hi,

On Mon, May 8, 2017 at 6:33 AM, Ingo Liebhardt <ingo.liebha...@ziggo.nl> wrote:
> 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.

okay :) that's export time on a full res image or for darkroom mode?
how does it change if you switch on the equalizer module, to give me a
sense how slow your machine is?

> 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.

okay. how much percent is step 2? i mean, how fast would it go if you
set the time to 0 (just skip the code for a test..)?

> Are you using FFTW in any part of darktable?

nope, we don't use it. so far every time someone wanted to use fourier
space it turned out to be better to do it another way. what exactly
are you using it for? convolutions? filtering in fourier space? could
you use a wavelet domain for this, too? from past experience however,
if you really need fourier, fftw usually rocks.

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

so there may be hope :)

cheers,
 jo


>
> 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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>>>
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