On Wed, Apr 27, 2016 at 10:59 AM, J. Liles <malnour...@gmail.com> wrote:
> > > On Wed, Apr 27, 2016 at 10:13 AM, Ingo Liebhardt <ingo.liebha...@ziggo.nl> > wrote: > >> Hi, >> >> In the original message, the 'and have had little trouble generating >> images that contain areas prone to demosaicing artifacts‘ caught my eye. >> In the meanwhile, I continued a bit on my demosaicing algorithm. >> >> So I gave it a try with the two problematic images. >> Results can be found in: >> https://www.dropbox.com/sh/un1y11uimbqxjjk/AAD3L-Rs9-ztwyBIm4rnCzK-a?dl=0 >> >> The tiff versions are straight from the algorithm, no correct white >> balance, no proper contrast curve, no noise reduction. >> The jpeg versions got a bit of white balance and contrast curve in >> darktable, but still no noise reduction. >> Please excuse the colors, my main interest was on the demosaicing, so I >> was very sloppy on the colors at this stage. >> The tiffs are 16 bit, so you can really play with them to your liking. >> >> Furthermore, I also continued working on a better chroma cleaning >> algorithm for the fine branches of my own torture test. >> Have a look at the chroma_cleaned_3. I found a way to very specifically >> address those problematic pixels, see map2, which I then further improved >> by adding a contrast curve to the map. >> >> The bird and person images didn’t get the chroma cleaning, because they >> don’t have fine high contrast areas, unlike the branches. >> >> Jo might be most interested in this, so the concept is in my latest git >> commit : https://github.com/ILiebhardt/xtrans. >> It’s not yet really stable and not to speak of performance… >> >> By the way, I also added my problematic raw, so that Jo can play with it >> if wanted. >> >> I’m working on the performance now. >> >> Cheers, >> Ingo >> >> > Your algorithm is also showing a grid of dots in the feathers. Can you see > what I'm referring to? You'll have to zoom way in to see it (playing with > the contrast may help). The camera JPGs don't exhibit this at all (well, I > could see *one* spot in the camera JPG). So I think whatever Fuji's doing > in-camera is designed to mitigate this particular artifact. > > Replying to myself: Actually, it could of course just be that the minimum NR/JPG compression in the camera is masking the artifacts. I suppose it's all about expectations. When I shoot RAW Bayer images at ISO 100-400, I usually don't apply any NR. Between 400 and 1000 or so I might add just some chroma NR. From there up I'd probably add luma too. My expectation is that I can work the same way with X-Trans images, which may or may not be reasonable. > > >> >> Am 27.04.2016 um 18:16 schrieb J. Liles <malnour...@gmail.com>: >> >> >> >> On Wed, Apr 27, 2016 at 6:56 AM, johannes hanika <hana...@gmail.com> >> wrote: >> >>> my 2min-version of the 2nd image: >>> >>> https://jo.dreggn.org/neon.jpg >>> >>> the neon lights are indeed something that doesn't seem to be covered >>> well at all by the reference it8 chart. we probably need to somehow >>> extend the darktable-lut module to read not only well defined colour >>> patches but also random images (as the basecurve tool does). but even >>> then it would just be cloning the jpg engine.. which is sub-optimal >>> imo. i get much improved results when switching on gamut clipping in >>> the input colour profile module (see xmp embedded in the jpg). i >>> suspect the camera manufacturers do similar things on chip. >>> >>> -jo >>> >>> >> Looks pretty close. I'd say in the case of Fuji an ability to extract a >> profile from sampling many RAWs+JPGs would probably produce a pretty good >> result. The colors in the camera jpeg were fairly true to life in this >> case, except a bit desaturated (they were shot using Provia/STD, I've since >> learned that many people believe Fuji mixed up the Provia and Astia >> simulations because Provia seems to have lower saturation than Astia). But >> as far as the hue goes, it's pretty spot on. Those purple neon lights can >> very easily turn blue. I too have found that enabling gamut clipping helps >> with that. >> >> >> >> >> >>> >>> On Tue, Apr 26, 2016 at 10:21 PM, J. Liles <malnour...@gmail.com> wrote: >>> > Here are some of my problem images. >>> > >>> > http://www.nevermindhim.com/fuji-xtrans-samples >>> > >>> > Also included on the page is my style for denoising. >>> > >>> > >>> > On Tue, Apr 26, 2016 at 11:04 AM, J. Liles <malnour...@gmail.com> >>> wrote: >>> >> >>> >> Group, >>> >> >>> >> I've recently acquired a camera with an X-Trans sensor, and have had >>> >> little trouble generating images that contain areas prone to >>> demosaicing >>> >> artifacts. >>> >> >>> >> Is anyone interested in these? If so, is there a certain place I >>> should >>> >> host/send them? I have camera generated JPG for comparison along with >>> the >>> >> RAF files. >>> >> >>> >> In playing around I've discovered a few things: >>> >> >>> >> 1) Color smoothing is mandatory, as fine lines and especially specular >>> >> highlights will always generate nasty color artifacts when using the >>> baisc >>> >> demosaicing. Seems like a smarter highlight recovery algorithm could >>> help >>> >> identify many of these problem spots. >>> >> >>> >> 2) None of the 'denoise' modules have sufficient parameter ranges to >>> deal >>> >> well with the X-Trans files. >>> >> >>> >> 3) When sufficient denoising is performed to remove maze and color >>> >> artifacts, the difference between VNG and Markesteijn demosaicing is >>> >> indiscernible. >>> >> >>> >> I have a style preset which can produce images that match the camera >>> JPGs >>> >> as far as noise/detail goes (utilizing the equalizer module) at ISO >>> 3200. >>> >> >>> >> Color is another matter, but I've ordered one of the Wolf Faust IT8 >>> charts >>> >> to try and make an ICC profile. >>> >> >>> >> (I tried making one using the imaging-resource.com multi target >>> studio >>> >> shots, and while the results were OK, they weren't great). >>> >> >>> >> P.S. Is there any plan to support Fuji's RawExposureBias exif tag? It >>> is >>> >> necessary to display high ISO RAF images at the correct brightnesss. >>> > >>> > >>> > >>> > >>> ___________________________________________________________________________ >>> > darktable developer mailing list to unsubscribe send a mail to >>> > darktable-dev+unsubscr...@lists.darktable.org >>> >> >> >> ___________________________________________________________________________ >> darktable developer mailing list to unsubscribe send a mail to >> darktable-dev+unsubscr...@lists.darktable.org >> >> >> > ___________________________________________________________________________ darktable developer mailing list to unsubscribe send a mail to darktable-dev+unsubscr...@lists.darktable.org
