31-12-2010, 12:33 PM
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INTRODUCTION
Invisibility has been on humanity's wish list at least since AmonRa, a deity who could disappear and reappear at will, joined the Egyptian pantheon in 2008 BC. With recent advances in optics and computing and with the advent of flexible electronics such as a flexible liquid crystal display, that would allow the background image to be displayed on the material itself, however, this elusive goal is no longer purely imaginary.
In 2003, three professors at University of Tokyo — Susumu Tachi, Masahi koInami and Naoki Kawakami — created a prototypical camouflage system in which a video camera takes a shot of the background and displays it on the cloth using an external projector. They can even reflect images when the material is wrinkled. The same year Time magazine named it the coolest invention of 2003. It is an interesting application of optical camouflage and is called the Invisibility Cloak. Through the clever application of some dirt-cheap technology, the Japanese inventor has brought personal invisibility a step closer to reality
Their prototype uses an external camera placed behind the cloaked object tore cord a scene, which it then transmits to a computer for image processing. The key development of the cloak, however, was the development of a new material called retro reflectum. Professor Tachi says that this material allows you to see a three dimension alimage. The computer feeds the image into an external projector which projects the image onto a person wearing a special retro reflective coat. This can lead to different results depending on the quality of the camera, the projector, and the coat, but by the latenineties, convincing illusions were created. That was only one invention created in this field and researches are still being carried out in order to implement it using nanotechnology.
OPTICAL CAMOUFLAGE – AN OVERVIEW
Optical camouflage is a kind of active camouflage which completely envelopes the wearer. It displays an image of the scene on the side opposite the viewer on it, so that the viewer can "see through" the wearer, rendering the wearer invisible. The idea is relatively straightforward: to create the illusion of invisibility by covering an object with something that projects the scene directly behind that object. If you project background image onto the masked object, you can observe the masked object just as if it were virtually transparent.
Optical camouflage can be applied for a real scene. In the case of a real scene, a photograph of the scene is taken from the operator’s viewpoint, and this photograph is projected to exactly the same place as the original. Actually, applying HMP-based optical camouflage to a real scene requires image-based rendering techniques.
As for camouflage, it means to blend with the surroundings. Camouflage is the method which allows an otherwise visible organism or object to remain indiscernible from the surrounding environment. Examples include a tiger's stripes and the battledress of a modern soldier. Camouflage is a form of deception. The word camouflage comes from the French word 'camoufler' meaning 'to disguise'. The camouflage technique of disguise is not as common as coloration, but can be found throughout nature as well.
Animals may disguise themselves as something uninteresting in the hopes that their predators will ignore them or as something dangerous so that predators will avoid them. And so had humans the desire to disguise themselves just as some animals could do. 19th century armies tended to use bright colors and bold, impressive designs. These were intended to daunt the enemy, attract recruits, foster unit cohesion, or allow easier identification of units in the fog of war. The transfer of camouflage patterns from battle to exclusively civilian uses is a recent phenomenon. The concept of camouflage - to conceal and distort shapes- is also a popular artistic tool.
ADVANTAGES----
Optical Camouflage can be used on surgical globes or equipments so they don’t block surgeon’s view during delicate operations.
In aviation, cockpit floors could become 'invisible' to assist pilots during landing.
DISADVANTAGES---
The weak point of this technique is that the observer needs to look through a half-mirror. The current system needs a half mirror and projectors, which were fixed on the ground.
TECHNOLOGY FOCUS
Although optical is a term that technically refers to all forms of light, most proposed forms of optical camouflage would only provide invisibility in the visible portion of the spectrum. Optics (appearance or look in ancient Greek) is a branch of physics that describes the behavior and properties of light and the interaction of light with matter. Optics explains optical phenomena. The pure science aspects of the field are often called optical science or optical physics.
This technology is currently only in a very primitive stage of development. Creating complete optical camouflage across the visible light spectrum would require a coating or suit covered in tiny cameras and projectors, programmed to gather visual data from a multitude of different angles and project the gathered images outwards in an equally large number of different directions to give the illusion of invisibility from all angles.
Sophisticated target-tracking software could ensure that the majority of computing power is focused on projecting false images in those directions where observers are most likely to be present, creating the most realistic illusion possible. This would likely require Phase Array Optics, which would project light of a specific amplitude and phase and therefore provide even greater levels of invisibility.
ALTERED REALITY
Optical camouflage doesn't work by way of magic. It works by taking
advantage of something called augmented-reality technology -- a type of technology that was first pioneered in the 1960s by Ivan Sutherland and his students at Harvard University and the University of Utah. Augmented reality (AR) is a field of computer research which deals with the combination of real world and computer generated data.
