PixInsight Forum (historical)

PixInsight => General => Off-topic => Topic started by: David Raphael on 2011 January 04 08:51:44

Title: General question about sharpening / ATWT
Post by: David Raphael on 2011 January 04 08:51:44
I've read many discussions about how deconv should be used - and one of the points that has been emphasized is that it is not intended to be used as a sharpening tool...

I've also read that ATWT can be used as a sharpening tool...

Maybe I'm missing something big here, but I don't understand how one would use ATWT as a sharpening tool.  Can anyone explain this to me?

Thanks,
Dave
Title: Re: General question about sharpening / ATWT
Post by: David Raphael on 2011 January 10 10:47:18
No one?

 :'(


Title: Re: General question about sharpening / ATWT
Post by: Andres.Pozo on 2011 January 11 02:33:43
Maybe I'm missing something big here, but I don't understand how one would use ATWT as a sharpening tool.  Can anyone explain this to me?
You only have to increase the weight of the smaller layers. This is a trivial example without masks:
Title: Re: General question about sharpening / ATWT
Post by: avastro on 2011 January 11 02:34:54
Hi Dave,
Let me try to explain you how I use ATWT for sharpening.
Depending a what part of the image I'm interested in sharpening, I build a mask to protect the other part.
Usually I build a star mask and invert it if needed.
I select in ATWT the number of layers adapted at my image usually 5 or more, then I use a positive bias to the layers corresponding to the part of the image I'm looking for sharpening. Usually between 0.1 and 0.05 in layer 2 and layer 1 sharpen quit well fine details.
If your image is noisy it's better to avoid increasing the bias in layer 1, just remove it.
I hope this quick explanation will help you.
Cheers

Antoine
http://astrosurf.com/avastro/
Title: Re: General question about sharpening / ATWT
Post by: David Raphael on 2011 January 11 07:55:16
Thanks gents!

Do you normally do this pre or post stretch?
Title: Re: General question about sharpening / ATWT
Post by: avastro on 2011 January 11 13:52:57
Hi Dave,
I generally do that at the end of my process, when I try to find the last small improvements.
Cheers
Antoine
http://astrosurf.com/avastro/