INNOVATIONS IN ELECTRO-OPTICAL CAMOUFLAGE PROJECT CHAMELEO (moved from ATSNN)

Advances in sensor and display technology have now risen to the point where the dream of invisibility that has long inspired fiction and film can soon become a reality and bring into clear focus the long neglected art of visual deception. The lines between fact and fiction in the world of invisibility have become intertwined and blurred to such an extent that the possible is often seen as the impossible and vice versa. The epic H.G. Wells novel, The Invisible Man, in 1897, along with the original movie in 1933, was followed by later film releases; likewise, The Shadow was a most popular radio show from 1936 until 1954 and was later made into movies. Much later in the popular 1980's television Star Trek series Klingon warships often surprised Captain Kirk and crew when they suddenly �decloaked� near their starship. Also, supposed real life mysteries like �The Philadelphia Experiment� where the US Navy is alleged to have made an entire battleship disappear in the harbor, in full view of hundreds of witnesses, by using some type of radio frequency waves, have further fueled the mystery of invisibility. In 1987 Arnold Schwarzenegger�s role in The Predator was pitted against an alien creature exhibiting a chameleonic ability to blend into the background, obviously a very advanced form of adaptive camouflage. However, the creature interestingly had certain vulnerabilites well known to physicists and optics engineers involving view angle and range dependency wherein the jungle appeared to be moving as the creature closed in on his victim. In the 1992 movie Memoirs of an Invisible Man, Chevy Chase suffered from exposure to a bizarre form of radiation and disappeared from ordinary view and was chased by Federal agents using infrared sensors. However, instead of invisibility resulting from mind tricks, radiation, chemical exposure, or futuristic Klingon cloaking systems, modern technology now has access to a wide array of sophisticated sensors and displays that can truly provide illusions of transparency of men, vehicles, and buildings.

The need for a truly adaptive camouflage arises out of the present state of the art of military camouflage in the visible light spectrum as present methods are generally limited to painting, coloring, and/or contour shaping to allow an object to better blend in with the background. Such methods do little to conceal moving objects as their appearance must be constantly controlled from the viewpoint of the observer to blend in with the changing background. During World War II there was military interest in a primitive form of experimentation with active camouflage born with Project Yehudi wherein bright lights were placed on the leading edge of aircraft to confuse the enemy facing an early morning horizon or an otherwise bright background. However, such experiments were not brought to fruition before the war ended. In the early 1990s the military again experimented with electrochromatic paints on aircraft but little has become available in the public sector concerning the actual results of developing and testing this technology. In 1993 adaptive electro-optical camouflage as manifested in Project Chameleo was introduced at the Association of Old Crows Fiestacrow Symposium in San Antonio but the feasibility of the concept was met with considerable skepticism by the military industrial complex present at this meeting. This was followed in 1999 by a paper presented at the American Physical Society Centennial in Atlanta, also with little fanfare and only a modicum of interest from the scientific community. In 2000 JPL contracted for some studies relative to adaptive camouflage and active-pixel sensor/display systems that would create illusions of transparency that seemed to arouse more interest and credibility in the concept. In 2002 the James Bond thriller, Die Another Day, featured a high tech automobile utilizing �adaptive camouflage.� A rather spectacular demonstration by Professor Susumu Tachi of Tokyo University in 2003 attained world-wide notoriety when he ignored all prior art and claimed to herald in for the first time the era of adaptive camouflage. Nevertheless, in spite of all of this publicity, little has been done to utilize modern advancements in opto-electronics, computers, or microminiature components to actively camouflage objects.

The need for the energy saving aspect of this system arises out of the present state-of-the-art of architecture and security systems to house and protect national resources. Conventional construction materials such as wood, steel, or concrete do not lend themselves to an adaptive appearance nor to rapid and efficient emission or thermal control. Also, present security system schemes are patently overt with high profile resources seen bristling with barbed wire fences, video cameras, and armed personnel, drawing immediate attention to the value of these resources. In addition, there has been little or no advancement in environmental enhancement of office or other working spaces that are currently fully realizable using off-the-shelf displays, cameras, and desktop computers to project outside or artificial scenes on the walls.

The parametrical design considerations relative to resolution, view angle and range dependency, parallax, tilt angle, and perspective were treated in depth by Schowengerdt and Schweizer and will only be summarized herein. The observer�s resolution is a function of wavelength divided by distance. The minimum range of an object necessary to escape detection by an observer who moves laterally a certain distance depends upon the resolving power of the optics available to the observer and the distance of the concealed object from the backgroud. As an example, if an unequipped observer rocks his head laterally by only one foot, he will be unable to distinguish an electro-optically camouflaged object from a background ten feet behind it, provided that the concealed object is at a range of more than 180 feet from the observer. If the background object is 20 feet behind the object, then the range from the concealed object to the observer must be at least 250 feet. On the other hand, if the observer has a ten inch telescope, then the minimum ranges become 2,200 and 3,200 feet respectively which, however, are still quite close on the battlefield.

The advanced state of present digital computer imagery using thin high definition liquid crystal display (LCD) panels, plasma displays, or arrays of active-pixel sensor/display units now allows the presentation of extremely realistic scenes on flat, curved, or even flexible shields, thus causing cloaking technology to become a reality at a reasonable cost. Field commanders in the 21st Century have access to a broad array of advanced imagery sensing, projection, and deception systems in the visual light spectrum. Even a few seconds of false information or diversionary scene provided to the enemy could be proven to be of great value in the heat of combat. The development of rugged composite nonspecular displays can overcome the problems of fragility and glint characterizing current off-the-shelf cathode ray tube, liquid crystal, plasma, or other displays. Another important feature of advanced display technology is the possibility of varying the reflection parameters of thin film displays. This allows the energy levels within a system or structure to be effectively controlled by using the electro-optical shutoff ability of emissive or absorptive display pixels. Integration of energy sources with screen display cells and sensors can also solve the problem of temperature stabilization within the system and reduce the infrared signature. This could prove to be of special value in concealing aircraft, vehicles, or weapons in shelters that would blend in with the surrounding terrain or vegetation. Also, tailored applications using monochrome patterns or artificial images in lieu of the actual background have also proven to be advantageous in certain scenarios. In addition, stealth techniques based upon application of various types of absorptive materials and planform shaping may be employed to minimize radar and sonar detection. Employment of advanced electro-optical camouflage in the 21st century will prove to be a valuable resource in defense, border patrol, anti-terrorism, and security operations. In the light of current urban warfare scenarios where insurgents or terrorists use basically the naked eye and rifles, the feasibility of effective electro-optical camouflage becomes even more realizable. At the Army Natick Soldier Center (NSC) officials have envisioned that their Future Warrior�s suit will contain �Sensors that �read� the environment and effect a chameleonic change in the uniform camouflage/color� with the ultimate effect of blending into the background.



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