Video with Depth
Lifewolf writes: "A new technology from 3DV Systems uses pulsed infrared illumination to capture depth information for every pixel of a video stream. This allows for neat tricks like realtime keying without need for color backgrounds. JVC is already selling a product based on this, the ZCAM."
This opens up some great possibilities for
digitizing 3D models. Anybody heard of this
technology already being used for that?
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I've never really seen what makes 3D video (or 4D to get particular) so difficult to record.
Humans have 2 eyes in the front of their heads, inches apart. All that is needed in a camera is for two syncronized tapes to run simultaneously, with the lenses just a few inches apart.
Playback the left half on the left eye, the right half on the right eye, and our own built-in systems have no problem building those two images into a single 3D image.
I think the difficulty is not in the recording of 3D information, but of building a display to play it back to multiple people.
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it's a bit bothering that you think someone's filming you with a camera.. but secretly making a 3D model of you! =)
Can you imagine using this technology to insert your favorite politician in a porn video? George Bush Does Dallas.
Used within a survellance camera, it could detect motion without getting tricked by that tree near the air vent.
It could also be used in surgical situations where a specialist located in another state can more easily study facets of the video being provided to him (cutting out noise, if you will).
You could do some really weird video editing where you could create a scene of a person standing in a verdant field in the middle of summer with snow falling within his 'mask'.
Items recorded in this way (presuming the mask is also recorded) could perhaps be admissable evidence that helps the court focus on a specific action that might otherwise get missed.
It might also provide a less-expensive way to make 3-D videos. Precursor to holographic movies?
And so it goes.
Part of it maybe that what you record stereoscoply you have to also playback with a stereoscope system (sorry for the spelling I am not english). Many system are/were tryed on various medium(blue/red glasses on TV, one frame over two on computer etc..). But every of those system have pro and contra (cost, quality, easy or nopt to use etc...). So in effect the problem looks easy but isn't (like the problem of path minimalisation, or even the "knot" problem). Furthermore I am not a biologue , but as far as I discussed with one there is another problem : eye aren't alone for us Human. The brain superpose a correction on what we see. Object it recognize it doesn't see them as "flat" even if seen with only one eye. It automatically add depth. Or something like that. Feel free to correct me as I am speaking out of my domain of expertise (Quantum Physic :))
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I didn't have a depth thingy to tell me how to replace the image, we had blue backgrounds which had to be equally lit, and pray nobody came with blue on.
The real reason blue was used is because if you see a video signal, it is only 11% of the signal, at most, and also a very rare color(saturation wise) in a picture. Most people don't wear blue tarp mascara, and it was acceptable.
The other type of keying was on an Amiga with a Gen Lock, using background color as the transparency, a static image over a live background. You could also set the transparency, so you could get ghost-like effects.
But with one of these, you can probably make a scrolling background with the occasional tree popping to front. If you were to do the same with an editing suite, you're looking at at least a good hour, and when you rent out facilities, you look for all the helpies you can. Just printing out a still from video can cost more if you're using a "video printer".
I wonder if you can set the depth manually, or if it's hard coded. It might be fun to see something pass "through" something else.
This mind intentionally left blank.
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Will that help to improve the compression algorithms?
:):):):))
Will the depth will be an useful data for the compression algorithms?
Yeah, ouais, Cool
Normally, when you want to key in a false background in a scene, you need to have a constant color in the background (Hence the use of blue and green screens). If the background isn't flat, then you either have to go at it with photoshop frame by frame, or use expensive border tracking software which is less than perfect. You could spend hours setting up a scene just right, with screens placed in all the right places, making sure that there is nothing else that is the same color as the key, and planning camera angles for an action sequence, not to mention the struggle of getting the keying to work just right.
with this new technology, however, you could film an actor just about anywhere with very little preperation, and key him/her out based on depth AND color (some situations may need both), and easily pop new things both in front and behind the actor. It could save movie studios a lot of time, effort, and money for doing special effects, especially after you consider how easily it would be to generate a virtual stunt double from the 3d mesh (film the actor from a few angles, and merge the resulting 3d wireframe. Voila, perfect model down to the wrinkles in the skin)
It'd be great if they could apply this sort of technology to previously recorded works of art like any movie with Ron Jeremy or John Holmes in it.
I'd certainly like to feel like I'm there in the action when Ron's banging some latino chick in the ass and she's begging for more!
3dstudio 4 has a plugin to render z buffer depth too to get scenes like the one's with this camera
it's great for doing depth based effects such as artificial depth of field (3ds4 didn't have that)
I'd love to have one of the cameras available for making live video stuff, I'm looking forward to getting my hands on one, I hope my local video facilities unit gets one (I'm going to mail them a link).
Coming soon to an MTV near you. Sadly probably not from my studio any more. I gave that up when 3dsMax came out, Seemed like there was no room left for a two man outfit (one gfx, one coder).
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Video recorded with this technology will give you two video streams:
* The normal video-stream that any video-camera will give you.
* Another video-stream containing depth information.
So, what you have, at best, is a way to tell the relative distance from the camera to each point in the image. Which, will let you adress seperate elements of the image based on depth. But, you _won't_ have anything more image-wise than you can record at home with your Sony.
Sorry, no 3D-porn.
"Once you capture live action footage in object video format, you can not only make it more visually engaging, but also sell advertising right in context of the live event."
Great, now you won't be able to distinguish between the show you're watching and the advertisement. Now when I'm watching TechTV, I can look forward to Britney Spears bouncing thru with a Pepsi at 30 second intervals.
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with this technology, NASA could fake the moon/mars landings again, and this time - get it right! rofl
You could do lots of interesting tricks with this - like changing the cut-off on the z-buffer, so when someone walks away from the camera, it looks like they're walking through a wall.
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Just amazing how DV cameras just keep getting smaller and smaller. I think I'll pick up that ZCAM, and get the optional belt case, so it's with me everywhere I go :-)
I guess this thing is targeted more for reporters and the media, than the consumer.
I assume "keying" is what we dumb consumers typically know as "blue screening" or "green screening", but this lets you do the same without a solid background, since it can separate out the people in the foreground using a depth cutoff instead.
Neat technology. I think there'll be more practical uses for this than you might think at first.
I wonder how accurately the z layer aligns with the pixels. Since it's a different infrared source, bounced off the subjects, I wonder if there's some fancy alignment that has to be done, or if the same pixels on the camera pick up the depth information. It'd be the difference between perfect alignment, and having sloppy edges around objects, which is pretty significant for a lot of uses.
-me
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You have a z-stream of data. When you are moving around this in 2d, the amount of effort is dependent on the gradient where you are going. I would think someone can come up with a glove attachment connected to 3D force feedback actuators that would let you touch the 3D models or porn.
IMHO, this technology would rather do the contrary. It makes photo forgeries so damn easy: no afternoon-long sessions with the gimp to get exact contours of people to delete from or insert into picutres: just use the ZCAM's distance keying and you get instant masks. The example given was scary: a business meeting, from which they could edit out people at will. The ideal tool for anybody that wants to rewrite history. So, forget about photos staying admissible as evidence in court.
Say no to software patents.
Would it be possible to economically do this with still cameras(preferrably film vs. digital)? Are there already products that do that? It would be cool to be able to record a depth 'image' with my photograps for later editing...
--
Benjamin Coates
Another fun use for this technology would be to create video that works with red and blue 3D glasses, that would allow the viewer to watch in 3D or "Normal" mode.
You can create a red and a blue version of the image where pixels are cloned into red and blue counterparts. The pixesls that represent closer points are farther apart, while pixels representing deeper points are paired closer together. This would make for more realistic 3D Images without the need for filming with a special double-lens camera. Without this information, the best you can do is manually Z-buffer different sections. The depth in this case is not dynamic, and objects would normally appear to lie on artificial incremental planes. For instance, an entire human face might be on one plane whereas with this technology, (depending on the sesitivity of the depth info) the nose will be 3-dimensional relative to the person. This is not a specifically useful application, but cool in any case.
Getting real-time depth information from the amount of IR reflected from a pulsed IR light is a pretty old technique. It's used in some input devices to detect where people are in front of the computer. The use of this information for video keying may be new, though.
Sounds like an interesting technology that'll make for some pretty cool effects/uses.
Apart from the obvious use getting virtual objects to pass correctly between/around objects in the real scene, or vice versa you've freed up the colour channel info being used as a depth key for other things.
Imagine keying an actors and his or her clothing in blue and using the depth keying to to replace the blue with a projected texture or somesuch using the depth information to do the texture calculations, or keying sports equipment in sports broadcasts.
Or if the technology eventually scales down to an affordable level it might make an interesting input device for playing video games.
it's called a dumb terminal.
Thank you.
The use of this camera technology for video composition is great, but if you bundle a panoramic (360 degree) camera with it, you solve the reason that accurate 3D visual reconstructions are expensive. I'm thinking: export a 3D map of every object in range, then feed that into CAD.
:P
Now take your CAD file, recompile and render with a Quake3 engine, apply sampled textures, and you've got a very cheap, fast, good 3D walkthrough - architects will enjoy this too, as will tourism sites.
It's also going to mean some great first-person-shooter maps
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I posted a comment a while ago that explained the uses in visual effects work for depth-cameras, and some of the problems with existing methods of pulling a matte off of live action plates...
We were actually talking about this at work the other day; mainly wondering how well it would deal with things like fine hair, smoke, transparent objects and stuff like film grain/video artifacts/lens artifacts etc...
Would love to try one and find out...
The ZCAM Videocam extension is available for more than half a year now.
That fact that it actually works as advertised is somewhat astonishing. If there's a large enough distance between fore and background (> 1,5 Meters) it Keys without any hassle. No more Blue or Greenscreens, that means.
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The biggest problems in color keying are Hair and glass (as in eyeglasses).
If this system, as it claims is simply making a z-buffer (depth buffer) of the image, then it's going to see hair and glass as a opaque lump, not the semi-transparent reality.
Blue and Green screening (not chroma keying) can do a very good job of pulling out variable opacity and thin items like hair. Especially with the newer LED screen illumination camera rings.
This technology has some nifty tricks and will allow more poor quality keying to continue, but it won't replace blue and green screens.
knowing the depth of something is one more feature we can use in a recognition by components model of the perceptual process. Introduce a context for top-down processing in conjunction with this empirical bottom up camera and computers could recognize all sorts of things.
You know the Microsoft destroys the night, Linux devides the day...
I assume "keying" is what we dumb consumers typically know as "blue screening" or "green screening"
That is, unless they use Windows 9x regularly ;-)
but this lets you do the same without a solid background
Actually, use of a still (non-solid) background would help even this technique, as post-processing can massage the background vs. foreground using traditional MPEG motion compensation for an even more accurate contrast between a background moving in one direction and a subject moving in the other.
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Hi Folks,
I was rather astonished to read about ZCAM today, as it is rather old.
I saw it working at last years NAB in Vegas.
It still is a little bit rough and the keyer is not performing as well as others do, but it is an interesting technology, esp. for local news stations or variety shows...
I don't believe nobody has posted about MPEG4. This is very interesting for that -- film using this, and you can encode into MPEG4 format with /huge/ compression almost automatically. The hard part about MPEG4 is object detection; this makes that almost free.
-Billy
You're absolutely right - this will make a huge difference for compressed video by separating out the layers of the image. Motion prediction (or rather background prediction) will become trivial. The potential for this goes well beyond the existing MPEG4 codecs - indeed I expect it to spawn a whole new generation of codecs based on RGBD colorspace. Not only that, it will allow you to easily build up a detailed 3 dimensional representation of the static objects in your video, which is a whole new technological potential.
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Why bother. A vertical split-screen image for left and right eye is all you need. Theres nothing stopping conventional television from broadcasting stereoscopic images. Get two camcorders, tape em together at the sides and videotape stuff in your house. Edit the video so that the left camera's image displays on the right-hand side of the screen, and vice versa. Bingo, 3D video.
See what I mean?
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I'm still waiting for those cool full-body suits with 3D goggles that let you have virtual sex. Who cares about the 3D, bring on the 3M!
NAB is the National Association of Broadcasters conference. The ZCAM was was being demoed then.
In the demos they had realtime keying so they could fly a 3D CGI character in front of and behind the live talent. There was only about a 40ms delay. This is impossible with normal keying (ie blue/green screen). (You can only put stuff behind the talent).
It's biggest limitation was the resolution of the 3D sensor was low - so you had rough edges (think jaggies).
They also demonstrated a 3D Realplayer and 3D Windows Media players (which you watched with stereo shutter glasses). These players were called 'deep players'. Pretty cool but definitely not new.
Looks rather simple, akin to simple range gating.
It's biggest limitation was the resolution of the 3D sensor was low - so you had rough edges (think jaggies).
Are you sure this was the problem?? I've been wondering how well this technology would actually work (it was announced quite some time ago), and have heard that indeed it had "jaggies".
Though I was under the impression it was due to the inherent problem with anti-aliasing z-depth based composites.... the depth is represented as grayscale, from white (nearest) to black (furthest). If you were to antialias a foreground subject (say it's white) onto a black background, you'd end up with various shades of gray pixels along the foreground object's edge.... this would translate to the edges of the foreground object being at a distance between foreground and background, which is obviously inaccurate, as you're still deaing with the foreground object.
Cameras have been sensing depth with infra-red for years. It's called auto-focus. All this camera has added is recording that data along with the rgb. There is a nifty little method of scanning film location for later 3D reconstruction using Lidar that has already been used in films for some time. Lidar is often also implemented for geographical surveys by folks such as NASA. The resolution of the ZCAM sounds very limited and will not be useful for truly realistic keying. Possibly guy-in-front-of-weathermap applications, but it doesn't look like it can handle fine hair, water, or other transparencies that most keying software can today. If you don't want to deal with a green/blue screen, there's also the option of a "difference key" that compares the shot without anyone in it to the shot when your person walks in. Some systems can now do real time insertions this way. The ZCAM still won't give convincing film quality compositing results. With the advances in photogrammetry and it's applications in movies, I don't think that ZCAM has much use potential