Department Of Electronics And Communications (ECE)
An Advanced Seminar on…
Thandra Paparaya Institute Of Science & Technology, Komatapalli,
Imagination is impetus to Creativity, creativity defines Art, art redefines Perfection and Science aims at understanding this perfection by developing Technologies. One such Technology which came into existence is OPTICAL CAMOUFLAGE. The word camouflage comes from the French word 'camoufler' meaning 'to disguise'. Optical is the term that refers to all forms of light and optical camouflage provide invisibility in the visible portion of the spectrum.camouflage is a method that allows an object to remain indiscernible from the surrounding environment.The principle of optical camouflage uses RPT Technology.RPT means Retro Reflective Projection technology.It is a projection based augmented reality system composed of projector with small iris and retro reflective screen.optical camouflage requires a cloak,video camera,a computer,a projecter,a combiner which are used in the procedure of making one invisible.The real time applications is in hospitals,pilots and cars etc. KEYWORDS:
Cloaks, optical camouflage, mutual existence, augmented reality system.
A retro-reflective material is covered with thousands and 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. To understand why this is unique, look at how light reflects off of other types of surfaces. A rough surface creates a diffused reflection because the incident (incoming) light rays get scattered in many different directions. A perfectly smooth surface, like that of a mirror, creates what is known as a specular reflection -- a reflection in which incident light rays and reflected light rays form the exact same angle with the mirror surface. In retro-reflection, the glass beads act like prisms, bending the light rays by a process known as refraction. This causes the reflected light rays to travel back along the same path as the incident light rays. The result: An observer situated at the light source receives more of the reflected light and therefore sees a brighter reflection.
Retro-reflective materials are actually quite common. Traffic signs, road markers and bicycle reflectors all take advantage of retro-reflection to be more visible to people driving at night. Movie screens used in most modern commercial theaters also take advantage of this material because it allows for high brilliance under dark conditions. In optical camouflage, the use of retro-reflective material is critical because it can be seen from far away and outside in bright sunlight -- two requirements for the illusion of invisibility.
The retro-reflective garment doesn't actually make a person invisible -- in fact, it's perfectly opaque. What the garment does is create an illusion of invisibility by acting like a movie screen onto which an image from the background is projected. Capturing the background image requires a video camera, which sits behind the person wearing the cloak. The video from the camera must be in a digital format so it can be sent to a computer for processing.
All augmented-reality systems rely on powerful computers to synthesize graphics and then superimpose them on a real-world image. For optical camouflage to work, the hardware/software combo must take the captured image from the video camera, calculate the appropriate perspective to simulate reality and...