Control of artificial lighting of a scene to reduce effects of motion in the scene on an image being acquired

• US 7,697,836 B2
• Filed: 10/25/2006
• Issued: 04/13/2010
• Est. Priority Date: 10/25/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Zoran Corporation (Qualcomm, Inc.)
• Inventors: Pozniansky, Eli, Pertsel, Shimon
• Primary Examiner(s): Perkey; W. B.
• Assistant Examiner(s): Hancock; Dennis
• Application Number:
  US11/552,717
• Publication Number:
  US 20080101786A1
• Time in Patent Office: 1,266 Days
• Field of Search: 396/159, 396/153, 396/263, 396/266
• US Class Current: 396/159
• CPC Class Codes: H04N 23/74 by influencing the scene brightness using illuminating means

Abstract

Motion of an image of a scene being captured by a digital image acquisition device is detected and used to control parameters of illumination of the scene by a flash lamp that is typically built into the device. Parameters that may be controlled include the intensity, duration and timing of light emitted by the flash lamp. Such control of the flash illumination is preferably performed in conjunction with adjusting one or more exposure parameters used to capture an image. Such exposure parameters include duration, aperture and sensor gain. Motion blur caused by movement of the camera or by movement of an object within the scene being photographed is reduced by selecting appropriate exposure parameters and flash light characteristics.

Claims

1. A method of controlling operation of an electronic imaging device to capture data of at least one image of a scene illuminated with at least one source of artificial light, wherein a magnitude of motion of the at least one image is ascertained prior to capturing data of the at least one image, and the ascertained magnitude of motion is used to set a magnitude of at least one of a duration, intensity or timing of a light pulse emitted by the at least one source of artificial light while capturing data of the at least one image, and wherein the ascertained magnitude of motion of the at least one image includes a forecast of the magnitude of motion as a function of time, and the ascertained magnitude of motion is used to calculate a time to initiate the capturing of data of the at least one image and the light pulse that is coincident with a minimum magnitude of the forecasted motion.

2. The method according to claim 1, wherein the ascertained magnitude of motion is used to set a magnitude of all of the duration, intensity and timing of the light pulse emitted by the at least one source of artificial light.

3. The method according to claim 1, wherein the ascertained magnitude of motion is also used to set a magnitude of at least one of a duration, aperture or gain of the electronic imaging device to capture data of the at least one image.

4. The method according to claim 3, wherein the magnitude of at least one of the duration, intensity or timing of the light pulse and the magnitude of at least one of the duration, aperture or gain of the electronic imaging device are set in coordination with each other.

5. The method according to claim 3, wherein the magnitude of the duration of the light pulse is set to be at least as large as the magnitude of the duration of the imaging device and occurring simultaneously therewith.

6. The method according to claim 1, wherein the ascertained magnitude of motion is also used to set a magnitude of all of a duration, aperture and gain of the electronic imaging device to capture data of the at least one image.

7. The method according to claim 1, wherein the ascertained magnitude of motion is used to set a magnitude of at least one of the duration, intensity or timing of the light pulse in a manner to reduce blur of the captured at least one image due to the motion.

8. The method according to claim 1, wherein the magnitude of motion of the at least one image is ascertained for global motion of the at least one image.

9. The method according to claim 1, wherein the magnitude of motion of the at least one image is ascertained for local motion of the at least one image.

10. The method according to claim 1, wherein the magnitude of motion of the at least one image is ascertained for both global and local motion of the at least one image.

11. The method according to claim 1, wherein the magnitude of motion of the at least one image is ascertained from data of two or more preview images of the scene.

12. The method according to claim 11, wherein the data of two or more preview images of the scene are acquired during illumination of the scene by preview light emitted by the at least one source of artificial light.

13. The method according to claim 1, wherein the magnitude of motion of the at least one image is ascertained prior to capturing data of the at least one image by capturing data of at least one preview image of the scene while illuminated with light emitted by the at least one source of artificial light.

14. The method according to claim 13, wherein the at least one source of artificial light used to illuminate the scene includes at least one gas discharge flash lamp.

15. The method according to claim 13, wherein the at least one source of artificial light used to illuminate the scene includes at least one light emitting diode.

16. A method of controlling operation of an electronic imaging device to capture data of at least one image of a scene with artificial lighting, comprising:

determining, prior to capturing data of an image, a magnitude of motion of the image,

calculating one or more exposure parameters including duration from at least the determined magnitude of image motion,

calculating one or more illumination parameters of the artificial lighting of the scene from at least the determined magnitude of image motion, and

thereafter capturing data of the image by use of the calculated one or more exposure parameters and with artificial lighting of the scene having the calculated one or more illumination parameters, wherein

the artificial lighting is provided by at least one source that emits at least one pulse of light,

determining the magnitude of motion of the image includes forecasting the magnitude of motion as a function of time, and

calculating one or more illumination parameters of the artificial lighting includes calculating a time to initiate the capturing of data of the image and the at least one light pulse that is coincident with a minimum magnitude of the forecasted motion.

17. The method of claim 16, wherein calculating one or more illumination parameters of artificial lighting includes calculating at least a duration of the at least one light pulse emitted by the at least one flash lamp while capturing data of the image.

18. The method of claim 17, wherein calculating one or more illumination parameters of the artificial lighting additionally includes calculating an intensity of the at least one light pulse.

19. The method of claim 17, wherein calculating one or more illumination parameters of the artificial lighting additionally includes calculating a timing of the at least one light pulse.

20. The method of claim 17, wherein the duration of the light pulse is calculated to be at least as long as the calculated exposure duration parameter and to occur simultaneously with the entire exposure duration.

21. The method of claim 16, wherein calculating one or more illumination parameters of the artificial lighting additionally includes calculating a duration of the at least one light pulse.

22. The method of claim 21, wherein calculating one or more illumination parameters of the artificial lighting additionally includes calculating an intensity of the at least one light pulse.

23. The method of claim 16, wherein determining a magnitude of motion of the image includes determining a global motion of the image.

24. The method of claim 23, wherein determining a magnitude of global motion of the image includes use of a mechanical motion sensor within the electronic imaging device.

25. The method of claim 23, wherein determining a magnitude of global motion of the image includes use of data of two or more preview images of the scene.

26. The method of claim 16, wherein determining a magnitude of motion of the image includes determining a local motion of the image.

27. The method of claim 26, wherein determining a magnitude of motion includes use of data of two or more preview images of the scene.

28. The method of claim 16, wherein determining a magnitude of motion of the image includes determining a combined global and local motion of the image.

29. The method of claim 28, wherein determining a magnitude of motion includes use of data of two or more preview images of the scene.

30. The method of claim 16, wherein determining a magnitude of motion includes use of data of two or more preview images of the scene.

31. The method of claim 16, wherein determining a magnitude of motion includes determining a magnitude of motion of both the camera and of an object within the scene.

32. A method of controlling operation of an electronic imaging device and at least one source of artificial light to capture data of at least one image of a scene, comprising:

determining, prior to capturing data of an image, a magnitude of motion of the image, including forecasting the magnitude of motion as a function of time, and a luminance of the scene,

calculating, from at least the magnitude of motion and the luminance of the scene, exposure parameters including at least a duration of exposure that minimizes a blur in the image due to the motion,

calculating, from at least the magnitude of motion, one or more parameters of at least one light pulse to be emitted from the source of artificial light, including calculating a time to initiate the capturing of data of the image and the at least one light pulse that is coincident with a minimum magnitude of the forecasted motion,

in response to the calculated one or more parameters of the at least one light pulse, modifying at least one of the calculated exposure parameters to obtain modified exposure parameters for capturing data of the at least one image, and

thereafter capturing data of the image by use of the modified exposure parameters and with artificial lighting of the scene having the calculated one or more light pulse parameters.

33. A method of controlling operation of an electronic imaging device and at least one source of artificial light to capture data of at least one image of a scene, comprising:

determining, prior to capturing data of an image, a magnitude of motion of the image, including forecasting the magnitude of motion as a function of time, and a luminance of the scene,

calculating, from at least the determined magnitude of image motion, one or more exposure parameters including duration and an intensity of the artificial light to illuminate the scene over the entire exposure duration and a time to initiate the capturing of data of the image and the artificial light that is coincident with a minimum magnitude of the forecasted motion, and

thereafter capturing data of the image by use of the calculated one or more exposure parameters and with the artificial light illuminating the scene with the calculated intensity over the entire exposure duration.

34. The method of claim 33, wherein the at least one source of artificial light includes at least one light emitting diode.

35. An electronic imaging device, comprising:

a photodetector,

an optical system that projects an image of a scene being captured onto the photodetector,

at least one source of artificial light adapted to illuminate the scene,

an electronic processor that receives data of the image projected onto the photodetector and processes the scene data to provide data of an image of the scene being captured, and

wherein the processor additionally quantifies, from data of the scene projected onto the photodetector, an amount of motion of the scene and uses this quantified motion to set a magnitude of at least one of a duration, intensity or timing of a light pulse emitted by the at least one source of artificial light while capturing data of the at least one image, and

wherein the quantified motion includes forecasting the magnitude of motion as a function of time and is further used to set a time to initiate the capturing of data of the image and the light pulse that is coincident with a minimum magnitude of the forecasted motion.

36. The device of claim 35, wherein the at least one source of artificial light includes a gas discharge flash lamp.

37. The device of claim 35, wherein the at least one source of artificial light includes a light emitting diode.

38. The device of claim 35, wherein the processor additionally uses the quantified motion to set one or more exposure parameters including an exposure duration used to capture the data of the at least one image.

39. The device of claim 38, wherein the processor additionally sets the magnitude of the light pulse emitted by the at least one source of artificial light and the one or more exposure parameters in coordination with each other.

40. The device of claim 38, wherein the one or more exposure parameters set by the processor additionally includes aperture and gain.

41. The device of claim 35, wherein the processor additionally quantifies an amount of motion of the scene from data of local motion of the scene.

42. The device of claim 35, wherein the processor additionally quantifies an amount of motion of the scene from data of global motion of the scene.

43. The device of claim 35, wherein the processor quantifies the amount of motion of the scene from data of at least two preview images of the scene individually acquired while simultaneously causing the at least one source of artificial light to emit light.

44. The device of claim 43, wherein the at least one source of artificial light includes a gas discharge flash lamp.

45. The device of claim 43, wherein the at least one source of artificial light includes a light emitting diode.