Optical Camouflage 55
Mike Siekkinen writes "This optical camouflage project is pretty interesting. It contains three videos demonstrating it in action. Basically they overlay a video projection of what the background behind the object to be camouflaged looks like. So if you were standing in front of a book shelf an image of the portion of the bookshelf you are blocking would be projected on to you. The results are probably better than you would expect."
It's still visible (Score:2, Informative)
So it won't work in a misty or foggy scenario like a jungle or in winter.
It might work in the desert, but so does netting.
Back to the drawing board!
holy sh*t (Score:1)
Re:holy sh*t (Score:2, Informative)
Re:holy sh*t (Score:3, Informative)
Just like in Ghost in the Shell (Score:1)
The video is very cool. It obviously has limited applications, since all the system does is project an image of the background onto an object in the foreground. The illusion is convincing.
What good applications are there, actually? Can anybody think of any? It could only work in a controlled environment, that is the biggest drawback.
Oh yeah, of course the dead giveaway that this system is in use would be the projector. 1000 watt point light source anybody?
Theator applications (Score:1)
Re:Theator applications (Score:3, Insightful)
Slashdot requires you to wait 2 minutes between each successful posting of a comment to allow everyone a fair chance at posting a comment.
Re:Theator applications (Score:1)
Re:Theator applications (Score:1, Offtopic)
So YOU'RE the bastard who keeps cutting in front of me and stealing my chance to post!
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That's because ITS FROM GHOST IN THE SHELL (Score:2, Interesting)
Publications
M. Shiro, Ghost in the Shell, Kodansya, 1991
M. Inami, N. Kawakami, D. Sekiguchi, Y. Yanagida, T. Maeda and S. Tachi, Visuo-Haptic Display Using Head-Mounted Projector, Proceedings of IEEE Virtual Reality 2000, pp.233-240, 2000(vr2000.pdf(350k))
M. Inami, N. Kawakami, Y. Yanagida, T. Maeda and S. Tachi, Method and Device for Providing Information, US PAT. 6,341,869 , 2002
I'm not sure if that means that Ghost In the Shell was the inspiration or an actual source or what... but clearly the connection is not accidental.
gg, try to look at the whole page next time.
Various translations... (Score:2)
English to Japanesse [altavista.com]
and...
Japanesse to English [altavista.com]
We can't let those scientists have the fun of putting up bilingual pages up. After all, what's science without bad translations, eh?
Still can't figure out how it works... (Score:3, Insightful)
A number of posters on those site feel it's no big deal, a guy holding things in front of a projector... That's what I thought at first. But what I can't figure out is why doesn't the image show on the guys hands and face. You'd think at least some light would be reflected off of his hands.
Re:Still can't figure out how it works... (Score:2)
I have no idea whether this is how they actually do it, it's just a thought.
Re:Still can't figure out how it works... (Score:5, Funny)
What guy?
Re:Still can't figure out how it works... (Score:3, Interesting)
1. Take a picture of the background.
2. Put an object in front of the camera, painted with an obviously different color than the objects in the background.
3. Profit... no wait, I mean... using a computer, replace all the pixels of that special color with the pixels of the background image, and you have modern television overlays.
4. But this only works through a video feed; to move into real-space, you need a video projector. Take the image with the special color, and use it as a mask... the image will only shine where the special color exists, and not shine where it doesn't. That's how they get the projector to not shine on the hands.
5. Note that their special color is silver; like a white screen, a sufficiently light color such that color projected on it will appear. Viola!
Re:Still can't figure out how it works... (Score:3, Funny)
If you use a different color, could you get, say, a cello, or perhaps a double bass?
Stereoscopy, too (Score:2)
Moreover, to project a stereoscopic image, the observer looks at the masking object more transparent.
While the grammar is somewhat ambiguous, I believe that what they're saying is that they attempt to project a stereoscopic image of the background onto the observer's eyes. However, it brings up the possibility of using a two-camera analysis of the scene to figure out where the silver coat is.
Re:Stereoscopy, too (Score:1)
Re:Still can't figure out how it works... (Score:2)
This is a variation on what's known as front-projection, invented back in the 1950s (by SF author William F. Jenkins, better known by his pen-name Murray Leinster) and used in "2001: A Space Odyssey" to film the "Dawn of Man" sequences.
The trick is the retro-reflective material (Scotchlite, originally). You can either use that as a backdrop or, as in this case, you coat an object or cloak with it. It's made up of tiny beads that reflect light back in the direction it came from. (The same stuff is used on the ping-pong balls that attach to your joints in a motion-capture setup -- the video camera doing the mo-cap is co-located with a light source of a particular color so that the balls show up as bright spots in that color).
Anyway, if you project an image using low-intensity light, that image will be washed out by ambient light to most observers. To somebody (or a camera) next to the projector, that image will be quite bright when bounced off the retroreflective material. In "2001", the scenes of the ape-men with the African landscape in the background were all filmed on a sound stage, with the landscape projected onto a front-projection screen behind them.
To do the invisibity trick, you set up a piece of the screen in the foreground -- whatever moves behind it will seem to have gone invisible.
(The half-mirror in the diagram is just there so that the camera and projector don't have to be physically in the same spot.)
Re:Still can't figure out how it works... (Score:5, Informative)
I guess it might be sort of like a dim flashlight hitting a bicycle reflector at night, you only see the reflector lit up.
That is so cool! (Score:4, Funny)
no Predator Costume demo? (Score:1)
i was expecting more (Score:1)
When are we going to see the day when adolescent males can buy a camouflage suit to sneak into the girls locker room?
Re:i was expecting more (Score:1)
A first in Slashdot history... (Score:2, Informative)
Ignore me... (Score:1)
We're now offtopic but... (Score:1)
Re:We're now offtopic but... (Score:2)
This is maybe halfway there (Score:2, Insightful)
What they need to do is figure out a way to create a piece of clothing which *is* the display, and not merely a reflector or a bluescreen like what they have now. Maybe take this foldable display technology I've read about (mainly geared towards disposable displays), and attach it to fabric. Then make a uniform out of it. Then, you can determine the image behind the person and display it on the uniform.
They're already halfway there, since they can determine what's behind the person and display it on a special colored material. Now all they need is a fabric that can display images, and then they can transmit the background onto the uniform.
Then we're talking about optical camouflage.
Re:This is maybe halfway there (Score:1)
Re:This is maybe halfway there (Score:1)
Re:This is maybe halfway there (Score:1)
Then you need your distributed CPU to maps each receptor to a set of pixels. That will probably require some way to map where each element is in space, then map what would someone see at each angle, then decide what color will blend best for all possible angles. That means compromising (and a lot of CPU power. you don't want your mapping to lag when you run. )
The result wouldn't be total invisibility, but you would look really fuzzy and translucent.
Alternatively, if you only care about one angle and can input that angle easily to your wearable computer, you can get a much better invisibility from that angle only.
All in all, we're pretty far from it, I'd say.
"The results are probably better than you would.." (Score:3, Interesting)
Instead of using projectors though, Q explained that the car was made up of a material that acted like a screen. I guess like a plasma screen, or even that new electronic paper, it may not be that far off.
It would be much better than a projector...hmmm...
Re:"The results are probably better than you would (Score:2)
Re:"The results are probably better than you would (Score:2, Redundant)
Yeah yeah, I'm being mildly sarcastic here. My point being that if you actually made the "Vanish" IRL the result would be more similar to what this guy has than to the the digitally processed movie.
I love the references they made (Score:3, Interesting)
ohhhhh-kaaaay (Score:4, Insightful)
One: depth perception. Because we're watching movies of the demonstration instead of seeing it in person, it looks fairly good. But if you saw this technique in person, with binocular vision, you would be able to tell without any difficulty what you were seeing. If the background is sufficiently cluttered-- like a jungle backdrop-- and if the camouflaged thing is stationary, it might be good enough to fool a passing glance. But then again, so is your average ghilie suit.
Two: parallax. (This has been mentioned upthread already.) The demonstrations are all shot with a stationary camera. If the camera were to move, the illusion would be ruined. I'd imagine from looking at the illustrations that the geometry of the projector, reflector, mirror, and observer are all pretty critical. If the observer takes a step in any direction, the illusion will be broken.
All in all, I can't see how this could ever be practical. The most important flaw is that it's not even remotely adaptive. You have to have a perfect still photograph of your background to project against the mirror. If a bird flies behind the camouflaged object or person, the game is up.
Neat trick, but not very impressive.
Why not a simpler method? (Score:4, Insightful)
Since this scheme is only good for hiding from one watcher at a time, and only from a one-eyed watcher when close, it seems that a simpler method will work.
Hold a rear-projection screen in front of you as a shield. It will have a pole coming toward you, that is long enough so the end of it is behind you when you hold the shield. On this end is a camera looking at the scene behind you.
Now it works without half-silvered mirrors, it is portable (you carry it around), and it works even if the background is moving.
Re:Why not a simpler method? (Score:2)
Re:Why not a simpler method? (Score:2)
We started by saying that the initial design only hid you from one direction. Both designs have the flaw you point out.
But if I were trying to hide a spy plane over Iraq, I might be able to assume that I am hiding from people on the ground, since we have already prevented Iraqi presence to my sides.
Re:Why not a simpler method? (Score:1)
Re:Why not a simpler method? (Score:1)
There also are pictures someplace showing a couple of soldiers with a vehicle on a ridge -- turning on the floodlights on the side of the vehicle blots them out, and they're no longer simple silhouette targets.
Re:Why not a simpler method? (Score:1)
This could be done around a vehicle, with a screen using the same vertical ridges used in children's move-to-animate images. This presents different vertical slices of images in different directions, so different viewpoints would be visible from different directions. Project images from several cameras, using projectors in line with the prism material (or cover the tank with flat screens with prism-covered screens). At a glance, observers would see clumps of trees and scattered bushes where expected -- closer looks would reveal discontinuities and movement would trigger the circuitry around the edge of the eye with flickering movement similar to windblown branches.
But as your tank pops out from behind the trees and the two enemies see each other, you'd like to have two seconds to aim your guns before they decide that they're seeing something...and you hope the infantry you're aiming at isn't surrounding a tank which you haven't seen yet.
(I did not propose painting the tank with reflective material because that tends to reflect directly back at the projector -- that's why roadside reflective paint works so well, because those beads send most of the light from your car right back toward the car. You'd need reflective material which is more selective, and we can assume the experts in the military have already been working on that for twenty years... or paint the tank with reflector and surround it with a half-silvered or polarized mirror which the projector beam can be reflected from.)
what for? (Score:1)