On 31 March 2013 16:48, Daniel J Blueman <[email protected]> wrote: > In my thesis a while back [1], I developed a strong algorithm and tool > [2] to automatically generate LCA correction data from an image. These > correction values hold for the given set of lens parameters usually > encoded in the image's EXIF fields. > > I wanted feedback onsome ideas to bring this tool to a wider audience: > - reduce runtime/memory usage > - generating lib lensfun-compatible output > - ability to work on a directory of images, averaging across related settings > - moving from python to C/C++ > > Finally, I find that LCA correction is depenendent on aperture and > potentially focus settings (as lens elements are moved); this isn't > encoded in the existing lensfun correction model [3]. Arguably, having > a more generalised model which curve-fits these parameters across the > focal range and perhaps includes error or some sample count will > provide a more robust solution. > > Or, perhaps the tradeoff of being compatible with the existing format > is sufficient, eg if we add a 'count' field (so we can see where we > have averaged over fewer lenses). That opens the possibility of users > being able to submit and access lens profile data in an easier way. > > What do you guys think? > > Daniel > > [1] http://quora.org/thesis-daniel-blueman.pdf > [2] http://quora.org/ca-correct
I've just uploaded a new version which just works with the current opencv version: $ sudo apt-get install libopencv-dev pythonopencv ... $ ./ca-correct -s uncorrected.png optimising RG plane... ... [ 0.00186529 -0.00299798 0.00015413] optimising BG plane... ... [ 0.00186529 -0.00299798 0.00015413] For best results, use minimal processing (eg linear demosaicing) on raw-converted files; the LCA correction results are good (eg zooming in to the bottom-right corner): http://quora.org/lca/uncorrected.jpg http://quora.org/lca/corrected.jpg Over the next days, I'll release a version which shows the lens parameters and can process a directory of images, giving a lensfun XML file. Thanks, Daniel -- Daniel J Blueman ------------------------------------------------------------------------------ Own the Future-Intel(R) Level Up Game Demo Contest 2013 Rise to greatness in Intel's independent game demo contest. Compete for recognition, cash, and the chance to get your game on Steam. $5K grand prize plus 10 genre and skill prizes. Submit your demo by 6/6/13. http://altfarm.mediaplex.com/ad/ck/12124-176961-30367-2 _______________________________________________ darktable-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/darktable-devel
