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Invisible
Invisibility is the state of an object that cannot be seen. An object in this state is said to be ''invisible'' (literally, "not visible"). The phenomenon is studied by physics and perceptual psychology. Since objects can be seen by light in the visible spectrum from a source reflecting off their surfaces and hitting the viewer's eye, the most natural form of invisibility (whether real or fictional) is an object that neither reflects nor absorbs light (that is, it allows light to pass through it). This is known as transparency, and is seen in many naturally occurring materials (although no naturally occurring material is 100% transparent). Invisibility perception depends on several optical and visual factors. For example, invisibility depends on the eyes of the observer and/or the instruments used. Thus an object can be classified as "invisible to" a person, animal, instrument, etc. In research on sensorial perception it has been shown that invisibility is perceived in cy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chroma Key
Chroma key compositing, or chroma keying, is a visual-effects and post-production technique for compositing (layering) two images or video streams together based on colour hues ( chroma range). The technique has been used in many fields to remove a background from the subject of a photo or video – particularly the newscasting, motion picture, and video game industries. A colour range in the foreground footage is made transparent, allowing separately filmed background footage or a static image to be inserted into the scene. The chroma keying technique is commonly used in video production and post-production. This technique is also referred to as colour keying, colour-separation overlay (CSO; primarily by the BBC), or by various terms for specific colour-related variants such as green screen or blue screen; chroma keying can be done with backgrounds of any colour that are uniform and distinct, but green and blue backgrounds are more commonly used because they differ most d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science Fiction
Science fiction (sometimes shortened to Sci-Fi or SF) is a genre of speculative fiction which typically deals with imaginative and futuristic concepts such as advanced science and technology, space exploration, time travel, parallel universes, extraterrestrial life, sentient artificial intelligence, cybernetics, certain forms of immortality (like mind uploading), and the singularity. Science fiction predicted several existing inventions, such as the atomic bomb, robots, and borazon, whose names entirely match their fictional predecessors. In addition, science fiction might serve as an outlet to facilitate future scientific and technological innovations. Science fiction can trace its roots to ancient mythology. It is also related to fantasy, horror, and superhero fiction and contains many subgenres. Its exact definition has long been disputed among authors, critics, scholars, and readers. Science fiction, in literature, film, television, and other media, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Camouflage
Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the battledress of a modern soldier, and the leaf-mimic katydid's wings. A third approach, motion dazzle, confuses the observer with a conspicuous pattern, making the object visible but momentarily harder to locate, as well as making general aiming easier. The majority of camouflage methods aim for crypsis, often through a general resemblance to the background, high contrast disruptive coloration, eliminating shadow, and countershading. In the open ocean, where there is no background, the principal methods of camouflage are transparency, silvering, and countershading, while the bioluminescence, ability to produce light is among other things used for counter-illumination on the undersides of cephalopods such as squid. Some animals, such as chamel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Active Camouflage
Active camouflage or adaptive camouflage is camouflage that adapts, often rapidly, to the surroundings of an object such as an animal or military vehicle. In theory, active camouflage could provide perfect concealment from visual detection. Active camouflage is used in several groups of animals, including reptiles on land, and cephalopod molluscs and flatfish in the sea. Animals achieve active camouflage both by Camouflage#Crypsis by changing skin pattern.2C colour, color change and (among marine animals such as squid) by counter-illumination, with the use of bioluminescence. Military counter-illumination camouflage was first investigated during the World War II, Second World War for marine use. More recent research has aimed to achieve crypsis by using cameras to sense the visible background, and by controlling Peltier panels or coatings that can vary their appearance. In animals Active camouflage is used in several groups of animals including cephalopod molluscs, fish, and r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metamaterial
A metamaterial (from the Greek word μετά ''meta'', meaning "beyond" or "after", and the Latin word ''materia'', meaning "matter" or "material") is any material engineered to have a property that is not found in naturally occurring materials. They are made from assemblies of multiple elements fashioned from composite materials such as metals and plastics. The materials are usually arranged in repeating patterns, at scales that are smaller than the wavelengths of the phenomena they influence. Metamaterials derive their properties not from the properties of the base materials, but from their newly designed structures. Their precise shape, geometry, size, orientation and arrangement gives them their smart properties capable of manipulating electromagnetic waves: by blocking, absorbing, enhancing, or bending waves, to achieve benefits that go beyond what is possible with conventional materials. Appropriately designed metamaterials can affect waves of electromagnetic radiation or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theories Of Cloaking
Theories of cloaking discusses various theories based on science and research, for producing an electromagnetic cloaking device. Theories presented employ transformation optics, event cloaking, dipolar scattering cancellation, tunneling light transmittance, sensors and active sources, and acoustic cloaking. A cloaking device is one where the purpose of the transformation is to hide something, so that a defined region of space is invisibly isolated from passing electromagnetic fields (see Metamaterial cloaking) or sound waves. Objects in the defined location are still present, but incident waves are guided around them without being affected by the object itself. Along with this basic "cloaking device", other related concepts have been proposed in peer reviewed, scientific articles, and are discussed here. Naturally, some of the theories discussed here also employ metamaterials, either electromagnetic or acoustic, although often in a different manner than the original demonstr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transformation Optics
Transformation optics is a branch of optics which applies metamaterials to produce spatial variations, derived from coordinate transformations, which can direct chosen bandwidths of electromagnetic radiation. This can allow for the construction of new composite artificial devices, which probably could not exist without metamaterials and coordinate transformation. Computing power that became available in the late 1990s enables prescribed quantitative values for the permittivity and permeability, the constitutive parameters, which produce localized spatial variations. The aggregate value of all the constitutive parameters produces an effective value, which yields the intended or desired results. Hence, complex artificial materials, known as metamaterials, are used to produce transformations in optical space. The mathematics underpinning transformation optics is similar to the equations that describe how gravity warps space and time, in general relativity. However, instea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meta Material
A metamaterial (from the Greek word μετά ''meta'', meaning "beyond" or "after", and the Latin word ''materia'', meaning "matter" or "material") is any material engineered to have a property that is not found in naturally occurring materials. They are made from assemblies of multiple elements fashioned from composite materials such as metals and plastics. The materials are usually arranged in repeating patterns, at scales that are smaller than the wavelengths of the phenomena they influence. Metamaterials derive their properties not from the properties of the base materials, but from their newly designed structures. Their precise shape, geometry, size, orientation and arrangement gives them their smart properties capable of manipulating electromagnetic waves: by blocking, absorbing, enhancing, or bending waves, to achieve benefits that go beyond what is possible with conventional materials. Appropriately designed metamaterials can affect waves of electromagnetic radiation or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filmmaking
Filmmaking (film production) is the process by which a motion picture is produced. Filmmaking involves a number of complex and discrete stages, starting with an initial story, idea, or commission. It then continues through screenwriting, casting, pre-production, shooting, sound recording, post-production, and screening the finished product before an audience that may result in a film release and an exhibition. Filmmaking occurs in a variety of economic, social, and political contexts around the world. It uses a variety of technologies and cinematic techniques. Although filmmaking originally involved the use of film, most film productions are now digital. Today, filmmaking refers to the process of crafting an audio-visual story commercially for distribution or broadcast. Production stages Film production consists of five major stages: * Development: Ideas for the film are created, rights to existing intellectual properties are purchased, etc., and the screenplay is writte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cloak Of Invisibility
A cloak of invisibility is an item that prevents the wearer from being seen. In folklore, mythology and fairy tales, a cloak of invisibility appears either as a magical item used by duplicitous characters or an item worn by a hero to fulfill a quest. It is a common theme in Welsh and Germanic folklore, and may originate with the cap of invisibility seen in ancient Greek myths. The motif falls under "D1361.12 magic cloak of invisibility" in the Stith Thompson motif index scheme. In folklore Cloaks of invisibility are magical items found in folklore and fairy tales. Such cloaks are common in Welsh mythology; a "Mantle of Invisibility" is described in the tale ''Culhwch and Olwen'' (c. 1100) as one of King Arthur's most prized possessions.Stephens (1998) p. 479 The mantle is described again, and in more detail, in the '' Breuddwyd Rhonabwy,'' and is later listed as one of the Thirteen Treasures of the Island of Britain. A similar mantle appears in the Second Branch of the Mabi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gunther Uhlmann
Gunther Alberto Uhlmann Arancibia (9 February 1952, Chile) is a mathematician whose research focuses on inverse problems and imaging, microlocal analysis, partial differential equations and invisibility. Education and career Uhlmann studied mathematics as an undergraduate at the Universidad de Chile in Santiago, gaining his Licenciatura degree in 1973. He continued his studies at MIT where he received a PhD in 1976. He held postdoctoral positions at MIT, Harvard and NYU, including a Courant Instructorship at the Courant Institute in 1977–1978. In 1980, he became Assistant Professor at MIT and then moved in 1985 to the University of Washington. He has been the Walker Family Professor at the University of Washington since 2006. During 2010-2012 he was on leave at the University of California, Irvine, as the Excellence in Teaching Endowed Chair. Uhlmann was Finnish Distinguished Professor 2012–2017. He is currently also the Si-Yuan Professor at the Institute for Advance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
