[Digikam-devel] Patch: fix automatic correction of lens chromatic aberration

Andi Clemens andi.clemens at gmx.net
Mon Mar 9 10:30:27 GMT 2009


I will take a look it the patch now...

Andi

On Sunday 08 March 2009 19:51:12 Gilles Caulier wrote:
> Matthias,
>
> Thanks a lots. this patch solve a task from my TODO list.
>
> This patch is a good candidate to go to 0.11 development branch and, if it
> doesn't break i18n, in 0.10 (trunk) before finale release.
>
> Marcel, Andi, can you check this patch for me and guide Matthias on the
> right way. I'm very busy here to prepare my evening classes presentation
> for next Wednesday. To test, just use these pictures :
>
> http://digikam3rdparty.free.fr/TEST_IMAGES/LENSFUN/
>
> Thanks in advance.
>
> Gilles Caulier
>
> 2009/3/8 Matthias Welwarsky <matze at welwarsky.de>
>
> > Hello,
> >
> > the attached patch fixes CA correction in the lens auto-correction tool.
> > The fix
> > consists of two parts:
> > 1.) set Alpha component of corrected pixel to "fully opaque", otherwise
> > corrected image is not visible (trivial)
> > 2.) Implement sub-pixel interpolation in class DImg, necessary for CA and
> > CI
> > correction with lensfun.
> > There are two new pixel color accessor functions: getSubPixelColor() and
> > getSubPixelColorFast(). The first one uses Lanczos interpolation to
> > compute subpixel colors, the second one bilinear interpolation. Lanczos
> > yields better
> > results, but is a lot slower than bilinear. Before using
> > getSubPixelColor(),
> > prepareSubPixelAccess() needs to be called to precompute the Lanczos
> > kernel.
> >
> > Lanczos implementation was adapted from ufraw, Bilinear was implemented
> > according to Wikipedia description.
> >
> > I would be happy to hear comments on how to optimize the computation,
> > it's probably not optimal yet.
> >
> > regards,
> >         matthias
> >
> > _______________________________________________
> > Digikam-devel mailing list
> > Digikam-devel at kde.org
> > https://mail.kde.org/mailman/listinfo/digikam-devel




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