Please come all to AstroFest in London to ask us (Mabula & Vincent) questions and to see live demos of APP!
2023-01-19: APP 2.0.0-beta13 has been released !
!!! Big performance increase due to optimizations in integration !!!
and upgraded development platform to GraalVM 22.3 based on openJDK19
We are very close now to releasing APP 2.0.0 stable with a complete printable manual...
Canon Banding Reduction
Would it be possible to add a Canon Banding Reduction option ?
Do you see it remaining an issue in a stack? I think it should already be a signal in the bias or darks, might be mistaken.. Dithering will also reduce this.
Yes, the banding is visible in the stack (see attached (extremely stretched) photos).
You are right to say it should be gone with darks.
However, since I use dithering and Bad Pixel Map, I found that I can process my photos with only Biases and Flats (as per option 1 in sticky post "Data calibration principles/rules") and achieve nearly the same result as with darks once the remaining banding is removed from the stack.
For this I use the process integrated in other processing softwares but it would be nice to have this function directly into APP.
edit: Maybe the banding reduction would be even more effective if applied on each sub, during calibration ?
Yes that would work better, but it’s not going to improve the data dramatically I think. It will reduce it of course, but I think you still get a better result in this case by using darks as well. That will be the actual data and not “guessed” by an algorithm.
In fact, it seems that this problem cannot be entirely solved with darks as the banding is not constant from one image to another.
There was a Yahoo group on this subject but those groups are now dead.
I did a test adding darks and here is the result.
Even though the problem has diminished, we can see that there are still bands.
I requested this feature because it is present in other programs and I thought it was a classic.
Unfortunately, this problem only affects Canon cameras (old ones ?) and only a few of them, I may be the only one who needs this feature.