Version: 0.7.3 (using KDE KDE 3.4.1) Installed from: Gentoo Packages OS: Linux Applying an unsharp mask effect to a digital image (photo, scan, ...) often results in amplification of unwanted chromatic noise. So, I always use the GIMP to split the image into seperate HSV layers and apply the unsharp mask only to the luma (V) channel. After merging back to RGB, it looks really good. Please add an option to the unsharp mask dialog to only apply the effect to the luma channel. Maybe the option can be called "suppress color noise" or something similar.
Try to use Refocus plugin instead UnsharpMask available in 0.8.0 release. Take a look in plugin handbook for more informations : http://docs.kde.org/development/en/extragear-graphics/digikamimageplugins/refocus.html Gilles Caulier
Dik, close this one?
That's something totally different: Refocus is a convolution filter. Unsharp mask is a simple sharpening filter which works by enhancing edge contrast. It's the sharpening filter of choice for "everyday" images. But it's quality can even improved by only applying it to the luma channel. There are many gimp/photoshop/... howtos about this. This can be done with scrips, but digikam does not support scripts. So it would be very convient to include this option into the unsharp mask filter.
I agree that refocus is something totally different than unsharp masking is. In general, you can't substitute one for the other.
Created attachment 104016 [details] Adding a checkbox that makes the unsharp mask filter get applied on luminosity channel only.
Git commit 78534f6f50a53f188366d9fc218243461a1787cc by Gilles Caulier. Committed on 13/02/2017 at 17:22. Pushed by cgilles into branch 'master'. apply patch #104016 from Shaza Ismail to reduce color noise with Unsharp Mask filter using HSL color space while processing image FIXED-IN: 5.5.0 M +3 -1 NEWS M +56 -32 libs/dimg/filters/sharp/sharpsettings.cpp M +7 -5 libs/dimg/filters/sharp/sharpsettings.h M +78 -49 libs/dimg/filters/sharp/unsharpmaskfilter.cpp M +4 -3 libs/dimg/filters/sharp/unsharpmaskfilter.h M +12 -4 utilities/imageeditor/tools/enhance/sharpentool.cpp M +2 -2 utilities/imageeditor/tools/enhance/sharpentool.h M +6 -2 utilities/queuemanager/tools/enhance/sharpen.cpp M +2 -2 utilities/queuemanager/tools/enhance/sharpen.h https://commits.kde.org/digikam/78534f6f50a53f188366d9fc218243461a1787cc