Hi & thx :-)

Well my machine I use for this is super-weak: intel core m3, 4.5W TDP. Very 
energy efficient :-( Takes around 30 sec with this machine.
It uses openmp.

It has basically 3 building blocks:
1. Markesteijn 1 pass for obtaining luma and directionality.
2. Some 11x11 correlation filtering, where the filter has complex numbers as 
filter values.
3. Median filtering of chroma.

Now, 1 is already pretty optimized.
3 is already quite OK.
I see quite some potential for 2. Some initial experiments I did show that 
using FFTW3 for the filtering could very well be worth it.
Are you using FFTW in any part of darktable?

As to OpenCL, yes there I see real potential, because the median filtering 
works quite well in OpenCL.

Cheers,
Ingo


> Am 07.05.2017 um 20:03 schrieb johannes hanika <hana...@gmail.com>:
> 
> heya,
> 
> nice results! especially the high iso one shows quite a bit more
> pleasant noise behaviour in the gray center patch.
> 
> how bad is the performance? do you think it could be improved? does it
> use SIMD/openmp yet and how promising would an opencl code path be?
> 
> cheers,
> jo
> 
> On Mon, May 8, 2017 at 4:53 AM, Ingo Liebhardt <ingo.liebha...@ziggo.nl> 
> wrote:
>> 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
>> 
>> 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
>> ISO 200 with Markesteijn 3 pass:
>> 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
>> ISO 3200 with Markesteijn 3 pass:
>> 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
>> 
>> 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>
>> 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.
>> 
>> 
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