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Getting rid of unwanted image noise

StevenUK

StevenUK

Hello,
I've nearly finished shooting my first short and I've come across a bit of a snag.

The learning curve has been steep and has resulted in the footage filmed at the end being better quality than that shot at the beginning.

I've managed to compensate for most of this using FCP, however some of the first footage was very contrasty, which was not a problem apart from the fact that where the image has burnt out, the white is a little buzzy, if you know what I mean. It has a speckled effect, which I would refer to as image noise.

I've tried every FCP filter with no effect, the only thing that comes close is a gaussian blur on the luminosity, but this effects the rest of the image considerable.

Any suggestions? I can't re-shoot, becasue it involved locations etc. If push comes to shove I could probably live with it, I'm the only person who's really noticed it, but as director it's staring me in the face everytime I watch it.
 
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Hi Knightly, here's the early footage with the noise, on this clip it's most noticable in the sky and the tree caugth in the sunlight:

http://www.cuddlescookieleftypixieandthepig.com/scene4.mov

Here's the less contrasty footage I shot later:

http://www.cuddlescookieleftypixieandthepig.com/scene9.mov

As you can tell the clips have been colour corrected to the 'desired' tone. Please note that the film will have 'widescreen' bars added at compression, hence the black bar at the top of scene9 which will be covered.

NOTE TO SELF, DON'T TRUST CRAPPY FIELD MONITOR ALWAYS CHECK THE VIEW FINDER!!!

Good Luck
Steven
 
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I actually see the compression/edge enhancement artifacts on both clips. The second clip just has less large hotspots to show it off due to the small foliage. What kind of camera are you shooting with? What are you using to import the footage (software).

I'm going to take a stab at it.
 
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Hi Knightly. I'm filming with a Canon XM1 (UK name) and capturing using Final Cut Pro on a MacBook 2GHz Intel Core 2 Duo, if that's any help.

"Compression/edge enhancement artifacts", thanks for that, I like to have a name for my pain.

Any advice gratefully received.
Steven
 
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For future shooting, I'd recommend turning your sharpness/detail setting down...mine's as low as it gets. All that does when turned up is finds high contrast edges (white against black and vice versa) and pushes the dark edge pure black and the white edge pure white. Look at the edges of the soldiers walking through the trees in the distance very carefully, you'll see an outline that doesn't exist there in real life.

If you need to add sharpness later, you can always do that with a filter in final cut.

What I'm playing with for this is taking a luma mask and blurring the darks and the whites separately while keeping the edges unaffected. I'm getting OK results, but I got better results just throwing a light blur on the whole image. In shake, I used a 5 pixel blur on the whole image and it fixed the problem...but the image was a bit blurry (which wasn't that painful to look at). See if a 3-5 pixel gaussian blur fixes the problem for you enough that you will be happy with it...let me know if not and I'll try to come up with another idea.
 
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How much of this could be attributed to encoding? I also see the "ghost" image around the soldiers in scene 4, but mostly what I see are compression artifacts (and a bug flying through the shot in scene 9). The beginning of scene 9 is darker, almost as though you were using auto exposure, unless you were fading up from black. The foliage gets lighter as they step into frame.

I don't think you'll get rid of the compression artifacts unless you use a smoothing filter of some sort. I've done this with still images in Photoshop with varying degrees of success.
 
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I think I need a cameraman, when I'm caught up with framing the shot, directing he actors, checking the props etc. etc., I seem to be forgetting about double checking things like settings. Especially as some of the settings seem to revert back to the default when I turn the camera off (which is in between most takes to save the battery packs). I tend to have to shoot very quickly. I think a check list is in order, the 35mm "check the gate" kind of thing.

I already knew about knocking back the sharpness, which has worked well in the past.

I'll try the things you suggest Knightly.

The flaws are reduced a little when compressed for DVD and are lot less visible when viewed on a CRT television.

Any other ideas welcomed.
Steven
P.S. the fly is fine, I've bought a nice soundeffect to go with it.
 
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if your settings are disappearing, you may need to change your clock battery in your camera. It's the little battery that keeps settings between battery changes. On the XL1s, it's in bottom of the handle.

Although it assumes you have the settings set before the shot, I have a checklist at: http://www.yafiunderground.com/checklist.html

let me know if the blur will be acceptable for you...I can get more complicated treatments figured out :)
 
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Thanks for all the advice.

Just to let you know that I've had acceptable results from using the noise reduction and edge sharpening filters in 'Compressor'. it's still a bit rough but it's more uniform and perhaps deliberate looking, so it doesn't jar the eye as much (well not the untrained eye anyway). I've also managed to work out how to increase the bit rate a little (it's only a 15min short).

Basically just blur and sharpen as suggested.

The only problem it gives is with some of my title graphics, but I'll just seperate them.

Thanks again
Steven
 
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If all else fails you can always "dumb down" your later footage a bit to even out the difference.. repair the early stuff, and mangle the later stuff.. so they both meet somewhere in the middle.

Being a PC guy, I don't know all the options to work with in FCP, but can you apply a blur to only a portion of the frame? If so, you might try just masking those sections that need it, and leave the rest as is.
 
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Will Vincent said:
If all else fails you can always "dumb down" your later footage a bit to even out the difference.. repair the early stuff, and mangle the later stuff.. so they both meet somewhere in the middle.

Being a PC guy, I don't know all the options to work with in FCP, but can you apply a blur to only a portion of the frame? If so, you might try just masking those sections that need it, and leave the rest as is.
Click to expand...

"Dumbing down",Yep, that's sort of what I'm trying to do. "Blurring just a portion of the frame" that's an interesting idea, I may give that a try. I'll have to work out how to do it first.

Cheers
Steven
 
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duplicate the video track and add a garbage matte to the upper one to isolate a portion of the image to blur out. That was kind of what I was originally trying to do by selecting the contrast edges (where the compression/sharpening noise lives) and blurring only the sides of those to reduce the noise...there was lots of complex luma masking going on in that shake file :)
 
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