Slashdot Mirror
Combining Two Kinects To Make Better 3D Video
suraj.sun sends this quote from Engadget about improving the Kinect 3D video recordings we discussed recently:
"[Oliver Kreylos is] blowing minds and demonstrating that two Kinects can be paired and their output meshed — one basically filling in the gaps of the other. He found that the two do create some interference, the dotted IR pattern of one causing some holes and blotches in the other, but when the two are combined they basically help each other out and the results are quite impressive."
awesome
How cost and/or physics prohibitive would it be to exploit the fact that "IR" actually covers a number of frequencies of invisible-to-the-naked-eye light with similar properties? Could one modify a Kinect with appropriate narrow-band filters, so that a second Kinect, with filters for a different narrow band wouldn't even see the dot pattern of the first? If possible, how many Kinects would it be possible for(or, at what point does the required narrowness and wavelength tolerance requirements become absurdly costly?)
Is that A)Wholly impractical, because of some sort of effect the reflecting materials would have on the IR wavelengths, B)Sure, it's possible; but have you checked the supplier's price list for narrowband IR filters recently, or C)Just a bit of ebay and some steady hands?
Perhaps more practically, I wonder if the Kinects could(with some mixture of hardware shutters and firmware or driver mods) be made to trade off sample rate for coverage(ie. if the kinects are ordinarily taking 60 frames/second, could two kinects be made to take 30 frames/second each, turning off their IR source when it isn't their turn, and turning it on when it is) or does their mechanism of operation require too much time to calibrate itself on startup?
What feat would that be that one stationary ear could do as well as kinect?
Recognize your voice from the kitchen
There is a class of visual inputs that makes the human brain just tie itself in knots, even once you know that the trick is, "optical illusions", Escher stuff, and the like.
I wonder what the class of "optical illusions" for the Kinect's vision system and algorithms is... Off the top of my head, I'd imagine that retroreflective materials might kind of freak it out; but I'd be curious to know if there are any stimuli that cause it to wig out in weird ways, the way that optical illusions do the human visual system.
Can you imagine a beowulf cluster of kinects??
The "good ol' brain" does a fairly crappy job, actually. 3D vision systems like these tend to perform quite a bit better than we do. And we only do as well as we do because we can use a lot of indirect clues based on our long experience with a 3D-world - we know how big stuff normally is, for instance, so we can judge distance from size. Mess up those clues and we completely lose it.
And even with good clues we don't actually measure distance well. Have somebody place items on a parking lot or some place like that, then try to guess the distances. Not going to be very accurate. Try to estimate distance vertically rather than horizontally and you'll do even worse; you have fewer clues and less experience to fall back on.
Trust the Computer. The Computer is your friend.
... is good, but I'm holding out for 4 Girls, 3 Kinects, 2 Boxes, 1 Cup :)
THE HONOUR OF THE KNIGHTS - CC Licensed Sci-Fi Novel
It's a mixture of the two. He used two cameras to film the live action scenes, but the output was reduced to stereoscopic 3D on the screen.
This is actual 3D on the screen, like a 3D game. You can't zoom in, or even focus, on the background in Avatar. In fact, attempting it gave me a massive headache. With this true 3D rendering of an object, you can zoom, focus, and more importantly pan around objects in the scene, in real time. That is the breakthrough this hack has brought about.
Finally had enough. Come see us over at https://soylentnews.org/
With this true 3D rendering of an object, you can zoom, focus, and more importantly pan around objects in the scene, in real time.
Er, if neither of the Kinect cameras is focused on the background, then it's going to be blurry no matter what.
Assuming we're talking about a recording, you'd be able to move the virtual camera, but you wouldn't be able to bring things into focus that were not in focus in the recording.
What this gives you is a 3D model, with an many textures mapped onto it as there are cameras.
When I first saw the video of one Kinect, I immediately wondered how you could get multiple units working together.
It wasn't until I watched the video again later that day that it hit me. I had just explained to someone how 3D theater projection works, and so I had an epiphany: The most sensible course is to use polarizing filters.
With filters on the IR emitters and cameras, the units should be able to only see their own IR illumination. Of course, it would only work for two Kinects with maximum effectiveness, but considering how well this turned out with the units at right-angles from each other, I don't see why you couldn't combine the two ideas for 3-4 units and get sufficient quality.
I wish I had the money to get a couple Kinects and test my idea, but I'm no good with coding anyway.
It'd be awesome to see the Blender Foundation put out a bounty for a Kinect-based open source motion capture and 3D scanning suite though. :D
Friend: "The NIC is misconfigured..." Me: "No prob, I'll just telnet in and fix it." *Silence*
As the video demonstrates, the Kinect is fooled by spurious pattern projections from other Kinects in the vicinity. This could be solved by replacing the IR source in the 'projector' (actually a point source and a pinhole grid) with one of a different wavelength, and adding appropriate filters to the IR cameras in each Kinect. Each Kinect would then only see IR light of the 'colour' it emits. This would probably require the use of slightly brighter IR emitters.
He's not the only one. My depth-first recursive post counter has found hundreds of such posts.
blog.sam.liddicott.com
I do, kinda.
Headings are for brief topic summaries (a few words.) Not content.
Every time I start to have faith in humanity, I ruin it by driving to work between 7 and 8 am.
Well, your wrong. "Connects" is a verb, and everybody knows that even plural verbs do not get apostrophe's. Sheesh man, do some research.