Feature: local destreaking

[minnerbe]

I implemented a first version of local de-streaking. The locality is based on the following algorithm:

1. de-streak with band-pass
2. threshold difference to get only the streaks
3. blur the result and threshold again to get a larger area around the streaks
4. blur the result again to get a smooth transition
5. use the result as a local weight between the original and the de-streaked image

The locality works reasonably well, the overall result looks not that convincing, though. This may be based on the non-linear intensity transformation that the de-streaking introduces (there are lighter and darker regions simultaneously).

Side note: My manual tests in FIJI looked a little better, which could be due to the different (i.e., not as invasive) band-pass that I applied there.

[minnerbe]

I implemented SmoothMaskStreakCorrector, a new smoother version of the FFT based band-pass filter that we had (see results below). IMHO, this yields much better results and in particular doesn't change local intensity that drastically.

Also, the new method has 3 tunable parameters:

• distance of cutoff from the middle
• width of cutoff band
• angle of cutoff band (orthogonal to streaks)

This should be a lot easier to tune than the current manual workflow.

[minnerbe]

Another update: a local version of the smoother mask works.