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Author Topic: More Topaz AI Sharpen Banding!!  (Read 958 times)

bobfriedman

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More Topaz AI Sharpen Banding!!
« on: April 20, 2019, 05:07:00 pm »

just getting lucky today..

Nikon D800M,Carl Zeiss Otus 1.4/55
1/60s f/4.5 at 55.0mm iso5600


AI Sharpen using Stabliize with Denoise at 75%

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Bob Friedman
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Bart_van_der_Wolf

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Re: More Topaz AI Sharpen Banding!!
« Reply #1 on: April 20, 2019, 06:30:46 pm »

just getting lucky today..

Nikon D800M,Carl Zeiss Otus 1.4/55
1/60s f/4.5 at 55.0mm iso5600

Hi Bob,

Feeding a Monochrome image (from an 800M if that's not a typo) to an application that is trained for color image input is not the best way to use that application.

I also wonder about the ISO setting as such, you'll probably get better noise performance with an ISO 1600 setting, and underexposing that if you need the short exposure time. Then in postprocessing compensate for the underexposure and know that you'll probably have full detail in the highlights.

Cheers,
Bart
« Last Edit: April 20, 2019, 06:33:52 pm by Bart_van_der_Wolf »
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bobfriedman

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Re: More Topaz AI Sharpen Banding!!
« Reply #2 on: April 20, 2019, 08:16:20 pm »

if you remember I got this with a color image as well..

https://forum.luminous-landscape.com/index.php?topic=129798.0


note: D800M is my own nomenclature to refer to a D800 that has been sensor modified to monochrome.

« Last Edit: April 20, 2019, 08:32:44 pm by bobfriedman »
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Bob Friedman
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bobfriedman

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Re: More Topaz AI Sharpen Banding!!
« Reply #3 on: April 20, 2019, 08:21:47 pm »

I also wonder about the ISO setting as such, you'll probably get better noise performance with an ISO 1600 setting, and underexposing that if you need the short exposure time.

Actually the Museum of Fine Art was so dark I had really no choice. Images were in fact underexposed. Not my first choice, believe me.
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Bob Friedman
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earlybird

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Re: More Topaz AI Sharpen Banding!!
« Reply #4 on: April 21, 2019, 09:24:41 am »

I have been assuming the patterns are artifacts of a divide, compute, and reassemble process that creates an array of subsets which may, or may not, be effectively stitched back together to appear seamless.

I similar pattern artifacts while demonstrating GigaPixel.

Topaz explained that they were aware of the issue, and suggested the artifacts are the result of a compromise that makes the computation times practical.

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bobfriedman

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Re: More Topaz AI Sharpen Banding!!
« Reply #5 on: April 21, 2019, 01:08:57 pm »

well, I decided to process the NEF file with Nikon Capture NX-D rather than ACR in Photoshop..

I employed a standalone AI Sharpen with Stabilize and Denoise at 80% at arrived at the image below free of banding.

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Bob Friedman
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Bart_van_der_Wolf

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Re: More Topaz AI Sharpen Banding!!
« Reply #6 on: April 21, 2019, 01:49:25 pm »

well, I decided to process the NEF file with Nikon Capture NX-D rather than ACR in Photoshop..

I employed a standalone AI Sharpen with Stabilize and Denoise at 80% at arrived at the image below free of banding.

Hi Bob,

Thanks for persevering. Who'd have thunk that, different Raw converter, such a different result ... Same settings in SAI?

I bet that the folks at Topaz would love to have both original examples, even though they are Achromatic. I know they are looking into the "Grid" issue that occasionally pops up on some images, and this might steer them in the direction of a solution. Their forum is closed for a planned upgrade right now, but Service Requests can always be opened via their Help Center when logged in.

Cheers,
Bart
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julianv

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Re: More Topaz AI Sharpen Banding!!
« Reply #7 on: April 21, 2019, 07:57:40 pm »

This might be another case where Topaz Sharpen AI is exacerbating subtle flaws in the original file. I can see hints of banding/blocking in the ACR (unsharpened) image.  Perhaps the NX-D version does not have those artifacts.
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bobfriedman

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Re: More Topaz AI Sharpen Banding!!
« Reply #8 on: April 21, 2019, 08:20:05 pm »

This might be another case where Topaz Sharpen AI is exacerbating subtle flaws in the original file. I can see hints of banding/blocking in the ACR (unsharpened) image.  Perhaps the NX-D version does not have those artifacts.

this happened with AI Denoise as well... so you wouldn't think that would amplify errors but he opposite.
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Bob Friedman
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Bart_van_der_Wolf

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Re: More Topaz AI Sharpen Banding!!
« Reply #9 on: April 21, 2019, 09:14:33 pm »

this happened with AI Denoise as well... so you wouldn't think that would amplify errors but he opposite.

Hi Bob and Julian,

Actually, this (potential) Raw converter dependency is a very fascinating observation that will take further investigation to validate. If so, it might suggest that in using the specific images used for training (the training set), the various models were derived from under-represented common ACR conversions. Then feeding ACR conversions, the supposed grid structure would look to an AI system as genuine detail to preserve and enhance, in whatever mode it was operating.

Again speculating, if so, it could lead to improvements in Raw conversion and/or of the "training set". Either way, it could lead to better tools.

Cheers,
Bart
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earlybird

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Re: More Topaz AI Sharpen Banding!!
« Reply #10 on: April 21, 2019, 11:37:23 pm »

If you look carefully you can see the banding is also buried deep in tonal range of the first image and the third image.

I down loaded the third and use Clarity to emphasize the grid pattern. I will not post a copy of your photo, but you may wish to try it to see what is buried in there.

I think my previously voiced assumption was probably a mistake.
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pegelli

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Re: More Topaz AI Sharpen Banding!!
« Reply #11 on: April 22, 2019, 05:04:35 pm »

There's now also a thread on Topaz Sharpen AI on GetDPI on this: Topaz artefacts

Here's my post with some test results:

Quote from: pegelli
I exported an image from about 2000 pixels from Lightroom, it gave very similar artifacts in Sharpen AI along the blue sky top border.
so it seems C1 is not the culprit. I thought it was very unlikely that it would, but now we're sure.


Edit 2: Here's my two examples:

Exported from LR, without any sharpening (slider at zero in the converter, none in the export dialog)




Above image, sharpened in Topaz AI (default parameters) ==> Artifacts galore along the top border




And added just for fun, first image, sharpened with Topaz Detail (minor small and middle details and .10 deblur) ==> No artifacts and slightly different result from sharpen AI on the statue, can't really decide which is better, they're just a tiny bit different.


Further it was suggested in the thread that the raw converter can have an effect but the thread shows there is little difference between Lightroom and C1, and I can't imagine Topaz not training their AI models on these two quite popular and widely used raw converters.

It was further tested and the artifacts do not appear when exporting the file without downsizing and then running through Sharpen AI

However exporting a downsized tiff (8 bit and 16 bit) gave the same artifacts as running sharpen AI on a jpeg.

So it seems downsizing is the culprit leading to the artifacts in solid colour areas.

I have reported this issue to Topaz this is what I got back:

Quote from: TOPAZ
I just tested your image on my computer and I can reproduce your issue. I will discuss with the leader of our R&D team to see if we can figure out the reason of this issue.
My suggestion for now is please try to use Sharpen AI before Lightroom adjustments. Our AI model sometimes can be sensitive and typically can do the best job on the very original image.
I find the advice kind of lame, since final sharpening for output size is usually done as the last step and at output resolution (at least that's how I get the best results, YMMV) and not as a first step before making any adjustments. I find capture sharpening in Lightroom (and C1) more than adequate and don't need Topaz sharpen AI for that step.

I'd be interested in your experiences (similar or otherwise) or some suggestions how to avoid this issue on downsized raw converter exports.
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pieter, aka pegelli

faberryman

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Re: More Topaz AI Sharpen Banding!!
« Reply #12 on: April 22, 2019, 05:38:12 pm »

If it gives artifacts, why use it? The whole point is to make the image better, not worse.

bobfriedman

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Re: More Topaz AI Sharpen Banding!!
« Reply #13 on: April 22, 2019, 07:17:53 pm »

If it gives artifacts, why use it? The whole point is to make the image better, not worse.

I agree... it is hard for me to accept that I need to be very careful using this tool.
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Bob Friedman
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pegelli

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Re: More Topaz AI Sharpen Banding!!
« Reply #14 on: April 23, 2019, 02:20:49 am »

If it gives artifacts, why use it? The whole point is to make the image better, not worse.
That's the wrong question in my mind, for me the real question is: "can Topaz fix it so it doesn't give artifacts and make it a useful tool"
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pieter, aka pegelli

pegelli

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Re: More Topaz AI Sharpen Banding!!
« Reply #15 on: April 23, 2019, 01:27:30 pm »

That's the wrong question in my mind, for me the real question is: "can Topaz fix it so it doesn't give artifacts and make it a useful tool"

And there is hope ;)

Quote from: Topaz
Hi Pieter,

Thanks for your reply!

I just checked our current models (which are NOT yet released) for Sharpen AI. I believe the new models can do a better job on your images. In fact, I just tried your image and the annoying artifacts are gone!
There will be a release for Sharpen AI in early May. We will continue improving our models. Thanks for your patience!

Sincerely,
Topaz Labs Support

Let's wait and see what the update in May brings.
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pieter, aka pegelli

Slobodan Blagojevic

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Re: More Topaz AI Sharpen Banding!!
« Reply #16 on: April 23, 2019, 01:44:27 pm »

And there is hope ;)

Welcome back! Where you've been the whole year?  :)

pegelli

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Re: More Topaz AI Sharpen Banding!!
« Reply #17 on: April 23, 2019, 02:41:01 pm »

Welcome back! Where you've been the whole year?  :)
Thanks Slobodan, I took a sabattical from Luminous Landscape and concentrated on photography and other ventures.

Kind of grew tired of some discussions with kindergarten pupils imposing as wise old men ;).
Still am btw, but the notion of Bart van der Wolf trying to sort through some of these Topaz technical issues made me come back for that.
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pieter, aka pegelli

brandon

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Re: More Topaz AI Sharpen Banding!!
« Reply #18 on: April 23, 2019, 09:33:52 pm »

Thanks Slobodan, I took a sabattical from Luminous Landscape and concentrated on photography and other ventures.

Kind of grew tired of some discussions with kindergarten pupils imposing as wise old men ;).
Still am btw, but the notion of Bart van der Wolf trying to sort through some of these Topaz technical issues made me come back for that.
Well put! The nuggets are worth hunting out...but at times the tailings are unecessarily large (and mostly unecessary fullstop)
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Arlen

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Re: More Topaz AI Sharpen Banding!!
« Reply #19 on: May 05, 2019, 04:15:56 pm »

There's now also a thread on Topaz Sharpen AI on GetDPI on this: Topaz artefacts

Here's my post with some test results:


Further it was suggested in the thread that the raw converter can have an effect but the thread shows there is little difference between Lightroom and C1, and I can't imagine Topaz not training their AI models on these two quite popular and widely used raw converters.

It was further tested and the artifacts do not appear when exporting the file without downsizing and then running through Sharpen AI

However exporting a downsized tiff (8 bit and 16 bit) gave the same artifacts as running sharpen AI on a jpeg.

So it seems downsizing is the culprit leading to the artifacts in solid colour areas.

I have reported this issue to Topaz this is what I got back:
 I find the advice kind of lame, since final sharpening for output size is usually done as the last step and at output resolution (at least that's how I get the best results, YMMV) and not as a first step before making any adjustments. I find capture sharpening in Lightroom (and C1) more than adequate and don't need Topaz sharpen AI for that step.

I'd be interested in your experiences (similar or otherwise) or some suggestions how to avoid this issue on downsized raw converter exports.

Pegelli, did you find a solution yet to those artifacts? I'm seeing the exact same sort of thing for some images that go through Gigipixel AI, rather than Sharpen AI. The pattern that you showed repeats at regular intervals along the top border for some (but not all) images with smooth blue skies. Hopefully if Topaz figures out how to fix it in one of the applications, it will work for both.
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