[Digikam-devel] selection code question

[Thorsten Schnebeck]

Hi,

and thank for helping. 

> Well, have a close look at the refocus performance compared to your
> smart-sharpening! refocus is far better, in that is has no halos and much
> more detail.

No, these are not details, this is high frequent noise, all pictures in the 
example are "oversharpened" :-)

> Your smart-sharpened image lacks a lot of detail.

The details are not there in the base image. Refocus looks like a 
noise-texture. If you look at Refocus pic in 200% you clearly see halos on 
the leaves. These halos disapear with Cicular 0.9 and Noisefilter: 0.030
That way you got a very well sharpened picture. A little bit lower contrast 
than smart-sharpen but like this "anti-engraved" stile :-)

> Just compare  
> your picture with the example at the website
> http://docs.kde.org/development/en/extragear-graphics/digikamimageplugins/c
>omparison-plugin-refocus.html
> I've looked with Gilles into the subject, and I'm convinced that it is
> pretty hard to beat refocus, theoretically it should not be possible to be
> better.

Ok, I have played a little bit more with refocus. I see the default value of 
0.9 cirular sharpness is nearly the limit. When using something over 1.0 I 
get halo effects and between 0.8 - 1.0 there are areas where sharpeness looks 
noisy. So, using 0.75 produces a good subtle sharpness with a clearly 
accentuation of  details. Using > 0,8 I have to play with the noise filter 
value to "blur the sharpness" and reduce halo effects.

Now my problem. I have not found a Refocus parameter set to sharpen a 
portrait. So I put an example on my server and maybe someone can send me a 
result that matches smart-sharpen.

Please use png-format so the results have no JPEG-compression artefacs.
Base-pic is 
http://www.schnebeck.de/test/base.png (1.1MB)
My smart-sharpen pic is
http://www.schnebeck.de/test/smart-sharpen.png (1.3 MB)
My Refocus pic is
http://www.schnebeck.de/test/refocus.png (1.5 MB)
Refocus was Circular: 1.5, Noise Filter: 0.16

There is also a
http://www.schnebeck.de/test/all_in_one.xfc (11MB)
where you easily can use GIMPs layer-tool to compare all 3 images at 100%

I know portait sharpening is subtle so watch right eye, hair, finger nail, 
lips. Comparing refocus with base I can only see a slightly accentuation of 
the skin - of course this is normally unwanted in portraits (of a woman :-) )

If this tend to go too offtoppic we can do this discussion in private mail, 
but I learned a lot about Refocus pros and cons during these hours :-)

Bye

  Thorsten

P.S.
Found bugs: showFoto has "save as" permanently grayed out, digikam does not 
switch to the "save-as" filename after saving and digiKam and showFoto can 
not translate and save a JPG to a PNG file by changing the filename 
extention.