Two-stage method to merge burst image frames

1. A method of multiple-exposure multiple-frame image capture, comprising:

capturing a first group of frames at an underexposed setting;

selecting a first key frame from the first group of frames;

aligning the first group of frames to the first key frame;

merging the first group of frames into one first frame based on the first key frame;

capturing a second group of frames at the underexposed setting;

selecting a second key frame from the second group of frames;

aligning the second group of frames to the second key frame;

merging the second group of frames into one second frame based on the second key frame;

selecting a main group of frames based on the first key frame and the second key frame;

aligning the first key frame and the second key frame based on the main group of frames; and

merging the first key frame and the second key frame based on the main group of frames.

2. The method of multiple-exposure multiple-frame image capture of claim 1 , further comprising:

capturing a next first group of frames at the underexposed setting;

indexing the first group of frames to the next first group of frames, resulting in an indexed first group of frames;

selecting a next first key frame from the next first group of frames;

aligning the next first group of frames to the next first key frame;

merging the next first group of frames into one next first frame based on the next first key frame;

capturing a next second group of frames at the underexposed setting;

indexing the second group of frames to the next second group of frames, resulting in an indexed second group of frames;

selecting a next second key frame from the next second group of frames;

aligning the next second group of frames to the next second key frame;

merging the next second group of frames into one next second frame based on the next second key frame;

reselecting the main group of frames based on the next first key frame and the next second key frame;

aligning the next first key frame and the next second key frame based on the main group of frames; and

merging the next first key frame and the next second key frame based on the main group of frames.

3. The method of multiple-exposure multiple-frame image capture of claim 1 , further comprising:

indexing a capturing of another first group of frames the underexposed setting by N; and

indexing a capturing of another second group of frames the underexposed setting by N.

4. The method of multiple-exposure multiple-frame image capture of claim 1 , further comprising:

iteratively indexing a capturing of another first group of frames at the underexposed setting by N; and

iteratively indexing a capturing of another second group of frames at the underexposed setting by N.

5. The method of multiple-exposure multiple-frame image capture of claim 1 , wherein the first group of frames and the second group of frames are raw data.

6. The method of multiple-exposure multiple-frame image capture of claim 1 , wherein the first group of frames and the second group of frames are low dynamic range.

7. The method of multiple-exposure multiple-frame image capture of claim 1 , wherein the first key frame is based on a best frame within the first group of frames.

8. The method of multiple-exposure multiple-frame image capture of claim 1 , wherein the second key frame is based on a best frame within the second group of frames.

9. The method of multiple-exposure multiple-frame image capture of claim 1 , wherein the first group of frames and the second group of frames are captured with approximately equivalent exposure.

10. The method of multiple-exposure multiple-frame image capture of claim 1 , wherein the first group of frames are buffered.

11. The method of multiple-exposure multiple-frame image capture of claim 1 , wherein the second group of frames are buffered.