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Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
Optical camouflage abhinav.ppt
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Optical camouflage abhinav.ppt

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Optical Camouflage

Optical Camouflage

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  • 1. Op ticalCamouflage By: Abhinav Sagar 1DS05EE002
  • 2. Is Harry Potter’s cloak really thatmagical?
  • 3. Could James Bond have aninvisible car?
  • 4. Outline Introduction Emerging Technological Innovation Key Challenges Markets & Application Future Conclusion
  • 5. begin? BEFORE NOW Tokyo ~ Professor Tachi Professor Tachi came up with from the University of Tokyo retro-reflective material which said that he had first had the causes the coat to act as a idea of developing something screen and gives a transparent to make objects invisible in - or invisible - effect. Similarly, 1977. But the image was flat Duke University is using and unrealistic. microwave beam deflection, making it appear almost as if nothing were there at all.
  • 6. WHAT IS OPTICAL CAMOUFLAGE?• Optical camouflage is a hypothetical type of active camouflage currently only in a very primitive stage of development. 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 .• 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.• 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. Prototype examples and proposed designs of optical camouflage devices range back to the late eighties at least, and the concept began to appear in fiction in the late nineties.
  • 7. OPERATION
  • 8. HOW DOES IT WORK?Creating complete optical camouflage across thevisible light spectrum would require a coating or suitcovered in tiny cameras and projectors, programmed togather visual data from a multitude of different anglesand project the gathered images outwards in an equallylarge number of different directions to give the illusion ofinvisibility from all angles. For a surface subject tobending like a flexible suit, a massive amount ofcomputing power and embedded sensors would benecessary to continuously project the correct images inall directions. This would almost certainly requiresophisticated nanotechnology, as our computers,projectors, and cameras are not yet miniaturizedenough to meet these conditions.
  • 9. INVISIBILITY CLOAK• The cloak that enables optical camouflage to work is made from a special material known as retro-reflective material .• 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.
  • 10. • 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
  • 11. WHAT DO WE NEED FOR AN INVISIBILITY CLOAK?• Optical camouflage doesnt work by way of magic. It works by taking advantage of something called augmented-reality technology• Augmented-reality systems add computer-generated information to a users sensory perceptions• Most augmented-reality systems require that users look through a special viewing apparatus to see a real-world scene enhanced with synthesized graphics. They also require a powerful computer. Optical camouflage requires these things, as well, but it also requires several other components• Heres everything needed to make a person appear invisible: • A garment made from retro-reflective material • A video camera • A computer • A projector • A special, half-silvered mirror called a combiner
  • 12. WHAT DO WE NEED FOR AN INVISIBILITY CLOAK?• Optical camouflage doesnt work by way of magic. It works by taking advantage of something called augmented-reality technology• Augmented-reality systems add computer-generated information to a users sensory perceptions• Most augmented-reality systems require that users look through a special viewing apparatus to see a real-world scene enhanced with synthesized graphics. They also require a powerful computer. Optical camouflage requires these things, as well, but it also requires several other components• Heres everything needed to make a person appear invisible: • A garment made from retro-reflective material • A video camera • A computer • A projector • A special, half-silvered mirror called a combiner
  • 13. The Complete System
  • 14. Once a person puts on the cloak made with the retro-reflective material , heres the sequence of events:• A digital video camera captures the scene behind the person wearing the cloak.• The computer processes the captured image and makes the calculations necessary to adjust the still image or video so it will look realistic when it is projected.• The projector receives the enhanced image from the computer and shines the image through a pinhole-sized opening onto the combiner.• The silvered half of the mirror, which is completely reflective, bounces the projected image toward the person wearing the cloak.• The cloak acts like a movie screen, reflecting light directly back to the source, which in this case is the mirror.• Light rays bouncing off of the cloak pass through the transparent part of the mirror and fall on the users eyes. Remember that the light rays bouncing off of the cloak contain the image of the scene that exists behind the person wearing the cloak.• The person wearing the cloak appears invisible because the background scene is being displayed onto the retro-reflective material. At the same time, light rays from the rest of the world are allowed reach the users eye, making it seem as if an invisible person exists in an otherwise normal-looking world.
  • 15. Difference Between Invisibility CloaksTokyo Method: Duke Method:1. Uses camera to capture 1. Rely on product called picture “metamaterial”2. Processes it to a 2. The metamaterial will computer influence the electromagnetic waves around it creating a3. Projected onto the “warped effect.” reflective cloak 3. This creates the invisible effect
  • 16. Metamaterial? Meta in Greek means “beyond”… Therefore the term “metamaterial” means to create something that doesnt exist in nature. Metamaterials,(MTMs) are a class of artificially engineered composite materials having extraordinary electromagnetic properties .
  • 17. A metamaterialpossesses… negative permittivity (ε < 0) and/or negative permeability (μ < 0) negative refractive index (n < 0)
  • 18. n = ± εµ OR n=± ( −ε ) ( −µ ) ABSORPTION +ε, -μ +ε, +μ POSITIVE REFRACTION NEGATIVE -ε, -μ -ε, +μ ABSORPTIONREFRACTION!!
  • 19. Where are we today?(1) Recent developments by Professor John Pendry have shown that… certain configurations of metal yield unique responses to electric and magnetic fields. This is the first time a substance with clean negative permeability has been found.
  • 20. Where are we today?(2) Pendrys initial idea was that metallic wires aligned along propagation direction could provide a metamaterial with negative permittivity (ε<0). Pendry demonstrated that an open ring with its axis along the propagation direction could provide a negative permeability(μ<0).
  • 21. Where are w e today?(3)This ‘C shaped’ ring is known as asplit-ring resonator.
  • 22. SRR s SRRs are pairs of concentric annular rings with splits in them at opposite ends. They are made of nonmagnetic metal like copper and have small gap between them. These tiny ring structures are assembled in a giant crystalline-like lattice.
  • 23. How do metamaterials work?(1) The design of SRR components looks back to the first principles of electronics--simple R-C-L circuits. The electromagnetic waves passing through arrays of tiny resistors,capacitors, inductors and other dielectric materials positioned in free space.
  • 24. How do metamaterials work? (2) The SRR acts as the "magnetic atom”. The ring and wire units act as atomic dipoles… the wire acts as a ferroelectric atom the ring acts as an inductor L the open section acts as a capacitor C the ring as a whole therefore acts as a LC circuit.
  • 25. How do metamaterials work? (3) When the electromagnetic field passes through the ring, an induced current is created and the generated field is perpendicular to the magnetic field of the light. • The magnetic resonance results in a negative permeability and index of refraction.
  • 26. So now what…?Now, in an SRR structure, we have sub-micronshapes of a metal, which acts an electrical conductor. When this sees the oscillating electric field due to an incident light wave, the free electrons in the metal wiggle around in a collective oscillation called a plasmon mode. These plasmons generate both electric and magnetic fields,whose behavior depends very sensitively on the size and shape of the object in which the electrons are sloshing around in.
  • 27. This is what…􀁺 Due to its negative refractive index􀁺 the net effect is of a wave propagating in the reverse direction of the light and energy flow. 􀁺 These tiny structures within the rings divert the incoming waves around the object preventing both reflection and absorption. 􀁺 Meeting up on the other side as if nothing were there.
  • 28. Types of Refraction NORMAL: METAMATERIAL: POSITIVE NEGATIVE TRANSPARENT MATERIAL VIRTUAL IMAGE REAL IMAGE
  • 29. We can use metamaterials as aninvisibility cloak LIGHT SOURCE LIGHT RAYS OBJECT METAMATERIAL
  • 30. Does the object need to beinside the cloak? CLOAKING LIMIT LETS LOOK AT THE RADIATION OBJECT BACKGROUND FIELD “NORMAL” UN-DISTURBED MATERIAL METAMATERIAL METAMATERIAL COATED CYLINDER
  • 31. What does an invisibility cloaklook like?
  • 32. T he Market Skillfully mixing the real world and the artificial world to make your life and work convenient• Four markets Medical Aviation Automotive Home Improvement
  • 33. Medical  Buyers: Hospitals  Users: patients and doctors  Function:  Improve psychological well being of patients  Improve the efficiency and precision of surgical procedures  Market: 7000 hospitals nationwide
  • 34. Application #1: Medical •Patient-centered design rooms •Improve the psychological well-being of people in closed environments
  • 35. Application #1: Medical  Surgery  Doctors could use the “invisibility” to see through their hands and tools to make the underlying tissue more “visible.”
  • 36. Aviation & Automotive  Buyers: Car and airplane manufacturers  Users: pilots and car drivers  Function:  More visibility when automating vehicles and airplanes  Increase in safety  Luxury feature  Market: privately owned cars 7 million manufactured cars 2 airplane manufacturers
  • 37. Application #2:Aviation Pilots could use optical camouflage to make cockpit floors transparent They can see through the cockpit floors to the runway and landing gear.
  • 38. Application #3: Automotive  Cars  A transparent rear hatch or tailgate would make it easy to know when to stop.
  • 39. Home Improvement Buyers: Home owners and construction companies Users: Home owners Function:  Improve interior designing  Allow spacious looking rooms  Increase in security  Luxury feature Market: 73.8 million homeowners in the United States
  • 40. Improvement  More fanciful application: Transparent ceiling to provide a view of the outside  Transparent door replaces peep hole
  • 41. Other Applications: Solar panels coated with metamaterials would be much more efficient than those coated with conventional black paint, which reflects 5 percent or more of incoming light. Telescopes lined with metamaterials would sop up random flecks of incident light, providing a blacker background to detect faint stars. In military,invisibility phenomena could be used to hide tanks, bunkers, submarines or make the warships invisible to radars.
  • 42. Limitations forMetamaterials The invisibility effect would work only for a specific range of wavelengths. It operates only over a narrow range of frequencies . The cloak could be made to cover a volume of any shape, but you cant flap your cloak. Moving the material around would spoil the effect.
  • 43. CONCLUSION• Now all of us have had a small tour of the interesting world of optical camouflage.• A lot of interesting thing have been done and already we have seen that anyone can be almost invisible with this technology.• But the future promises us a lot more.• Research work is going on and soon we will have even more astonishing results.

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