Underwater Creature Camouflage

CLAMOUFAGE


NOUN:
1.An outward semblance that misrepresents the true nature of something
2.Fabric dyed with splotches of green and brown and black and tan; intended to make the wearer of a garment made of this fabric hard to distinguish from the background
3.Device or stratagem for concealment or deceit
4.The act of concealing the identity of something by modifying its appearance

VERB
Disguise by camouflaging; exploit the natural surroundings to disguise something
"The troops camouflaged themselves before they went into enemy territory"

Pics of invisible cloak and arrangement

Invisible cloak

Man can ever be invisible?



INVISIBILITY CLOAKS



AND



OPTICAL CAMOUFLAGE TECHNOLOGY



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 “ INVISIBILITY CLOAKS AND OPTICAL CAMOUFLAGE TECHNOLOGY ”. Optical camouflage works by taking advantage of something called augmented-reality technology. Augmented-reality systems add computer-generated information to a user's sensory perceptions. In addition to Augmented-reality systems, Optical camouflage requires a Cloak, a Video camera, a Computer, a Projector, a Combiner which are used in the procedure of making one Invisible.Advancements in this Technology is minimizing its sophistication procedure. Real time applications of this technology is in hospitals, pilots, cars and also introduced a new concept of mutual telexistence

Optical camouflage delivers a similar experience to Harry Potter's invisibility cloak, but using it requires a slightly more complicated arrangement.
First, 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. Next, 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. The photograph on the right below shows you what Person B would see. If Person B were viewing from a slightly different location, he would simply see Person A wearing a silver garment . Still, despite its limitations, this is a cool piece of technology. Not only that, but it's also a technology that's been around for a while.

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. You can read more about augmented reality in How Augmented Reality Will Work, but a quick recap will be helpful here.

Augmented-reality systems add computer-generated information to a user's sensory perceptions. Imagine, for example, that you're walking down a city street. As you gaze at sites along the way, additional information appears to enhance and enrich your normal view. Perhaps it's the day's specials at a restaurant or the show times at a theater or the bus schedule at the station. What's critical to understand here is that augmented reality is not the same as virtual reality. While virtual reality aims to replace the world, augmented reality merely tries to supplement it with additional, helpful content

Augmented-reality displays overlay computer-generated graphics onto the real world.
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. Here's everything needed to make a person appear invisible:
A garment made from highly reflective material
A video camera
A computer
A projector
A special, half-silvered mirror called a combiner
Let's look at each of these components in greater detail.

The Cloak:
The cloak that enables optical camouflage to work is made from a special material known as retro-reflective material.

Invisibility cloak:
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 seculars 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 Video Camera and Computer:
Video Camera:
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.

Computer:
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 transform the captured image into the image that will be projected onto the retro-reflective material.

The Projector and Combiner:
The Projector:
The modified image produced by the computer must be shone onto the garment, which acts like a movie screen. A projector accomplishes this task by shining a light beam through an opening controlled by a device called an iris diaphragm. An iris diaphragm is made of thin, opaque plates, and turning a ring changes the diameter of the central opening. For optical camouflage to work properly, this opening must be the size of a pinhole. Why? This ensures a larger depth of field so that the screen (in this case the cloak) can be located any distance from the projector.
The Combiner:
The system requires a special mirror to both reflect the projected image toward the cloak and to let light rays bouncing off the cloak return to the user's eye. This special mirror is called a beam splitter, or a combiner -- a half-silvered mirror that both reflects light (the silvered half) and transmits light (the transparent half). If properly positioned in front of the user's eye, the combiner allows the user to perceive both the image enhanced by the computer and light from the surrounding world. This is critical because the computer-generated image and the real-world scene must be fully integrated for the illusion of invisibility to seem realistic. The user has to look through a peephole in this mirror to see the augmented reality.

The Complete System:
Now let's put all of these components together to see how the invisibility cloak appears to make a person transparent. The diagram below shows the typical arrangement of all of the various devices and pieces of equipment.

Once a person puts on the cloak made with the retro-reflective material, here's the sequence of events:
A digital video camera captures the scene behind the person wearing the cloak.
1. 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.
2. The projector receives the enhanced image from the computer and shines the image through a pinhole-sized opening onto the combiner.
3. The silvered half of the mirror, which is completely reflective, bounces the projected image toward the person wearing the cloak.
4. The cloak acts like a movie screen, reflecting light directly back to the source, which in this case is the mirror.
5. Light rays bouncing off of the cloak pass through the transparent part of the mirror and fall on the user's 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.
6. 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 user's eye, making it seem as if an invisible person exists in an otherwise normal-looking world.

Head-mounted Displays:
Of course, making the observer stand behind a stationary combiner is not very pragmatic -- no augmented-reality system would be of much practical use if the user had to stand in a fixed location. That's why most systems require that the user carry the computer on his or her person, either in a backpack or clipped on the hip. It's also why most systems take advantage of head-mounted displays, or HMDs, which assemble the combiner and optics in a wearable device.
There are two types of HMDs: optical see-through displays and video see-through displays. Optical see-through displays look like high-tech goggles, sort of like the goggles Cyclops wears in the X-Men comic books and movies. These goggles provide a display and optics for each eye, so the user sees the augmented reality in stereo. Video see-through displays, on the other hand, use video-mixing technology to combine the image from a head-worn camera with computer-generated graphics.

In this arrangement, video of the real world is mixed with synthesized graphics and then presented on a liquid-crystal display. The great advantage of video see-through displays is that virtual objects can fully obscure real-world objects and vice versa.
The scientists who have developed optical-camouflage technology are currently perfecting a variation of a video see-through display that brings together all of the components necessary to make the invisibility cloak work.

They call their apparatus a head-mounted projector (HMP) because the projection unit is an integral part of the helmet. Two projectors -- one for each eye -- are required to produce a stereoscopic effect.
Real-World Applications:
While an invisibility cloak is an interesting application of optical camouflage, it's probably not the most useful one. Here are some practical ways the technology might be applied:
• Pilots landing a plane could use this technology to make cockpit floors transparent. This would enable them to see the runway and the landing gear simply by glancing down.
• Doctors performing surgery could use optical camouflage to see through their hands and instruments to the underlying tissue
• Providing a view of the outside in windowless rooms is one of the more fanciful applications of the technology, but one that might improve the psychological well-being of people in such environments.
• Drivers backing up cars could benefit one day from optical camouflage. A quick glance backward through a transparent rear hatch or tailgate would make it easy to know when to stop.
• One of the most promising applications of this technology, however, has less to do with making objects invisible and more about making them visible. The concept is called mutual telexistence: working and perceiving with the feeling that you are in several places at once. Here's how it works:

Human user A is at one location while his telexistence robot A is at another location with human user B. Human user B is at one location while his telexistence robot B is at another location with human user A. Both telexistence robots are covered in retro-reflective material so that they act like screens. With video cameras and projectors at each location, the images of the two human users are projected onto their respective robots in the remote locations.
This gives each human the perception that he is working with another human instead of a robot.
Right now, mutual telexistence is science fiction, but it won't be for long as scientists continue to push the boundaries of the technology. For example, pervasive gaming is already becoming a reality. Pervasive gaming extends gaming experiences out into the real world, whether on city streets or in remote wilderness. Players with mobile displays move through the world while sensors capture information about their environment, including their location. This information is used to deliver users a gaming experience that changes according to where they are and what they are doing.

CONCLUSION:
Invisibility of a person is no more a Fiction today, as it was in the previous times-found only in some fiction, comic books etc. With the advent of Optical Camouflage Technology it has been turned into reality. This technology uses a way of Optical illusion on people’s viewing. As on today the system is very complex but unending efforts are being made to make it simple and more powerful. Improvement of this technology may lead to advancements in dealing with security threats. Also the concept of mutual telexistance opens a new era for advancements in Robotic applications. High equipment leading to high costs and complexity in maintenance remain a backlog to this technology. But all efforts are being made to bring this exciting technology to common man, to make them feel invisibility and experience being invisible.

URL’s:
BBC News. "Inventor plans 'invisible walls,'" BBC News, published June 14, 2004.
http://news.bbc.co.uk/2/hi/technology/3791795.stm

M. Inami, N. Kawakami, D. Sekiguchi, Y. Yanagida, T. Maeda and S. Tachi. "Visuo-Haptic Display Using Head-Mounted Projector."
http://projects.star.t.u-tokyo.ac.jp/projects/MEDIA/xv/oc.html

M. Inami, N. Kawakami and S. Tachi. "Optical Camouflage Using Retro-reflective Projection Technology," Proceedings of the Second IEEE and ACM International Symposium on Mixed and Augmented Reality (ISMAR 03).
http://projects.star.t.u-tokyo.ac.jp/projects/MEDIA/xv/oc.html

S. Feiner. "Augmented reality: A new way of seeing," Scientific American. April 2002, pp. 48-55.

S. Tachi. "Telexistence and Retro-reflective Projection Technology (RPT)," Proceedings of the 5th Virtual Reality International Conference (VRIC2003), pp. 69/1-69/9.
http://projects.star.t.u-tokyo.ac.jp/projects/MEDIA/xv/oc.html











BASIC ELECTRONICS

DIGITAL vs ANALOG

GRE WORDS WITH PICTURES

1. Foible [foi-buhl] (noun)

Meaning: A small weakness; slight frailty in character
Synonyms: frailty, quirk, crotchet, eccentricity, peculiarity
Antonyms: strength.
















  



Usage:  
1. Although, he was a good man but he has a foible due to addiction of liquor. 
2. Even the most perfect man will have some foible, otherwise he will become equivalent to god. 
3. She was a wit, she was a moralist, she had a profound understanding of the foibles of human nature.
4. Altman is at heart a satirist, and his unrelenting dissection of the foibles of mankind is what gives his movies their punch.
5.She's a vibrant character with so many foibles one can't help but " go along for the ride.

2. Loath [lohth] (adj)

Meaning: Unwilling; reluctant
Synonyms: reluctant, regretful, unwilling,reluctant, disinclined, uneager
Antonyms: approving, for unopposed, willing
















Usage:
1. Once people get settled in one particular city, they are expected to be loath to get transferred. 
2. Corrupt officials are too loath to do work in stipulated time without any bribe. 
3. Talking of lighting, I'm loath to admit that we nearly fused all the lights with a faulty kettle!
4. My brothers left the farm when they came of age, but I stayed a year longer, loath to leave home.
5. Clearly members wanted management but were still loath to give ' management ' any power. 

3. Kanban [kahn-bahn] (noun)

Meaning: A method or system of arranging to have parts, raw materials etc. delivered just as they are needed in the manufacturing process  

 












Usage:  
1. It can often be cost effective to go to a higher cost supplier who offers kanban deliveries.
2. Most of the companies today are working on kanban model so as to reduce their inventory levels.
3. Kanban is implemented on the production line in order to provide material just in time when it is required.
4. All work should be carried out to a schedule or in response to a kanban signal.
5. All work in kanban areas must be under kanban control, no " squirrel " stores.

4. Magniloquence [mag-nil-uh-kwuhnce] (noun)

Meaning: the ability to speak in a grand or bombastic style
Synonyms: boastful, bombast, eloquence, grandiloquence,grandiosity,flowery language, fustian, grandiloquence, loftiness, pompousness, pomposity, pretentiousness, rhetoric
Antonyms: conciseness 
 


















Usage:
1.The sublime theme and the magniloquence of phraseology has made Milton’s Paradise Lost a master piece.
2.You speak of her with the magniloquence of a poet and the feeling of a troubadour
3. Without his vanity and his magniloquence it is possible that he might never have acquired the sonorous elocution which is so useful and even necessary an instrument in political life.
4. It might have indicated dismissal, magniloquence or implacable fury. 
5. However, Johnson's attempt to appease him was a curious specimen of his magniloquence.  

5. Turpitude [tur-pi-tood, -tyood] (noun)

Meaning: baseness, depravity
Synonyms: wickedness, immortality, corruption, corruptness, vice, degeneracy, evil, baseness
Antonyms: virtue, honour
















Usage: 
1. He was sentenced to imprisonment for his act of turpitude.
2. I'm also very worried I may have to tick the ' have you ever engaged in moral turpitude?
3. Have you ever been arrested or convicted for an offense involving moral turpitude? 
4. In a kind of torpitude, or sleeping state 

 
You might want to check some more here 





EMBEDDED SYSTEMS

EMBEDDED SYSTEMS RELATED TOPICS



**POWERING THE HARDWARE



First of all what is a power?

ans:power is the rate that energy is expended or work is performed.

This means that in the alternating current(AC) and direct current(DC) circuits, the power associated with each element on the board equals the current through the element and voltage across the element(P=VI).



You all know that every electronic circuit requires power.Lets know about what an embedded system requires.



Accurate power and energy calculations must be done for all elements on an embedded board to determine the power consumption requirements of that particular board.This is because each element can only handle certain type of power, so AC-DC converters,DC-AC,direct AC-AC converters, and so on may be required.

Also, each element has a limited amount of power that it requires to function,that it can handle, or that it dissipates.These calculations determine the type of voltage source that can be used on a board and how powerful the voltage source needs to be.



In embedded systems,both AC and DC voltage sources are used because each current generation technique has its pros and corns.AC is easier to generate in large amounts using generators driven by turbines turned by everything form wind to water. Producing large amounts of DC from electrochemical cells(batteries) is not as practical.Also, because transmitting current over long transmission lines results in a significant loss of energy due to the resistance of the wire, most modern electric company facilities transmit electricity to outlets in AC current, since AC can be transformed to lower or higher voltages much more easily than DC.With AC a device called a transformer, located at the service provider, is used to efficiently transmit current over longer distances with lower losses.

The transformer is a device that transfers electrical energy from one circuit to another and can make changes to the current and voltage during the transfer.

The service provider transmits lower levels of current at a higher voltage rate from the power plant, and then a transformer at the customer site decreases the voltages to value required. On the flip side, at very high voltages, wires offer less resistance to Dc than AC, thus making DC more efficient to transmit than AC over very large distances.



Some embedded boards integrate or plug into power supplies. Power supplies can be either AC or DC. To use an AC power supply to supply power to components using only DC, AC-DC converters can be used to convert AC to lower DC voltages required by the various components on an embedded board, which typically require 3.3, 5,0r 12 volts.

Other embedded boards or components on a board such as non volatile memory rely on batteries as voltage sources, which can be more practical to provide power because of their size.

Battery-powered boards don't rely on a power plant for energy, and they allow portability of embedded devices that don't need to be plugged into an outlet. Also because batteries supply DC current, as is needed with boards that rely on a power supply and outlet supplying AC. Batteries, however, have a limited life and must be either recharged or replaced.




Analog vs Digital Signals



A digital system processes only digital data, which is data represented by only 0's and 1's. On most boards, two voltages represent "0" and "1", since all data is represented as some combination of 1's and 0's. No voltage (0 volts) is referred to as ground, VSS , or low and 3,5, or 12 volts are commonly referred to as VCC, VDD, or high. All signals within the system are one of the two voltages or are transitioning to one of the two voltages.

Systems can define "0" as LOW and "1" as HIGH, on some range of o-1 as LOW and 4-5 volts as HIGH for instance.Other signals can base the definition of a "1" or "0" on edges (low to high) or (high to low). Because most of the components on an embedded board, such as processors, inherently process the 1's and 0's of digital signals, a lot of embbeded hardware is digital by nature. However an embedded can still process analog signals, which are continuous-that is not only 1's and 0's but values in between as well. Obviously, a mechanism is needed on a board to covert analog signals to digital signals. An analog signal is digitalized  by sampling process, and the resulting digtal data can be translated back into a voltage "wave" that mirrors the original analog waveform.



One of the most serious problems in both the analog and digital signal realm involves noise distorting incoming signals, thus corrupting and affecting the accuracy of the data. Noise is generally any unwanted signal alteration from an input source, any part of input signal generated from the sensor other than a sensor, or even the noise generated from the sensor itself. Noise is a common problem with analog signals. Digital signal on the other hand, are at greater risk if the signals are not generated ocally to the embedded processor, so any digital signals coming coming across a longer transmission medium are more susceptible to noise problems.



Analog noise can come from a wide variety of sources- radio signals, lightning, power line, the microprocessor, or the analog sensing electronics themselves. The same is true for digital noise, which can come from mechanical contacts used as computer inputs, dirty slip rings that transmit power/data, limits in accuracy/dependability of input source, and so forth.


AC and DC

AC and DC difference

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