and 204d.

The distance calculators 207a and 207b calculate distances from the images of the eyes photographed by the image sensors 204a, 204b, 204c and 204d. The distance calculators 207a and 207b may be designed as independent IC modules or may be integrated into a processor (not shown) that actually performs iris recognition through comparison with a database.

4A and 4B illustrate a method of measuring distance by photographing by the plurality of image sensors 204a, 204b, 204c, and 204d.

In the case of measuring the left eye 210 in Figure 3 will be described as an example. When the left eye 210 is photographed by two image sensors 204a and 204b spaced apart from each other by a predetermined distance, the image 41 captured by the left sensor 204a and the image captured by the right sensor 204b as shown in FIG. 4A ( 42) is different. That is, the same object is photographed, but the position of the object is different in the photographed image.

The image photographed by each image sensor is superimposed as shown in FIG. 4B, and the difference value is calculated. The smaller the difference is, the farther the distance is from the image sensor, and the larger the difference is, the closer the image sensor is. The distance may be calculated by making a database of the actual distance according to the difference value, or the distance may be calculated using the distance value and the difference value between the image sensors 204a and 204b.

According to an exemplary embodiment, the difference value may be used as shown in FIG. 4B, or the photographed image may be superimposed, and the distance may be calculated using how much coincidence, that is, the matching amount. In addition, the distance can be calculated in various ways.

In addition, according to the exemplary embodiment, the distance may be measured using only one line data constituting one frame, rather than comparing the entire image photographed by the spaced image sensors. For example, when the image photographed by the image sensors 204a and 204b is an image of 752 × 480 resolution, it is not necessary to use the entire image data for the actual distance measurement. Accordingly, the distance to the user can be measured by selecting only one line data at the same position of the images photographed by the image sensors 204a and 204b and comparing them. In this case, the amount of data computation performed by the distance calculators 207a and 207b can be reduced.

According to the embodiment, instead of comparing the entire line, only a part of the line can be selected and used for the distance calculation.

In addition, the image used to calculate the distance need not be an image of the eye as shown in FIGS. 4A and 4B, and the distance calculation may be performed even with an image of an arbitrary part of the user's face, for example, an image including the forehead, eyebrows, and the like. Can be.

On the other hand, according to an embodiment of the present invention, as shown in Figure 2, may further include an infrared filter 201 to block light other than infrared from the outside. The infrared filter 201 includes an opening 209 that passes through all the light without blocking it.

The user places his eye close to the opening 209 of the infrared filter 201 so that the image sensor 204a, 204b, 204c, 204d can be illuminated. Preferably both eyes are brought between the openings 209 of the infrared filter 201. The user places the two eyes in a symmetrical position about the optical axis 208.

According to an embodiment of the present invention, as shown in FIG. 2, the display unit 206 may further include a display unit 206 for indicating to the user whether the user is in an appropriate operating area for iris recognition.

The display unit 206 may be any light emitting device that can give information to the user. In some embodiments, the display unit 206 may be displayed by a voice or a display device outside the iris recognition device. The display unit 206 may be a point light source by a visible light LED, or may be a visible light LED array in which a plurality of LEDs are arranged on a substrate.

The display unit 206 is preferably disposed on the optical axis 208 so that the user's head and the display unit 206 coincide with each other when viewed by the user.

According to an embodiment of the present invention, as shown in FIG. 2, the condenser lens 203 may further include a condenser lens for adjusting the position of the image to be displayed to the user. When the display unit 206 is present in the iris recognition device, the user can determine whether the user's position is within the operating area while looking at the display unit 206, and the position where the image of the display unit 206 actually viewed is formed. It depends on the focal length of the condenser lens 203. Therefore, by appropriately selecting and designing a focal length of the condenser lens 203, the position where the image of the display unit 206 actually viewed by the user can be adjusted.

As the condenser lens 203, a Fresnel lens is preferably used.

In order to provide a comfortable image to the eyes of the user, the image of the display portion 206 shown to the user is preferably formed on the opposite side of the condenser lens 203 by the same distance from the condenser lens 203 to the user.

According to an embodiment, other than the display unit 206 may be visible to the user through the condenser lens 203.

In addition, according to an embodiment of the present invention, it is disposed outside the condenser lens 203 to reflect the user's appearance to the user, and at the same time the inside of the display unit 206 or the iris recognition device can be seen. A half mirror 202 may be further included.

The half mirror 202 is a device that can act as a mirror and glass at the same time, and allows the user to see his / her appearance and the information displayed by the display unit 206.

There may be a variety of methods for inducing a user to place his or her eye in the center of the opening 209 of the infrared filter 201. For example, since the opening 209 is a portion exposed to the outside of the iris recognition device, the opening of the iris may be placed at the center of the iris recognition device. By matching, you can also get your eyes close to the proper position for iris recognition.

In FIG. 2, all components are disassembled and illustrated for explanation, but in the actual product, the half mirror 202 may be inserted and mounted in the drilled space of the infrared filter 201.

In addition, the half mirror 202 and the condenser lens 203 may be completely in contact with each other. In addition, the half mirror 202 and the condenser lens 203 may be formed as one element by coating a metal material having excellent reflectivity on one surface of the condenser lens 203.

On the other hand, the operation region of the iris recognition device according to an embodiment of the present invention, that is, the position of the user's eye suitable for iris recognition is set as follows.

As described above, in the iris recognition apparatus according to the present invention, since the image sensors 204a, 204b, 204c, and 204d are narrow-angle image sensors, a narrow-angle lens is used as the lens. And a short focal length lens may be used.

When using a lens that can be adjusted in focus, the operating range will be the range in which focus can be achieved by adjusting the focus.

In the case of using a short focal lens, the depth of focus of the lens, that is, the range in which the focus is achieved, is used to set the operating area.

In the case of using an image sensor having a short focal length lens, the depth of focus is determined according to the characteristics of the lens as shown in Equation 1 below, and the depth of focus becomes an operation region of the iris recognition device.

(식 1)

(Equation 1)

Here, Fnumber is the F number of the lens, f is the focal length of the lens, δ is the pixel size of the image sensor, and S is the distance from the lens surface to the object to be photographed.

The above variables may vary depending on the device design, and the designer may select an appropriate depth of focus and set an operation area as needed.

Referring back to Figure 2 will be described the operation of the user guidance device for iris recognition device according to the present invention.

When the user approaches the eye near the opening 209, the image sensors 204a, 204b, 204c, 204d or any other sensor detects movement to initiate an iris recognition operation.

Infrared light is irradiated near the opening 209 by the illumination light sources 205a, 205b, 205c, and 205d, and a plurality of narrow-angle infrared image sensors 204a, 204b, 204c, and 204d are respectively illuminated by the infrared light. Your eyes.

At this time, the user's eyes are adjusted up, down, left and right as described above by the user looking at the display unit 206 or the like through the half mirror 202 or by directly approaching the eye at the center of the opening 209.

The eye image data captured by the plurality of narrow-angle infrared image sensors 204a, 204b, 204c, and 204d are transferred to the distance calculators 207a and 207b, respectively, and the distance calculators 207a and 207b respectively show FIGS. 4A and 4B. The distance from the field to the user's eyes is calculated based on the method described with reference to FIG.

Then, the display unit 206 displays the calculated distance to the user. As the display unit 206, a visible light LED may be used. For example, the display unit 206 may display a green light when the user's eyes are in the operating area, and display a red color when the user's eyes are outside the operating area.

When the user's eyes are in the motion range, the iris recognition process is performed by well-known methods. The iris recognition process may be performed by a separate processor (not shown).

In the above, an example of measuring the distance to both eyes has been described. However, in order to simplify the system by reducing the amount of calculation, only the distance to one eye is measured, and the user is positioned in the operation area based on the distance. Then iris recognition can be performed.

The image used for iris recognition will vary depending on the iris recognition algorithm used in some embodiments.

Although the present invention has been described through the above embodiments, the above embodiments are merely intended to illustrate the spirit of the present invention, and the present invention is not limited thereto. Those skilled in the art will appreciate that various modifications may be made to the embodiments described above. The scope of the invention is defined only by the interpretation of the appended claims.

1 illustrates an example of an iris recognition system according to a conventional method.

Figure 2 is an exploded view showing the configuration of the user distance induction device for iris recognition according to the present invention.

3 is a view for explaining the principle of the user distance inducing apparatus according to the present invention.

4A and 4B are views for explaining a method of measuring a user distance according to the present invention.

※ Description of main part of drawing ※

201: infrared filter 202: half mirror

203: condenser lens 204a, 204b, 204c, 204d: image sensor

205a, 205b, 205c, 205d: Illumination light source 206: Display portion

207a and 207b: Distance calculator 208: Optical axis

209: infrared filter opening

Claims (11)

An illumination light source that illuminates infrared rays toward the eyes of a user; A plurality of narrow-angle image sensors configured to photograph the eyes of the user illuminated by the illumination light source and are arranged to photograph each of the eyes of the user at a predetermined interval; And And a distance calculator configured to calculate a distance from the image captured by the narrow-angle infrared image sensor to the user's eyes. The method of claim 1, The iris recognition device further comprises a condenser lens for adjusting the position of the image to the image shown to the user. The method of claim 1, And an indicator configured to display whether the user is at an appropriate distance according to the distance calculated by the distance calculator. The method of claim 1, The iris recognition device further comprises an infrared filter for blocking light other than infrared rays of the light incident on the condensing lens. The method of claim 1, And a half mirror disposed outside the condenser lens to reflect the user's appearance to the user and to view the inside of the iris recognition device. The iris recognition device of claim 1, wherein the display unit is a visible light LED displaying a color differently according to a distance calculated by the distance calculator. The method of claim 1, The condensing lens is a Fresnel lens. Illuminating infrared light in a user's eyes; Photographing each eye of the user illuminated by the infrared rays with a plurality of narrow-angle infrared cameras spaced apart from each other by a predetermined distance; Calculating a distance from the eye images captured by the plurality of narrow-angle infrared cameras to the user's eyes; And Performing iris recognition based on the captured image; Iris recognition method comprising a. The method of claim 8, Computing the distance to the user's eyes, Comparing the images photographed by the plurality of cameras, respectively; Calculating a difference value of the image; And Calculating a distance based on the difference value; Iris recognition method comprising a. The method of claim 8, Iris recognition method further comprising the step of displaying the calculated distance to the user. The method of claim 10, Displaying the calculated distance to the user, Iris recognition method comprising the step of changing the color of the light source according to the calculated distance.

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