Removing FPN/banding in post

alignment1

alignment1

Well-known member
OK- so for GH-1 owners/users - some have experienced the dreaded FPN/banding issues more than others. Some say- light your scene better darn it! There's talk about first gen vs. newer gen sensors. Some say they get banding but no FPN, and the opposite, or both....or none at all! but there is some kind of consensus that it IS a problem and it IS prevalent in one case or another in regards to CMOS sensors and has been for quite some time.

Now- when you're on the run-n-gun, it's dusk, and you don't have your trusty Arri kit or some cool strap-on LED's, but need to get THAT shot! Low and behold in the EVF/LCD there is the awesome purple, yellow, and other cool psychedelic, (srcasm) color FPN & banding lines. I'm thinkin, is the shot worth it?? Now, 8 out of 10 times I won't even hit record, b/c I'm thinkin it's a throw away-...The has to be another solution....

I'm wondering what anyone's techniques in post are to remove such noise without comprimising the integrity of the shot itself. I've read a bunch of links where photographers have been dealing with this for a long time and quite easily remove this noise from their stills. Is there a way to do this effectively for digital cinema? at say 24/30/60 stills(frames) per second. Does anyone have a foolproof way of achieving nice clean imagery in post?

Side note** I know that the guys in the 'HDSLR shootout' had a colorist on board, did he 'clean' up any of that low-light footage for the GH-1 Were we looking at RAW footage from all of those cams or were they touched up? B/C I saw NO banding/FPN in any of that footage....noise, yes, banding?FPN no

THOUGHTS/SUGGESTIONS PLEASE?

ALSO**** Thanks to Tester13 in the 'GH-1 researchers' thread if you haven't seen it, check it out and donate to the cause!!! Some brilliant minds doing excellent work over there!!!
 
I suggest to write special image processing filter.
Shoot evently lit background at various ISO, determinate pattern save it to presets.
And after that you must decompress each frame and apply interpolation to each point according to preset (from none to heavy horizontal or vertical one for very visible).
If any software developer want to do this it can be popular product.
 
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alignment1 said:
OI've read a bunch of links where photographers have been dealing with this for a long time and quite easily remove this noise from their stills.
Click to expand...

This is interesting, I have a few shots on a video I shot where I see banding and I wouldn't mind trying out these methods the still people use.

Export all the 120 frames of my 5 sec clip that needs banding removal and automate photoshop to do it.

Could you point out to these links you mention so I could give it a shot?

Sami
 
hunter richards said:
The Neatvideo plug-in solves this problem (and most other camera related noise problems).
Click to expand...

This thing is not good for removing fixed noise of CMOS sensors.
I had few talks with these guys many years ago and they just use transform to frequency domain and filtering is based on this.
In case of fixed patterns you need some kind of interpolation and not standard noise removal.
 
You could always crunch the contrast so it goes deeper into shadow, or you could try rotoscoping your subject and increasing blur on areas where it's happening to create a DOF effect but also removing the banding.

The main thing I do when I see banding on set and I can't do anything about it is try my best to get fully static shots...you have a much harder time noticing it that way.
 
Essami said:
This is interesting, I have a few shots on a video I shot where I see banding and I wouldn't mind trying out these methods the still people use.

Export all the 120 frames of my 5 sec clip that needs banding removal and automate photoshop to do it.

Could you point out to these links you mention so I could give it a shot?

Sami
Click to expand...

Does the pattern actually move?

Couldn't you just do this to the video clip in the editor?

Whenever I had that fixed pattern noise show up, it was usually when I was under exposed. Usually, increasing the iso cleared it up- good enough for me at least.

Banding, if you're talking about color banding, not bands of fixed pattern noise, but bands of color that show up best on gradients seemed to be best solved by adding noise.

Those two issues are what sold me most on the 7D.
 
Tim Joy said:
Does the pattern actually move?

Couldn't you just do this to the video clip in the editor?

Whenever I had that fixed pattern noise show up, it was usually when I was under exposed. Usually, increasing the iso cleared it up- good enough for me at least.

Banding, if you're talking about color banding, not bands of fixed pattern noise, but bands of color that show up best on gradients seemed to be best solved by adding noise.
Click to expand...

The pattern doesnt move. Can I do it in the editor? If it's possible I dont know how? By adding noise I didnt get very good results at least...

Heres a 100% crop of the area that shows the noise stripes. I think I'm actually talking about fixed noise patterns?
 

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I don't exactly know either, :) but I think it would be something like this- get a shot of the banding by itself, invert it, then use that over your video track and set the composite mode to Subtract. Or maybe you wouldn't invert it? Or you would multiply instead of subtract.
 
tester13 said:
This thing is not good for removing fixed noise of CMOS sensors.
I had few talks with these guys many years ago and they just use transform to frequency domain and filtering is based on this.
In case of fixed patterns you need some kind of interpolation and not standard noise removal.
Click to expand...

I think they may have adjusted their algorithms a bit, its worked on everything ive thrown at it from film grain to digital noise. Download the latest version and check it out.
 
As for banding; that's an 8bit issue. 8bit Color banding is the result of the image being way to clean for this 8bit codec; the results are banding on shaded transitions going on in the frame. Those of us that have been working in AE and PS for many years have always dithered to deal with that when it came up. This is where I miss a little real noise in the signal, and not the mushy kind on DLSR.



Michael Pappas
http://www.pbase.com/Arrfilms
http://www.PappasArts.com
http://SumeriusChronicles.com/
http://TheOrbisTerrarum.com/
 
I tried the Neat image plug in over the weekend against Noise Ninja. It seems to do a great job with banding in blue skies, which has been one of my biggest problems with the codec, rather than mud. It also seems to not go as plastic looking as quickly, though I've not really played with it long enough to tell.

As for banding; that's an 8bit issue.
Click to expand...
I tried loads of different codecs a few months back, but found that transcoding to the AJA 10 bit codec seems to rescue a lot of this to my eye. So maybe going to this or a 16 bit image sequence, with treatment in Neat image is a possible solution for problem shots?
 
thanks all- appreciate the suggestions- Thanks Hunter, I downloaded the Neatvideo demo for both AE & FCP, the AE version let me do more, however still limited in options, (demo only). Seems to work pretty well in some situations. thanks again
 
Martti Ekstrand said:
If you got AE try it's included Remove Grain filter, has worked very well for me in removing the little FPN I get with my GH1.
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actually I have, per your suggestion- but for some of the shots in say:

http://www.vimeo.com/9159302

@ 0:42 - 0:46
@1:32 - 1:38
especially @ 2:17

I really felt it softened the shot and made the faces 'plasticky'.

On another note- since I haven't seen this vid for some time, returning to it today with 'fresh' eyes it really doesn't look as bad as I remembered. You know how it is when you're 'too close' to the project, analyzing/scrutinizing every fleck/detail of every frame....it's easy to get caught up....at this point unless I go back to the original footage, I don't realize how bad it actually was to begin with.

Thanks for the help Martti as usual:beer:

Z
 
I think we already covered this on the vimeo page--per your suggestion I tried, but re-introduce some different noise.

I shot some stuff on a trip up north (snowboarding), I'll have to post some footage from inside the lodge we rented. Low-light Beer pong in the garage- there are great exmples of this horrible black&multicolored lines-fpn-banding. I f I have some time, I'll post before and after w/ original vs. Neatvideo vs. 'remove grain/unsharp mask'.
 
Cool. Very interested to see that comparison. The banding issue is the last real factor in me getting a GH1.

On that note. Realistically how often in day to day shooting does the problem come up? Can you basically not use practical lighting at all? (Seeing the banding on the bulb in the Zacuto low light test was a little disheartening).

Cheers.
 
Interesting.

It's so frustrating that the gh1 footage wasn't more flat to make comparisons easier. The gh1 stuff in the shootout does indeed look more like a final look than a flat, almost negative look, that you'd actually use to shoot for lattitude. In the comparison at iso 1250 linked, I probably still prefer the mark ii (I think the area around the light is nicer on the gh1- which had been my biggest concern earlier because of banding), though only because of the obvious lattitude it allows for post. I love the gh1 look. In my opinion it's really wonderful, but I'm the slightest bit apprehensive about it's ability to shoot flat (though, thanks to everyone and various examples posted on threads here, it seems fairly clear you CAN shoot more flat than the Zacuto shootout would lead you to believe).

I'm also intrigued by the fader nd idea you mentioned in a lower post. Has anyone tried this? Anyone gotten to the root of the cause of banding on the gh1 and know a (relatively at least) simple workaround to consistently avoid it?
 
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