[Digikam-devel] Fwd: New GreyCstoration

[Gilles Caulier]

---------- Forwarded message ----------
From: Mike Bing <mvoorberg at yahoo.com>
Date: 12 mars 2007 12:25
Subject: Re: [Digikam-devel] New GreyCstoration
To: Gilles Caulier <caulier.gilles at gmail.com>



*Gilles Caulier <caulier.gilles at gmail.com>* wrote:

I'm currently porting the code (:=)))

I have just completed "Restoration" plugin at now. The speed is impressive
(more than 3x : around 10x i think).

I will finalize all source code during this week, including Inpainting and
Blowup plugins.

I will very appreciate all feedback about this port using current
implementation from svn...

I will post a commit message in this mailing list when the code will be
ready to test.

Gilles Caulier

Gilles,

Awesome news. I have sent David a very noisy 400ISO Canon 8Mp image to work
with and its NeatImage output. He is currently working on getting similar
results which might gives us some more insights to the correct values of the
many switches.

As for the speed increase, I'm happy to say I have at least contributed a
bit there by suggesting to David he include tiling in the processing in
order to minimize HDD swapping due to memory constraints. I sent him a proof
of concept in the form of a bash script and he took up on that challenge
ending up adding even more memory tweaks which resulted in the current
situation.

The parameter "-tile"  is important to tweak the memory footprint so I
assume (and hope) it is a setting in the new restoration plugin?

Mike Bing wrote:
>
> Do you have any tips on parameters for high-ISO noise? I use:
> greycstoration -restore $X.jpg -dl 1.5 -sigma 3.0 -p1 0.1 -p2 0.9
> -prec 3 -linear 0 -da 45 -dt   DT  -iter ITER  -visu off -o $X-nr.jpg
> where I have the following presets:
>
>
When you have high-iso noise, a good idea is to increase the '-alpha'
parameter rather than the 'sigma' one. Actually, it is not very clear
for me what set of
 parameters are the best ones. I'm still trying to
understand the exact role of each parameter, I mean not the
mathematical
meaning (I can explain this very well..) but the effect in terms of
psychovision or something like this.
That's unfortunately research work and a lot of open questions
remain...

Regards,

David.



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