Apparatus and method for reducing image blur in a digital camera

• US 20070188617A1
• Filed: 04/10/2007
• Published: 08/16/2007
• Est. Priority Date: 01/08/2003
• Status: Active Grant

• Current Assignee: Donald Stavely
• Original Assignee: Donald Stavely
• Inventors: Stavely, Donald
• Granted Patent: US 7,787,015 B2
• Time in Patent Office: Days
• US Class Current: 348/207.990
• CPC Class Codes: H04N 23/68 for stable pick-up of the scene, e.g. compensating for camera body vibrations
• CPC Class Codes: H04N 23/6811 based on the image signal
• CPC Class Codes: H04N 23/684 performed by controlling the image sensor readout, e.g. by controlling the integration time

Abstract

A digital camera delays the capture of a digital image after image capture has been requested until the motion of the digital camera satisfies a motion criterion. The digital camera thereby reduces image blur that would otherwise occur due to camera motion.

Claims

1. A digital camera, comprising:

an input control to initiate capture of a digital image;

a motion tracking subsystem responsive to the input control to track motion of the digital camera, an output of the motion tracking subsystem indicating the quantity of motion of the digital camera as a function of time; and

control logic configured to delay capture of the digital image until the output of the motion tracking subsystem satisfies a motion criterion, wherein the motion tracking subsystem includes an imaging module to convert optical images to digital images, the imaging module being capable of operation in a video preview mode, the video preview mode producing a series of digital preview frames, a portion of each digital preview frame comprising a motion measurement region, wherein

the motion tracking subsystem also includes motion measurement logic configured to measure the motion of the digital camera by comparing at least one picture element in a first digital preview frame with at least one picture element in a second digital preview frame, the at least one picture element in each of the first and second digital preview frames lying within the motion measurement region of that digital preview frame.

15. The digital camera of claim 1, wherein the imaging module comprises one of a CCD sensor array and a CMOS sensor array.

16. The digital camera of claim 1, wherein the video preview mode of the digital camera is substantially the same as that employed during autofocus, and the motion measurement region coincides with an autofocus region within which autofocus is performed on a different series of digital preview frames.

17. The digital camera of claim 1, wherein the motion measurement region of each of the first and second digital preview frames comprises a central portion of that digital preview frame.

18. The digital camera of claim 1, wherein the motion measurement region of each of the first and second digital preview frames comprises a peripheral portion of that digital preview frame.

19. The digital camera of claim 1, wherein the motion measurement logic is configured to apply a window function that attenuates an edge sub-region of the motion measurement region of each of the first and second digital preview frames.

20. The digital camera of claim 1, wherein the at least one picture element in each of the first and second digital preview frames comprises a horizontal set of picture elements.

21. The digital camera of claim 1, wherein the at least one picture element in each of the first and second digital preview frames comprises a vertical set of picture elements.

22. The digital camera of claim 1, wherein the motion measurement logic is configured to compute horizontal and vertical motion components.

23. The digital camera of claim 1, wherein the motion tracking subsystem comprises at least one accelerometer.

24. The digital camera of claim 1, wherein the motion tracking subsystem comprises at least one gyroscope.

25. The digital camera of claim 1, wherein the output of the motion tracking subsystem comprises the square root of the sum of a horizontal motion component squared and a vertical motion component squared.

26. The digital camera of claim 1, wherein the output of the motion tracking subsystem comprises the sum of the absolute value of a horizontal motion component and the absolute value of a vertical motion component.

2-14. -14. (canceled)

27-38. -38. (canceled)

39. A method for reducing image blur in a digital camera, comprising:

tracking motion of the digital camera in response to a first input signal; and

delaying capture of a digital image, following receipt of a second input signal, until the motion of the digital camera satisfies a motion criterion, wherein

tracking motion of the digital camera includes acquiring a series of digital preview frames in a video preview mode of the digital camera, a portion of each digital preview frame comprising a motion measurement region; and

wherein

tracking motion of the digital camera also includes comparing at least one picture element in a first digital preview frame with at least one picture element in a second digital preview frame, the at least one picture element in each of the first and second digital preview frames lying within the motion measurement region of that digital preview frame.

40. The method of claim 39, wherein the video preview mode of the digital camera is substantially the same as that employed during autofocus, and the motion measurement region coincides with an autofocus region within which autofocus is performed on a different series of digital preview frames.

41. The method of claim 39, wherein the motion measurement region of each of the first and second digital preview frames comprises a central portion of that digital preview frame.

42. The method of claim 39, wherein the motion measurement region of each of the first and second digital preview frames comprises a peripheral portion of that digital preview frame.

43. The method of claim 39, further comprising:

applying a window function that attenuates an edge sub-region of the motion measurement region of each of the first and second digital preview frames.

44. The method of claim 39, wherein the at least one picture element in each of the first and second digital preview frames comprises a horizontal set of picture elements.

45. The method of claim 39, wherein the at least one picture element in each of the first and second digital preview frames comprises a vertical set of picture elements.

46. The method of claim 39, wherein comparing at least one picture element in a first digital preview frame with at least one picture element in a second digital preview frame comprises computing horizontal and vertical motion components.

47. The method of claim 39, wherein tracking motion of the digital camera comprises measuring the motion of the digital camera using at least one accelerometer.

48. The method of claim 39, wherein tracking motion of the digital camera comprises measuring the motion of the digital camera using at least one gyroscope.

49. A digital camera, comprising:

means for initiating capture of a digital image;

means for tracking motion of the digital camera responsive to the means for initiating capture of a digital image, an output of the means for tracking motion of the digital camera indicating the quantity of motion of the digital camera as a function of time; and

means for delaying capture of the digital image until the output of the means for tracking motion of the digital camera satisfies a motion criterion.