Single lens splitter camera

• US 7,933,507 B2
• Filed: 03/02/2007
• Issued: 04/26/2011
• Est. Priority Date: 03/03/2006
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Honeywell International Inc.
• Inventors: Jelinek, Jan, Phinney, Thomas
• Primary Examiner(s): Perkey, W. B.
• Assistant Examiner(s): Reisner, Noam
• Application Number:
  US11/681,505
• Publication Number:
  US 20080075441A1
• Time in Patent Office: 1,516 Days
• Field of Search: 396/77, 396/18, 396/51, 396/446, 359/353, 359/839, 348/342, 348/344, 348/78, 348/162, 348/164
• US Class Current: 396/18
• CPC Class Codes: G06V 40/19 Sensors therefor

Abstract

A camera system may be used to capture iris images of targeted people who may be unaware of being targeted and hence their movement may not be constrained in any way. Iris images may be used for identification and/or tracking of people. In one illustrative embodiment, a camera system may include a focus camera and an iris camera, where the focus camera is sensitive to ambient light or some spectrum thereof, and the iris camera is sensitive to infrared or some other wavelength light. The focus camera and the iris camera may share an optical lens, and the focus camera may be used to auto-focus the lens on a focus target. A beam splitter or other optical element may be used to direct light of some wavelengths to the focus camera for auto-focusing the lens, and other wavelengths to the iris camera for image capture of the iris images.

Claims

1. A camera system comprising:

an iris camera having an optical axis, the iris camera configured to acquire iris images suitable for human identification;

a focus camera having an optical axis, wherein the optical axis of the focus camera is angularly offset from the optical axis of the iris camera;

an autofocus lens for receiving incoming light and for providing the incoming light to both the iris camera and the focus camera, wherein an output of the focus camera is used in auto-focusing the autofocus lens;

a beam splitter arranged downstream of the autofocus lens, the beam splitter directing a first wavelength or range of wavelengths of the incoming light to the focus camera and a second wavelength or range of wavelengths of the incoming light to the iris camera; and

a controller coupled to the iris camera and the autofocus lens, the controller configured to correct a focus setting of the autofocus lens to provide a focused image in the second wavelength or range of wavelengths to the iris camera after the output of the focus camera has been used to auto-focus the autofocus lens using the first wavelength or range of wavelengths of the incoming light, the controller further configured to activate the iris camera to capture an iris image of a subject that is suitable for human identification after the focus setting of the autofocus lens has been corrected.

2. The camera system of claim 1, wherein the optical axis of the focus camera is arranged at least substantially perpendicular to the optical axis of the iris camera.

3. The camera system of claim 1, wherein the beam splitter is configured to permit the second wavelength or range of wavelengths of incoming light to pass straight through the beam splitter.

4. The camera system of claim 1, wherein the first wavelength or range of wavelengths of light includes ambient light.

5. The camera system of claim 1, wherein the first wavelength or range of wavelengths of light includes visible light.

6. The camera system of claim 1, wherein the second wavelength or range of wavelengths of light includes flash illumination light.

7. The camera system of claim 1, wherein the second wavelength or range of wavelengths of light includes infrared light.

8. The camera system of claim 1, wherein the focus camera is sensitive to visible light or some sub spectra thereof.

9. The camera system of claim 1, wherein the iris camera is sensitive to infrared light or some sub spectra thereof.

10. The camera system of claim 1, wherein the output of the focus camera is used to locate a given focus target within the field of view of the focus camera.

11. The camera system of claim 10, wherein the output of the focus camera is used to auto-focus the lens on the focus target.

12. The camera system of claim 1, further comprising a near infrared flash that is controlled by the controller and is used in conjunction with the iris camera.

13. A camera system comprising:

a lens;

an auto-focus element for auto-focusing the lens;

a first camera that is sensitive to ambient light, the first camera providing an output to the auto-focus element suitable for auto-focusing the lens onto a person of interest;

a second camera that is sensitive to light from a flash discharge, the second camera capturing an infrared image of an iris of the person of interest suitable for human identification;

a beam splitter disposed downstream of the lens, the beam splitter splitting the light passing through the lens into an ambient light image that is directed to the first camera, and a flash light image that is directed to the second camera;

a controller configured to apply a correction factor to correct the focus of the lens so as to provide a focused image in infrared light to the second camera after the lens has been auto-focused using the output of the first camera that is sensitive to ambient light but before the second camera captures an infrared image of the iris; and

wherein the lens, when corrected to provide a focused image in infrared light to the second camera does not provided a focused image in ambient light to the first camera.

14. A method of capturing an iris image of an iris of a person of interest using a camera system comprising a focus camera, an iris camera and a lens disposed upstream of and shared by the focus camera and the iris camera, the method comprising the steps of:

finding a focus target in a focus camera image;

focusing the lens on the focus target using the focus camera;

modifying a focus setting of the lens to provide a focused image to the iris camera after the lens has been focused by the focus camera;

once the focus setting has been modified, initiating iris camera shutter control; and

capturing the iris image using the iris camera, wherein the iris image of the iris of the person of interest is suitable for human identification.

15. The method of claim 14, wherein the focus camera focuses the lens using ambient light or some spectra thereof.

16. The method of claim 14, further comprising a step of finding a focus target within an image seen or sensed by the focus camera.

17. The method of claim 16, further comprising a step of extracting image data and using the image data to precisely auto focus the focus camera.

18. The method of claim 14, further comprising the step of splitting the light that passes through the shared lens into an ambient light based image and an infrared light based image, wherein the ambient light based image is directed to the focus camera and the infrared light based image is directed to the iris camera.