Avoiding image artifacts caused by camera vibration

• US 20070127902A1
• Filed: 12/05/2005
• Published: 06/07/2007
• Est. Priority Date: 12/05/2005
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Ziemkowski, Theodore
• Granted Patent: US 7,460,773 B2
• Time in Patent Office: Days
• US Class Current: 396/52
• CPC Class Codes: G02B 27/646 compensating for small deviations, e.g. due to vibration or shake movement of one or more optical elements for control of motion blur in cameras, projectors or printers G03B2205/0007; image stabilisation in cameras peculiar to the presence or use of an electronic image sensor H04N23/68
• CPC Class Codes: H04N 23/68 for stable pick-up of the scene, e.g. compensating for camera body vibrations
• CPC Class Codes: H04N 23/6812 based on additional sensors, e.g. acceleration sensors
• CPC Class Codes: H04N 23/684 performed by controlling the image sensor readout, e.g. by controlling the integration time

Abstract

Methods and apparatus are disclosed for avoiding image artifacts caused by camera vibration. The taking of one or more photographic exposures is timed in relation to the vibration, so as to avoid motion blur, video jitter, or both. The vibration may be characterized by motion sensors, or by analysis of image data.

Claims

1. A method, comprising timing the taking of at least one photographic exposure by a camera, the camera mounted on a vibrating object causing the camera to vibrate, in relation to the vibration so as to substantially avoid image degradation caused by the vibration.

2. The method of claim 1, further comprising monitoring motion of the camera caused by the vibration, and wherein timing the taking of a photographic exposure further comprises delaying the starting time for the exposure until the monitored motion satisfies a motion criterion.

3. The method of claim 2, wherein the motion criterion is a reversal of direction of the camera motion.

4. The method of claim 2, wherein the motion criterion is a reversal of acceleration of the camera.

5. The method of claim 1, wherein timing the taking of a photographic exposure further comprises delaying the taking of the exposure until the camera position deviates from a reference position by less than a predetermined threshold amount.

6. The method of claim 5, wherein the camera position deviation is evaluated by comparing a trial video frame with a reference video frame.

7. The method of claim 6, wherein comparing the trial video frame with the reference video frame further comprises computing a correlation value for the two frames.

8. The method of claim 6, wherein only a portion of each frame is used in the comparison.

9. The method of claim 1, further comprising:

receiving an indication that a photographic exposure is to be taken; and

delaying the taking of the photographic exposure until either the camera position deviates from a reference position by less than a predetermined threshold amount or a predetermined maximum delay time has elapsed.

10. The method of claim 9, further comprising resetting the reference position after the predetermined maximum delay time has elapsed.

11. The method of claim 1, wherein timing the taking of a photographic exposure further comprises:

receiving an indication that a video frame is to be taken;

taking a predetermined number of trial video frames;

comparing each trial video frame with a reference frame; and

selecting as the requested video frame the trial frame that most closely correlates with the reference frame.

12. The method of claim 11, wherein comparing the trial video frame with the reference video frame further comprises computing a correlation value for the two frames.

13. The method of claim 11, wherein only a portion of each frame is used in the comparison.

14. The method of claim 1, wherein video jitter is avoided due to the effect of aliasing between a frequency of the vibration and a frequency at which video frames are taken.

15. A camera, comprising logic, the camera mounted on a vibrating object causing the camera to undergo a vibrating motion, the logic configured to time the taking of at least one photographic exposure by the camera in relation to the vibration so as to substantially avoid image degradation caused by the vibrating motion.

16. The camera of claim 15, further comprising a motion sensing unit, and wherein the logic is further configured to delay the taking of a photographic exposure until the camera motion, as sensed by the motion sensing unit, satisfies a motion criterion.

17. The camera of claim 16, wherein the motion criterion is a reversal of direction in the vibrating camera motion.

18. The camera of claim 15, wherein the logic is further configured to time the taking of a photographic exposure by delaying the taking of the exposure until the camera position deviates from a reference position by less than a predetermined threshold amount.

19. The camera of claim 18, further comprising a motion sensing unit for determining the camera position.

20. The camera of claim 19, wherein the deviation of the camera position from the reference position is characterized by comparing a trial video frame with a reference video frame.

21. The camera of claim 20, wherein the comparison is performed by computing a correlation value from the trial video frame and the reference video frame.

22. The camera of claim 15, wherein the logic is further configured to receive an indication that a video frame is to be taken, take a predetermined number of trial video frames, compare each trial video frame with a reference frame, and select as the requested video frame the trial frame that most closely correlates with the reference frame

23. A camera, comprising:

means for characterizing camera motion resulting from the camera being mounted on a vibrating object; and

means for timing the taking of at least one photographic exposure in relation to the vibration so as to substantially avoid image artifacts caused by the vibration.