31 May 2021: APP 1.083-beta2 has been released ! APP 1.083 stable will follow soon afterwards. It includes a completely new Star Reducer Tool, New File Saver Module, Improved Comet registration and much more, check the release notes here!
Mosaic seems to be adding artifacts
Before anything I have verified that stacking both panels seperately does not produce the artifacts, this only seems ot be happening when I use the Mosaic Funcion in APP, you can see here some of the artifacts. The artifacts get worse the higher the LNC Degree and/or iterations of LNC
Last image above here is the same region with just the single panel stacked and STF applied as above
As I said, if I stack both the panels seperately there is no issue, but then I cannot perform the mosaic stack, and believe me the mosaic stack method is far more reliable (aside from the artifacts) than any other method I have found.
But I would really like to find out why the artifacts are appearing.
All settings are default except for
Scale Start = 1
Scale End = 10
Use Dynamic Distortion Correction
Registration mode = Mosaic
LNC Degree = Tried 1 or 2
LNC Iterations = Tried 1, 2 and 3 with above
Enable MBB 20% (Frames overlap by 20%)
Everything else is defailt
Anyone else experienced these kinds of artifacts with Mosaic Mode?
Mmm interesting, these look like hot-pixels. However, if you already stacked the panels that should be gone. Would you be able to share the data (just the minimum which produces the issue) to our server?
Go to https://upload.astropixelprocessor.com and use upload1 as username and upload1 as password.
Create a directory named “stastro-mosaicartefacts” and upload in there. Thank you!
@vincent-mod I do not have specific frames that cause this, and it happens in both panels during the mosaic, but none of the panels when processed seperately, I am going to re-run with Mosaic but without LNC and see what happens, I have Over 160 frames each are 62mpx
@vincent-mod Also if it was hot pixels, I would expect all the artifacts to show up in a similar pattern, which they do not, would you agree?
@vincent-mod I fixed it by adding Sigma Rejection, sigma rejection gets rid of the artifacts
Note to self....Use Sigma rejection on Mosaics 🙂
Interesting, I thought the panels would already have had rejection applied as you didn't see the issue on those? Otherwise I'd advise to use it also for regular data.
@vincent-mod Yeah I have never had to use any rejection method in the past, this is the first time with creating a mosaic in APP, for normal frames I never use rejection method
Could indicate that your camera has developed some hot pixels maybe. The automatic setting in tab 6 will always use rejection based on the number of frames. It shouldn't affect your data in a negative way really, as the kappa values are pretty mild.
@vincent-mod I would agree but if that was the case then they would show up when stacking the single panels
I agree, that is indeed puzzling. I think more data/investigation will tell us what's going on. 🙂
I meant, for you to take more data so it may become clearer. 😉
@vincent-mod So I created some new darks last night, and processed without any Rejection Algorithm and the artifacts are there in exactly the same place, so it cannot be due to hot pixels
Well it could still be as darks are not necessarily getting rid of 100% of them, as that would usually cause more data damage. This is where the rejection algorithms do the final touch basically.
@vincent-mod Still doesn't explain why I do not see them in normal stacks, when I do not use any rejection algorithm at all (And have not done since I started using APP), I even processed with the new Darks and still no artifacts, it only seems to be happening in Mosaic mode
Yes, that remains odd. Do you want to upload the panels? Would be interesting if I can replicate that.
🙂 We do, but wouldn't just say, 2 panels also show the issue? Just the already integrated panels I mean.
@vincent-mod OK I'll upload the following
1. Mosaic Integration
2. Panel 1 Integration
3. Panel 2 Integration
Would that be OK?
Also is there a way to perform the Mosaic on the two separate stacks? So basically if I take the two separate stacks, can I perform a Mosaic function in APP somehow?