Adaptive camouflage

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Introduction
Active camouflage technology allows object to blend into surroundings by altering, appearance, color, luminance , reflective properties, prevent shadows and provides perfect concealment from virtual detection. Ideally avoids detection by human eye and optical sensors. Active camouflage provides concealment in two important ways: makes the camouflaged object appear not merely similar to its surroundings, but effectively invisible through the use of mimicry; secondly, active camouflage changes the appearance of the object as changes occur in the background. Ideally, active camouflage mimics nearby objects as well as objects as distant as the horizon.


.Light surface reflectivity
A cloak is used to shield the object to be hidden and a projector projects the image behind the object to create the illusion of transparency. The cloak that enables optical camouflage to work is made from a special material known a retro- reflective material. A retro-reflective material is covered with thousands of small beads. When light strikes one of these beads, the light rays bounce back exactly in the same direction from which they came.



TV & Camera method
A typical adaptive camouflage system would likely include a network of flexible electronic flat-panel display units arrayed in the form of a blanket that would cover all observable surfaces of an object that one seeks to cloak. Each display panel would contain an active-pixel sensor (APS) that would look outward from the panel through an aperture that would occupy only a small fraction of the area of the panel. The blanket would also contain a wiring harness that would include a cross-connected fiber-optic network, through which the image from each APS would be transferred to a complementary display panel on the opposite side of the cloaked object.




a. Ccd technology
The sensor is able to transport the built up charge across itself without compromising the image quality. The first row of the array is read into an output register, which in turn is fed into an amplifier and an analog to digital converter. After the first row has been read, it is dumped from the read out register and the next row of the array is read into the register. The charges of each row are ‘coupled’ so as each row moves down and out, the successive rows follow in turn. The digital data is then stored as a file that can be viewed and manipulated.

b. CMOS sensors
CMOS sensors are cut from a CMOS wafer which is cheaper to produce then a CCD wafer, provides less power consumption, and also allow for more involved circuitry along side of the photosite array. Each photosite in the CMOS sensor has three or more transistors which has its benefits and its draw backs. The transistors allow for processing to be done right at the photosite, and each pixel/photosite can be accessed independently. Because the transistors occupy space on the array, some of the incoming light hits the transistors and not the photosites, which leads to picture noise. CMOS sensors also function at a very low gain which may contribute to noise.