Hand jitter reduction system for cameras

• US 8,120,658 B2
• Filed: 09/25/2006
• Issued: 02/21/2012
• Est. Priority Date: 01/19/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Quan, Shuxue, Chiu, Chinchuan Andrew, Jiang, Xiaoyun, Li, Jingqiang, Noyes, Ying Xie, Atanassov, Kalin
• Primary Examiner(s): Ye, Lin
• Assistant Examiner(s): DAGNEW, MEKONNEN D
• Application Number:
  US11/534,993
• Publication Number:
  US 20070166020A1
• Time in Patent Office: 1,975 Days
• Field of Search: 348/208.12, 348/208.13, 348/208.99, 348/229.1
• US Class Current: 348/208.12
• CPC Class Codes: G06T 2207/10024 Color image
• CPC Class Codes: G06T 2207/20201 Motion blur correction
• CPC Class Codes: G06T 5/50 using two or more images, e.g. averaging or subtraction
• CPC Class Codes: G06T 5/73 Deblurring; Sharpening
• CPC Class Codes: H04N 23/68 for stable pick-up of the scene, e.g. compensating for camera body vibrations
• CPC Class Codes: H04N 23/72 Combination of two or more compensation controls
• CPC Class Codes: H04N 23/73 by influencing the exposure time
• CPC Class Codes: H04N 23/76 by influencing the image signals

Abstract

A camera system in normal mode and hand jitter reduction (hjr) mode may comprise generating a first exposure time-gain product by multiplying the normal mode exposure time with the normal mode gain. It may further comprise modifying the normal mode exposure time and gain and multiplying these modified parameters to generate a second exposure time-gain product for a hjr mode that reduces the difference between the first exposure time-gain product and the second exposure time-gain product. To reduce the difference the normal mode frame rate may also be modified. Operation of a camera in normal mode may be in response to a sensed light level being above a threshold. The hjr mode may be selected by the user while the camera is operating. The hjr mode may be used in response to a sensed light level being lower than the threshold.

Claims

1. A device comprising normal mode auto-exposure parameters, the device comprising:

means for identifying a light level in at least one captured image;

means for detecting selection of a hand jitter reduction mode; and

means for dynamically selecting hand jitter mode auto-exposure parameters to image process the at least one captured image, the hand jitter reduction mode auto-exposure parameters having an exposure time-gain product that corresponds to the exposure time-gain product of the normal mode auto-exposure parameters, and the hand jitter mode auto-exposure parameters including a hand jitter reduction mode gain that is greater than a corresponding normal mode gain of the normal mode auto-exposure parameters.

2. The device of claim 1, wherein the hand jitter mode auto-exposure parameters comprise gain and exposure time.

3. The device of claim 1, wherein the hand jitter mode auto-exposure parameters further comprise frame rate.

4. A computer-readable medium storing a set of instructions, wherein the set of instructions when executed by one or more processors performs a method of:

identifying a light level in at least one captured image;

detecting selection of a hand jitter reduction mode; and

dynamically selecting hand jitter mode auto-exposure parameters to image process the at least one captured image, the hand jitter reduction mode auto-exposure parameters having an exposure time-gain product that corresponds to the exposure time-gain product of normal mode modified auto-exposure parameters, and the hand jitter mode auto-exposure parameters including a hand jitter reduction mode gain that is greater than a corresponding normal mode gain of the normal mode auto-exposure parameters.

5. The computer-readable medium of claim 4, wherein the hand jitter mode auto-exposure parameters comprise the hand jitter reduction mode gain and exposure time.

6. The computer-readable medium of claim 4, wherein the hand jitter mode auto-exposure parameters further comprise frame rate.

7. A device that performs image processing comprising a hand jitter reduction mode comprising:

means for detecting a light level of a captured frame;

means for selecting single frame noise reduction or multiple frame noise reduction based on the detected light level of only the captured frame; and

means, responsive to the detected light level, for reducing hand jitter comprising single frame noise reduction when the light level is in a first range and multiple frame noise reduction when the light level is in a second range.

8. The device of claim 7, wherein the reduction of hand jitter includes modified auto-exposure parameters.

9. The device of claim 8, wherein the modified auto-exposure parameters are gain, exposure time, and frame rate.

10. The device of claim 7, wherein the multiple frame noise reduction reduces blurriness through multiple frame registration.

11. The device of claim 7, wherein the single frame noise reduction is bayer filtering.

12. The device of claim 11, wherein the detected light level is mapped to an auto-exposure index.

13. The device of claim 7, wherein image processing in hand jitter reduction mode occurs when the detected light level is above a minimum amount of light level used when removing blur in a digital picture.

14. The device of claim 7, wherein in the first range when the first frame rate reaches maximum the first frame rate is lowered to generate a second frame rate to increase an exposure time.

15. The device of claim 14, wherein a gain is lowered in response to the increased exposure time.

16. The device of claim 7, wherein the second range comprises two ranges, a third range and a fourth range.

17. The device of claim 16, wherein a second boundary between the third range and the fourth range is determined by the light level not meeting a luma target.

18. The device of claim 17, wherein a digital gain is applied in the third range and the fourth range.

19. The device of claim 7, wherein the first range is between boundary_a and boundary_b.

20. The device of claim 7, wherein the second range is beyond boundary_b.

21. An integrated circuit, comprising:

means for identifying at least one captured image;

means for detecting selection of hand jitter reduction mode;

means for identifying a light level associated with the at least one captured image;

means for mapping the light level to a corresponding gain and exposure time in a normal mode;

means for computing a first exposure time-gain product from the corresponding gain and exposure time; and

means for generating modified auto-exposure parameters in response to the computation of the exposure time-gain product, to reduce hand jitter.

22. The device of claim 21, wherein the means for generating modified auto-exposure parameters in response to the computation of the exposure time-gain product comprises modifying the gain and exposure time.

23. The device of claim 22, wherein the means for generating modified auto-exposure parameters further comprises computation of a second exposure time-gain product.

24. The device of claim 21, wherein the integrated circuit is an MSM™

.

25. A method of generating modified auto-exposure parameters comprising:

capturing at least one frame after a snapshot;

entering a hand jitter reduction mode;

associating a detected light level with unmodified auto-exposure parameters;

retrieving an exposure time and gain from a memory;

calculating a first exposure time-gain product from the retrieved exposure time and gain; and

generating modified auto-exposure parameters based on the first exposure time-gain product.

26. The method of claim 25, wherein the generating modified auto-exposure parameters based on the first exposure-time gain product includes multiplying, subtracting, adding, or dividing the retrieved exposure time and gain.

27. The method of claim 25, wherein the modified auto-exposure parameters comprise gain and exposure time.

28. The method of claim 27, wherein the modified auto-exposure parameters further comprise frame rate.

29. An apparatus comprising normal mode auto-exposure parameters, the apparatus comprising:

an image sensor for detecting a light level in at least one captured image;

a front-end image processing module coupled to the image sensor, comprising a hand jitter control module for dynamically selecting hand jitter mode auto-exposure parameters to image process the at least one captured image, the hand jitter reduction mode auto-exposure parameters having an exposure time-gain product that corresponds to an exposure time-gain product of normal mode auto-exposure parameters, and hand jitter mode auto-exposure parameters including a hand jitter reduction mode gain that is greater than a corresponding normal mode gain of the normal mode auto-exposure parameters; and

an auto-exposure control module, for providing the normal mode auto-exposure parameters.

30. The apparatus of claim 29, wherein the hand jitter mode auto-exposure parameters comprise the hand jitter reduction mode gain and exposure time.

31. The apparatus of claim 29, wherein the hand jitter mode auto-exposure parameters further comprise frame rate.

32. The apparatus of claim 29, wherein the normal mode auto-exposure parameters comprise the normal mode gain and exposure time.

33. The apparatus of claim 29, wherein the normal mode auto-exposure parameters further comprise normal mode frame rate.