Digital still camera with multiple frames combined into a single frame for digital anti-shake/anti-blur
View Patent ↗A method of capturing a still frame is disclosed. The method generally includes the steps of (A) generating a plurality of initial frames with a sensor in response to an optical signal and (B) generating the still frame by combining the initial frames using a noise reduction technique.
1. A method of capturing a still frame, comprising the steps of:
(A) generating a plurality of initial frames with a sensor in response to an optical signal;
(B) generating a filtered frame by combining at least a first of said initial frames and a second of said initial frames using a noise reduction technique; and
(C) generating said still frame after said filtered frame has been generated by combining a third of said initial frames with said filtered frame using said noise reduction technique, wherein said initial frames are motion compensated with reference to a central one of said initial frames such that said still frame is temporally aligned with the central initial frame.
2. The method according to claim 1 , wherein said noise reduction technique comprises the sub-step of:
motion compensating said first initial frame before combining with said second frame.
3. The method according to claim 2 , wherein said noise reduction technique further comprises the sub-step of:
generating a plurality of motion vectors corresponding to said first initial frame using said second initial frame as a reference.
4. The method according to claim 2 , wherein (i) said first initial frame comprises a plurality of blocks and (ii) said motion compensating operates independently on each of said blocks.
5. The method according to claim 3 , wherein said first initial frame is generated temporally before said second initial frame.
6. The method according to claim 3 , wherein said first initial frame is generated temporally after said second initial frame.
7. The method according to claim 1 , wherein said noise reduction technique comprises the sub-step of:
updating said filtered frame by combining said filtered frame with a fourth of said initial frames.
8. The method according to claim 1 , wherein said noise reduction technique comprises the sub-step of:
generating a plurality of motion vectors by motion estimating said filtered frame using said third initial frame as a reference.
9. The method according to claim 8 , wherein said noise reduction technique further comprises the sub-step of:
motion compensating said filtered frame using said motion vectors.
10. The method according to claim 9 , wherein said filtered frame and said current frame are combined after said filtered frame is motion compensated.
11. The method according to claim 1 , wherein said noise reduction technique comprises the sub-step of:
generating said filtered frame by combining each subsequent frame of said initial frames to an accumulation of all earlier frames of said initial frames.
12. The method according to claim 1 , wherein said noise reduction technique comprises the sub-steps of:
generating a plurality of first frames by motion compensating one of said initial frames in each of a plurality of first neighboring pairs of said initial frames; and
generating a plurality of second frames by spatially combining said first frames and another of said initial frames in each of said first neighboring pairs.
13. The method according to claim 12 , wherein said noise reduction technique further comprises the sub-steps of:
generating a third frame by motion compensating one of said second frames in each of at least one second neighboring pair of said second frames; and
generating a fourth frame by spatially combining said third frames and another of said second frames in each of said second neighboring pairs.
14. The method according to claim 1 , wherein said initial frames are combined in a pyramid fashion having at least three levels of combinations.
15. The method according to claim 1 , wherein said filtered frame and said second initial frame are generated in parallel.
16. The method according to claim 1 , wherein said still frame and said third initial frame are generated in parallel.
17. The method according to claim 1 , wherein said still frame is generated after said third initial frame has been generated.
18. The method according to claim 1 , wherein at least one of said initial frames that is motion compensated is temporally separated by more than a frame distance from said central frame.
19. A non-transitory computer readable medium containing processor executable instructions configured to perform the steps of claim 1 .