Bug 194722

Summary: Only sharpen one channel, e.g. the "value" channel of HSV
Product: [Applications] digikam Reporter: S. Burmeister <sven.burmeister>
Component: Plugin-Editor-SharpenAssignee: Digikam Developers <digikam-bugs-null>
Status: RESOLVED FIXED    
Severity: wishlist CC: caulier.gilles, shaza.ismail.k
Priority: NOR    
Version: 0.10.0   
Target Milestone: ---   
Platform: openSUSE   
OS: Linux   
Latest Commit: Version Fixed In: 8.0.0

Description S. Burmeister 2009-05-31 10:32:26 UTC 
Version:           0.10 (using KDE 4.2.3)
OS:                Linux
Installed from:    SuSE RPMs

Since the value channel shows the largest differences in terms of brightness, it is useful to use it for sharpening an image without touching the hue or saturation.

I'm not sure this is useful for other tools as well, but digikam could provide the facilities to automatically create a hsv temp file while the user adjusts the tool and write that temp file back if the user saves the changes.

That way the user can pick the channel the tool should work on while editing a picture without any knowledge about conversion to hsv etc.
Comment 1 Shaza 2017-03-09 22:21:39 UTC 
Currently an option for "Suppress color noise" is added to unsharp masking if the checkbox is selected the filter is applied on luminosity(value) channel only, is that sufficient?
Comment 2 caulier.gilles 2023-04-06 15:51:23 UTC 
The Image Editor GMIC-Qt Details/Constrained Sharpen allows to use plenty of color spaces other than RGB* and apply changes on a dedicated channel.

https://i.imgur.com/M5LCPBi.png

Gilles Caulier