Abstract:
The present invention relates to an iris recognition system which can extract an iris image of the user, by upwardly and downwardly rotating around a hinge bracket in order to be exactly rapidly controlled to a position of the user&#39;s eyes. The conventional iris recognition system has disadvantages in that the system size is huge, the time for obtaining the iris image is quite long, and the system is difficult to handle. Accordingly, the iris recognition system includes: an optical imager for obtaining an iris image of the user at an optimal state, an inner casing at which the optical imager is disposed, an outer casing for supporting the inner casing, and surrounding surfaces of the inner casing, except for the front surface thereof, a control unit for receiving iris images outputted from the optical imager, and controlling the optical imager and a hinge bracket disposed at both side portions of the outer casing, for supporting the inner casing, and enabling the inner casing to upwardly and downwardly rotate. As a result, the system size is small, and the iris image can be easily rapidly precisely obtained.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an iris recognition system, and in particular to an iris recognition system which can extract an iris image of a user, by upwardly and downwardly rotating around a hinge bracket in order to be exactly rapidly controlled to a position of the user&#39;s eyes. 
     2. Description of the Background Art 
     In an automatic access control system and an automatic commercial transaction system using an internet, the user&#39;s biological characteristics have been recently utilized in order to identify the user. The biological characteristics are fingerprints, voice, retinas, faces, irises and the likes. Especially, every human being has different irises, and the irises are impossible to imitate and not varied for the entire life. Thus, the characteristics of the irises is applied to the systems, and used to identify the user. 
     Here, the iris implies a peripheral portion of a pupil of the animal&#39;s eye. The iris is a muscle controlling opening/closing of the pupil, and serves to control an amount of light which is externally incident on eyeball. 
     In general, the human being&#39;s eyes have been generally formed for the six months of pregnancy. Thereafter, a hole is formed at the pupil, and wrinkles are outwardly generated in a chaos pattern. The growth of the wrinkles is stopped within a few years after birth, and the wrinkles are not varied for the whole life. Accordingly, the iris including the wrinkles has its own pattern. Generally, the right iris of a person is different from the left iris of the person, and even identical twins have different irises as well. 
     Therefore, the iris recognition is to identify the shape of the iris having a specific pattern. That is, the irises photographed by a video camera are image-processed, and stored in a data base. Thereafter, a pattern of a currently-inputted iris is compared with that of the stored iris, thereby identifying the user having the currently-inputted iris. 
     An iris recognition system and a method thereof have been disclosed in the U.S. Pat. Nos. 4,641,349, 5,291,560 and 5,572,586. 
     Especially, the U.S. Pat. Nos. 4,641,349 and 5,291,560 relate to an iris imager for extracting an iris image, a system for analyzing the extracted iris image and an algorithm for generating an iris code of 256 bytes by using the iris image. 
     FIG. 1 is a cross-sectional view illustrating a conventional optical imager. As shown therein, the conventional optical imager includes: a camera  1  photographing eyes of the human beings, an optical lens  2  gathering light inputted to the camera  1 , a light source unit  6  emitting light in order to photograph the eyes of the human beings, an LCD unit  4  displaying an image of the eyes of the user photographed by the camera  1 , and a beam splitter  3  reflecting light incident from the eyes of the user to the camera  1 , and passing an image of the eyes of the user incident from the LCD unit  4  toward the eyes of the user. 
     The conventional optical iris imager has a disadvantage in that a size of the system is large. In addition, the camera does not have an automatic zoom and focus function, and accordingly the user must directly focus on the camera at a predetermined distance. 
     As a result, it is difficult to focus the position and shape of the eyes of the user on the camera. 
     In addition, when the shape of the eyes of the user is photographed, a large amount of visible light is incident on the camera, and thus the image of the eyes cannot be exactly obtained. 
     Accordingly, the conventional optical iris imager has a low iris recognition rate. 
     A device for overcoming the aforementioned disadvantages has been described in the U.S. Pat. No. 5,572,596 (owned by Davio Sarnoff Research Center, Inc.). It uses an algorithm that traces his/her irises of the user. 
     However, although this system is convenient, three cameras for searching for the head and eyes of the human being and extracting the iris image, a device for controlling an angle of a mirror, and a plurality of high-power infrared light source units for lighting a peripheral region of the iris are necessary, thereby increasing the system size and cost. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is a primary object of the present invention to provide a small-sized and low cost iris recognition system which can be easily operated, and which can exactly extract an iris image for a short time. 
     It is another object of the present invention to provide an iris recognition system which can extract an iris image of the user, by upwardly and downwardly rotating around a hinge bracket in order to be exactly rapidly controlled to a position of the user&#39;s eyes. 
     In order to achieve the above-described objects of the present invention, there is provided an iris recognition system including, an optical imager obtaining an iris image of the user at an optimal state, an inner case at which the optical imager is disposed, an outer case supporting the inner case, and surrounding the surfaces of the inner case, except for the front surface thereof, a control unit receiving a signal outputted from the optical imager, and controlling the optical imager according to the signal, and a hinge bracket disposed at both side portions of the outer case, for supporting the inner case, and enabling the inner case to upwardly and downwardly rotate. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become better understood with reference to the accompanying drawings which are given only by way of illustration and thus are not limitative of the present invention, wherein: 
     FIG. 1 is a cross-sectional view illustrating a conventional optical imager; 
     FIG. 2 is a perspective view illustrating an optical imager in accordance with the present invention; 
     FIG. 3 is an inside perspective view illustrating the optical imager in accordance with the present invention; and 
     FIG. 4 is a structure view illustrating an iris recognition system in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The constitution and operation of an iris recognition system in accordance with the present invention will now be described. 
     FIG. 2 is a perspective view illustrating an outer casing  100 - 1  and a front outer case  100 - 2  of an optical imager  100  of the iris recognition system in accordance with the present invention. 
     The outer casing  100 - 1  includes a parallel port  28 - 1 , a serial port  28 - 2 , a video port  28 - 3  and a power port  28 - 4 . In addition, the front outer case  100 - 2  includes, a hinge bracket  27  supporting the front outer casing  100 - 2  in order to rotate centering around the hinge bracket  27 , an upper slide unit  30 - 1  and a lower slide unit  30 - 2  sliding into an inner portion of the outer casing  100 - 1 , centering around the hinge bracket  27 , push units  29 - 1 ,  29 - 2 ,  29 - 3 ,  29 - 4  which the user pushes so that the front outer case  100 - 2  can rotate centering around the hinge bracket  27 , an optical window  12  receiving light reflected from the eyes of the human being, infrared filters  26 - 1 ,  26 - 2  intercepting light, except for the infrared light an outside speaker protection net  20 - 1  externally connecting a speaker  20 - 2  installed inside, and an outside indicator  22  indicating a result with predetermined lamps after identifying the iris of the user. 
     So that the user can identify his/her eyes with an optical axis of a camera  10 , the front outer casing  100 - 2  can be upwardly and downwardly rotated from a balanced position by approximately+/−30 degrees, centering around the hinge bracket  27 , according to pushing of the push units  29 - 1 ,  29 - 2 ,  29 - 3 ,  29 - 4 . 
     According to the preferred embodiment of the present invention, it is exemplified that the user rotates the front outer casing  100 - 2  by pushing the units  29 - 1 ,  29 - 2 ,  29 - 3 ,  29 - 4 . However, for example, the front outer casing  100 - 2  can be rotated by using a power source driven by electricity, such as a motor. 
     Also, the front outer casing  100 - 2  is designed to be concave in regard to the front surface in order to reduce the system size. 
     FIG. 3 is an inside perspective view illustrating the optical imager of the iris recognition system in accordance with the present invention. There is depicted in more detail an inner casing  100 - 3  disposed at the back of the front outer casing  100 - 2 , for upwardly and downwardly rotating with the front outer casing  100 - 2 , centering around the hinge bracket  27 . 
     The inner casing  100 - 3  includes a distance detector  18  measuring a distance when the user accesses to the front outer casing  100 - 2 , an optic window  12  receiving light reflected from the eyes of the human being, except for the ultraviolet light, a cold mirror  14  receiving the light incident through the optical window  12 , and passing the infrared light, except for the visible light, a camera  10  receiving the infrared light incident through the cold mirror  14 , and photographing the eyes of the human being, light source units  16 - 1 ,  16 - 2 ,  16 - 3  emitting the infrared light in order to photograph the iris of the user by the camera  10 , an outside indicator  22 /speaker  20 - 2  comparing the iris of the user photographed by the camera  10  with an image data which is previously stored in a data base, and visually/audibly informing that the user is a right one, and an optical imager driving unit  24  controlling various circuit units arranged at the inner casing  100 - 3 . Here, the optical imager driving unit  24  receives control signals from a control unit to be discussed later, and drives the distance detector  18 , the camera  10  and the light source units  16 - 1 ,  16 - 2 ,  16 - 3 , an outside indicator  22  and speaker  20 - 2  which are arranged at the inner case  100 - 3 . 
     According to the embodiment of the present invention, the components are arranged as shown in FIG.  3 . However, the position of the components may be varied. In addition, according to the present invention, the distance detector  18  measures a distance by using the infrared light. However, a detector using an ultrasonic wave may be employed. 
     The speaker  20 - 2  can inform the iris recognition result by a sound or voice, and can be operated simultaneously with the outside indicator  22 . 
     The light source units  16 - 1 ,  16 - 2 ,  16 - 3  are respectively at the upper side of the camera  10 , and at both bottom sides of the camera  10 , thereby forming an three infrared LED boards shape. In the respective light sources  16 - 1 ˜- 16 - 3 , a plurality of infrared chips (for example, eight infrared chips) having a different wavelength are formed as one package. So that the camera can photograph the iris image by a regular light strength, an amount of the current flowing into the light source units is controlled according to a distance between the camera and the iris, thereby adjusting a strength of the infrared light. Here, the infrared light outputted from the light source units is externally outputted through the infrared filters  26 - 1  or  26 - 2 . 
     The cold mirror  14  reflects the visual light, and passes only the infrared light, thereby preventing an influence by the external light. Especially, the position where the iris must be positioned is marked on the cold mirror  14 , and thus the user can easily confirm the position of his/her eyes. 
     FIG. 4 is a structure view illustrating the iris recognition system in accordance with the present invention. The iris recognition system includes a frame grabber  202  receiving an image signal outputted from the optical imager  100  as shown in FIG. 3, and a control unit  200  receiving and processing the image signal outputted from the frame grabber  202 , comparing the IrisCodes™ generated from the currently inputted iris image with the stored lrisCodes™ and controlling the optical  100  and the camera  10 . 
     The operation of the iris recognition system according to the present invention will now be described in more detail. 
     When the user accesses to the front outer case  100 - 2 , the distance detector  18  measures a distance between the user and the optical imager, and transmits the measured distance value to the controller  200  through the optical imager driving unit  24 . The control unit  200  judges whether the eye of the user is positioned within a predetermined operational range. 
     When it is judged that the user is positioned within the operational range, the control unit  200  outputs the control signal to the optical imager  100 , thereby automatically enabling the optical imager  100 . That is, the camera  10  prepares for capturing the iris image of the user, and simultaneously optical imager driving unit  24  outputs to the outside indicator  22  an active signal informing that the optical imager  100  is enabled. 
     Thereafter, the user pushes one of the push units  29 - 1 ,  29 - 2 ,  29 - 3 ,  29 - 4 , thereby rotating the inner case  100 - 3  connected with the front outer case  100 - 2 . When the eyes of the user are positioned at the optical axis of the camera  10  through the optical window  12 , the cold mirror  14  reflects the visible light, and passes only the infrared light. At this time, the position at which the iris must be positioned is marked on the cold mirror  14 , and thus the user can easily confirm whether his/her eyes are precisely positioned at the optical axis of the camera. 
     When the user accesses to the optical imager, and is positioned within a operatinal range, the distance detector  18  detects a distance signal having a small variation width corresponding to the distance, and outputs it to the control unit  200  through the optical imager driving unit  24 . The control unit  200  receives the distance value, computes a zoom-in/zoom-out value and a focus value by using a property table of the camera according to a value corresponding to the distance value, and controls a zoom motor and a focus motor of the camera according to the computed value. 
     That is, the control unit  200  decides a zoom magnification from the zoom magnification table of the camera according to the previously-set distance by using the distance value between the camera and the iris, transmits the control signal to the camera, and controls the zoom motor of the camera. Accordingly, the zoom lens is directly moved, the focus lens is moved to a corresponding position by controlling the focus motor, and thus the focus is directly controlled. As a result, the focusing speed is increased. 
     On the other hand, when the optical imager driving unit  24  alternately controls the light source units installed at the upper and lower sides of the camera  10  by using the measured distance value, the camera  10  photographs the iris image, and transmits the iris image to the control unit through the frame grabber. Thereafter, the control unit  200  selects the iris image having smallest specular reflection among the inputted iris images, and outputs the control signal to the optical imager driving unit  24  in order to control the operated light source unit. According to the control signal outputted from the control unit  200 , the optical imager driving unit  24  selects one of the light source units, and supplies the current in proportion to the measured distance value to the infrared LED of the light source unit. Therefore, the iris image photographed by the camera  10  can be extracted by the regular light (intensity of illumination), regardless of the distance between the iris and the camera. 
     Accordingly, when the eye of the user is positioned at the optical axis of the camera through the optical window, the infrared light passing through the optical window and the cold mirror reaches to the camera, thereby automatically photographing the iris of the user. 
     The iris image photographed as described above is outputted to the frame grabber  202  through the video port  28 - 3 . The frame grabber  202  processes the iris image to be easily analyzed, and outputs it to the control unit  200 . The control unit  200  analyzes the inputted iris image, compares it with the previously-stored iris image in the data base, and recognizes the iris of the user. 
     Therefore, the control unit  200  informs the user of the iris recognition result through the parallel port  28 - 1  of the outer casing  100 - 1  by using the outside indicator  22  and/or speaker  20 - 2 . Here, the speaker outputs the sound or voice. 
     The iris recognition system in accordance with the present invention enables the inner case of the optical imager  100  to rotate centering around the hinge bracket. Accordingly, when the user easily positions his/her irises at the optical axis of the camera, the strength of illumination incident on the optical window is constantly maintained on the basis of the distance value between the iris of the user and the camera, which is detected by the distance measurement detector, and at the same time the zoom lens and the focusing lens are directly controlled. As a result, the iris image can be precisely rapidly extracted. 
     In addition, in accordance with the present invention, the front outer case of the iris recognition system is concave according to the user&#39;s taste. There are employed one distance measurement detector, one camera and three light source units, thereby reducing the size and the cost of the system. 
     In addition, in accordance with the present invention, the front outer casing of the iris recognition system is concave according to the user&#39;s taste. There are employed one distance measurement detector, one camera and three light source units, thereby reducing the size and cost of the system. 
     Moreover, in accordance with the iris recognition system of the present invention, the optical window, the cold mirror and the camera lens are disposed in parallel, thereby easily aligning the optical axis. Also, the recognition rate of the iris images photographed by the camera is improved by passing the infrared light and intercepting the visible light and ultravilot light. 
     Furthermore, the infrared LED having a small output power is employed for the light source units, and thus less stimulates the eyes of the user compared with a light source units used by the conventional optical imagers. The iris is exactly photographed and recognized, regardless of existence or absence of the visible light. When the iris image is recognized, the iris recognition result is informed through the speaker and/or the outside indicator. 
     As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiment is not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended claims.