02-02-2013, 03:02 PM
OPTICAL CAMOUFLAGE
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Abstract:
The concept of optical camouflage is explained as: to create the illusion of invisibility by covering an object with something that projects the scene directly behind that object. Optical Camouflage uses the Retro-reflective Projection Technology, a projection-based augmented–reality system composed of a projector with a small iris and a retro-reflective screen. The object that needs to be made transparent is painted or covered with retro-reflective material. Then a projector projects the background image on it making the masking object virtually transparent. Over all system needs the following components like a garment made from highly reflective material, a video camera ,a projector and a special half silvered mirror called a combiner. This system was produced with the primary view in mind of concealing stationary or moving objects such as men, vehicles, or aircraft from view and it has practical military, law enforcement and various security applications.
Introduction
What is Term optical:
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.
What is term camouflage:
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 thehopes that their predators will ignore them or as something dangerous so that predators will avoid them. Camouflage is a form of deception. And so had humans the desire to disguise themselves just as some animals could do.
What is optical camouflage?
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.
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. At present, most AR research is concerned with the use of live video imagery which is digitally processed and"augmented" by the addition of computer generated graphics. Advanced research includes the use of motion tracking data, fiducial marker recognition using machine vision, and the construction of controlled environments containing any number of sensors and actuators. The real world and a totally virtual environment are at the two ends of this continuum with the middle region called Mixed Reality. Augmented reality lies near the real world end of the line with the predominate perception being the real world augmented by computer generated data. Augmented virtuality is a term created by Milgram (Milgram and Kishino 1994; Milgram, Takemura et al. 1994) to identify systems which are mostly synthetic with some real world imagery added such as texture mapping video onto virtual objects. This is a distinction that will fade as the technology improves and the virtual elements in the scene become less distinguishable from the real ones.
How it works:
For using optical camouflage, the following steps are to be followed –
1) The person who wants to be invisible (let's call her Person A) dons a garment that resembles a hooded raincoat. The garment is made of a special material that we'll examine more closely in a moment.
2) An observer (Person B) stands before Person A at a specific location. At that location, instead of seeing Person A wearing a hooded raincoat, Person B sees right through the cloak, making Person A appear to be invisible.
Video Camera
Professional video camera (often called a Television camera even though the use has spread) is a high-end device for recording electronic moving images (as opposed to a movie camera that records the images on film). Originally developed for use in television studios, they are now commonly used for corporate and educational videos, music videos, direct-to-video movies, etc. Less advanced video cameras used by consumers are often referred to as camcorders. There are two types of professional video cameras: High end portable, recording cameras (which are, confusingly, called camcorders too) used for
ENG image acquisition, and studio cameras which lack the recording capability of a camcorder, and are often fixed on studio pedestals. It is common for professional cameras to split the incoming light into the three primary colors that humans are able to see, feeding each color into a separate pickup tube (in older cameras) or charge-coupled device (CCD). Some high-end consumer cameras also do this, producing a higher-quality image than is normally possible with just a single video pickup.
Conclusion:
The current system needs a half-mirror and projectors, which were fixed on the ground. Also one of the weak point of this system is that the observer needs to look through a half mirror i.e. through the combiner. We can concluded in the following way.