Hi guys, you might have observed that some of our modules can produce banding artifacts. Main candidates are vignetting and graduated neutral density. There are certainly other situations as well where banding might hit you.
It was easy to add a dithering option to vignetting by adding some random noise. Graduated neutral density on the other hand is problematic as it comes very early in pixelpipe. Any added random noise will scale in an unpredictable way and there are some modules after gnd that will do their best to eliminate noise again... For that reason I developed a general dithering module which comes late in pixelpipe, just before gamma. It supports random dither and error diffusion (Floyd-Steinberg). The latter with just a few output options. I left some room for future enhancements. Namely one could think about dithering into a user-defined color palette and such. With dithering there is some inherent issue when you scale the image. Rendering a scaled-down version into 1-bit b&w would look completely different than seeing the same image dithered with original resolution from some distance. I did a few tricks with dithering levels in order to make zooming halfways intuitive. All is kept in a separate branch 'dither'. Please give it a try, tell me your feedback and vote if you think this should move into master. Ulrich ------------------------------------------------------------------------------ LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial Remotely access PCs and mobile devices and provide instant support Improve your efficiency, and focus on delivering more value-add services Discover what IT Professionals Know. Rescue delivers http://p.sf.net/sfu/logmein_12329d2d _______________________________________________ darktable-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/darktable-devel
