Hi all, Maybe you still remember that I tried an alternative approach to X-Trans demosaicking (using guided filtering) in March / April this year… In the end, I was not satisfied, and I gave up on that approach. The problems were comparable to the Markesteijn algorithm, and the improvements marginal.
After giving up on that approach, I was again browsing conference papers trying to get some inspiration. I came across the work of E. Dubois, which looked promising. It is promising, not so much when applied alone, but very much so when combined with a gradient based approach like Markesteijn. I like Jo’s xtrans fringes profile a lot, but the colors get somewhat muted, overall. Contrary to my first approach, this one finally seems to give reasonable results. I managed to get good output for the redline bug #10333. You can have a look here: dropbox link <https://www.dropbox.com/sh/un1y11uimbqxjjk/AAD3L-Rs9-ztwyBIm4rnCzK-a?dl=0> This is the output just with demosaic + base curve, nothing else. If you want to try some nasty X-Trans images yourself, I made a little proof-of-concept. This in form of a fork of darktable, which you can find here: https://github.com/ILiebhardt/darktable.git <https://github.com/ILiebhardt/darktable.git> For trying, just compile, deactivate openCL (only C code thus far), and choose ‚1 pass Markesteijn‘ as demosaicking method (doesn’t work for 3-pass, and wouldn’t really yield advantages, either). Have fun trying, and let me know if you think that this one’s worth pursuing further (only quick hack so far, and the used correlation filters are a slow, naive implementation O(m n p q)). If you’d like to read some basics concerning the idea, I made a mini-blog here: http://xtransdemosaicking.blogspot.nl <http://xtransdemosaicking.blogspot.nl/> Cheers, Ingo P.S.: concerning my previous approach, J Liles spotted single pixel artifacts. I found out that these are not related tot the demosaicking as such. X-Trans 2 and X-Trans 3 have hybrid AF, and the pixels used for phase detection show higher noise. These are all green pixels of a 4-group of pixels; never a red or blue, and never a solitary green. But solving this would be a whole different project... ___________________________________________________________________________ darktable developer mailing list to unsubscribe send a mail to darktable-dev+unsubscr...@lists.darktable.org
