Hi, There is an issue (http://redmine.darktable.org/issues/10333) with some RAWs which exhibit problems. I don't know if your demosaicing helps on this, but I thought it would be worth mentionning.
Regards Marc On 09/02/2016 20:40, Ingo Liebhardt wrote: > Hi Dan, > > My present algorithm (3 pass) takes about 11 to 12 secs on my machine > (Intel on-processor graphics, so nothing fancy). > Markstein (3 pass) via dcraw takes about 35 secs on my machine. Both > for a 16 megapixel x-trans raw. > > However, I use openCL not only for speed reasons, but also because I > like the modularity that the kernels give me. I’m presently still > pretty much in the experimental phase, and I like that I can change > order and parameters of the kernels and then see how that impacts the > quality of the output. > > So far, my emphasis is not yet on speed, and I’m quite optimistic that > I can squeeze out some more speed once all the design decisions are taken. > > Most importantly: > 1. Presently, I use guided filtering / upsampling not only for > constructing the green pane, but also afterwards for red and blue. For > red and blue, DCI would be another option once green is there. This > could not only improve speed, but also improve quality. I’m presently > working on some experiments in this direction. > > 2. My approach is iterative, starting from a provisional green. > Presently my provisional green is created in quite a sophisticated > manner. I think I might overdo this a bit - I could likely simplify > this part without sacrificing quality, but I don’t expect the savings > to be revolutionary. > > 3. As said, my approach is iterative. The above time is with three > passes. If I reduce to two passes, about 2 to 3 seconds can be shaved > off. My first impression is that after two passes further visual > improvements become marginal, but I want to check this a bit more > before prematurely concluding. > > So the 11 to 12 secs are already a bit of a worst case scenario. > > Now as to documentation: don’t be too optimistic ;-) , so far I > only documented a rough outline of my idea. > > Concerning a CPU variant: once all design decisions are taken, this > shouldn’t be that much of an effort. > But even before that, I’d clean up my GPU variant. As said, presently > it’s still quite experimental. > > Cheers, > Ingo > > >> Am 08.02.2016 um 23:52 schrieb Dan Torop <d...@pnym.net >> <mailto:d...@pnym.net>>: >> >> Hi Ingo, >> >> This is quite interesting work to see... A x-trans demosaic algorithm >> which is well described, high quality, open source, and fast is >> something which I'm sure many people are awaiting. Though of course >> having all of these qualities is a lot to ask! It's great to see >> continued work on this, and in particular addressing the color >> artifacts. >> >> How does the speed of your code when hooked into dcraw compare to 1-pass >> or 3-pass Markesteijn via dcraw? The dt version of Markesteijn is about >> 2-3x faster than dcraw's, if I recall right, but dcraw's Markesteijn >> could still be a good basis of comparison. >> >> How much work would it be to make a CPU variant? So far as I know, all >> of darktable is built to function on CPUs with the possibility of GPU >> speed-up in certain cases. >> >> I can't speak for the dt core developers regarding their interest & >> priorities, of course... >> >> Best, >> Dan >> >> >> >> On Mon, Feb 8, 2016, at 03:42 PM, Ingo Liebhardt wrote: >>> Hi all, >>> >>> Congrats to version 2.0.1. >>> >>> Would you maybe be interested in an alternative approach to the >>> Markesteijn x-trans demosaicing? >>> >>> I see that for Bayer patterns you have a fast one, plus two >>> different high-quality ones (AMaZE and VNG4). >>> >>> The only high-quality one for x-trans seems to be Markesteijn. >>> I personally find that Markesteijn is producing very sharp results, >>> but also quite some false colour artifacts. >>> I’ve been playing around with an alternative approach, and I’m >>> slowly starting to get reasonable results. (even images with lots of >>> green - always problematic - start looking okay(ish)). >>> >>> If you want to have a look: >>> https://github.com/ILiebhardt/xtrans >>> >>> And some sample comparisons to Markesteijn, plus a brief explanation >>> of the idea: >>> https://www.storehouse.co/stories/b8sj2 >>> >>> Don’t be mistaken by my version number: there’s still a lot of work >>> to be done, and I also still have quite some ideas for improvements… >>> >>> So at this stage I just want to carefully pre-inquire if there could >>> be some interest, in principle. >>> >>> Thanks a lot for letting me know. >>> >>> Cheers, >>> Ingo >>> >>> >>> >>> ___________________________________________________________________________ >> 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 >> > > > ___________________________________________________________________________ > 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
