84-493: The Holographic Versatile Disc ( HVD ) is an optical disc technology that was expected to store up to several terabytes of data on an optical disc 10 cm or 12 cm in diameter. Its development commenced in April 2004, but it never arrived due to lack of funding. The company responsible for HVD went bankrupt in 2010. The reduced radius reduces cost and materials used. It employs a technique known as collinear holography , whereby
168-426: A computer-generated hologram , which can show virtual objects or scenes. Optical holography needs a laser light to record the light field. The reproduced light field can generate an image that has the depth and parallax of the original scene. A hologram is usually unintelligible when viewed under diffuse ambient light . When suitably lit, the interference pattern diffracts the light into an accurate reproduction of
252-425: A 10 cm disc. The system used a green laser , with an output power of 1 watt which is high power for a consumer device laser. Possible solutions include improving the sensitivity of the polymer used, or developing and commoditizing a laser capable of higher power output while being suitable for a consumer unit. HVD is not the only technology in high-capacity, holographic storage media. InPhase Technologies
336-475: A 120 mm disc that uses a holographic layer to store data to a potential 3.9 TB , a format called Holographic Versatile Disc . As of September 2014, no commercial product has been released. Another company, InPhase Technologies , was developing a competing format, but went bankrupt in 2011 and all its assets were sold to Akonia Holographics, LLC. While many holographic data storage models have used "page-based" storage, where each recorded hologram holds
420-477: A 200 GB HVD "recordable cartridge" and ECMA-378, defining a 100 GB HVD-ROM disc. Its next stated goals were 30 GB HVD cards and submission of these standards to the International Organization for Standardization for ISO approval. General Electric Global Research Centers created a holographic disc that could hold many times the data of a Blu-Ray — up to 500 GB . As the technology
504-415: A blue-green and red laser beam are collimated in a single beam. The blue-green laser reads data encoded as laser interference fringes from a holographic layer near the top of the disc. A red laser is used as the reference beam to read servoinformation from a regular CD-style aluminium layer near the bottom. Servoinformation is used to monitor the position of the read head over the disc, similar to
588-533: A document is submitted directly for approval as a draft International Standard (DIS) to the ISO member bodies or as a final draft International Standard (FDIS), if the document was developed by an international standardizing body recognized by the ISO Council. The first step, a proposal of work (New Proposal), is approved at the relevant subcommittee or technical committee (e.g., SC 29 and JTC 1 respectively in
672-453: A large amount of data, more recent research into using submicrometre-sized "microholograms" has resulted in several potential 3D optical data storage solutions. While this approach to data storage can not attain the high data rates of page-based storage, the tolerances, technological hurdles, and cost of producing a commercial product are significantly lower. In static holography, recording, developing and reconstructing occur sequentially, and
756-442: A long process that commonly starts with the proposal of new work within a committee. Some abbreviations used for marking a standard with its status are: Abbreviations used for amendments are: Other abbreviations are: International Standards are developed by ISO technical committees (TC) and subcommittees (SC) by a process with six steps: The TC/SC may set up working groups (WG) of experts for
840-557: A permanent hologram is produced. There also exist holographic materials that do not need the developing process and can record a hologram in a very short time. This allows one to use holography to perform some simple operations in an all-optical way. Examples of applications of such real-time holograms include phase-conjugate mirrors ("time-reversal" of light), optical cache memories, image processing (pattern recognition of time-varying images), and optical computing . The amount of processed information can be very high (terabits/s), since
924-533: A proposal to form a new global standards body. In October 1946, ISA and UNSCC delegates from 25 countries met in London and agreed to join forces to create the International Organization for Standardization. The organization officially began operations on 23 February 1947. ISO Standards were originally known as ISO Recommendations ( ISO/R ), e.g., " ISO 1 " was issued in 1951 as "ISO/R 1". ISO
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#17328512280151008-436: A relatively small number of standards, ISO standards are not available free of charge, but rather for a purchase fee, which has been seen by some as unaffordable for small open-source projects. The process of developing standards within ISO was criticized around 2007 as being too difficult for timely completion of large and complex standards, and some members were failing to respond to ballots, causing problems in completing
1092-420: A set of point sources located at varying distances from the medium. The second (reference) beam illuminates the recording medium directly. Each point source wave interferes with the reference beam, giving rise to its own sinusoidal zone plate in the recording medium. The resulting pattern is the sum of all these 'zone plates', which combine to produce a random ( speckle ) pattern as in the photograph above. When
1176-582: A single disc around US$ 120–180, although prices were expected to fall steadily. Since InPhase Technologies was unable to deliver their promised product, they ran out of funds and went bankrupt in 2010. The Holography System Development Forum (HSD Forum; formerly the HVD Alliance and the HVD FORUM) is a coalition of corporations purposed to provide an industry forum for testing and technical discussion of all aspects of HVD design and manufacturing. As of March 2012,
1260-540: A small relay -controlled shutter, loaded a plate into the holder in the dark, left the room, waited a few minutes to let everything settle, then made the exposure by remotely operating the laser shutter. In 1979, Jason Sapan opened the Holographic Studios in New York City . Since then, they have been involved in the production of many holographs for many artists as well as companies. Sapan has been described as
1344-552: A small (typically 5 mW) helium-neon laser and inexpensive home-made equipment. Holography had been supposed to require a very expensive metal optical table set-up to lock all the involved elements down in place and damp any vibrations that could blur the interference fringes and ruin the hologram. Cross's home-brew alternative was a sandbox made of a cinder block retaining wall on a plywood base, supported on stacks of old tires to isolate it from ground vibrations, and filled with sand that had been washed to remove dust. The laser
1428-408: A very intense and extremely brief pulse of laser light is used, a hazardous procedure which is rarely done outside of scientific and industrial laboratory settings. Exposures lasting several seconds to several minutes, using a much lower-powered continuously operating laser, are typical. A hologram can be made by shining part of the light beam directly into the recording medium, and the other part onto
1512-444: A way to create holograms that can be viewed with natural light instead of lasers. These are called rainbow holograms . Holography is a technique for recording and reconstructing light fields. A light field is generally the result of a light source scattered off objects. Holography can be thought of as somewhat similar to sound recording , whereby a sound field created by vibrating matter like musical instruments or vocal cords ,
1596-485: A way to express themselves and to renew Concrete Poetry . A small but active group of artists still integrate holographic elements into their work. Some are associated with novel holographic techniques; for example, artist Matt Brand employed computational mirror design to eliminate image distortion from specular holography . The MIT Museum and Jonathan Ross both have extensive collections of holography and on-line catalogues of art holograms. Holographic data storage
1680-637: Is "to develop worldwide Information and Communication Technology (ICT) standards for business and consumer applications." There was previously also a JTC 2 that was created in 2009 for a joint project to establish common terminology for "standardization in the field of energy efficiency and renewable energy sources". It was later disbanded. As of 2022 , there are 167 national members representing ISO in their country, with each country having only one member. ISO has three membership categories, Participating members are called "P" members, as opposed to observing members, who are called "O" members. ISO
1764-423: Is a technique that can store information at high density inside crystals or photopolymers. The ability to store large amounts of information in some kind of medium is of great importance, as many electronic products incorporate storage devices. As current storage techniques such as Blu-ray Disc reach the limit of possible data density (due to the diffraction-limited size of the writing beams), holographic storage has
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#17328512280151848-462: Is a voluntary organization whose members are recognized authorities on standards, each one representing one country. Members meet annually at a General Assembly to discuss the strategic objectives of ISO. The organization is coordinated by a central secretariat based in Geneva . A council with a rotating membership of 20 member bodies provides guidance and governance, including setting the annual budget of
1932-464: Is abused, ISO should halt the process... ISO is an engineering old boys club and these things are boring so you have to have a lot of passion ... then suddenly you have an investment of a lot of money and lobbying and you get artificial results. The process is not set up to deal with intensive corporate lobbying and so you end up with something being a standard that is not clear. International Workshop Agreements (IWAs) are documents that establish
2016-508: Is an abbreviation for "International Standardization Organization" or a similar title in another language, the letters do not officially represent an acronym or initialism . The organization provides this explanation of the name: Because 'International Organization for Standardization' would have different acronyms in different languages (IOS in English, OIN in French), our founders decided to give it
2100-481: Is an active area of research. The most common materials are photorefractive crystals , but in semiconductors or semiconductor heterostructures (such as quantum wells ), atomic vapors and gases, plasmas and even liquids, it was possible to generate holograms. A particularly promising application is optical phase conjugation . It allows the removal of the wavefront distortions a light beam receives when passing through an aberrating medium, by sending it back through
2184-971: Is an independent, non-governmental , international standard development organization composed of representatives from the national standards organizations of member countries. Membership requirements are given in Article 3 of the ISO Statutes. ISO was founded on 23 February 1947, and (as of July 2024 ) it has published over 25,000 international standards covering almost all aspects of technology and manufacturing. It has over 800 technical committees (TCs) and subcommittees (SCs) to take care of standards development. The organization develops and publishes international standards in technical and nontechnical fields, including everything from manufactured products and technology to food safety, transport, IT, agriculture, and healthcare. More specialized topics like electrical and electronic engineering are instead handled by
2268-512: Is approved as an International Standard (IS) if a two-thirds majority of the P-members of the TC/SC is in favour and not more than one-quarter of the total number of votes cast are negative. After approval, the document is published by the ISO central secretariat , with only minor editorial changes introduced in the publication process before the publication as an International Standard. Except for
2352-481: Is commonly glass, but may also be plastic. When the two laser beams reach the recording medium, their light waves intersect and interfere with each other. It is this interference pattern that is imprinted on the recording medium. The pattern itself is seemingly random, as it represents the way in which the scene's light interfered with the original light source – but not the original light source itself. The interference pattern can be considered an encoded version of
2436-452: Is created by digitally modeling and combining two wavefronts to generate an interference pattern image. This image can then be printed onto a mask or film and illuminated with an appropriate light source to reconstruct the desired wavefront. Alternatively, the interference pattern image can be directly displayed on a dynamic holographic display. Holographic portraiture often resorts to a non-holographic intermediate imaging procedure, to avoid
2520-495: Is encoded in such a way that it can be reproduced later, without the presence of the original vibrating matter. However, it is even more similar to Ambisonic sound recording in which any listening angle of a sound field can be reproduced in the reproduction. In laser holography, the hologram is recorded using a source of laser light, which is very pure in its color and orderly in its composition. Various setups may be used, and several types of holograms can be made, but all involve
2604-399: Is expanded into a wave that appears to diverge from the focal point of the lens. Thus, when the recorded pattern is illuminated with the original plane wave, some of the light is diffracted into a diverging beam equivalent to the original spherical wave; a holographic recording of the point source has been created. When the plane wave is incident at a non-normal angle at the time of recording,
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2688-459: Is explained below purely in terms of interference and diffraction. It is somewhat simplified but is accurate enough to give an understanding of how the holographic process works. For those unfamiliar with these concepts, it is worthwhile to read those articles before reading further in this article. A diffraction grating is a structure with a repeating pattern. A simple example is a metal plate with slits cut at regular intervals. A light wave that
2772-522: Is funded by a combination of: International standards are the main products of ISO. It also publishes technical reports, technical specifications, publicly available specifications, technical corrigenda (corrections), and guides. International standards Technical reports For example: Technical and publicly available specifications For example: Technical corrigenda ISO guides For example: ISO documents have strict copyright restrictions and ISO charges for most copies. As of 2020 ,
2856-400: Is incident on a grating is split into several waves; the direction of these diffracted waves is determined by the grating spacing and the wavelength of the light. A simple hologram can be made by superimposing two plane waves from the same light source on a holographic recording medium. The two waves interfere, giving a straight-line fringe pattern whose intensity varies sinusoidally across
2940-512: Is located where this light, after being reflected or scattered by the subject, will strike it. The edges of the medium will ultimately serve as a window through which the subject is seen, so its location is chosen with that in mind. The reference beam is expanded and made to shine directly on the medium, where it interacts with the light coming from the subject to create the desired interference pattern. Like conventional photography, holography requires an appropriate exposure time to correctly affect
3024-406: Is possible to make a hologram for any type of wave . A hologram is a recording of an interference pattern that can reproduce a 3D light field using diffraction . In general usage, a hologram is a recording of any type of wavefront in the form of an interference pattern. It can be created by capturing light from a real scene, or it can be generated by a computer, in which case it is known as
3108-425: Is produced, for example, for audio and video coding standards is called a verification model (VM) (previously also called a "simulation and test model"). When a sufficient confidence in the stability of the standard under development is reached, a working draft (WD) is produced. This is in the form of a standard, but is kept internal to working group for revision. When a working draft is sufficiently mature and
3192-412: Is quite similar to CD, DVD, and Blu-ray technologies, the players were to be cross-compatible with these formats. Holography Holography is a technique that enables a wavefront to be recorded and later reconstructed. It is best known as a method of generating three-dimensional images , and has a wide range of other uses, including data storage, microscopy, and interferometry. In principle, it
3276-590: Is restricted. The organization that is known today as ISO began in 1926 as the International Federation of the National Standardizing Associations ( ISA ), which primarily focused on mechanical engineering . The ISA was suspended in 1942 during World War II but, after the war, the ISA was approached by the recently-formed United Nations Standards Coordinating Committee (UNSCC) with
3360-414: Is then captured on a physical medium. When the recorded interference pattern is later illuminated by the second wavefront, it is diffracted to recreate the original wavefront. The 3D image from a hologram can often be viewed with non-laser light. However, in common practice, major image quality compromises are made to remove the need for laser illumination to view the hologram. A computer-generated hologram
3444-522: The Greek words ὅλος ( holos ; "whole") and γραφή ( graphē ; " writing " or " drawing "). The Hungarian - British physicist Dennis Gabor invented holography in 1948 while he was looking for a way to improve image resolution in electron microscopes . Gabor's work was built on pioneering work in the field of X-ray microscopy by other scientists including Mieczysław Wolfke in 1920 and William Lawrence Bragg in 1939. The formulation of holography
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3528-630: The International Electrotechnical Commission . It is headquartered in Geneva , Switzerland. The three official languages of ISO are English , French , and Russian . The International Organization for Standardization in French is Organisation internationale de normalisation and in Russian, Международная организация по стандартизации ( Mezhdunarodnaya organizatsiya po standartizatsii ). Although one might think ISO
3612-725: The University of Nottingham art gallery in 1969. This was followed in 1970 by a solo show at the Lisson Gallery in London, which was billed as the "first London expo of holograms and stereoscopic paintings". During the 1970s, a number of art studios and schools were established, each with their particular approach to holography. Notably, there was the San Francisco School of Holography established by Lloyd Cross , The Museum of Holography in New York founded by Rosemary (Posy) H. Jackson,
3696-475: The "last professional holographer of New York". International Organization for Standardization Early research and development: Merging the networks and creating the Internet: Commercialization, privatization, broader access leads to the modern Internet: Examples of Internet services: The International Organization for Standardization ( ISO / ˈ aɪ s oʊ / )
3780-565: The 1972 New York exhibit of Dalí holograms had been preceded by the holographic art exhibition that was held at the Cranbrook Academy of Art in Michigan in 1968 and by the one at the Finch College gallery in New York in 1970, which attracted national media attention. In Great Britain, Margaret Benyon began using holography as an artistic medium in the late 1960s and had a solo exhibition at
3864-478: The HVD alliance hoped to improve this efficiency with capabilities of around 60,000 bits per pulse in an inverted, truncated cone shape that has a 200 μm diameter at the bottom and a 500 μm diameter at the top. High densities are possible by moving these closer on the tracks: 100 GB at 18 μm separation, 200 GB at 13 μm, 500 GB at 8 μm, and most demonstrated of 5 TB for 3 μm on
3948-743: The Royal College of Art in London and the Lake Forest College Symposiums organised by Tung Jeong . None of these studios still exist; however, there is the Center for the Holographic Arts in New York and the HOLOcenter in Seoul, which offers artists a place to create and exhibit work. During the 1980s, many artists who worked with holography helped the diffusion of this so-called "new medium" in
4032-563: The art world, such as Harriet Casdin-Silver of the United States, Dieter Jung of Germany , and Moysés Baumstein of Brazil , each one searching for a proper "language" to use with the three-dimensional work, avoiding the simple holographic reproduction of a sculpture or object. For instance, in Brazil, many concrete poets (Augusto de Campos, Décio Pignatari, Julio Plaza and José Wagner Garcia, associated with Moysés Baumstein ) found in holography
4116-479: The case of MPEG, the Moving Picture Experts Group ). A working group (WG) of experts is typically set up by the subcommittee for the preparation of a working draft (e.g., MPEG is a collection of seven working groups as of 2023). When the scope of a new work is sufficiently clarified, some of the working groups may make an open request for proposals—known as a "call for proposals". The first document that
4200-418: The central secretariat. The technical management board is responsible for more than 250 technical committees , who develop the ISO standards. ISO has a joint technical committee (JTC) with the International Electrotechnical Commission (IEC) to develop standards relating to information technology (IT). Known as JTC 1 and entitled "Information technology", it was created in 1987 and its mission
4284-421: The confidence people have in the standards setting process", and alleged that ISO did not carry out its responsibility. He also said that Microsoft had intensely lobbied many countries that traditionally had not participated in ISO and stacked technical committees with Microsoft employees, solution providers, and resellers sympathetic to Office Open XML: When you have a process built on trust and when that trust
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#17328512280154368-702: The dangerous high-powered pulsed lasers which would be needed to optically "freeze" moving subjects as perfectly as the extremely motion-intolerant holographic recording process requires. Early holography required high-power and expensive lasers. Currently, mass-produced low-cost laser diodes , such as those found on DVD recorders and used in other common applications, can be used to make holograms. They have made holography much more accessible to low-budget researchers, artists, and dedicated hobbyists. Most holograms produced are of static objects, but systems for displaying changing scenes on dynamic holographic displays are now being developed. The word holography comes from
4452-413: The document, the draft is then approved for submission as a Final Draft International Standard (FDIS) if a two-thirds majority of the P-members of the TC/SC are in favour and if not more than one-quarter of the total number of votes cast are negative. ISO will then hold a ballot among the national bodies where no technical changes are allowed (a yes/no final approval ballot), within a period of two months. It
4536-410: The following companies are members of the forum: As of March 2012, the following companies are supporting companies of the forum: On December 9, 2004, at its 88th General Assembly, the standards body Ecma International created Technical Committee 44, dedicated to standardizing HVD formats based on Optware's technology. On June 11, 2007, TC44 published the first two HVD standards: ECMA-377, defining
4620-497: The head, track, and sector information on a conventional hard disk drive . On a CD or DVD this servoinformation is interspersed among the data. A dichroic mirror layer between the holographic data and the servo data reflects the blue-green laser while letting the red laser pass through. This prevents interference from refraction of the blue-green laser off the servo data pits and is an advance over past holographic storage media, which either experienced too much interference, or lacked
4704-460: The hologram is illuminated by the original reference beam, each of the individual zone plates reconstructs the object wave that produced it, and these individual wavefronts are combined to reconstruct the whole of the object beam. The viewer perceives a wavefront that is identical with the wavefront scattered from the object onto the recording medium, so that it appears that the object is still in place even if it has been removed. Early on, artists saw
4788-405: The hologram. Holography may be better understood via an examination of its differences from ordinary photography : For a better understanding of the process, it is necessary to understand interference and diffraction. Interference occurs when one or more wavefronts are superimposed. Diffraction occurs when a wavefront encounters an object. The process of producing a holographic reconstruction
4872-484: The holographic method". Optical holography did not really advance until the development of the laser in 1960. The development of the laser enabled the first practical optical holograms that recorded 3D objects to be made in 1962 by Yuri Denisyuk in the Soviet Union and by Emmett Leith and Juris Upatnieks at the University of Michigan , US. Early optical holograms used silver halide photographic emulsions as
4956-420: The interaction of light coming from different directions and producing a microscopic interference pattern which a plate , film, or other medium photographically records. In one common arrangement, the laser beam is split into two, one known as the object beam and the other as the reference beam . The object beam is expanded by passing it through a lens and used to illuminate the subject. The recording medium
5040-434: The medium. The spacing of the fringe pattern is determined by the angle between the two waves, and by the wavelength of the light. The recorded light pattern is a diffraction grating. When it is illuminated by only one of the waves used to create it, it can be shown that one of the diffracted waves emerges at the same angle at which the second wave was originally incident, so that the second wave has been 'reconstructed'. Thus,
5124-660: The necessary steps within the prescribed time limits. In some cases, alternative processes have been used to develop standards outside of ISO and then submit them for its approval. A more rapid "fast-track" approval procedure was used in ISO/IEC JTC 1 for the standardization of Office Open XML (OOXML, ISO/IEC 29500, approved in April 2008), and another rapid alternative "publicly available specification" (PAS) process had been used by OASIS to obtain approval of OpenDocument as an ISO/IEC standard (ISO/IEC 26300, approved in May 2006). As
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#17328512280155208-489: The next stage, called the "enquiry stage". After a consensus to proceed is established, the subcommittee will produce a draft international standard (DIS), and the text is submitted to national bodies for voting and comment within a period of five months. A document in the DIS stage is available to the public for purchase and may be referred to with its ISO DIS reference number. Following consideration of any comments and revision of
5292-410: The object in such a way that some of the scattered light falls onto the recording medium. A more flexible arrangement for recording a hologram requires the laser beam to be aimed through a series of elements that change it in different ways. The first element is a beam splitter that divides the beam into two identical beams, each aimed in different directions: Several different materials can be used as
5376-421: The operation is performed in parallel on a whole image. This compensates for the fact that the recording time, which is in the order of a microsecond , is still very long compared to the processing time of an electronic computer. The optical processing performed by a dynamic hologram is also much less flexible than electronic processing. On one side, one has to perform the operation always on the whole image, and on
5460-464: The original light field, and the objects that were in it exhibit visual depth cues such as parallax and perspective that change realistically with the different angles of viewing. That is, the view of the image from different angles shows the subject viewed from similar angles. A hologram is traditionally generated by overlaying a second wavefront, known as the reference beam, onto a wavefront of interest. This generates an interference pattern, which
5544-402: The other side, the operation a hologram can perform is basically either a multiplication or a phase conjugation. In optics, addition and Fourier transform are already easily performed in linear materials, the latter simply by a lens. This enables some applications, such as a device that compares images in an optical way. The search for novel nonlinear optical materials for dynamic holography
5628-449: The pattern formed is more complex, but still acts as a negative lens if it is illuminated at the original angle. To record a hologram of a complex object, a laser beam is first split into two beams of light. One beam illuminates the object, which then scatters light onto the recording medium. According to diffraction theory, each point in the object acts as a point source of light so the recording medium can be considered to be illuminated by
5712-426: The potential of holography as a medium and gained access to science laboratories to create their work. Holographic art is often the result of collaborations between scientists and artists, although some holographers would regard themselves as both an artist and a scientist. Salvador Dalí claimed to have been the first to employ holography artistically. He was certainly the first and best-known surrealist to do so, but
5796-423: The potential to become the next generation of popular storage media. The advantage of this type of data storage is that the volume of the recording media is used instead of just the surface. Currently available SLMs can produce about 1000 different images a second at 1024×1024-bit resolution which would result in about one- gigabit-per-second writing speed. In 2005, companies such as Optware and Maxell produced
5880-411: The preparation of a working drafts. Subcommittees may have several working groups, which may have several Sub Groups (SG). It is possible to omit certain stages, if there is a document with a certain degree of maturity at the start of a standardization project, for example, a standard developed by another organization. ISO/IEC directives also allow the so-called "Fast-track procedure". In this procedure,
5964-409: The recorded light pattern is a holographic recording as defined above. If the recording medium is illuminated with a point source and a normally incident plane wave, the resulting pattern is a sinusoidal zone plate , which acts as a negative Fresnel lens whose focal length is equal to the separation of the point source and the recording plane. When a plane wave-front illuminates a negative lens, it
6048-402: The recording medium. One of the most common is a film very similar to photographic film ( silver halide photographic emulsion ), but with much smaller light-reactive grains (preferably with diameters less than 20 nm), making it capable of the much higher resolution that holograms require. A layer of this recording medium (e.g., silver halide) is attached to a transparent substrate, which
6132-409: The recording medium. They were not very efficient as the produced diffraction grating absorbed much of the incident light. Various methods of converting the variation in transmission to a variation in refractive index (known as "bleaching") were developed which enabled much more efficient holograms to be produced. A major advance in the field of holography was made by Stephen Benton , who invented
6216-407: The recording medium. Unlike conventional photography, during the exposure the light source, the optical elements, the recording medium, and the subject must all remain motionless relative to each other, to within about a quarter of the wavelength of the light, or the interference pattern will be blurred and the hologram spoiled. With living subjects and some unstable materials, that is only possible if
6300-458: The same aberrating medium with a conjugated phase. This is useful, for example, in free-space optical communications to compensate for atmospheric turbulence (the phenomenon that gives rise to the twinkling of starlight). Since the beginning of holography, many holographers have explored its uses and displayed them to the public. In 1971, Lloyd Cross opened the San Francisco School of Holography and taught amateurs how to make holograms using only
6384-424: The scene, requiring a particular key – the original light source – in order to view its contents. This missing key is provided later by shining a laser, identical to the one used to record the hologram, onto the developed film. When this beam illuminates the hologram, it is diffracted by the hologram's surface pattern. This produces a light field identical to the one originally produced by the scene and scattered onto
6468-594: The servo data entirely, making them incompatible with current CD and DVD drive technology. Standards for 100 GB read-only holographic discs and 200 GB recordable cartridges were published by ECMA in 2007, but no holographic disc product has ever appeared in the market. A number of release dates were announced, all since passed, likely due to high costs of the drives and discs itself, lack of compatibility with existing or new standards, and competition from more established optical disc Blu-ray and video streaming . Current optical storage saves one bit per pulse, and
6552-468: The short form ISO . ISO is derived from the Greek word isos ( ίσος , meaning "equal"). Whatever the country, whatever the language, the short form of our name is always ISO . During the founding meetings of the new organization, however, the Greek word explanation was not invoked, so this meaning may be a false etymology . Both the name ISO and the ISO logo are registered trademarks and their use
6636-501: The subcommittee is satisfied that it has developed an appropriate technical document for the problem being addressed, it becomes a committee draft (CD) and is sent to the P-member national bodies of the SC for the collection of formal comments. Revisions may be made in response to the comments, and successive committee drafts may be produced and circulated until consensus is reached to proceed to
6720-414: The typical cost of a copy of an ISO standard is about US$ 120 or more (and electronic copies typically have a single-user license, so they cannot be shared among groups of people). Some standards by ISO and its official U.S. representative (and, via the U.S. National Committee, the International Electrotechnical Commission ) are made freely available. A standard published by ISO/IEC is the last stage of
6804-703: Was an unexpected result of Gabor's research into improving electron microscopes at the British Thomson-Houston Company (BTH) in Rugby , England, and the company filed a patent in December 1947 (patent GB685286). The technique as originally invented is still used in electron microscopy, where it is known as electron holography . Gabor was awarded the Nobel Prize in Physics in 1971 "for his invention and development of
6888-492: Was developing a rival holographic format called Tapestry Media , which they claimed would eventually store 1.6 TB with a data transfer rate of 120 MB/s, and several companies are developing TB-level discs based on 3D optical data storage technology. Such large optical storage capacities compete favorably with the Blu-ray Disc format. However, in 2006, holographic drives were projected to initially cost around US$ 15,000, and
6972-420: Was securely mounted atop the cinder block wall. The mirrors and simple lenses needed for directing, splitting and expanding the laser beam were affixed to short lengths of PVC pipe, which were stuck into the sand at the desired locations. The subject and the photographic plate holder were similarly supported within the sandbox. The holographer turned off the room light, blocked the laser beam near its source using
7056-513: Was suggested at the time by Martin Bryan, the outgoing convenor (chairman) of working group 1 (WG1) of ISO/IEC JTC 1/SC 34 , the rules of ISO were eventually tightened so that participating members that fail to respond to votes are demoted to observer status. The computer security entrepreneur and Ubuntu founder, Mark Shuttleworth , was quoted in a ZDNet blog article in 2008 about the process of standardization of OOXML as saying: "I think it de-values
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