[Digikam-devel] [patch] Noisereduction updates

Peter Heckert lists at hphsite.de
Fri Apr 28 23:16:12 CEST 2006


I implemented new gaussian filter for Noisereduction, so that 
Noisereduction is equal to
current gimp-plugin dcamnoise2-0.64.

I am aware that this is a quick'n dirty implementation. However I wish, 
that the filter
makes the best image quality possible when it is released to the public.
I intend a complete rewrite that implements 2-dimensional filtering, but 
this will not be
ready for next beta release - too much work.
While I developed the gimp-plugin-algorithm I did about 10 times 
fundamental changes
to the algorithm, and this  is, why  current code is  very confused, I 
hope to deliver
better quality and portability when I rewrite it.

Changes to noisereduction.cpp & noisereduction.h:
Implemented fir filter,  removed iir filter.
Partially removed sharpening filter, because new noise-filter has better 
Tried to speed up mypow().

Changes to imageeffect_noisereduction.cpp:

Set default for threshold to 0.13 to take different (improved) filter 
behaviour in account.
Set precision for Luminance and Color rubbers to "2" so that finer 
adjustment is possible.
(In the gimp plugin I used logarithmic rubbers, because high ajustment 
accuracy often
 is needed for very low values)
Remaining bugs:
Sometimes mousepointer stays connected with a rubber. The only way to 
cure this, is
to restart the plugin.
Progress-bar is almost unvisible, because it is only 3-4 mm long.

I cannot find errors in my code, that could be the reason.
Possibly one reason is, that the filter is slow compared to other 
filters  and the mouse and
rubber can move while the filter is busy and another
reason could be, that I use a preemptive linux-kernel.

Possibly these bugs have to do with my Qt-version, I use:
Qt: 3.3.5
KDE: 3.5.2-0.1.fc5 Red Hat



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