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Upcoming YafaRay-E v3.0.0

Ask here your questions about development and about raytracing theory & implementation. Here you can post your patches for review.

Re: Upcoming YafaRay-E v3.0.0

Post Tue Jun 21, 2016 5:44 pm

Unfortunately Blender API is too limited for that, and to allow real time dynamic changes in YafaRay would require a lot of work.

However in v3 you can save/load the internal film so you dont need to do a full re-render. It's what I did to generate the examples.
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David Bluecame
 
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Re: Upcoming YafaRay-E v3.0.0

Post Wed Jun 22, 2016 9:06 pm

Hello,

While testing the new denoise feature, I noticed banding effects in many of the denoised images.

I was checking if this was a problem in the denoise code or algorithm, but I found out something that probably many of you already know but I hadn't realized until now: noise is sometimes our friend.

Banding is most often caused by limitations in the hardware. Computer screens are normally designed to show 24bit colors (3 channels "RGB" x 8bit/channel). This means that each channel (red, green, blue) has only 256 "steps" from fully off up to fully on.

When there is no noise and we are rendering a surface with a very smooth "gradient", or a blue sky for example, the screen cannot show all intermediate tones due to the "steps" and therefore it causes visible bands of color that are *very* annoying (at least to me).

Banding can be made worse by lossy formats such as JPG, and lossy algorithms, etc, but the main limitation is usually the screen, as we cannot show properly high dynamic range formats such as EXR or HDR in a regular display.

When rendering we normally think that noise is the enemy and that a fully de-noised and smooth image is what we should aim for. However, you will rarely find banding in a "noisy" render. The reason is that noise can actually create colors that the display cannot show, just because the brain "mixes" the pixels of the noise ang creates the illusion of a new color. In the past when displays and VGA cards were primitive and only showed 16 colors for example, there was a technique called "dithering" that allowed to create more colors than the display could actually show, by using noise.

So, I've been thinking how to solve this problem and after some time and attempts, I've come up with a simple idea that I think could be good enough. I've added a new parameter called "Mix", so for the final result I will use a combination of the de-noised image and the original (noisy) image. This way, we can "use" the noise to reduce the banding effect.

The next example is exactly the same I uploaded in a previous post. The difference is that, in this case, I mixed the denoised image generated with h(lum=5),h(col)=5 (that had a bit of banding in several places) with the original noisy image. In this example I used a proportion of 80% denoised + 20% original noisy.

I think that the result is better than both the original and the 100% denoised. I can barely see the banding (only if I make an effort to see it), and the noise is not getting in the way (at least in my opinion).

Moreover, I also have the feeling that this image feels more "real" than the 100% denoised, probably because of the "half color tones" the noise helps to show.

example with denoise Mix=0.8 (80pct denoised and 20pct original), hlum=5, hcol=5.jpg


I hope you find this interesting.
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David Bluecame
 
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Re: Upcoming YafaRay-E v3.0.0

Post Tue Jun 28, 2016 7:27 am

Hi david,

Can you post the scene to make some tests? (to test postpro denoise, not the filtering, of course I don't have the filtering build :) )

Thanks
surena
 
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Re: Upcoming YafaRay-E v3.0.0

Post Thu Jun 30, 2016 4:46 pm

Hello,

I've attached the scene.
Attachments
samo balls scene Photons tutorial dolphin - denoise tests.blend.zip
(470.41 KiB) Downloaded 74 times
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David Bluecame
 
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Re: Upcoming YafaRay-E v3.0.0

Post Sat Jul 02, 2016 10:34 am

Thanks
surena
 
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Upcoming YafaRay v3.0.0

Post Mon Jul 04, 2016 2:09 pm

Hello,

For your information, still working on the new v3.0.0. I'm getting closer to get to the point where I can release it as a public beta, but please be patient with me for a bit longer.

Last changes I've added are: smartIBL and Texture color controls (brightness, contrast, saturation, etc).

You have more details in the bug tracker: http://www.yafaray.org/development/bugtracker/yafaray

Best regards!
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David Bluecame
 
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Re: Upcoming YafaRay-E v3.0.0

Post Mon Jul 04, 2016 2:32 pm

Don't worry, you're doing a great work here!

Thanks!
surena
 
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Re: Upcoming YafaRay-E v3.0.0

Post Tue Jul 12, 2016 6:14 pm

Hello,

For your information, YafaRay v3.0.0-beta will be released soon, hopefully this week.

I hope you will like it! (I hope...)
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David Bluecame
 
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Re: Upcoming YafaRay-E v3.0.0

Post Tue Jul 12, 2016 7:01 pm

:-D

I'm waiting for the incredible post on blenderartists that leaves everybody astonished!

Thanks for your efforts.
surena
 
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