CAMERA WITH AUTO FOCUS CAPABILITY

• US 20080075445A1
• Filed: 03/02/2007
• Published: 03/27/2008
• Est. Priority Date: 03/03/2006
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Honeywell International Inc.
• Inventors: Whillock, Rand, Jelinek, Jan, Ahrens, Terry, Determan, Gary, Jacobson, Vincent
• Granted Patent: US 8,049,812 B2
• Time in Patent Office: Days
• US Class Current: 396/106
• CPC Class Codes: G02B 7/28 Systems for automatic generation of focusing signals
• CPC Class Codes: G02B 7/36 using image sharpness techniques , e.g. image processing techniques for generating autofocus signals image data processing per se G06T; in cameras having a solid state image sensor H04N23/67
• CPC Class Codes: H04N 23/667 Camera operation mode switching, e.g. between still and video, sport and normal or high- and low-resolution modes
• CPC Class Codes: H04N 23/67 Focus control based on electronic image sensor signals

Abstract

A method and apparatus for automatically focusing a camera that may rely upon ambient light for auto focusing and flash illumination for image capture. A correction factor may be determined that is based at least in part on a range between the camera and a desired subject. The camera focus may be adjusted in accordance with the correction factor prior to capturing a capture image using flash illumination.

Claims

1. A camera system comprising:

a camera having a lens, the camera having an auto focus mode and an non-auto focus mode for the lens;

a range sensor that is adapted to determine a range between a subject and the camera; and

a focus actuator adapted to effect a focus setting of the lens when the camera is in the non-auto focus mode.

2. The camera system of claim 1, further comprising a control switch that is adapted to switch the camera between the auto focus mode and the non-auto focus mode.

3. The camera system of claim 2, further comprising an offset computation module that determines an offset value based at least in part on the range between the subject and the camera.

4. The camera system of claim 3, wherein the focus actuator is adapted to effect the focus setting of the lens in accordance with the offset value after the auto focus mode of the camera has focused the camera and the camera has been placed in the non-auto focus mode by the control switch.

5. The camera system of claim 1, wherein the auto focus mode relies upon ambient light to automatically focus the camera.

6. The camera system of claim 1, wherein the camera is adapted to take pictures using infrared light.

7. A method of capturing an image of a subject, the method comprising steps of:

aiming a camera at the subject;

focusing the camera on the subject using ambient light;

determining a range to the subject;

adjusting the focus of the camera based at least in part on the range to the subject; and

capturing an image of the subject.

8. The method of claim 7, wherein focusing the camera using ambient light comprises engaging an auto focus mode of the camera.

9. The method of claim 7, wherein adjusting the focus of the camera comprises actuating an actuator.

10. The method of claim 7, wherein adjusting the focus of the camera comprises determining a correction factor based on the range to the subject, and then actuating an actuator to adjust the focus of the camera based on the correction factor.

11. The method of claim 7, wherein determining a range to the subject is done before focusing the camera.

12. The method of claim 7, wherein determining a range to the subject is done while focusing the camera.

13. The method of claim 7, wherein determining a range to the subject is done after focusing the camera.

14. The method of claim 10, wherein calculating a correction factor is done any time after determining the range to the subject.

15. A method of focusing a camera having ambient and flash illumination capability, the method comprising the steps of:

aiming the camera at a subject;

focusing the camera on the subject using ambient light;

determining a subject range between the camera and the subject;

determining a correction factor based at least in part on the subject range; and

adjusting the camera focus based on the correction factor.

16. The method of claim 15, further comprising a subsequent step of capturing an image of the subject using flash illumination.

17. The method of claim 16, wherein capturing an image of the subject using flash illumination comprises capturing an infrared image of the subject.

18. The method of claim 15, wherein adjusting the camera focus comprises activating a non-auto focus mode and then adjusting the focus.

19. The method of claim 15, wherein determining a subject range comprises using a range sensor.

20. The method of claim 15, wherein determining a subject range comprises using a photographic analysis technique.