The Amazing 'Invisible' Coat

Kazutoshi Obana's gray, hooded coat doesn't just keep him dry in a downpour. It can also make him seem invisible.

On a clear day at Tokyo University, Obana stands outside and dons the coat. Viewed through a special projector lens, the people behind him appear as images in a fuzzy, greenish tint on his coat — as if he were see-through.

"This is a kind of augmented reality," said Susumu Tachi, a Tokyo University professor of computer science and physics, during the recent demonstration of his invention.

Tachi, who is also the founding head of the Virtual Reality Society of Japan, designed the coat using microscopic reflectors which act like a movie screen. They can even reflect images when the material is wrinkled.

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.

Philip Moynihan, a scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif., said the idea has broad applications in medical surgery, construction and aviation, although it remains in an "embryonic stage."

"I think it's got tremendous potential, once it's refined," Moynihan said. One of the hurdles will be to make the technology small, affordable and viewable with the naked eye, he added.

Tachi acknowledges that the technology still requires too many parts: It can't be seen without peering through the projector lens. Also, an affordable product is years away.

Moynihan said the U.S. military has studied similar technology as futuristic camouflage for years. In the mid-1990s, he and another scientist conceived of "adaptive camouflage" images for stealth or armored vehicles that could help them blend in with any type of surroundings.

"We wanted something that could adapt to changing light conditions because present camouflage can be spotted at certain angles and can be seen in infrared lighting," Moynihan said. They never made a prototype and abandoned the project when their funding ran out.

Still, Moynihan thinks adaptive camouflage technology could one day allow soldiers to take a picture of their surroundings and digitally transfer the image using a hand-held computer to the surface of their clothing.

Others, such as Richard Schowengerdt, a military researcher in Lakewood, Calf., are looking into the technology as a possible way of hiding sprawling top-secret facilities. Schowengerdt's "Project Chameleo" is examining modified versions that might emit or absorb energy to minimize radar or sonar detection.

But nonmilitary applications are Tachi's primary goal.

In the future, surgeons may not need to make large incisions if they wear gloves that project what's on the inside of a patient using a CAT scan or MRI data, Tachi said.

Another idea is to coat the inside of an airplane cockpit with micro reflectors. Hard landings would be a thing of the past if pilots could gauge how far they are above the ground just by looking at an image of the outside terrain projected on the floor, he said.