On Thu, Nov 3, 2016 at 5:57 PM, Andy <t3k...@gmail.com> wrote: > Hi all. > I'm new to darktable and somewhat new to raw image processing so please > excuse me if this is a naive question. > I was trying to denoise some images from my Sony a7 II R shot at 51200 ISO. > I followed some tutorials that recommended applying wavelet denoise with > blend=color and non-local means with blend=lightness. Also do try blend=hsv color and blend=hsv lightness.
> I noticed some bright green highlights appearing. I played around with the > demosaic-ing and noticed that it even happened with > the "rough monochrome" demoisaicing and so I thought it might be worth > asking if this is a bug or some odd interaction of the filters. > You can find a picture here: > https://whttps://www.dropbox.com/s/ozjy3dk84zgvs6s/DSC00961.ARW?dl=0 and the > xmp here: ww.dropbox.com/s/fr24nz7zgz7xgd9/DSC00961.ARW.xmp?dl=0 > > If you go to the highest zoom level with wavelet denoising on the color and > raw monochrome demosaic, you will see the bright green artifacts. Monochrome demosaic is NOT meant to be used to "monochromly" demosaic the normal raw files. It is only meant to be used for the raw files from cameras with color filter array physically removed, scraped off. > They disappear when disabling the color denoising with wavelets. The profiled denoise is tuned to the properly-demosaiced image. If it does exhibit some artifacts when used on non-demosaiced input (because that is basically what monochrome demosaic does), i would not be surprised. Because monochrome is, as far i'm concerned, the exact opposite of color. > Using any other demosaic algorithm, you'll see magenta artifacts in the > highlights as soon as you turn the color denoising on. > My question is: is this expected? In particular with the monochrome demosaic > the artifacts seem very odd. I'd *personally* say yes. > But in general > I'd love to get rid of the bright green / magenta artefacts in the > highlights when doing the color denoise. > > Thank you! > > Andy Roman. > ____________________________________________________________________________ > darktable user mailing list > to unsubscribe send a mail to darktable-user+unsubscr...@lists.darktable.org > ____________________________________________________________________________ darktable user mailing list to unsubscribe send a mail to darktable-user+unsubscr...@lists.darktable.org
