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Background Matting: The World is Your Green Screen

grail.cs.washington.edu

51–60 of 60 posts

Re: Background Matting: The World is Your Green Screen

#51
post #39

Very cool. Next step would be to emulate lighting in the target scene, but that probably requires pose detection and facial landmarks for accurate shading.

I have been thinking that a killer zoom product would be a USB controller for an rgb led strip that helps match color with your virtual background.

Re: Background Matting: The World is Your Green Screen

#52
post #27

This does look like an interesting step forward however I’ve found the biggest limitations of previous techniques to be - people who are using occupying a wider z-axis (for example leaning forwards in the camera or who have arms in front of them) - people holding objects like cups How well do your method handle those kind of situations?

I'm not associated with the paper, but I don't think this will have the same kinds of effects. It's effectively using a photo without the user to discriminate the background from any subjects in the scene.

The neural network used seems mostly for allowing for variations in lighting and dealing with the fuzzy effects you'll usually get around the subject. Depth of the subject doesn't appear to be relevant here.

Re: Background Matting: The World is Your Green Screen

#53
post #27

This does look like an interesting step forward however I’ve found the biggest limitations of previous techniques to be - people who are using occupying a wider z-axis (for example leaning forwards in the camera or who have arms in front of them) - people holding objects like cups How well do your method handle those kind of situations?

I'm not sure how either of those situations would trip up the system they're using. For a system trained on the background image, what difference does it make if the subject is holding a cup? The cup is not the background image, and it would be obvious in the same way that it's obvious the subject isn't the background image.

He might be referring to transparent/translucent/refractive objects, like a glass cup. Supposedly this technique can manage the transparency, but not refraction (and maybe the refraction could trip the transparency into failing).

Re: Background Matting: The World is Your Green Screen

#54
post #43

Anybody know of any work done to improve greenscreen keying? The current old school techniques work quite poorly and require so much manual work. I would imagine with the new work coming out with neural nets etc. there would be possibilities for improvement. This is very cool work and good for certain applications, but seems to produce similar problems like greenscreen to some edges.

Modern green screen plugins/filters are miles better than what they used to be to the point that if the keying is hard, then the image must not have been produced well. By that, I mean an evenly list background (no light fall off producing gradients). Proper lighting of the subject. Proper distance from the background (helps reduce the edges and color tinting).

Re: Background Matting: The World is Your Green Screen

#55
post #51
post #39

Very cool. Next step would be to emulate lighting in the target scene, but that probably requires pose detection and facial landmarks for accurate shading.

I have been thinking that a killer zoom product would be a USB controller for an rgb led strip that helps match color with your virtual background.

Very good idea. And change in real-time if the background is dynamic. And allow the user to set styles such as warming the FG subject, shimmering as if there is a fire or candlelight in the room, etc.

Re: Background Matting: The World is Your Green Screen

#56

Peripheral: What is the benefit of halving these artificial backgrounds? Apart from „it’s fun“, which wears off after about a minute? In my experience (Zoom Meetings), there’s blurring/artefacts around the edge of the head and the image quality seems to suffer as well. I had a meeting where one participant uses an actual green screen, and the difference was remarkable, with none of the issues above.

Some people feel the need to hide their shitty apartment.

I've seen someone advised that the background on their webcam makes them "look poor", where the concern was that looking poor is a (perverse) impediment to getting paid work, but they can't exactly move, especially under lockdown. It may be better to use a calm artificial background in that case.

See also people doing online-conference presentations and Youtube videos. I've seen quite a few of those are using virtual backgrounds.

Perhaps for the same reason - thousands of people may see the video, and some people, having made the effort to put on a nice suit/makeup/etc, get a haircut, and look their best, don't want thousands of people to see what their not so nice home looks like behind it.

Re: Background Matting: The World is Your Green Screen

#57
post #43

Anybody know of any work done to improve greenscreen keying? The current old school techniques work quite poorly and require so much manual work. I would imagine with the new work coming out with neural nets etc. there would be possibilities for improvement. This is very cool work and good for certain applications, but seems to produce similar problems like greenscreen to some edges.

Modern green screen plugins/filters are miles better than what they used to be to the point that if the keying is hard, then the image must not have been produced well. By that, I mean an evenly list background (no light fall off producing gradients). Proper lighting of the subject. Proper distance from the background (helps reduce the edges and color tinting).

I work quite a bit with green screen keying. I see the same keylights, ultimattes and primattes used still even in big productions I have worked. Fixing the key can take weeks. Maybe industry is bit conservative and I haven't seen cool new stuff bubbling under, but would love to have new tools in the toolset to approach difficult shots.

Re: Background Matting: The World is Your Green Screen

#58

Earlier quoted context omitted.

Ex-VFX person here. Green screens are crap with hair, because its translucent the green/blue bleeds through which means that it has to be cleaned up by hand. Then there are the situations where there isn't a green screen. Again manual cleanup is required. Each frame needs to be cut out by hand. 24 times a second. The same with a difference matte. Cameras are noisy, so there is constant noise in the alpha channel. Thi…

Ex-VFX part-time software team member here. I can assure you they read these papers. If it is good, it will be part of a future version of the software.

100%, Its how we managed to justify flying out to siggaph each year.

The foundry have been trying to get this into Nuke for years. The problem is that normally you get flickering, as you'll have seen.

Re: Background Matting: The World is Your Green Screen

#59
post #33

Earlier quoted context omitted.

Ex-VFX person here. Green screens are crap with hair, because its translucent the green/blue bleeds through which means that it has to be cleaned up by hand. Then there are the situations where there isn't a green screen. Again manual cleanup is required. Each frame needs to be cut out by hand. 24 times a second. The same with a difference matte. Cameras are noisy, so there is constant noise in the alpha channel. Thi…

Are there no tools that automate the cleanup of green-screen artifacts?

Not really. The green screen gets you 85% of the way there, the rest needs a human to make an artistic decision as to how much hair to cut round.

Re: Background Matting: The World is Your Green Screen

#60
post #3

The originally submitted URL ( https://www.catalyzex.com/paper/arxiv:2004.00626 ) points to https://github.com/senguptaumd/Background-Matting , which points to https://grail.cs.washington.edu/projects/background-matting , which points to https://arxiv.org/abs/2004.00626 , which points to https://arxiv.org/pdf/2004.00626.pdf , which is inlined at the originally submitted URL. I'm not sure what's going on here, but on…

Hi, I'm one of the folks building CatalyzeX (https://www.catalyzex.com). It's intended primarily as a free resource for machine learning practitioners (research engineers, developers, students, and generally anyone interested in R&D) to discover interesting ML projects and papers, easily access the code and datasets, and communicate with the authors or other experts.

The link share here was likely with keeping the relevance of this project to HN in mind, and that easy access to the code and authors would be valuable for anyone here looking to take it further.

Thanks for clarifying the convention here on HN, being transparent, and for updating accordingly. Much appreciated.

Always open to feedback if you have any as well! :)

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