What if it was possible to walk down the street without anyone knowing you were there? The possibilities would be endless. It is an idea that grabs the minds of science fiction enthusiasts and military think tanks alike. With the recent work by University of Tokyo Engineering Professor Susumu Tachi may make that all possible some time in the not too distant future.
The latest attempt at an invisible cloak is a very advanced optical illusion. It begins with a camera placed behind the subject to be cloaked. The camera is linked to an infrared projector, which beams the image onto the subject wearing the coat. While the coat is nothing unusual, the material it is made of makes it all possible.
The special material converts the infrared wavelength to the visible spectrum, thus producing an image despite no visible light flooding the subject like a projector in a movie theater. The image is a perfect replica of the photographed image, but it has an eerie green glow that draws your suspicion. And since the video camera is taking a real time picture of the background, the viewer believes there is nothing there.
According to CNN.com, Dr. Tachi expects the technology to have far ranging implications in fields ranging from medicine to aviation to military applications. By adding the reflective material to surgical gloves and projecting an image of an MRI or CAT scan, the doctor could simply see what in under the skin and bone by placing his hand over the area of interest.
CAT scans and MRIs scan inside the body. According to Science Net, MRI scanners do not involve x-rays, but work on the principle of atomic nuclear-spin resonance. They use massive magnetic fields, so far thought to be harmless to the body, and radio signals to deflect atoms and cause them to emit tiny signals that can be localised.
These produce computer-constructed images of amazing detail. MRI scanners can resolve detail in the brain and spinal cord so fine that the individual plaques in multiple sclerosis for instance can be seen.
Both devices are somwhat similar, but have several important differences. CAT scans use X-rays to scan the body whereas MRI uses a high magnetic field and radio waves. Both techniques are capable of imaging both bone and soft tissue within the body and for imaging it is important to be able to distinguish one soft tissue from another
By allowing the interior of the body to be visible to surgeons without large incisions, patient recovery time would be greatly reduced.
The most dangerous part of any flight is of course the landing. If the interior of the cockpit was coated with the reflective material with external cameras linked to the projector, a pilot would be able to visually gauge the height off the ground when attempting a difficult landing. With added visibility, flights would become safer and landings less bumpy.
In its current beginning state, this technology has several drawbacks. Most notably is the complexity of the device. The unit is made up of four separate parts: a camera, a projector, a screen, and a special viewing filter. While the camera and screen could be combined and the technology could be improved so the viewing filter could be removed, combining the projector and screen together would be rather difficult. Current LCD and plasma displays are more promising than the projector method.
Projection technology on a whole also lacks quite a bit when applied to a real world environment. In a closed setting where ambient light, dust, and weather can be controlled, projectors are easy and effective for imposing an image on a surface.
How ever, at odd view angles, or in the presence of a strong ambient light source, like the sun, projection becomes fruitless. The image is washed out and lacks any depth. As a military application, weather and dust adversely affect the projection process. If anything blocks the projector, the camouflaging image is distorted or non-existent.
Lastly, as militaries around the world become more technologically integrated, the threat of infrared detection increases. This is probably the most striking draw back of the projection system.
Not only does this technology not block the infrared signature of the human body, but it generates its own thermal signature. Because Tachi device uses an infrared projector to transmit the image to the screen, thus the device would actually illuminate troops in the field if the enemy had infrared goggles. The use of this device would achieve the exact opposite of the intended goal.
While this recent development has received a fair amount of media attention, it is not the first attempt to create an adaptive camouflage technology. In the mid-1990's, the military funded several attempts to create a similar technology.
The most successful was "Project Chameleo." While "Project Chameleo" was designed for hiding facilities and much larger objects than a human body, it used similar projection technology.
Because it was housing a far larger object, the final design of "Project Chameleo" placed the projector inside the screen, much like a projection screen television. "Chameleo" also had many of the same drawbacks as the current Tachi device. In daylight the image becomes washed out and fairly ineffective and at night it is useless altogether.
Stealth technologies have long been a driving force in military technologies. According to popular conspiracy theories, during the Second World War the Navy attempted, unsuccessfully, to create a stealth mode for ships using varying magnetic fields. Since the 1950's, the Air Force has been developing various stealth technologies.
From the first stealth aircraft, the SR-71 "Blackbird," to the current FA-117 Stealth Fighters and B-2 Stealth Bombers, stealth has been a key component to modern air warfare.
And while heavy equipment has been getting steady improvement in stealth, the basic infantryman's camouflage has changed little since in was first employed. Recently, the Army switched to new camouflage that has a more digitized appearance.
But the military is also attempting to develop "chameleonic camouflage," an active camouflage that actually changes with the surroundings. This gives a soldier's uniform far more versatility. In Iraq, soldiers have to work in three major environments: desert, vegetation, and urban landscape. An active camouflage would allow a soldier to be well hidden in all three, even while wearing the same uniform.
With continued work in this field striving for both commercial and military applications, we could someday live in a world similar to what we saw in movies like Star Trek and Predator.
