WO2009154368A2 - Iris image acquisition system using panning and tilting of mirror at long distance - Google Patents

Abstract

The present invention relates to an iris image acquisition system using the panning and tilting of a mirror at a long distance. Through a mirror member (for example, hot mirror), the iris image acquisition system matches the optical angles of a WFOV (Wide Field Of View) camera for photographing a visible ray image, an NFOV (Narrow Field Of View) camera for photographing an infrared ray image, and a near-infrared illuminator for the NFOV camera. The iris image acquisition system controls the matched optical angles with a single mirror PT (Pan-Tilt) device to acquire an iris image of a user at a long distance. According to the invention, the near-infrared illuminator lights up only the view angle range of the NFOV camera such that the optical angle of the NFOV camera is matched with that of the WFOV camera through the single-mirror PT device so that a high-quality bright iris image may be acquired without additional light control. Compared with known illuminators, the present illuminator can be configured on a small scale at a low cost and the lighting is safer for the eye since only the illumination for the view angle of the NFOV camera is required. Furthermore, a low-light camera (for example, low-light VGA camera), or a near-infrared camera, etc., that is cheaper than known megapixel NFOV cameras and able to acquire an iris image at a low illumination intensity can be used as the NFOV camera.

Description

Remote Iris Image Acquisition System Using Panning and Tilting of Mirrors

The present invention relates to an iris image acquisition technology, and more particularly, to match the optical axis of the wide-angle camera for visible light imaging, the narrow-angle camera for infrared imaging, and the near-infrared illumination device for the narrow-angle camera, and the matched optical axis is one mirror PT (Pan). A remote iris image acquisition system using panning and tilting of a mirror controlled by a device to obtain an iris image of a remote user, that is, an iris recognition target.

Among the iris image acquisition techniques commonly applied to conventional iris recognition systems, the portal system developed by Sarnoff Corporation under the product name "Iris On the Move" has two single-focus megapixels with no movement. A high-resolution camera is used, and a remote user is a system that passes through a gate that the camera is shooting, and has an advantage of displaying a high processing speed (20 subjects / min).

At Mitsubishi Corporation, on the other hand, Pan-Tilt (PT) devices, one wide-field-of-view (WFOV) camera, and one megapixel narrow-field (NFOV) The iris image acquisition method was introduced by using a camera to detect a face of a remote user in a relatively wide range of motion and using a distance prediction method using extracted facial feature information.

However, the above-described Saroff Corporation's Portal system has limitations on the position and posture of the user passing through the gate. In particular, since the area photographed by the camera is the entire gate, the gate is used to illuminate the entire shooting area. A significant number of infrared lights are attached throughout, which increases the overall system cost.

In addition, while the above-mentioned iris image acquisition technique of Mitsubishi Corporation has an advantage of having a relatively wide operating range due to the PT (Pan-Tilt) function, it is sufficient to illuminate the shooting area of the megapixel narrow angle camera. As a result, a large-scale near-infrared light that exhibits high power characteristics is required, and thus, it is difficult to control large-scale lights to produce high power.

The present invention is to solve the conventional problems as described above, an object of the present invention is to match the optical axis of the wide-angle camera for visible light imaging, the narrow angle camera for infrared imaging and the near-infrared illumination device for the narrow angle camera through a mirror member. In addition, by controlling the matched optical axis with one mirror PT (Pan-Tilt) device, the near-infrared illuminator that illuminates the shooting area of the narrow-angle camera only when the narrow-angle camera is operated to operate the non-optically remote user, that is, the iris recognition subject. It is to provide a distant iris image acquisition system using panning and tilting of a mirror to acquire an iris image of a.

The present invention is to solve the conventional problems as described above, another object of the present invention is an ultra-wide-angle camera having a relatively larger angle of view than a wide-angle camera to detect the eye position of the user, that is, the iris recognition subject first And a single mirror PT (Pan-Tilt) device to match the optical axis of the wide angle camera for visible light imaging, the narrow angle camera for infrared imaging, and the near-infrared illumination device for the narrow angle camera, and the photographing area of the narrow angle camera only when the narrow angle camera operates. It is to provide a remote iris image acquisition system using panning and tilting of a mirror that acquires an iris image of a non-coercive distant user, that is, an iris recognition subject, by using a near-infrared illumination device that illuminates.

In order to achieve the object of the present invention as described above, an embodiment of a remote iris image acquisition system using the panning and tilting of the mirror according to the present invention, a wide-angle camera for photographing the user sensed image; A narrow angle camera having a zoom lens and a focus lens adjusting function to capture a user iris image; A near-infrared illumination device that illuminates a photographing area of the narrow-angle camera only when the narrow-angle camera operates; A mirror member that transmits or reflects visible light or transmits or reflects infrared rays so that the optical axes of the wide-angle camera and the narrow-angle camera coincide with each other while being disposed in front of the wide-angle camera and the narrow-angle camera; Pan-Tilt (PT-mirror) to change the shooting direction of the wide-angle camera and the narrow-angle camera whose optical axis is matched by changing the path of visible light or infrared light passing through the mirror member or reflected by the mirror member by panning or tilting a total reflection mirror. Device; And panning or tilting the total reflection mirror of the mirror PT device such that the eye is located at the center of the captured image of the wide-angle camera according to a result of detecting the eye position after the face is identified from the user-sensing image captured by the wide-angle camera. Next, pan or tilt the total reflection mirror of the mirror PT device while operating the near-infrared illumination device to obtain an iris image having a size suitable for iris recognition when the user's eyes are positioned at the center of the captured image of the narrow angle camera. And a main processor for acquiring an iris image by varying the zoom magnification necessary for auto focusing and auto focusing.

In order to achieve the object of the present invention as described above, another embodiment of the remote iris image acquisition system using the panning and tilting of the mirror according to the present invention, a wide-angle camera for photographing the user sensed image; An ultra wide angle camera having a relatively larger angle of view than the wide angle camera; A narrow angle camera having a zoom lens and a focus lens adjusting function to capture a user iris image; A near-infrared illumination device that illuminates a photographing area of the narrow-angle camera only when the narrow-angle camera operates; A mirror member that transmits or reflects visible light or transmits or reflects infrared rays so that the optical axes of the wide-angle camera and the narrow-angle camera coincide with each other while being disposed in front of the wide-angle camera and the narrow-angle camera; Pan-Tilt (PT-mirror) to change the shooting direction of the wide-angle camera and the narrow-angle camera whose optical axis is matched by changing the path of visible light or infrared light passing through the mirror member or reflected by the mirror member by panning or tilting a total reflection mirror. Device; Panning or tilting the total reflection mirror of the mirror PT device such that the eye is located at the center of the captured image of the wide-angle camera according to a result of detecting the eye position after the face is identified from the user-sensing image captured by the ultra-wide-angle camera. Next, pan or tilt the total reflection mirror of the mirror PT device while operating the near-infrared illumination device to obtain an iris image having a size suitable for iris recognition when the user's eyes are positioned at the center of the captured image of the narrow angle camera. And a main processor for acquiring an iris image by varying the zoom magnification necessary for auto focusing and auto focusing.

As described above, according to the present invention, since the optical axis of the narrow angle camera always matches the optical axis of the wide angle camera with one mirror PT device, the near-infrared illumination controls only the field of view angle of the narrow angle camera, so that no separate lighting control is required. Since it is possible to obtain high quality bright iris image and to illuminate only the angle of view of the narrow angle camera, it is possible to improve the eye safety for lighting while implementing the lighting device on a smaller scale at a relatively low price compared to the conventional art. In addition, a low-light camera (eg, a VGA-level low light camera) or a near-infrared camera that can obtain an iris image with less illumination than a conventional megapixel-type narrow angle camera can be used as the narrow angle camera.

1 is a first embodiment showing a far-field iris image acquisition system using panning and tilting of a mirror according to the present invention;

Figure 2 is an embodiment showing a state of use of the near-infrared illumination device for the narrow angle camera of Figure 1;

Figure 3 is another embodiment showing the state of use of the near-infrared illumination device for the narrow angle camera of Figure 1;

4 is a flowchart illustrating an operation process of a far iris image acquisition system using panning and tilting of a mirror according to a first embodiment of the present invention.

5 is a second embodiment showing a system for acquiring a distant iris image using panning and tilting of a mirror according to the present invention;

6 is a third embodiment showing a system for acquiring a distant iris image using panning and tilting of a mirror according to the present invention;

7 is a fourth embodiment showing a system for acquiring a distant iris image using panning and tilting of a mirror according to the present invention;

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

[First Embodiment]

1 to 3, the wide-angle camera 10 is a camera for capturing a visible light image. The wide-angle camera 10 captures a user's sensed image, and has an angle of view of 15 ° or more to secure an angle of view larger than the size of the user's face in a general color camera. It is preferable to use a camera with a lens attached thereto.

The narrow angle camera 20 is a camera for capturing infrared images through visible light blocking and infrared transmission filters. The narrow angle camera 20 is equipped with a zoom lens and a focus lens adjusting function to capture a user iris image.

The narrow angle camera 20 has an infrared wavelength compared to a low light camera (eg, a VGA low light camera) or a general surveillance camera that amplifies a small amount of electrical signal generated by a CCD sensor when a small amount of light is received to obtain a brighter image than a general camera. It is preferable to use a near-infrared camera having high reactivity.

The narrow angle camera 20 preferably uses a camera having a zoom lens having an angle of view of 1 ° to 4 ° in a low light camera that can obtain a brighter image than other cameras even in low light. For reference, the narrow angle camera ( 20) If you use a low-light camera with a higher resolution than a VGA-level low-light camera, you can use a short focus lens instead of a zoom lens.

The near-infrared illumination device 30, 30 'is mounted on the outer surface of the body of the narrow angle camera 20 to cooperate with the narrow angle camera 20, as shown in Figure 2, or as shown in Figure 3, the mirror It is mounted around a member (eg, a hot mirror) to illuminate the photographing area of the narrow angle camera 20 only when the narrow angle camera 20 is operated, and preferably irradiate near infrared rays around the face of the user.

The near-infrared illumination device 30, 30 'preferably has an irradiation angle as long as it illuminates the area photographed by the narrow angle camera 20, and is, for example, 4 ° with respect to a narrow angle camera having a maximum angle of view of 4 ° as described above. A near-infrared illumination device having an irradiation angle is used.

The near-infrared illumination device (30, 30 ') is mounted on the outer surface of the body or the mirror member of the narrow angle camera 20 is a single illumination device that illuminates the photographing area of the narrow angle camera 20 only when the narrow angle camera 20 is operated. Alternatively, a plurality of lighting devices may be used, and in the case of using only a single lighting device, the reflected light may be reflected above or below the iris that is not used for iris recognition, or in FIGS. 2 (a) and 2 (b) or 3. As shown, in the case of using a plurality of lighting devices, the lighting is formed on the user's glasses or contact lenses by alternately switching the lighting devices located on the upper and lower sides or the left and right sides of the body of the narrow angle camera 20, or the upper and lower or left and right sides of the mirror member. Reflected light can also be avoided.

The mirror member transmits or reflects visible light or transmits or reflects infrared rays in a state of being disposed in front of the wide angle camera 10 and the narrow angle camera 20 so that the optical axis of the wide angle camera 10 and the narrow angle camera 20 To match.

The mirror member transmits visible light of the wide-angle camera 10 while being disposed at an angle of inclination of 45 ° in front of the wide-angle camera 10 and the narrow-angle camera 20, and the infrared rays of the narrow-angle camera 20 are It may consist of a single hot mirror that reflects.

The pan-tilt (PT) device 40 pans or tilts the total reflection mirror 41 to change the path of visible light passing through the mirror member and infrared rays reflected by the mirror member, thereby making the wide-angle camera 10 match the optical axis. ) And an illumination direction in which the near-infrared illumination device (30,30 ') illuminates an area photographed by the narrow angle camera (20) and the shooting direction of the narrow angle camera (20). To match.

The main processor 50 is configured such that the eye is located at the center of the captured image of the wide-angle camera 10 according to a result of detecting the eye position after the face is identified from the user-sensed image captured by the wide-angle camera 10. Pan or tilt the total reflection mirror 41 of the mirror PT device 40, and then pan or tilt the total reflection mirror 41 of the mirror PT device 40 while operating the near-infrared illumination device 30,30 '. When the user's eyes are located at the center of the captured image of the narrow angle camera 20, the zoom lens of the narrow angle camera 20 is changed to a zoom ratio necessary for obtaining an iris image having a size suitable for iris recognition, and the auto focus is adjusted to adjust the iris image. Acquire.

The main processor 50 uses the distance information obtained by the distance measuring device between the iris image acquisition system and the user to zoom the zoom lens of the narrow angle camera 20 to a zoom ratio necessary for obtaining an iris image having a size suitable for iris recognition. An initial value for the accuracy of the process of performing auto focusing can be estimated by a variable and auto focusing algorithm.

The main processor 50 controls the operation of the wide-angle camera 10, the narrow angle camera 20, the near-infrared illumination device (30, 30 '), the mirror PT device (40).

The main processor 50 finds a face of the user through a face detection method (eg, AdaBoost, light reflection tracking, PCA, ICA, etc.) in the user sensed image captured by the wide-angle camera 10. Can be verified. When the face is detected and confirmed, the eye position method (eg, AdaBoost, light reflection tracking technique, histogram, etc.) may find or confirm the eye position or the eye.

The main processor 50 may transfer the obtained iris image to a separate iris recognition system to perform iris recognition, or may perform iris recognition using an iris image obtained by directly performing an iris recognition algorithm.

The far iris image acquisition system using the panning and tilting of the mirror according to the first embodiment of the present invention configured as described above operates as follows.

First, it is assumed that the main processor 50 has an iris recognition function.

Referring to FIG. 4, the main processor 50 detects a moving object, for example, a user by generating a difference image from an existing background image from a user sensing image captured by the wide angle camera 10 (S10). A face is detected from the corresponding user detection image by using a face detection method (S20).

If the face is detected, the eye position is detected through the eye detection method described above (S30).

Thereafter, the total reflection mirror 41 of the mirror PT device 40 is panned or tilted so that the eye is positioned at the center of the captured image of the wide-angle camera 10 according to the result of detecting the eye position (S40). The narrow angle camera 20 automatically looks at the eye area.

Subsequently, the main processor 50 performs the focus adjustment of the narrow angle camera 20 while operating the near-infrared illuminators 30 and 30 '(S50), and then sequentially in the image photographed by the narrow angle camera 20. The eye position is again found and verified (S60), and the total reflection mirror 41 of the mirror PT device 40 is finely panned again so that the eye is exactly at the center of the captured image of the narrow angle camera 20 at the verified eye position. Or adjust the eye position by tilting (S70), and finally checks whether the user's eyes are in the angle of view range of the narrow angle camera 20 (S80). When the eye is detected by the narrow angle camera 20, an eye detection method (eg, a circular hough transform, a circular boundary tracking method, etc.) capable of finding a circular boundary is used.

At this time, if the eye is not detected, the main processor 50 returns to the process S60 to find the eye position again, and returns to the process S30 when the eye is not confirmed for a predetermined number of repetitions (N) (S90). .

On the other hand, when the eye is detected, the main processor 50 verifies the size of the iris area necessary for iris recognition in the image photographed by the narrow angle camera 20 and uses the zoom ratio necessary for acquiring an iris image having a size suitable for iris recognition. The zoom lens of the narrow angle camera 20 is varied and auto focus is adjusted to finally obtain an iris image (S100, S110, and S120).

When the final iris image is obtained as described above, the main processor 50 performs iris recognition using the iris image obtained by directly performing an iris recognition algorithm (S130), and on the other hand, separates the iris image obtained from the iris image. It can be passed to the recognition system to perform iris recognition.

Second Embodiment

Referring to FIG. 5, in the configuration of the second embodiment, the mirror PT device 40 including the wide-angle camera 10, the narrow angle camera 20, the near-infrared illumination devices 30 and 30 ′, and the total reflection mirror 41 is provided. The main processor 50 operates as described in the first embodiment, except that the mirror member is disposed at an angle of inclination of 45 ° in front of the wide angle camera 10 and the narrow angle camera 20. In this case, the visible light of the wide-angle camera 10 is reflected, and the infrared rays of the narrow-angle camera 20 are different from each other in that they are configured as a single cold mirror.

Therefore, in the second embodiment, the mirror pan-tilt (PT) device 40 pans or tilts the total reflection mirror 41 to provide a path of infrared light passing through the mirror member and visible light reflected by the mirror member. By changing the optical direction of the wide-angle camera 10 and the narrow-angle camera 20 is matched to the optical axis, and the illumination direction in which the near-infrared illumination device (30, 30 ') illuminates the area photographed by the narrow-angle camera 20 Is changed to match the shooting direction of the narrow angle camera 20.

The operation of the far iris image acquisition system using the panning and tilting of the mirror according to the second embodiment of the present invention configured as described above is the same as the contents S10 to S130 described with reference to FIG. 4 in the first embodiment. Since the operation is performed, detailed operation description is omitted.

Third Embodiment

6, in the configuration of the third embodiment, the wide-angle camera 10, the narrow-angle camera 20, the near-infrared illuminators 30 and 30 ′, the mirror members (eg, hot mirrors) and the total reflection mirrors 41 are described. The mirror PT device 40 including) operates as described in the above-described first embodiment, except that the ultra wide-angle camera 10a is additionally configured separately from the wide-angle camera 10. The operation of the processor 50 'is somewhat different.

The ultra wide-angle camera 10a is a camera having a relatively larger angle of view than the wide-angle camera 10, and is a two-dimensional operating range of the iris recognition system limited to the angle of view of the conventional wide-angle camera 10, that is, the wide-angle camera 10 ) Can widen the horizontal and vertical ranges taken by the ultra wide angle or the angle of view of the fisheye lens.

The far iris image acquisition system using the panning and tilting of the mirror according to the third embodiment of the present invention configured as described above operates as follows.

Referring to FIG. 4, the main processor 50 ′ generates a difference image from an existing background image from a user sensing image captured by the ultra wide-angle camera 10a, and detects a moving object, for example, a user (S10). The face is detected from the corresponding user detection image by using the face detection method as described above (S20).

If a face is detected, the eye position is detected through the eye detection method (S30), and then the eye is positioned at the center of the captured image of the wide-angle camera 10 according to the result of detecting the eye position. Panning or tilting the total reflection mirror 41 of the mirror PT device 40 (S40), the following operation process (S50 ~ S130) is performed in the same manner as described with reference to Figure 4 in the first embodiment, Operational description is omitted.

[Example 4]

Referring to FIG. 7, in the configuration of the fourth embodiment, the mirror PT device 40 including the wide-angle camera 10, the narrow angle camera 20, the near-infrared illumination devices 30 and 30 ′, and the total reflection mirror 41 is provided. The main processor 50 'operates as described in the third embodiment, except that the mirror member is disposed at an angle of inclination of 45 ° in front of the wide angle camera 10 and the narrow angle camera 20. In this state, the visible light of the wide-angle camera 10 reflects the visible light and the infrared light of the narrow-angle camera 20 is different from the point consisting of a single cold mirror (cold mirror).

Thus, in the fourth embodiment, the mirror pan-tilt (PT) device 40 pans or tilts the total reflection mirror 41 so as to pass a path of infrared rays passing through the mirror member and visible light reflected by the mirror member. By changing the optical direction of the wide-angle camera 10 and the narrow-angle camera 20 is matched to the optical axis, and the illumination direction in which the near-infrared illumination device (30, 30 ') illuminates the area photographed by the narrow-angle camera 20 Is changed to match the shooting direction of the narrow angle camera 20.

The operation of the far iris image acquisition system using the panning and tilting of the mirror according to the fourth embodiment of the present invention configured as described above is the same as the contents S10 to S130 described with reference to FIG. 4 in the third embodiment. Since the operation is performed, detailed operation description is omitted.

The far iris image acquisition system using the panning and tilting of the mirror according to the present invention described above is not limited to the above-described embodiments, and the present invention belongs without departing from the gist of the present invention as claimed in the following claims. To those skilled in the art, the technical spirit is to the extent that anyone can make various changes.

Claims (7)

A wide-angle camera 10 for capturing a user sensed image; A narrow angle camera 20 having a zoom lens and a focus lens adjusting function to capture a user iris image; A near-infrared illumination device (30,30 ') that illuminates the photographing area of the narrow angle camera (20) only when the narrow angle camera (20) operates; In the state disposed in front of the wide-angle camera 10 and the narrow angle camera 20 transmits or reflects visible light or transmits or reflects infrared rays to match the optical axis of the wide-angle camera 10 and the narrow angle camera 20. Mirror members; Pan or tilt the total reflection mirror 41 to change the path of visible light or infrared light that passes through or is reflected by the mirror member, thereby adjusting the photographing direction of the wide-angle camera 10 and the narrow-angle camera 20 that are coincident with the optical axis. A mirrored pan-tilt (PT) device 40; And The mirror PT device 40 so that the eye is located at the center of the captured image of the wide-angle camera 10 according to the result of detecting the eye position after the face is identified from the user-sensing image captured by the wide-angle camera 10. Pan or tilt the total reflection mirror 41 of the user, and then pan or tilt the total reflection mirror 41 of the mirror PT device 40 while operating the near-infrared illuminators 30 and 30 '. In the center of the photographed image of 20, the main lens 50 that changes the zoom lens of the narrow angle camera 20 to a zoom factor necessary for acquiring an iris image having a size suitable for iris recognition and obtains an iris image by auto focusing. ); Far iris image acquisition system using a panning and tilting of the mirror, characterized in that consisting of. A wide-angle camera 10 for capturing a user sensed image; An ultra wide angle camera having a larger angle of view than the wide angle camera 10; A narrow angle camera 20 having a zoom lens and a focus lens adjusting function to capture a user iris image; A near-infrared illumination device (30,30 ') that illuminates the photographing area of the narrow angle camera (20) only when the narrow angle camera (20) operates; In the state disposed in front of the wide-angle camera 10 and the narrow angle camera 20 transmits or reflects visible light or transmits or reflects infrared rays to match the optical axis of the wide-angle camera 10 and the narrow angle camera 20. Mirror members; Pan or tilt the total reflection mirror 41 to change the path of visible light or infrared light that passes through or is reflected by the mirror member, thereby adjusting the photographing direction of the wide-angle camera 10 and the narrow-angle camera 20 that are coincident with the optical axis. A mirrored pan-tilt (PT) device 40; And The mirror PT device 40 so that the eyes are located at the center of the captured image of the wide-angle camera 10 according to a result of detecting the eye position after the face is identified from the user-sensing image captured by the ultra-wide-angle camera 10a. Pan or tilt the total reflection mirror 41 of the user, and then pan or tilt the total reflection mirror 41 of the mirror PT device 40 while operating the near-infrared illuminators 30 and 30 '. In the center of the photographed image of 20, the main lens 50 that changes the zoom lens of the narrow angle camera 20 to a zoom factor necessary for acquiring an iris image having a size suitable for iris recognition and obtains an iris image by auto focusing. '); Far iris image acquisition system using a panning and tilting of the mirror, characterized in that consisting of. The system of claim 1 or 2, wherein the narrow angle camera is a low light camera or a near infrared camera. According to claim 1 or 2, wherein the near-infrared illumination device 30 is mounted on the outer surface of the body of the narrow angle camera 20, the illumination to illuminate the photographing area of the narrow angle camera 20 only when the narrow angle camera 20 is operated. Far iris image acquisition system using a panning and tilting of the mirror, characterized in that the device. The illumination device according to claim 1 or 2, wherein the near-infrared illumination device 30 'is mounted around the mirror member to illuminate the photographing area of the narrow-angle camera 20 only when the narrow-angle camera 20 is operated. Far iris image acquisition system using a panning and tilting of the mirror. The visible light of the wide-angle camera 10 is transmitted according to claim 1 or 2, wherein the mirror member is disposed at an angle of inclination of 45 ° in front of the wide-angle camera 10 and the narrow-angle camera 20. And an infrared ray of the narrow angle camera 20 reflects a single hot mirror. The visible light of the wide-angle camera 10 is reflected in the mirror member of claim 1 or 2, wherein the mirror member is disposed at an angle of inclination of 45 ° in front of the wide-angle camera 10 and the narrow-angle camera 20. And the infrared ray of the narrow angle camera 20 transmits a single cold mirror.

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