SYSTEM AND METHOD FOR ILLUMINATING AND IMAGING THE IRIS OF A PERSON

• US 20120163783A1
• Filed: 08/08/2011
• Published: 06/28/2012
• Est. Priority Date: 12/22/2010
• Status: Active Grant

• Current Assignee: Michael Braithwaite
• Original Assignee: Michael Braithwaite
• Inventors: Braithwaite, Michael, Chaikin, Jason, Date, Andrew Philip Govan, Moustafa, Mohamed Nabil
• Granted Patent: US 8,254,768 B2
• Time in Patent Office: Days
• US Class Current: 396/18
• CPC Class Codes: G06F 18/254 of classification results, e.g. of results related to same input data
• CPC Class Codes: G06V 10/141 Control of illumination
• CPC Class Codes: G06V 10/143 Sensing or illuminating at different wavelengths
• CPC Class Codes: G06V 10/145 Illumination specially adapted for pattern recognition, e.g. using gratings
• CPC Class Codes: G06V 40/166 using acquisition arrangements
• CPC Class Codes: G06V 40/172 Classification, e.g. identification
• CPC Class Codes: G06V 40/45 Detection of the body part being alive

Abstract

A system and method for capturing an image of one or both irises. To image an iris, a person stands or moves in a target zone. A flash element provides an incoherent flash of light through an aperture. The flash is filtered to produce filtered light. The filtered light has primary wavelengths in the far red and near infrared portions of the spectrum. The filtered light is not perceived well by the human eye due to short duration, NIR color and small size. The intensity of the filtered light at the target area surpasses the intensity of all ambient light. In this manner, a person'"'"'s face in the target area will always be properly illuminated, even if that person were backlit by full sunlight. An image of the person'"'"'s face is taken with a camera. The image of the face is analyzed to obtain any iris pattern information.

Claims

1. A method of capturing an image of a person'"'"'s iris, comprising the steps of:

providing a flash element that provides a flash of light when activated;

integrating said flash of light in a refection chamber, wherein said flash of light exits said reflection chamber through an exit aperture;

filtering said flash of light to produce filtered light having primary wavelengths over 720 nm;

directing said filtered light toward a predetermined target zone;

providing a camera that is directed toward said target zone wherein said camera is positioned offset from said flash element by at least twelve degrees as measured from said target zone;

activating said flash element when a person is in said target zone, wherein said filtered light illuminates at least one iris; and

recording an image of at least one iris with said camera.

2. The method according to claim 1, wherein said step of activating said flash element results in a flash of light having a duration of between 40 microseconds and 3 milliseconds.

3. The method according to claim 1, wherein said aperture has an area of between one square millimeter and one square centimeter.

4. The method according to claim 1, further including the step of confining said filtered light into a narrow beam of light that illuminates said target zone.

5. The method according to claim 1, wherein said step of confining said filtered light includes shining said filtered light through at least one focusing lens.

6. The method according to claim 1, wherein said step of filtering said flash of light includes passing said flash of light through a optical pass filter.

7. The method according to claim 6, further including the step of proving an optical focusing element that focuses said camera on said target zone.

9. The method according to claim 1, further including the step of providing an illuminated display, wherein said camera and said flash element are mounted proximate said illuminated display.

8. (canceled)

10. A method of imaging a person'"'"'s iris, comprising the steps of:

providing a flash chamber having a restricted exit aperture, wherein said restricted exit aperture has an area of between one square millimeter and one square centimeter;

flashing a flash element within said flash chamber that produces incoherent light, wherein said incoherent light exits said flash chamber through said restricted exit aperture;

filtering said incoherent light to have primary wavelengths over 720 nm;

directing said incoherent light toward a predetermined target zone;

providing a camera, wherein said camera is directed toward said target zone and wherein said camera captures light in said primary wavelengths of said incoherent light;

activating said light source when at least one iris is in said target area, wherein said incoherent light illuminates said at least one iris; and

recording an image of said at least one iris with said camera.

11. The method according to claim 10, further including the step of creating phase variations in said incoherent light.

13. The method according to claim 10, wherein said flash of incoherent light has a flash duration of between 40 microseconds and 3 milliseconds.

12. (canceled)

16. The method according to claim 12, wherein said step of filtering said incoherent light includes directing said incoherent light through a pass filter that primarily passes light over 740 nm.

17. The method according to claim 16, further including the step of focusing said incoherent light on said target area.

14. (canceled)

15. (canceled)

18. In an environment having background ambient light, a method of illuminating an iris for imaging, comprising the steps of:

providing a flash element that produces a flash of incoherent light when activated;

passing said flash of incoherent light though a restricted aperture, wherein said aperture has an area less than one square centimeter;

filtering said flash of incoherent light to produce a filtered light flash having primary wavelengths over 720 nm; and

directing said filtered light flash toward the iris to illuminate said iris with an intensity greater than that of said background ambient light.

19. The method according to claim 18, further including the step of generating phase variations in said flash of light.

20. The method according to claim 18, further including the step of limiting said flash of light to a flash duration of between 40 microseconds and 3 milliseconds.

21. A method of capturing an image of a person'"'"'s iris, comprising the steps of:

providing a flash element that provides a flash of light when activated;

integrating said flash of light in a refection chamber, wherein said flash of light exits said reflection chamber through an exit aperture;

filtering said flash of light to produce filtered light having primary wavelengths over 720 nm;

directing said filtered light toward a predetermined target zone;

providing a camera that is directed toward said target zone;

providing an illuminated display, wherein said camera and said flash element are mounted proximate said illuminated display;

activating said flash element when a person is in said target zone proximate said illuminated display, wherein said filtered light illuminates at least one iris; and

recording an image of at least one iris with said camera.