Hi all, Coming back to this old topic, I have the next iteration of my alternative approach to X-Trans demosaicking ready.
For those of you who’d like to try, the GitHub fork is at https://github.com/ILiebhardt/darktable <https://github.com/ILiebhardt/darktable> There’s a menu item in the demosaicking module saying ‚Frequency Domain Chroma‘. If you take the original image of bug #10333, you’ll see that the moire isn’t completely removed, but improved so much that a little bit of bilateral filter is enough to remove it completely. I also did a straightforward treatment of the test images of the X-T1 images downloaded from dpreview in raw: just base curve + demosaic + export to jpeg 95%. No further noise processing. ISO 200 with my approach: https://www.dropbox.com/s/x74i19mitd33grq/DSCF6827_FDC_ISO200.jpg?dl=0 <https://www.dropbox.com/s/x74i19mitd33grq/DSCF6827_FDC_ISO200.jpg?dl=0> ISO 200 with Markesteijn 3 pass: https://www.dropbox.com/s/0n2f3pw37r8itgq/DSCF6827_MS3pass_ISO200.jpg?dl=0 <https://www.dropbox.com/s/0n2f3pw37r8itgq/DSCF6827_MS3pass_ISO200.jpg?dl=0> ISO 3200 with my approach: https://www.dropbox.com/s/qpw4rcj0lrzgnb4/DSCF6839_FDC_ISO3200.jpg?dl=0 <https://www.dropbox.com/s/qpw4rcj0lrzgnb4/DSCF6839_FDC_ISO3200.jpg?dl=0> ISO 3200 with Markesteijn 3 pass: https://www.dropbox.com/s/gynk21ttl73cpyr/DSCF6839_MS3pass_ISO3200.jpg?dl=0 <https://www.dropbox.com/s/gynk21ttl73cpyr/DSCF6839_MS3pass_ISO3200.jpg?dl=0> Many thanks to J. Liles for quite some testing and feedback, and also to François Guerraz for the hint to use quick select for calculating medians. For the geeks, some of my design choices explained in my last blog post: http://xtransdemosaicking.blogspot.nl <http://xtransdemosaicking.blogspot.nl/> Quality wise, I am now so far as to consider contributing this to darktable if it should be wanted, but speed wise, I am not yet happy at all (but I heave some ideas that I still want to try in this respect..). Thanks for informing me what you think. Cheers, Ingo > Am 04.03.2017 um 03:34 schrieb J. Liles <malnour...@gmail.com>: > > > On Fri, Feb 24, 2017 at 10:52 AM, Ingo Liebhardt <ingo.liebha...@ziggo.nl > <mailto:ingo.liebha...@ziggo.nl>> wrote: > Hi all, > > For those who want to give it a try, I made some further improvements to the > below-mentioned fork with the experimental approach to X-Trans demosaicking. > In particular to the issue of colour bleeding found by J Liles, this should > be much less now. > There was also still some hue shift, which I think should be gone now. > I finally managed to obtain the filters training them from multiple reference > images of the McMaster (previously IMAX) reference image set. > > As a general remark, this approach doesn’t magically solve all the issues, > some further processing, e.g. bilateral filtering, might still be needed for > difficult image contents. However, especially for images with high frequency > in luma and for high ISO images, the starting point should be a quite bit > better than the other approaches. You’ll see that e.g. oftentimes less > bilateral filtering is needed to make the same image usable. > > For those of you who want to get an impression how subtle changes in the > filters change the image, I included 4 alternative filter sets that can be > used in lieu of the present filtercoeff.h (filtercoeff_11_4.h, broadest, > filtercoeff_var_3.h, narrowest, and filtercoeff_11_3.h, filtercoeff_var_4.h > in between). > > Thankful for further feedback. > > Cheers, > Ingo > > > Ingo, > > I just had a chance to take a look at your latest version. I no longer see > the color bleeding. Low ISO images appear virtually unchanged from > Markesteijn. High ISO images look considerably better. I think you're right > about it being a better starting point. Moire in the redmine example doesn't > appear much affected, though. > > > ___________________________________________________________________________ > darktable developer mailing list to unsubscribe send a mail to > darktable-dev+unsubscr...@lists.darktable.org > <mailto:darktable-dev+unsubscr...@lists.darktable.org> ___________________________________________________________________________ darktable developer mailing list to unsubscribe send a mail to darktable-dev+unsubscr...@lists.darktable.org
