[Digikam-devel] selection code question

[Gerhard Kulzer]

> 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
>
Thank you very much for getting so deeply involved, first of all, Thorsten. 
Portraits and any other picture with large almost smooth surfaces are 
difficult subjects for all sharpening tools.

 I'm sorry to say that in my opinion you proved convincingly that refocus does 
the better job with your portrait. Have a close look at the right eyebrows 
and the nose tip and the forehead skin, the smart-sharpen details look 
artificial and clotty, whereas the refocus show real detail and look more 
natural. 

When I say 'real' I mean it. 
> The details are not there in the base image. Refocus looks like a 
> noise-texture. 
Refocus does indeed reconstruct details that don't seem to exist. It inverses 
the unsharpening effect of a annular opening (aperture) interference pattern. 
It's the same magic than a hologram. The information is spread out over a 
certain area and can be reconstructed.

Gerhard