Let's not compare this monster watermark to a logo and start pulling out the tired old interpolation tools.
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Does it work on this one?
Forgive my ignorance, but doesn't the alpha channel get flattened at render, unless it's rendered to a PNG still sequence? So how can it be reversed?
AFAIK, what we're dealing with here is similar to a halftone or dither like you get in magazines or newspapers. It's final, and has to be dealt with like an overexposed image.
If by "reverses alpha transparency logos" you mean it takes your supplied sample and overlays(composites) it and color corrects it using an algorithm, then that's what intracube did.
However, if I'm wrong, please correct me.
What I would really like to learn is how to isolate a logo without manual masking. Maybe using effects.Last edited by budwzr; 16th Aug 2011 at 10:24.
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You're NOT wrong.
That's what I was insinuating, too, by mentioning it being a simple white slightly-translucent obstruction. Because I can already see somebody (with next to zero knowledge on imaging) thinking this is some sort of magical fairy wand, to be waived at any video, with the ability to remove logos and watermarks.
Add some color, it gets harder.
Make it more less translucent, it gets much harder.
Make it complex shapes with multiple colors, it can be impossible.
Intracube did a great little demo for us, but people need to understand this is very scenario-based, and has many limits. I've done quite a few of these, too, with Premiere, and by way of creating a negative overlay to hide the damaged image area. To make it perfect, you have to continuous change the opacity with the lighting of the scenes. It's tedious manual editing work.
As far as removing logos/etc, to be quite blunt, the "delogo" filters out there are just garbage that butcher video with blobs. If I wanted blobs, I can do that with a lot less effort. Most of them are just glorified alpha channel makers anyway, splatting a blob on top of the target area.Last edited by lordsmurf; 16th Aug 2011 at 11:09.
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Yeah, smurf, I bought into that "reverse polarity" concept early on, and it turned out to be a hoax. Maybe the OP was having fun with us, hahahaha.
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It looks exactly any TV alpha blend logo, just larger. I'm not going to spend the time to do it myself, but I think it would work.
Not perfectly reversed. Obviously if the alpha channel was separate you could just discard it.
But it does reverse the effect though I suppose the masked area will be posterised* somewhat, more so the brighter the logo/watermark.
Yes, I think he used basically the same method. The filter is a lot simpler to use though.
I was responding to the question whether it had ever been done before, when it has, several times.
My point was however that it's not "interpolation", at least not of the kind that used to repair solid colour logos. That method can't be perfect or even close, but it often works well enough on a small area in the corner to be unobtrusive.
If you had software that could detect and isolate a logo on an arbitrary background, it could trivially remove it as well.
Most of the time you can find a frame with the logo on a plain, preferably black, background and just screencap it, then desaturate and possibly play with levels.
If it isn't easy to find a clean logo, I just use a solid logo remover, like Xlogo, where the mask doesn't have to be so precise; just as long as it covers the area. Often though you can find the same logo used on multiple videos. So in that case there is no work at all, I just edit the image name in the script to one that looks likely and refresh and see if it matches.
*(corrected terminology)Last edited by AlanHK; 17th Aug 2011 at 23:36.
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Not "reversed" at all. "reverse" implies "undo"
Last edited by budwzr; 17th Aug 2011 at 12:25.
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Last edited by AlanHK; 17th Aug 2011 at 13:43.
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I agree with AlanHK. The translucent ones can be pretty much completely removed or 'undone'. The following link shows before and after pics together with a YouTube clip of the whole song which once had the logo all the way through it (and throughout the entire movie). It was removed using LogoTools/NoLogo in AviSynth:
https://forum.videohelp.com/threads/331100-Remove-DVD-Protection?p=2051629&viewfull=1#post2051629
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Hey, anyway, now that it's 2011 and good compositing tools exist, I think it's reasonable to try and isolate the offending logo right there on the timeline and thereby getting an exact mask that travels too.
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Actually, jagabo, you're the last person I want to argue with. I already know your credentials, however, Vegas has an overlay function that can be tweaked by a formula, and I've been waiting for you to get back with your results from post 13, when this dickhead jumped in and thinks he can give a dissertation to me and the thread about stuff that is common knowledge.
Your equation is common sense, but the method of isolating the area of concern (the logo) is the 800 lb. gorrilla in the room.Last edited by budwzr; 17th Aug 2011 at 22:13.
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Just an update from me; I've been quite busy the last few days. I want to try out some alternative methods for logo removal before I post a more detailed response. But briefly -
budwzr; As you said in post #33, any alpha channel that might have existed when the video was produced would be flattened at render/encode time. AIUI, AlanHK's point was that a semi transparent logo shows the original scene 'through' it. It's often a straightforward task of working out the method in which the logo/watermark was overlayed and do the inverse of that. That's what I did. Jagabo also posted an example formula on the first page of this thread. There are other formulas/methods for overlaying (and subsequently removing) logos that I might cover in a later post.
lordsmurf; You're right that colour overlays make things more complex - especially if they're less transparent. Right now I'm thinking about a (fairly) simple procedure that would be able to reverse complex coloured logos, even if a clean reference image of the logo on a black background isn't available. In fact, a black background reference image isn't always the most helpful to highlight transparencies/colour variations in a logo. Seeing some logos on different backgrounds - black, grey, white or coloured can give more insight into any colour/alpha variations.
The dynamic range of the area under the logo wouldn't be affected - but the number of levels would be reduced. If an almost solid logo was reversed, posterization/quantization might become visible.
The method I used didn't require any manual changes over the length of the video. If a particular logo removal method looks right on some scenes, but needs to be manually corrected on others, it suggests that it isn't accurately reversing the 'formula' that was used to overlay the logo.
I've sometimes had the same problem - a logo seems to be corrected well, but then the video jumps from an indoor scene to an outside location and the logo shows up in the sky, for example.
I have a vague idea for an automated system to analyse a video and isolate a logo - even one with complex shapes, multiple colours and shading. The only caveat is the logo needs to be partially transparent. More on that in a later post. -
@intracube - That would be great, and I apologize for being a dick.
Actually, the great work you did inspired me to think about "the possibilities", and usefulness of being able to pull any kind of mask imaginable. -
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Yes, careless terminology, I'll correct it.
I was thinking that the original image data is effectively compressed when the watermark is applied, reducing the dynamic range.
Though the range is restored by the "reversal", it has lost information, which now manifests as posterisation.Last edited by AlanHK; 18th Aug 2011 at 00:02.
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Please stick to the OP's original question and refrain from personal attacks or this thread will be closed.
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