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Invisible Cloaks, Translucent Walls
jd writes "The University of Tokyo has developed the illusion of invisibility, under the name of 'Optical Camouflage.' The system is remarkably simple - you have a mix of light-sensitive and light-emitting devices attached to an adapted reflective surface. The devices are hooked to a computer, which simply projects on each side whatever is on the opposite side. The result is more of a translucent look, than real invisibility, but the potential is there. The inventer's next objective is to make walls that are invisible, using the same technology. Project a real outside image onto an interior wall without windows. This almost sounds more frightening than the cloak, since there's no reason why the sensors would have to be placed outside. Imagine a world where PHBs can turn their office wall into a window onto any cube. Zero privacy. The technology is great, but the potential for abuse is definitely there." Update: 06/15 00:20 GMT by T : You may remember we mentioned this project when it was cloak-only.
This works great until you get into three dimensions at which point it all goes sour.
Because light's reflecting off of the coat itself. Plus, the shape of the cloak is not symetrical. I just don't see how it even works. Sure, I could imagine something like a sheet of paper partially working.
As for see-thru wall, it's probably a lot easier then this guy wants it to be...
Just make the wall itself clear. Then use an lcd-like mechanism to act as a 'shutter', allowing the outside light in. Note that each 'pixel' could be quite large (several inches).
In other words, when the wall's off, it's opaque. When current's applied to a section, the liquid inside the wall becomes clear and the wall is see-through. Not sure if the technology's there yet, though....
-- If you try to fail and succeed, which have you done? - Uli's moose
Interesting, this stuff belongs in the internal areas of cars in the so-called blind spots. Probably needs to improve upon the resolution a bit though. Kind of like wearing a digital CCD/CMOS.
The IR thing is more of a problem. Heck, we already have an excellent visible light stealth system. It's called DARK. All night vision systems track IR since it's generally around in abundence at night.
You are also still a target on Radar, and probably Lidar as the system still reflects or absorbs high amplitude pulses of light differently that the background.
You also run into interesting problems with lighting. If someone shines a spotlight on you, your shadow would still be dark, so you would stand out as a dark spot.
There are undoubtedly computational ways around all that, but after a while your number cruncher is going to be more of an emmission signature than whatever you are hiding.
"Learning is not compulsory... neither is survival."
--Dr.W.Edwards Deming
Actually, I thought of this many years ago, to have a cube that can sit on the shelf, but it can be opened so you can hide something in it. In plain sight, but not visible.
You are being MICROattacked, from various angles, in a SOFT manner.
They were doing this kind of stuff at UNC about 5 years ago when I was there. (US News recently ranked them first in Graphics) Still very cool though.
I've used welding helmets very much like you describe. They're triggered by very bright light to become extremely (you can only see the arc) dark. As soon as you turn the welder off, the helmet goes clear (well, actually, green). My impression is that this isn't too novel.
True, in it's current form it's merely a cool demo. But I imagine one could design an LCD that projected a different image depending on the angle you viewed it from. Kind of like those ribbed plastics (can it, beavis) that show different parts of the image depending on the angle... and thus alow simple animation and 3-d looking objects through small movements.
Of course, the image would also have to be grabbed from different angles... so we're talking a load of optics and processing and projecting. But I imagine it could be done in the next 25 years if someone wanted it badly enough.
Cheers.
By my take on the diagram of how it works, the system requires itself to have a static copy of the background to be mimmiced. In all the demos, you never see the camera move, because that would change the background that is being mimmiced, and would probably give the hardware an aneurism trying to keep up with the updates. They most likely had to take a shot of the background before the demonstrator and his "stealth object" came into view, to use for the projection part of the process. That, and they're probably using a visual comparison system to determine how to mask off the projector so it doesn't project light of any sort anywhere except where the cloaked item is.
This means it's not really possible to cloak something that's in front of a changing backdrop, at least not with this implementation of the technology.
I work for the Department of Redundancy Department.
Actually, they are already working on this in a way with planes. In order to prevent visual detection, the bottom of of the plane radiates light, so as to replace the light that it would normally block from the sky. (the tops of the planes are painted to resemble the ground). The same could be true of a soldier wearing this material... No matter what color you're wearing, in the desert during the day you pretty much block out the light. Add some additional luminescence of the proper color and viola! Slightly less visible.
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