AU5772201A - Iris scanner - Google Patents

Description

S&FRef: 566206

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Canon Kabushiki Kaisha 30-2, Shimomaruko 3-chome, Ohta-ku Tokyo 146 Japan Ian Richard Gibson, Rupert William Galloway Reeve, Kieran Gerard Larkin Spruson Ferguson St Martins Tower,Level 31 Market Street Sydney NSW 2000 (CCN 3710000177) Iris Scanner .o ASSOCIATED PROVISIONAL APPLICATION DETAILS [33] Country [31] Applic. No(s) AU PQ9704 The following statement is a full description of this invention, performing it known to me/us:- [32] Application Date 28 Aug 2000 including the best method of 5815c -1 I t4 Iris Scanner Technical Field of the Invention The present invention relates generally to the automatic estimation of pattern and texture of a human iris and, in particular, to using the optical system of a digital camera eyepiece to estimate that pattern and texture of the human iris. Accordingly, the present invention relates to a method and apparatus for capturing an image of an iris of an eye.

Background Art As is the case with fingerprints, each human has a unique iris pattern. This property of the human iris therefore lends itself for use in human identification. A number of systems exist for scanning human irises for identification and security purposes. Typical systems require that the eye to be scanned is brought into close proximity of an imaging device, such as a camera, so that the imaging device can capture Is a close-up image of the iris. In many situations the positioning of the imaging device is awkward and causes inconvenience to the person.

ooooo To avoid the inconvenience, some iris scanners use zoom or telephoto lenses to form a suitably sized image of the iris. However, these systems suffer the disadvantage that the imaging device must be either able to track and find the eye and iris, or the eye must be carefully placed in a small region for a fixed imaging device to capture an •appropriate image.

Disclosure of the Invention It is an object of the present invention to substantially overcome, or at least ameliorate, one or more disadvantages of existing arrangements.

566206.doc According to a first aspect of the invention, there is provided an apparatus for capturing an image of an iris of an eye, the eye being positioned before an eyepiece of said apparatus, said apparatus comprising: an optical system for projecting a virtual image of a scene to said eye through said eyepiece; an optical redirection means for redirecting at least a portion of light reflected from said iris; and an image sensor for capturing said light reflected from said iris to provide said image of said iris.

According to a second aspect of the invention, there is provided a method of capturing an image of an iris of an eye, said method comprising the steps of: positioning said eye before an eyepiece of an optical device; projecting a virtual image of a scene to said eye; 15 redirecting at least a portion of light reflected from said iris; and capturing said light reflected from said iris to provide said image of said iris.

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Brief Description of the Drawings A number of preferred embodiments of the present invention will now be described with reference to the drawings, in which: Figs. 1A and 1B show the activities of taking a photograph and a video, and the positioning of an eye; Fig.2 shows a typical optical layout of a viewing system implemented in the imaging devices shown in Figs. 1A and 1B; Fig. 3 shows a first embodiment of the invention; and Fig. 4 shows a second embodiment of the invention.

566206 doc 1 P -3- Detailed Description including Best Mode Where reference is made in any one or more of the accompanying drawings to features which have the same reference numerals, those features have for the purposes of this description the same function(s) or operation(s), unless the contrary intention appears.

Figs. 1A and 1B show two everyday activities in which a human eye is placed in close proximity to an optical imaging device and typical eye locations. Fig. 1A shows the activity of taking a photo on a camera 20, and Fig. 1B shows the activity of shooting a video sequence using a video camera recorder Fig. 2 shows a typical optical layout of a viewing system 40 of the imaging devices 20 and 30 shown in Figs. 1A and lB. The viewing system 40 includes a number of lenses 50 and 60 allowing the eye 10 to focus on a display device 70 which presents a virtual image of the scene being captured by the imaging device 20 or 30. In one o• embodiment, the display device 70 is an illuminated display, and the image being shown 15 on the illuminated display may be a previously captured image. In an alternative embodiment wherein the imaging device 20 is based on single lens reflex (SLR) designs, *o the display device 70 is in the form of a focussing screen and the viewing system 40 may contain a pentaprism instead of the lens 50. Therefore, in the context of this specification, the term display device 70 is a generic term for an illuminated display or a focussing screen. Here "lens", by convention, may also referred to a collection of separate single lens elements forming a compound lens.

An exit pupil of the viewing system 40 is defined as the image of the aperture stop as seen from an axial point on the image plane through the lenses 50 and Therefore, the cone of light leaving the viewing system is controlled by the exit pupil.

The eye 10 is said to be perfectly located relative to the exit pupil of the viewing system if the eye 10 can see the entire image being displayed on the display device 566206.doc F li_ i;:i~Lil;Ti- m~i~ il; Typical viewing systems 40 present a virtual image to the eye 10, with the virtual image located at infinity. The exit pupil is designed to allow reasonable separation between the last lens 60 and the eye 10 without losing image regions. This separation is called eye relief. An eyepiece, such as the eyepiece 32 of Fig. 1B, is generally designed to allow good viewing over a range of horizontal distances centered on the nominal eye relief.

Also, the diameter of the exit pupil is usually significantly larger than the eye pupil 11, allowing vertical misalignment without image obscuration.

A careful redesign of a camera's viewing system 40 allows the eye 10 to simultaneously view an image presented on the display device 70, while the imaging device 20 or 30 captures the eye's iris (not illustrated). Fig. 3 shows an optical system 100, which uses part of the existing optical system 40 of an imaging device 20 and 30 to acquire the iris pattern of the human eye S The viewing system 40 is split using a beam-splitter 110 to divert part of the light reflected from the eye 10 towards an additional (compound) lens 80. This allows for the formation of an image of the iris upon a suitable electronic image sensor 90. If the sensor 90 is formed with 256x256 pixels or more, sufficient resolution for the purpose of oo.oo °capturing an image of the iris may be obtained. Sufficient light to illuminate the iris can be derived from the display device 70. This light is already directed to the eye 10. The beam-splitter 110 may be a conventional type with transmission to reflection ratio of 20 90%: 10% or alternatively 70%:30%, or other values depending on the exact requirements.

O o Alternatively, the beam-splitter 110 may be a polarising type to better utilise the polarised output from the display device 70. Typical polarising beam-splitters (PBS) transmit most of one (linear) polarisation while reflecting most of the orthogonal polarisation. This means that the PBS can transmit most of the light from the display device 70 to the eye 10, resulting in high efficiency. The light scattered by the eye and the iris in particular, is relatively depolarised. Consequently, about half the light 566206.doc scattered back into the eyepiece is reflected by the PBS onto the image sensor 90 via lens An optical system 200 is shown in Fig. 4 using an alternative illumination system. An additional beam-splitter 150 has been added (compared to the system 100 shown in Fig. 3) to allow a light source 160, independent of the display device 70, to illuminate the eye 10. One advantage of this optical system 200 is that the light source 160 may be intermittent flashed) and possibly of an invisible wavelength such as infrared or ultraviolet.

Once the iris image has been captured by the imaging device 20 or 30, it may be 1o used for various security, recognition, and authentication purposes. In a simplest case, the iris image may be embedded in some or all of the conventional images taken by the imaging device 20 or 30. The embedding method may be appending of digital data corresponding to the iris image to the conventional image, or may be such as watermarking the conventional image with an image corresponding to the iris image.

In an alternative system, the iris pattern may be matched against a database of iris patterns, allowing the authenticity of the user of the imaging device 20 or 30 to be verified. In yet another system the iris pattern may be used with other information to add tamper-proof features to the conventional image captured by the imaging device 20 or In a further embodiment, an imaging device 20 or 30 which recognises the iris pattern of the person using the imaging device 20 or 30 automatically sets up the user :.o.preferences of the imaging device 20 or 30, such as exposure mode (aperture priority, shutter priority, more complex priorities etc), metering matrix mode, flash setting etc.

An imaging device 20 or 30 that recognises the user's iris pattern can set up communications settings of the device 20 or 30, so that images can be sent to a particular IP address, dial-up phone number, or mail address for images. In yet another embodiment, the imaging device 20 or 30 has a Global Positioning System (GPS) for 566206.doc -6finding the position of the device 20 or 30. This allows the device 20 or 30 to determine the local phone number for dial-in access.

An imaging device 20 or 30 that recognises iris patterns of authorised users allows certain modes of the imaging device 20 or 30, such as image capture, to be blocked if the iris pattern is not recognised. In an alternative embodiment, the imaging device 20 or 30 sends the iris pattern of the unauthorised user to the police or security agency. The GPS position may also be sent, if available.

An imaging device 20 or 30 that recognises the user's iris pattern can encrypt the conventional image captured, along with its associated metadata, with a public key belonging to the user and send the encrypted file to an email address of the user.

An imaging device 20 or 30 that recognises the user's iris can record details of the settings and metadata of each image the user keeps, or are subsequently sent over a communication channel, and compare those with the settings and metadata of the images which are deleted and not sent. The details may be used to learn about certain desirable V 15 properties of images and further customise the camera settings for identified users.

The iris pattern detected by the camera may be encrypted by the camera using a public key (of a designated recipient such as the camera owner, or the camera company) and attached to a file containing the conventional image or embedded in the file containing the conventional image. This allows for only the designated recipient to then decrypt the iris pattern. Alternatively the imaging device 20 or 30 encrypts the iris pattern with its own secret key, and decryption is only possible with this secret key. By such means knowledge of the user's identity through the iris pattern is limited to certain persons.

The iris pattern detected by the imaging device 20 or 30 may be associated with a known user (ie the user is identified) and the user's ID code can be combined with other metadata and then processed with a hash function. The image data can also be hashed 566206.doc and the image and metadata hashes can be combined together in one overall hash. The final hash is then added to the image file (tagged) along with the original metadata and user's ID. If the recipient of the tagged file repeats the process using the specific hash functions, then it is possible to detect whether or not the image or metadata and user's ID s have been tampered with in any way. If the regenerated hash code is different to the tagged hash code, then it can be assumed that a change has been made and the image file fails to authenticate.

The foregoing describes only some embodiments of the present invention, and modifications and/or changes can be made thereto without departing from the scope and spirit of the invention, the embodiments being illustrative and not restrictive.

In the context of this specification, the word "comprising" means "including principally but not necessarily solely" or "having" or "including" and not "consisting only of'. Variations of the word comprising, such as "comprise" and "comprises" have cn corresponding meanings.

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Claims (13)

1. Apparatus for capturing an image of an iris of an eye, the eye being positioned before an eyepiece of said apparatus, said apparatus comprising: an optical system for projecting a virtual image of a scene to said eye through said eyepiece; an optical redirection means for redirecting at least a portion of light reflected from said iris; and an image sensor for capturing said light reflected from said iris to provide said 1o image of said iris.

2. Apparatus according to claim 1 further comprising a display device for displaying said virtual image of said scene, and wherein said display device is a light source of said light reflected from said iris.

3. Apparatus according to claim 1 further comprising a light source for providing •said light reflected from said iris.

4. Apparatus according to claim 3, wherein said light source emits light with an wavelength outside the human visible range. :•go Apparatus according to claim 3 or 4, wherein said light source emits intermittent light.

6. Apparatus according to any one of claims 1 to 5, wherein said optical redirection means comprises a beam splitter and at least one lens. 566206doc a

7. Apparatus according to any one of claims 1 to 6 further comprising: an image capture device for capturing an image of said scene; and a processor means for embedding said image of said iris with said image of said scene.

8. Apparatus according to any one of claims 1 to 6 further comprising: an image capture device for capturing an image of said scene; and an encryption means for encrypting said image of said scene with a key.

9. Apparatus according to any one of claims 1 to 8 further comprising a matching means for matching said image of said iris with a database of images of irises and for verifying the authenticity of the user.

10. Apparatus according to any one of claims 1 to 7 further comprising a matching 15 means for matching said image of said iris with a database of images of irises and for identifying the user. S *SS.

11. Apparatus according to claim 8 further comprising a matching means for matching said image of said iris with a database of images of irises and for identifying the user, and wherein said key is associated with said user.

12. Apparatus according to claim 10 or 11 further comprising an adjustment means for setting user preferences of said apparatus.

13. A method of capturing an image of an iris of an eye, said method comprising the steps of:

566206.doc positioning said eye before an eyepiece of an optical device; projecting a virtual image of a scene to said eye; redirecting at least a portion of light reflected from said iris; and capturing said light reflected from said iris to provide said image of said iris. 14. A method according to claim 13, said method comprising the further step of illuminating said eye with a light source for providing said light reflected from said iris. A method according to claim 14, wherein said light source emits light with a io wavelength outside the human visible range. C C 0° C C.o CC S °o o oo eo "22. oo oo oe, oo oo o oooo o 16. A method according to claim 14 or 15, wherein said light source emits light intermittently. 17. A method according to any one of claims 13 to 16 further comprising the steps of: capturing an image of said scene; and embedding said image of said iris with said image of said scene. 20 18. A method according to any one of claims 13 to 16 further comprising the steps of: capturing an image of said scene; and encrypting said image of said scene with a key. 19. A method according to any one of claims 13 to 18 further comprising the steps of: 566206.doc -11 matching said image of said iris with a database of images of irises; and verifying the authenticity of the user. A method according to any one of claims 13 to 17 further comprising the steps of: matching said image of said iris with a database of images of irises; and for identifying the user. 21. A method according to claim 18 further comprising the steps of: matching said image of said iris with a database of images of irises; and identifying the user, wherein said key is associated with said user. 22. Apparatus according to claim 20 or 21 further comprising the step of setting user s15 preferences of said apparatus. oo°.o. 23 Apparatus for capturing an image of an iris of an eye, said apparatus being substantially as described herein with reference to Fig. 2, 3 or 4 of the drawings. 24. A method of capturing an image of an iris of an eye, said method being substantially as described herein with reference to Fig. 2, 3 or 4 of the drawings. DATED this Twenty Eighth Day of July 2001 Canon Kabushiki Kaisha Patent Attorneys for the Applicant SPRUSON FERGUSON 566206.doc 1