This is cheating but: I recently took a series of images under appalling light conditions (actually in a cellar with stone walls), in the very darkest areas I needed to remove those red spots in areas where there was no basic color anyway. I simply drew a mask around the offending area and then reduced the red saturation.
OK, I know it's a nasty thing to do but since I was working on basically a gray background anyway it solved the problem and is quite unnoticeable. Doing the above allowed me to reduce other noise settings and get better overall definition. David On 13-10-06 10:30 PM, suni wrote: > Fighting the red dots in high ISO images is one of the largest > challenges in processing of my images taken by SONY A550 camera. To > beat it I use the hot pixels module with threshold set to 0 and > usually checked the detect by 3 neighbours option as well or I use > the demosaic module with colour smoothing option set to two times. > Sometimes one time is enough. But I definitely have no idea what of > these two is better approach regarding the negative effect on the > overall image quality or if these two approaches shout be avoided in > favour of another one. Any advice from much more experienced user > would be appreciated. > > > 2013/10/3 Willem Ferguson <[email protected]> > >> I use a Canon 7D. On several occasions, when taking photographs at >> relative high ISO (e.g. 1600 or 2000), I have noticed red dots on >> the image. See this image: >> https://www.dropbox.com/s/i0ck3yx4o341npb/IMG_9300.jpg Look at the >> crest of the turaco and also in the dark areas at the base of the >> tail. When viewing the image on different image viewers, the red >> dot is present in the original CR2. I conclude this is not an >> artifact of image processing, although it becomes much more obvious >> when doing some edits, e.g. increasing the brightness and the red >> dots change when magnifying an image. I have 2 questions: 1) What >> causes this? 2) Is there an easy way in dt to remove it? Kind >> regards, Willem Ferguson >> >> >> >> >> >> ------------------------------------------------------------------------------ >> >> October Webinars: Code for Performance >> Free Intel webinars can help you accelerate application >> performance. Explore tips for MPI, OpenMP, advanced profiling, and >> more. Get the most from the latest Intel processors and >> coprocessors. See abstracts and register > >> http://pubads.g.doubleclick.net/gampad/clk?id=60134791&iu=/4140/ostg.clktrk >> >> _______________________________________________ >> Darktable-users mailing list [email protected] >> https://lists.sourceforge.net/lists/listinfo/darktable-users >> > > > > ------------------------------------------------------------------------------ > > October Webinars: Code for Performance > Free Intel webinars can help you accelerate application performance. > Explore tips for MPI, OpenMP, advanced profiling, and more. Get the > most from the latest Intel processors and coprocessors. See abstracts > and register > > http://pubads.g.doubleclick.net/gampad/clk?id=60134791&iu=/4140/ostg.clktrk > > > > _______________________________________________ > Darktable-users mailing list [email protected] > https://lists.sourceforge.net/lists/listinfo/darktable-users ------------------------------------------------------------------------------ October Webinars: Code for Performance Free Intel webinars can help you accelerate application performance. Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from the latest Intel processors and coprocessors. See abstracts and register > http://pubads.g.doubleclick.net/gampad/clk?id=60134791&iu=/4140/ostg.clktrk _______________________________________________ Darktable-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/darktable-users
