ACDNR Strange anomaly around stars?

[ctemple]

Hi All,

We've been noticing some strange anomaly around our stars after applying ACDNR.

Attaching a series of images for reference.

#1 - Integrated and Histogram Transformation:


#2 - ACDNR to remove small scale noise (the anomaly is showing now):


#3 - Second pass of ACDNR to remove large scale noise (stars are worse now):


I feel it has something to do with edge protection not allowing to smooth all the way to the star edge but I'm not sure.  Is it possible that something in the integration or registration that is the root cause?

Any help is greatly appreciated!
- C&T

[pfile]

i see stuff like this all the time, it's as you suspect, the mask near the star is causing this...

rob

[ctemple]

Thanks Rob!  Any tips on how to avoid this?
- C&T

[erikgu]

Hi, try TGVDenoise instead. It requires some experimenting but for me it gives a better result. I have started to do the initial noise reduction at linear stage a think it is easier to get a good result.

Here is an example, second with a very little noise reduction. The support setting is enabled leaved to default.





Erik G

[pfile]

i have started using TGVDenoise as well. at the linear stage a 'support image' is mandatory. a good way to get the parameters for the support image is to do an AutoSTF on the image, then open STF's parameters dialog box (the little wrench) and copy the blacks and mid tones to the TGVDenoise tool's support parameters.

as for the junk around the stars, i usually use a clone of the image which has been stretched to protect the foreground. i do still see some 'grain' around the stars from time to time but it does seem less bad than ACDNR.

rob

[Juan Conejero]

Hi,

That happens because your edge protection and/or star protection thresholds are too low. If you upload the image, I can try to find an optimal set of ACDNR parameters for you.

[ctemple]

Juan,

That would be great!  I have uploaded 3 different FIT files and added to the end of the filenames what has been done to them.
(DBE, ATWT and HT).

Thanks!!

DBE only: http://cnttemple.astrophotogallery.org/dl/IC1848_CloseUp_SVR105_QSI_Ha_DC_DBE2.fit
DBE & ATWT:http://cnttemple.astrophotogallery.org/dl/IC1848_CloseUp_SVR105_QSI_Ha_DC_DBE2_ATWTnr.fit
DBE, ATWT, & HT: http://cnttemple.astrophotogallery.org/dl/IC1848_CloseUp_SVR105_QSI_Ha_DC_DBE2_ATWTnr_HT2.fit

- C&T