Method and apparatus to determine ambient light using a camera

• US 20060274161A1
• Filed: 06/03/2005
• Published: 12/07/2006
• Est. Priority Date: 06/03/2005
• Status: Abandoned Application

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Diefenbaugh, Paul, Agnihotri, Manoj, Ing, Stephen
• Application Number:
  US11/144,539
• Publication Number:
  US 20060274161A1
• Time in Patent Office: Days
• US Class Current: 348/229.100
• CPC Class Codes: H04N 23/70 Circuitry for compensating brightness variation in the scene

Abstract

A system includes a camera that may be used for multiple applications including an application to measure the ambient light. The camera may include an automatically set a gain or an aperture as well as a shutter speed. The shutter speed and the gain or aperture from the camera may be used to determine the ambient light. Brightness of a display may be adjusted based on the ambient light.

Claims

1. A method, comprising:

getting shutter speed and gain of a camera, wherein the shutter speed and the gain are set automatically by the camera; and

determining ambient light using the shutter speed and the gain.

2. The method of claim 1, further comprising adjusting brightness of a display based on the ambient light.

3. The method of claim 2, wherein determining the ambient light using the gain comprises taking a logarithm of the gain.

4. The method of claim 3, wherein determining the ambient light using the shutter speed comprises determining shutter speed frequency using the shutter speed.

5. The method of claim 4, wherein determining the ambient light comprises scaling the shutter speed frequency and applying a linear offset.

6. A system to measure ambient light, comprising:

an image capturing device configured to set a shutter speed and a gain, the image capturing device having an interface to provide the shutter speed and the gain;

logic to determine shutter speed frequency using the shutter speed;

logic to determine logarithm of the gain; and

logic to determine the ambient light using the shutter speed frequency and the logarithm of the gain.

7. The system of claim 6, wherein the image capturing device is coupled to a display, and wherein the ambient light is used to adjust brightness of the display.

8. The system of claim 7, wherein the image capturing device is a digital camera configured with an automatic gain control (AGC) feature to automatically set the gain.

9. The system of claim 8, wherein the image capturing device is configured to set a fixed aperture.

10. A system, comprising:

a processor;

a display coupled to the processor; and

a camera coupled to the display, the camera including an automatic exposure control to set shutter speed, wherein the processor is to determine ambient light using the shutter speed.

11. The system of claim 10, wherein the automatic exposure control is further to set an aperture or a gain, and wherein the processor is to determine the ambient light using the shutter speed and the aperture or the gain.

12. The system of claim 11, wherein the processor is to further adjust brightness of the display using the determined ambient light.

13. The system of claim 12, wherein the processor is to determine the ambient light by determining shutter speed frequency using the shutter speed and determining a logarithm of the gain or the aperture.

14. A tangible medium storing machine-accessible, wherein the data, when accessed, results in a machine performing a method comprising:

getting shutter speed and gain or aperture automatically set by a camera coupled to a display; and

adjusting brightness of the display using the shutter speed and one of the gain and the aperture.

15. The medium of claim 14, wherein adjusting the brightness of the display comprises determining ambient light using the shutter speed and one of the gain and the aperture.

16. The medium of claim 15, wherein determining the ambient light using one of the gain and the aperture comprises taking a logarithm of the gain or the aperture.

17. The medium of claim 16, wherein determining the ambient light using the shutter speed comprises determining a ratio of one over the shutter speed.

18. A method, comprising:

getting shutter speed and aperture from an image capturing device configurable to automatically set the shutter speed and opening of the aperture;

determining shutter speed frequency using the shutter speed;

determining logarithm of the aperture;

determining ambient light using the shutter speed frequency and the logarithm of the aperture; and

adjusting brightness of a display coupled to the image capturing device based on the determined ambient light.

19. The method of claim 18, wherein determining the ambient light comprises applying a scaling factor to the shutter speed frequency.

20. The method of claim 19, wherein the image capturing device is a digital camera, and wherein the aperture is variable.