PDA

View Full Version : Invisible Cloak



grewwalk
2005-Jan-06, 07:16 PM
I ran across this article about a type of invisible cloak in Popular Science.
I have a hard time imagining that we could do this already.

http://www.popsci.com/popsci/photogallery/0,21036,1007164_1,00.html

Swift
2005-Jan-06, 07:24 PM
It's real, I saw several pieces (TV, print media, web) about it last year
one web story (http://www.ananova.com/news/story/sm_747591.html?menu=news.latestheadlines)

It is the brainchild of Professor Susumu Tachi who is in the early stage of research he hopes will eventually make camouflaged objects virtually transparent.
second story (http://www.wired.com/news/technology/0,1282,58286,00.html)

In fact, Tachi's "invisibility" coat is a camera trick.

A video camera behind the coat is linked to a projector, which bounces the image off the front of the coat's reflective surface. Because there is no time lag between what's happening behind the wearer and the image cast on the front of the coat, the viewer has the illusion he is seeing straight through the coat.

Gullible Jones
2005-Jan-06, 10:55 PM
Neat. Real-life alpha transparency... :P

(In the photo, the coat is plainly visible, but I bet they could do better.)

Irishman
2005-Jan-06, 11:24 PM
I think you may have missed a comment:

One of the hurdles will be to make the technology small, affordable and viewable with the naked eye, he added... It can't be seen without peering through the projector lens.

That's right, you have to look through a projector lens to see the effect. And currently the effect is about as good as walking in front of a film projector while wearing a white shirt - observers can see the projected image, but it's obvious there's something else there.

That doesn't mean it isn't a cool effect - it is rather intriguing to sync the image to a camera on the backside. But it is a long way from being useful for the suggested applications, or pretty much anything. Because you need the camera to pick up the image on the backside, and the projector, and if the observer is at a different angle than the projector and camera, he won't get the right projected image.

I could possibly see the pilot landing scenario implemented, but why not just add a landing camera to the landing gear and a display on the dash? Just as effective, should be easier to implement, no need to project the image on the pilot's lap.

Maybe this is a step on the long ladder to fully adaptive "transparency camoflage" technology like something out of Star Trek, but it's a baby step on a long ladder.

Maksutov
2005-Jan-07, 04:21 AM
The obvious solution here is to eliminate the projector and screen, and, instead, use a flexible, hi-res plasma display as the "cloak". Software could make real-time adjustments to the image to eliminate the effects of parallax, wrinkles in the cloak, etc., problems.

Richard of Chelmsford
2005-Jan-07, 09:12 AM
When I was about 10 (in 1958), my Dad said to me that the way to make someone invisible would be to find his refractive index.

He wasn't a scientist. :(

A Thousand Pardons
2005-Jan-07, 10:12 AM
When I was about 10 (in 1958), my Dad said to me that the way to make someone invisible would be to find his refractive index.
and, you have to make him transparent somehow :)

that's a neat effect--just drop a glass object inside a bottle of mineral spirits.

Kizarvexis
2005-Jan-08, 12:41 AM
The obvious solution here is to eliminate the projector and screen, and, instead, use a flexible, hi-res plasma display as the "cloak". Software could make real-time adjustments to the image to eliminate the effects of parallax, wrinkles in the cloak, etc., problems.

I think that figuring out how a cuttlefish can do it's 'invisible' thing will go a long way to make something like this work.

Kizarvexis