Stretching for Bill Blanshan’s narrowband normalisation tool Bill Blanshan Narrowband Normalization PixelMath · Craig Dixon · ... · 7 · 1006 · 1

craigdixon1986 2.15
...
· 
·  2 likes
Hi All.

I use a OSC camera and find Bill’s narrowband normalisation tool really useful for creating images in the HOO palette. However, it’s recommended not to colour calibrate beforehand. Normally I use Bill’s “Unlinked HT Stretch” tool before narrowband normalisation but I’ve been learning GHS and would like to start using GHS to stretch. However, if I don’t colour calibrate, I just get a green overlay when using GHS due to the RGGB bayer pattern.

Do those of you who use narrowband normalisation stretch via GHS and if so, how do you overcome this issue?

Thanks.
Like
TurtleCat 4.62
...
· 
My typical procedure, and it's worked great for me, is to run SPCC and DBE before I do NarrowbandNormalization. I only use Mode 2 for HOO since I'm using the L-Ultimate dual band. I believe on the PixInsight forum that was the only recommended option for a dual band setup. I may try it without color calibrating. I'll load up an image I have handy and see if it looks any different. I just looked and it looked the same to me. 

Calib.jpg
Like
TurtleCat 4.62
...
· 
Now in both of those cases, I should add, I did background extraction before running SPCC and/or NN which takes care of the green bias.
Edited ...
Like
craigdixon1986 2.15
...
· 
·  1 like
Thanks, that’s really helpful. I’ll try this on some data today.
Like
craigdixon1986 2.15
...
· 
I've had a go at using SPCC and then GHS but I can't get the narrowband normalisation tool to work as expected using this method. I'm still getting far better results by just using Bill's "unlinked stretch" tool.
Like
TurtleCat 4.62
...
· 
·  1 like
I would do GHS after you’ve done NN. It’s much better used before any stretching IMO.
Like
Danny_Astro 2.86
...
· 
I had the same issue, narrowband normalisation (NN) works best on an unlinked stretch but stretching with GHS first didn't produce good results with NN. 

You could try a combination and as Turtlecat has said, try applying a light unlinked STF or Bill's stretch, run NN and you can then try and get a bit more with GHS after narrowband normalisation.
Like
craigdixon1986 2.15
...
· 
I didn’t realise I could use NN before stretching so thanks for that. I’ll try on the next image I process.
Like
 
Register or login to create to post a reply.