PixInsight Forum (historical)

PixInsight => Tutorials and Processing Examples => Topic started by: gloicq on 2017 January 18 03:55:57

Title: Noisy picture after DBE
Post by: gloicq on 2017 January 18 03:55:57

Hi there !

I'm working on a M33 picture and find that my picture is a LOT more noisy after DBE than before (see picture). How can I fix it ? Any idea ?
It happens sometimes but I have to admit that I never had any idea about fixing it...

THANKS A LOT !

Title: Re: Noisy picture after DBE
Post by: georg.viehoever on 2017 January 18 06:50:14

Its not that DBE introduces the noise. It is just that it makes the existing noise more visible. If you choose equivalent STF functions before and after DBE, both images will show the same noise.

Georg

Title: Re: Noisy picture after DBE
Post by: wimvb on 2017 January 19 14:47:36

Since DBE takes away part of the "signal", but not the noise, the signal to noise ratio decreases. Noise is usually quite easy to reduce by using TGVDenoise or MMT/MLT with noise reduction set for various layers. Personally for small scale noise in luminance, I prefer to use TGVDenoise in Lab mode on just L. For chrominance noise in DSLR images, I use MMT on about 7 layers with chrominance (restore CIE Y) as target. Quite heavy on the lower number layers, and decreasing in strength on the higher number layers.

Hope this helps,