Bug 224293 - wavelets NR tool confuses red and blue
Summary: wavelets NR tool confuses red and blue
Status: RESOLVED FIXED
Alias: None
Product: digikam
Classification: Applications
Component: Plugin-Editor-NoiseReduction (show other bugs)
Version: 1.1.0
Platform: openSUSE Linux
: NOR normal
Target Milestone: ---
Assignee: Digikam Developers
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2010-01-26 09:27 UTC by S. Burmeister
Modified: 2016-06-30 11:36 UTC (History)
1 user (show)

See Also:
Latest Commit:
Version Fixed In: 1.1.0
Sentry Crash Report:


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Description S. Burmeister 2010-01-26 09:27:50 UTC
Version:           1.1.0 svn (using KDE 4.3.4)
OS:                Linux
Installed from:    openSUSE RPMs

svn Rev: 1079999


I noticed a lot of blue spots in the black areas and thus set luminance and Chrominance red to 0, i.e. only used Chrominance blue, yet the blue spots did not go away. Then I set blue to 0 and red to some value >0 and the blue spots disappeared.

So here is my dumb question, am I wrong assuming that red should get rid of the red spots and blue of the blue ones and that there is a bug that those two are interchanged?

Then I thought that maybe a treshold of 0 means that it will erase all kinds of blue. Yet if I set both red and blue to 0 I get more blue noise compared to blue set to 0 and red to some value >0. Which seems odd as I did not change any value for blue thus blue noise should stay at the same level.
Comment 1 caulier.gilles 2010-01-26 09:34:17 UTC
I agree, sound like something is inverted somewhere.

To be sure, can you test with this gimp tool if problem is the same, because it's the same algorithm used (in YCbCr color space)

http://registry.gimp.org/node/4235

Thanks in advance

Gilles Caulier
Comment 2 S. Burmeister 2010-01-26 10:44:37 UTC
Ok, I think I got it.

Gimp shopws some tooltips and explains that the treshold is the value below
which everything is considered noise. I think it might be useful to add this to
digikam as well.

Further. If I set Y and Cb to 0 I get the full blue noise. Increasing the
treshold for Cr does not change anything about that so it seems that digikam
has a bug.

Increasing Cb gets rid of the blue noise.
Comment 3 caulier.gilles 2010-01-26 11:39:01 UTC
SVN commit 1080460 by cgilles:

CRed and CBlue parameters are inverted
BUGS: 224293


 M  +20 -20    noisereductionsettings.cpp  


WebSVN link: http://websvn.kde.org/?view=rev&revision=1080460