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KARWY ARW2 Repair Tool

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profhankd View Drop Down
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Post Options Post Options   Quote profhankd Quote  Post ReplyReply Direct Link To This Post Topic: KARWY ARW2 Repair Tool
    Posted: 25 September 2015 at 22:08
KARWY, the free software tool I've been building for credible repair of Sony ARW2 raw artifacts , is now live as a Beta-test version. It uses analysis of pixel value uncertainty and computational texture synthesis to create an improved raw, which it returns as a DNG file.

The current version is run via a WWW form interface, so you don't need to install anything to use it. The home page for this research project is:

http://aggregate.org/DIT/KARWY/

A link to the WWW form for running your own images through is posted there.


 



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arj View Drop Down
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Post Options Post Options   Quote arj Quote  Post ReplyReply Direct Link To This Post Posted: 26 September 2015 at 17:18
Interesting tool, I am curious to see some examples from users on how the tool worked out
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pegelli View Drop Down
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Post Options Post Options   Quote pegelli Quote  Post ReplyReply Direct Link To This Post Posted: 26 September 2015 at 20:49
Indeed an interesting tool and I tried it on my only picture with a A7Rii that I ever was able to see these compression artifacts.

left is unrepaired, right is karwy repaired. both files got the same development in lightroom (shadows + 100, exposure + 0,4 EV (artifact areas circled):


Couple of observations:
- karwy worked very well next to the light openings in the right black beam, but less successful in the left one.
- the darks also got a shift towards more brown/yellow (probably easily corrected in post)

For some context:
Here's the full shot processed this way, so it doesn't really look very nice that way:



A bit more normal processing:


And this is how the unrepaired crop of the same area looks with "normal"processing, so the artifacts are still visible but hardly noticable:


@ profhankd, thanks for all your efforts, feel free to use my uploaded raw file for further experimenting and/or demo's. PM me if you need the KARWY image id. from your server.
Mind the bandwidth of others, don't link pictures larger then 1024 wide or 960 pix high, see here
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Post Options Post Options   Quote profhankd Quote  Post ReplyReply Direct Link To This Post Posted: 27 September 2015 at 04:40
The color shift is probably because I used Adobe DNG Converter to create the DNG wrapper that I insert repaired data into. Adobe's raw data doesn't match the standard decoding of the ARW2 files, so there is probably something interesting happening relative to some EXIF data. I originally generated my own DNG wrapper (actually using 16 bits per pixel), but colors were much farther off and RawTherapee crashed reading my DNGs -- although other tools were fine with them.

The remaining artifacts appear where the apparently correct pixel is well outside of the computed uncertainty range for that spot. In other words, data that's bad beyond what the compression logic should be able to cause. The "smoothing" option in KARWY effectively allows the texture synthesis to be more aggressive -- try 100% 100% 100% instead of the default 0% 0% 0% and there's a lot less of that type of artifacting left. The default setting is sufficient to virtually eliminate artifacting that is directly due to the compression.

In any case, the more test images I get, the better I can make the repairs -- the KARWY you're using is a brand new Beta-test version. There's also a decent chance I'll switch the output from DNG to whatever uncompressed format Sony uses for the new 14-bit uncompressed encoding (assuming I can figure-out how to set the multitude of EXIF fields).
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Post Options Post Options   Quote puddleduck Quote  Post ReplyReply Direct Link To This Post Posted: 27 September 2015 at 10:20
Interesting work - rather than try to fix the ARW files, would it not be better to focus on getting this fix into the ARW conversion side of things once it's got out of beta?

Maybe it could be forked into DCRAW or Rawtherepee etc?

Appreciate the effort, just wondering if trying to put this fix where it is is the best place for it...? If it was put in the conversion side of thing, you'd also gain access to localised tools, for example to paint the area you want to fix rather than examine the whole file.
--Andy
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Post Options Post Options   Quote pegelli Quote  Post ReplyReply Direct Link To This Post Posted: 27 September 2015 at 12:10
Here's my result with smoothing settings 100 "bad", 80 "near bad" and 60 "other"

Lightroom settings default for both files except exposure +0.5, shadows +100 and clarity +50



I think the smoothed version is a slight improvement, especially for the artifacts on the left beam. At the right beam the unsmoothed version was already near perfect. I also feel there is a very slight loss of detail (eg. the wood grain) due to the smoothing.

This was with a loaner A7Rii and the only shot I ever saw artifacts in, but if I ever see them again I will turn here first to see how to best repair it. Again thanks for all the work
Mind the bandwidth of others, don't link pictures larger then 1024 wide or 960 pix high, see here
 



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Post Options Post Options   Quote profhankd Quote  Post ReplyReply Direct Link To This Post Posted: 27 September 2015 at 12:43
Originally posted by puddleduck puddleduck wrote:

Interesting work - rather than try to fix the ARW files, would it not be better to focus on getting this fix into the ARW conversion side of things once it's got out of beta?

Maybe it could be forked into DCRAW or Rawtherepee etc?

Appreciate the effort, just wondering if trying to put this fix where it is is the best place for it...? If it was put in the conversion side of thing, you'd also gain access to localised tools, for example to paint the area you want to fix rather than examine the whole file.


Heck yeah! It should be inside the basic ARW2 decoding. The problem is that I don't control all those things. Honestly, KARWY will be a pain to install and color quality will always be subject to guesses about what EXIF data Adobe really wants in the DNG vs. what Sony provides in the ARW2. Once the algorithms have been tweaked a bit more and research publication and full source code are out, I'm hoping people will just stick the code into everything, including dcraw.

It should be noted, however, that this isn't a local fix. It is actually repairing everywhere that there is pixel value ambiguity... which is everywhere, but with varying degrees of repair strength.
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Post Options Post Options   Quote puddleduck Quote  Post ReplyReply Direct Link To This Post Posted: 27 September 2015 at 12:59
Originally posted by profhankd profhankd wrote:

   Once the algorithms have been tweaked a bit more and research publication and full source code are out, I'm hoping people will just stick the code into everything, including dcraw.


Yes, this really needs to be put there - this case should be treated no differently than hot pixel fixes, CA fixing etc and done as part of the processing pipeline.

I'm very dubious about the merits of converting to DNG too be honest, although I can see why you've done it as a proof of concept.

--Andy
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Post Options Post Options   Quote profhankd Quote  Post ReplyReply Direct Link To This Post Posted: 27 September 2015 at 13:16
Originally posted by pegelli pegelli wrote:

Here's my result with smoothing settings 100 "bad", 80 "near bad" and 60 "other" ...

I think the smoothed version is a slight improvement, especially for the artifacts on the left beam. At the right beam the unsmoothed version was already near perfect. I also feel there is a very slight loss of detail (eg. the wood grain) due to the smoothing.


It's typically "near bad" pixels that are out of their computed error bounds, i.e., pixels in a block adjacent to a block that suffered severe loss of accuracy. I don't know for certain, but this is probably either an analog converter gain-change slew rate issue or a minor bug in Sony's implementation of the compression logic.

KARWY's processing actually tends to enhance textures slightly. The "smoothing" allows sharp edges to be changed more to match textures found elsewhere in the image, which generally lowers microcontrast.
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