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 --- [3] <lens> <maker>Nikon</maker> <model>Nikkor 16-85mm f/3.5-5.6G AF-S ED VR DX</model> <mount>Nikon F AF</mount> <cropfactor>1.5</cropfactor> <calibration> <distortion model="ptlens" focal="16" a="0.0199837" b="-0.0681903" c="0.0388181" /> <distortion model="ptlens" focal="18" a="0.0101226" b="-0.0323001" c="0.00392398" /> <distortion model="ptlens" focal="20" a="0.00337762" b="-0.0059244" c="-0.0160513" /> <distortion model="ptlens" focal="22" a="-0.00565925" b="0.0323698" c="-0.0738213" /> <distortion model="ptlens" focal="24" a="0.00498966" b="-0.0163608" c="0.011626" /> <distortion model="ptlens" focal="35" a="0.00452151" b="-0.0101545" c="0.00874731" /> <distortion model="ptlens" focal="50" a="0.00822439" b="-0.0246265" c="0.0257984" /> <distortion model="ptlens" focal="85" a="-0.00473509" b="0.0253574" c="-0.0342333" /> </calibration> </lens> -- 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
