1.
Liquid-crystal display
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A liquid-crystal display is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals. Liquid crystals do not emit light directly, instead using a backlight or reflector to produce images in color or monochrome and they use the same basic technology, except that arbitrary images are made up of a large number of small pixels, while other displays have larger elements. LCDs are used in a range of applications including computer monitors, televisions, instrument panels, aircraft cockpit displays. Small LCD screens are common in consumer devices such as digital cameras, watches, calculators. LCD screens are used on consumer electronics products such as DVD players, video game devices. LCD screens have replaced heavy, bulky cathode ray tube displays in all applications. LCD screens are available in a range of screen sizes than CRT and plasma displays, with LCD screens available in sizes ranging from tiny digital watches to huge. Since LCD screens do not use phosphors, they do not suffer image burn-in when an image is displayed on a screen for a long time. LCDs are, however, susceptible to image persistence, the LCD screen is more energy-efficient and can be disposed of more safely than a CRT can. Its low electrical power consumption enables it to be used in battery-powered electronic equipment more efficiently than CRTs can be, by 2008, annual sales of televisions with LCD screens exceeded sales of CRT units worldwide, and the CRT became obsolete for most purposes. Without the liquid crystal between the filters, light passing through the first filter would be blocked by the second polarizer. Before an electric field is applied, the orientation of the molecules is determined by the alignment at the surfaces of electrodes. In a twisted nematic device, the surface alignment directions at the two electrodes are perpendicular to other, and so the molecules arrange themselves in a helical structure. This induces the rotation of the polarization of the incident light, and this light will then be mainly polarized perpendicular to the second filter, and thus be blocked and the pixel will appear black. By controlling the voltage applied across the liquid crystal layer in each pixel, color LCD systems use the same technique, with color filters used to generate red, green, and blue pixels. The optical effect of a TN device in the state is far less dependent on variations in the device thickness than that in the voltage-off state. Because of this, TN displays with low content and no backlighting are usually operated between crossed polarizers such that they appear bright with no voltage. When no image is displayed, different arrangements are used, for this purpose, TN LCDs are operated between parallel polarizers, whereas IPS LCDs feature crossed polarizers
2.
Raster graphics
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Raster images are stored in image files with varying formats. A raster is technically characterized by the width and height of the image in pixels, the printing and prepress industries know raster graphics as contones. The opposite to contones is line work, usually implemented as vector graphics in digital systems, the word raster has its origins in the Latin rastrum, which is derived from radere. It originates from the scan of cathode ray tube video monitors. By association, it can refer to a rectangular grid of pixels. The word rastrum is now used to refer to a device for drawing musical staff lines, most modern computers have bitmapped displays, where each on-screen pixel directly corresponds to a small number of bits in memory. The screen is refreshed simply by scanning through pixels and coloring them according to set of bits. The refresh procedure, being speed critical, is implemented by dedicated circuitry. Most computer images are stored in raster graphics formats or compressed variations, including GIF, JPEG, and PNG, three-dimensional voxel raster graphics are employed in video games and are also used in medical imaging such as MRI scanners. GIS programs commonly use rasters that encode geographic data in the values as well as the pixel locations. Raster graphics are resolution dependent, meaning they cannot scale up to a resolution without loss of apparent quality. This property contrasts with the capabilities of graphics, which easily scale up to the quality of the device rendering them. Raster graphics deal more practically than vector graphics with photographs and photo-realistic images, typically, a resolution of 150 to 300 PPI works well for 4-color process printing. However, for printing technologies that perform color mixing through dithering rather than through overprinting, printer DPI and image PPI have a different meaning. Thus, for instance, printing an image at 250 PPI may actually require a printer setting of 1200 DPI, when an image is rendered in a raster-based image editor, the image is composed of millions of pixels. At its core, an image editor works by manipulating each individual pixel. Most pixel-based image editors work using the RGB color model, and this article is based on material taken from the Free On-line Dictionary of Computing prior to 1 November 2008 and incorporated under the relicensing terms of the GFDL, version 1.3 or later
3.
Dot matrix
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A dot matrix is a 2-dimensional patterned array, used to represent characters, symbols and images. Every type of modern technology uses dot matrices for display of information, including phones, televisions. They are also used in textiles with sewing, knitting, in printers, the dots are usually the darkened areas of the paper. In displays, the dots may light up, as in an LED, CRT, or plasma display, or darken, as in an LCD. As an impact printer, the term refers to low-resolution impact printers, with a column of 8,9 or 24 pins hitting an ink-impregnated fabric ribbon, like a typewriter ribbon. It was originally contrasted with both daisy wheel printers and line printers that used fixed-shape embossed metal or plastic stamps to mark paper. Impact printers survive where multi-part forms are needed, as the pins can impress dots through multiple layers of paper to make a carbonless copy, all types of electronic printers typically generate image data as a two-step process. External raster image processing was possible such as to print a graphical image, depending on the printer technology the dot size or grid shape may not be uniform. Some printers are capable of producing smaller dots and will intermesh the small dots within the larger ones for antialiasing. A dot matrix is useful for marking materials other than paper, in manufacturing industry, many product marking applications use dot matrix inkjet or impact methods. This can also be used to print 2D matrix codes, e. g. Datamatrix. Although the output of modern computers is generally all in the form of dot matrices, vector data encoding requires less memory and less data storage, in situations where the shapes may need to be resized, as with font typefaces. For maximum image quality using only dot matrix fonts, it would be necessary to store a separate dot matrix pattern for the different potential point sizes that might be used. Instead, a group of vector shapes is used to render all the specific dot matrix patterns needed for the current display or printing task. An LED matrix or LED display is a large, low-resolution form of dot-matrix display and it consists of a 2-D diode matrix with their cathodes joined in rows and their anodes joined in columns. By controlling the flow of electricity through each row and column pair it is possible to control each LED individually, by multiplexing, scanning across rows, quickly flashing the LEDs on and off, it is possible to create characters or pictures to display information to the user. By varying the rate per LED, the display can approximate levels of brightness. Multi-colored LEDs or RGB-colored LEDs permit use as an image display
4.
Display device
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A display device is an output device for presentation of information in visual or tactile form. When the input information is supplied has a signal, the display is called an electronic display. Common applications for visual displays are televisions or computer monitors. Some displays can show only digits or alphanumeric characters and they are called segment displays, because they are composed of several segments that switch on and off to give appearance of desired glyph. The segments are usually single LEDs or liquid crystals and they are mostly used in digital watches and pocket calculators. There are several types, Seven-segment display Fourteen-segment display Sixteen-segment display HD44780 LCD controller a widely accepted protocol for LCDs and they use electro-mechanical parts to dynamically update a tactile image so that the image may be felt by the fingers. Optacon, using metal rods instead of light in order to convey images to blind people by tactile sensation, in the history of display technology, a variety of display devices and technologies have been used
5.
Sampling (signal processing)
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In signal processing, sampling is the reduction of a continuous-time signal to a discrete-time signal. A common example is the conversion of a wave to a sequence of samples. A sample is a value or set of values at a point in time and/or space, a sampler is a subsystem or operation that extracts samples from a continuous signal. A theoretical ideal sampler produces samples equivalent to the value of the continuous signal at the desired points. Sampling can be done for functions varying in space, time, or any other dimension, then the sampled function is given by the sequence, s, for integer values of n. The sampling frequency or sampling rate, fs, is the number of samples obtained in one second. Reconstructing a continuous function from samples is done by interpolation algorithms, the Whittaker–Shannon interpolation formula is mathematically equivalent to an ideal lowpass filter whose input is a sequence of Dirac delta functions that are modulated by the sample values. When the time interval between adjacent samples is a constant, the sequence of functions is called a Dirac comb. Mathematically, the modulated Dirac comb is equivalent to the product of the function with s. That purely mathematical abstraction is sometimes referred to as impulse sampling, most sampled signals are not simply stored and reconstructed. But the fidelity of a reconstruction is a customary measure of the effectiveness of sampling. That fidelity is reduced when s contains frequency components whose periodicity is smaller than 2 samples, the quantity ½ cycles/sample × fs samples/sec = fs/2 cycles/sec is known as the Nyquist frequency of the sampler. Therefore, s is usually the output of a lowpass filter, without an anti-aliasing filter, frequencies higher than the Nyquist frequency will influence the samples in a way that is misinterpreted by the interpolation process. In practice, the signal is sampled using an analog-to-digital converter. This results in deviations from the theoretically perfect reconstruction, collectively referred to as distortion, various types of distortion can occur, including, Aliasing. Some amount of aliasing is inevitable because only theoretical, infinitely long, Aliasing can be made arbitrarily small by using a sufficiently large order of the anti-aliasing filter. Aperture error results from the fact that the sample is obtained as a time average within a sampling region, in a capacitor-based sample and hold circuit, aperture error is introduced because the capacitor cannot instantly change voltage thus requiring the sample to have non-zero width. Jitter or deviation from the precise sample timing intervals, noise, including thermal sensor noise, analog circuit noise, etc
6.
RGB color model
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The RGB color model is an additive color model in which red, green and blue light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three primary colors, red, green and blue. Before the electronic age, the RGB color model already had a theory behind it. Thus an RGB value does not define the same color across devices without some kind of color management, typical RGB input devices are color TV and video cameras, image scanners, video games, and digital cameras. Typical RGB output devices are TV sets of technologies, computer and mobile phone displays, video projectors, multicolor LED displays. Color printers, on the hand are not RGB devices. This article discusses concepts common to all the different color spaces that use the RGB color model, to form a color with RGB, three light beams must be superimposed. Each of the three beams is called a component of color, and each of them can have an arbitrary intensity, from fully off to fully on. The RGB color model is additive in the sense that the three beams are added together, and their light spectra add, wavelength for wavelength. This is essentially opposite to the color model that applies to paints, inks, dyes. When the intensities for all the components are the same, the result is a shade of gray, darker or lighter depending on the intensity. When the intensities are different, the result is a colorized hue, a secondary color is formed by the sum of two primary colors of equal intensity, cyan is green+blue, magenta is red+blue, and yellow is red+green. The RGB color model itself does not define what is meant by red, green and blue colorimetrically, and so the results of mixing them are not specified as absolute, but relative to the primary colors. When the exact chromaticities of the red, green and blue primaries are defined, the normal three kinds of light-sensitive photoreceptor cells in the human eye respond most to yellow, green, and violet light. As an example, suppose that light in the range of wavelengths enters the eye. Light of these wavelengths would activate both the medium and long wavelength cones of the retina, but not equally—the long-wavelength cells will respond more, the difference in the response can be detected by the brain, and this difference is the basis of our perception of orange. Thus, the appearance of an object results from light from the object entering our eye and stimulating the different cones simultaneously. The first experiments with RGB in early color photography were made in 1861 by Maxwell himself, to reproduce the color photograph, three matching projections over a screen in a dark room were necessary
7.
CMYK color model
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The CMYK color model is a subtractive color model, used in color printing, and is also used to describe the printing process itself. CMYK refers to the four used in some color printing, cyan, magenta, yellow. Though it varies by print house, press operator, press manufacturer, the K in CMYK stands for key because in four-color printing, cyan, magenta and yellow printing plates are carefully keyed, or aligned, with the key of the black key plate. Some sources suggest that the K in CMYK comes from the last letter in black and was chosen because B already means blue. Some sources claim this explanation, although useful as a mnemonic, is incorrect, the CMYK model works by partially or entirely masking colors on a lighter, usually white, background. The ink reduces the light that would otherwise be reflected, such a model is called subtractive because inks subtract brightness from white. In additive color models such as RGB, white is the combination of all primary colored lights. In the CMYK model, it is the opposite, white is the color of the paper or other background. To save cost on ink, and to produce deeper black tones, unsaturated and dark colors are produced by using black ink instead of the combination of cyan, magenta, with halftoning, a full continuous range of colors can be produced. To improve print quality and reduce moiré patterns, the screen for each color is set at a different angle. Common reasons for using black ink include, In traditional preparation of color separations, in some cases a black keyline was used when it served as both a color indicator and an outline to be printed in black. Because usually the black plate contained the keyline, the K in CMYK represents the keyline or black plate, also sometimes called the key plate. A combination of 100% cyan, magenta, and yellow inks soaks the paper with ink, making it slower to dry, causing bleeding, adding black ink absorbs more light and yields much better blacks. Using black ink is less expensive than using the corresponding amounts of colored inks. When a very dark area is desirable, a colored or gray CMY bedding is applied first, then a black layer is applied on top, making a rich, deep black. A black made with just CMY inks is sometimes called a composite black, the amount of black to use to replace amounts of the other ink is variable, and the choice depends on the technology, paper and ink in use. Processes called under color removal, under addition, and gray component replacement are used to decide on the final mix. CMYK or process color printing is contrasted with spot color printing, some printing presses are capable of printing with both four-color process inks and additional spot color inks at the same time
8.
Image sensor
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An image sensor or imaging sensor is a sensor that detects and conveys the information that constitutes an image. It does so by converting the variable attenuation of light waves into signals, the waves can be light or other electromagnetic radiation. As technology changes, digital imaging tends to replace analog imaging, early analog sensors for visible light were video camera tubes. Currently, used types are semiconductor charge-coupled devices or active pixel sensors in complementary metal–oxide–semiconductor or N-type metal-oxide-semiconductor technologies, analog sensors for invisible radiation tend to involve vacuum tubes of various kinds. Digital sensors include flat panel detectors, today, most digital cameras use a CMOS sensor, because CMOS sensors perform better than CCDs. An example is the fact that they incorporate an integrated circuit, CCD is still in use for cheap low entry cameras, but weak in burst mode. Both types of sensor accomplish the task of capturing light. Each cell of a CCD image sensor is an analog device, when light strikes the chip it is held as a small electrical charge in each photo sensor. This process is repeated until all the lines of pixels have had their charge amplified. A CMOS image sensor has an amplifier for each compared to the few amplifiers of a CCD. Some CMOS imaging sensors also use Back-side illumination to increase the number of photons that hit the photodiode, CMOS sensors can potentially be implemented with fewer components, use less power, and/or provide faster readout than CCD sensors. They are also vulnerable to static electricity discharges. Another approach is to utilize the very fine dimensions available in modern CMOS technology to implement a CCD like structure entirely in CMOS technology and this can be achieved by separating individual poly-silicon gates by a very small gap. These hybrid sensors are still in the phase and can potentially harness the benefits of both CCD and CMOS imagers. There are many parameters that can be used to evaluate the performance of a sensor, including dynamic range, signal-to-noise ratio. For sensors of comparable types, the ratio and dynamic range improve as the size increases. In order to avoid interpolated color information, techniques like color co-site sampling use a mechanism to shift the color sensor in pixel steps. 3CCD, using three discrete image sensors, with the color separation done by a dichroic prism, while in general digital cameras use a flat sensor, Sony prototyped a curved sensor in 2014 to reduce/eliminate Petzval field curvature that occurs with a flat sensor
9.
Portmanteau
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In linguistics, a portmanteau is defined as a single morph that represents two or more morphemes. A portmanteau also differs from a compound, which not involve the truncation of parts of the stems of the blended words. For instance, starfish is a compound, not a portmanteau, of star and fish, whereas a hypothetical portmanteau of star and fish might be stish. Humpty Dumpty explains the practice of combining words in various ways by telling Alice, for instance, take the two words fuming and furious. Make up your mind that you will say both words, but leave it unsettled which you will say first … if you have the rarest of gifts, in then-contemporary English, a portmanteau was a suitcase that opened into two equal sections. The etymology of the word is the French porte-manteau, from porter, to carry, in modern French, a porte-manteau is a clothes valet, a coat-tree or similar article of furniture for hanging up jackets, hats, umbrellas and the like. It has also used especially in Europe as a formal description for hat racks from the French words porter. An occasional synonym for portmanteau word is frankenword, an autological word exemplifying the phenomenon it describes, blending Frankenstein, many neologisms are examples of blends, but many blends have become part of the lexicon. In Punch in 1896, the word brunch was introduced as a portmanteau word, in 1964, the newly independent African republic of Tanganyika and Zanzibar chose the portmanteau word Tanzania as its name. Similarly Eurasia is a portmanteau of Europe and Asia, a scientific example is a liger, which is a cross between a male lion and a female tiger. Jeoportmanteau. is a category on the American television quiz show Jeopardy. The categorys name is itself a portmanteau of the words Jeopardy, responses in the category are portmanteaus constructed by fitting two words together. The term gerrymander has itself contributed to portmanteau terms bjelkemander and playmander, oxbridge is a common portmanteau for the UKs two oldest universities, those of Oxford and Cambridge. Many portmanteau words receive some use but do not appear in all dictionaries, for example, a spork is an eating utensil that is a combination of a spoon and a fork, and a skort is an item of clothing that is part skirt, part shorts. On the other hand, turducken, a made by inserting a chicken into a duck. Similarly, the word refudiate was first used by Sarah Palin when she misspoke, though initially a gaffe, the word was recognized as the New Oxford American Dictionarys Word of the Year in 2010. The business lexicon is replete with newly coined portmanteau words like permalance, advertainment, advertorial, infotainment, a company name may also be portmanteau as well as a product name. By contrast, the public, including the media, use portmanteaux to refer to their favorite pairings as a way to. giv people an essence of who they are within the same name and this is particularly seen in cases of fictional and real-life supercouples
10.
Voxel
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A voxel represents a value on a regular grid in three-dimensional space. As with pixels in a bitmap, voxels themselves do not typically have their position explicitly encoded along with their values, instead, the position of a voxel is inferred based upon its position relative to other voxels. In contrast to pixels and voxels, points and polygons are often represented by the coordinates of their vertices. Voxels are frequently used in the visualization and analysis of medical, some volumetric displays use voxels to describe their resolution. For example, a display might be able to show 512×512×512 voxels, the word voxel is based on a contraction of vox and el, similar formations with el for element include the words pixel and texel. A volume described as voxels can be visualized either by direct volume rendering or by the extraction of polygon iso-surfaces that follow the contours of given threshold values, the marching cubes algorithm is often used for isosurface extraction, however other methods exist as well. Both ray-tracing and ray-casting, as well as rasterisation, can be applied to data to obtain 2D raster graphics to depict on a monitor. Another technique for voxels involves raster graphics where you simply raytrace every pixel of the display into the scene, a typical implementation will raytrace each pixel of the display starting at the bottom of the screen using what is known as a y-buffer. There is a downside to voxel rasterization when transformation is applied which causes severe aliasing. The advantage was the ability to rasterise using cheap integer calculations on a CPU without hardware acceleration, Outcast, and other 1990s video games employed this graphics technique for effects such as reflection and bump-mapping and usually for terrain rendering. Outcasts graphics engine was mainly a combination of a ray casting engine, used to render the landscape, although Outcast is often cited as a forerunner of voxel technology, this is somewhat misleading. The game does not actually model three-dimensional volumes of voxels, instead, it models the ground as a surface, which may be seen as being made up of voxels. The ground is decorated with objects that are modeled using texture-mapped polygons, when Outcast was developed, the term voxel engine, when applied to computer games, commonly referred to a ray casting engine. On the engine technology page of the website, the landscape engine is also referred to as the Voxels engine. The engine is purely software-based, it does not rely on hardware-acceleration via a 3D graphics card, john Carmack also experimented with Voxels for the Quake III engine. One such problem cited by Carmack was the lack of graphics cards designed specifically for such rendering requiring them to be software rendered, Comanche was also the first commercial flight simulation based on voxel technology. NovaLogic used the proprietary Voxel Space engine developed for the company by Kyle Freeman to create open landscapes and this rendering technique allowed for much more detailed and realistic terrain compared to simulations based on vector graphics at that time. A voxel represents a sample, or data point, on a regularly spaced
11.
Texel (graphics)
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A texel, texture element, or texture pixel is the fundamental unit of a texture map, used in computer graphics. Textures are represented by arrays of texels representing the texture space, texels can also be described by image regions that are obtained through a simple procedure such as thresholding. Voronoi tesselation can be used to define their spatial relationships and this means that a division is made at the half-way point between the centroid of each texel and the centroids of every surrounding texel for the entire texture. The result is that each texel centroid will have a Voronoi polygon surrounding it and this polygon region consists of all points that are closer to its texel centroid than any other centroid. When texturing a 3D surface or surfaces, the renderer maps texels to appropriate pixels in the output picture, on modern computers, this operation is accomplished on the graphics processing unit. The texturing process starts with a location in space, the location can be in world space, but typically it is in Model space so that the texture moves with the model. A projector function is applied to the location to change the location from a three-element vector to a two-element vector with values ranging from zero to one and these values are multiplied by the resolution of the texture to obtain the location of the texel. When a texel is requested that is not on an integer position, when a texel is requested that is outside of the texture, one of two techniques is used, clamping or wrapping. Clamping limits the texel to the size, moving it to the nearest edge if it is more than the texture size. Wrapping moves the texel in increments of the size to bring it back into the texture. Wrapping causes a texture to be repeated, clamping causes it to be in one spot only
12.
Jet Propulsion Laboratory
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The Jet Propulsion Laboratory is a federally funded research and development center and NASA field center in La Cañada Flintridge, California and Pasadena, California, United States. The JPL is managed by the nearby California Institute of Technology for NASA, the laboratorys primary function is the construction and operation of planetary robotic spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASAs Deep Space Network and they are also responsible for managing the JPL Small-Body Database, and provides physical data and lists of publications for all known small Solar System bodies. The JPLs Space Flight Operations Facility and Twenty-Five-Foot Space Simulator are designated National Historic Landmarks, JPL traces its beginnings to 1936 in the Guggenheim Aeronautical Laboratory at the California Institute of Technology when the first set of rocket experiments were carried out in the Arroyo Seco. Malinas thesis advisor was engineer/aerodynamicist Theodore von Kármán, who arranged for U. S. Army financial support for this GALCIT Rocket Project in 1939. In 1941, Malina, Parsons, Forman, Martin Summerfield, in 1943, von Kármán, Malina, Parsons, and Forman established the Aerojet Corporation to manufacture JATO motors. The project took on the name Jet Propulsion Laboratory in November 1943, during JPLs Army years, the laboratory developed two deployed weapon systems, the MGM-5 Corporal and MGM-29 Sergeant intermediate range ballistic missiles. These missiles were the first US ballistic missiles developed at JPL and it also developed a number of other weapons system prototypes, such as the Loki anti-aircraft missile system, and the forerunner of the Aerobee sounding rocket. At various times, it carried out testing at the White Sands Proving Ground, Edwards Air Force Base. A lunar lander was developed in 1938-39 which influenced design of the Apollo Lunar Module in the 1960s. The team lost that proposal to Project Vanguard, and instead embarked on a project to demonstrate ablative re-entry technology using a Jupiter-C rocket. They carried out three successful flights in 1956 and 1957. Using a spare Juno I, the two organizations then launched the United States first satellite, Explorer 1, on February 1,1958, JPL was transferred to NASA in December 1958, becoming the agencys primary planetary spacecraft center. JPL engineers designed and operated Ranger and Surveyor missions to the Moon that prepared the way for Apollo, JPL also led the way in interplanetary exploration with the Mariner missions to Venus, Mars, and Mercury. In 1998, JPL opened the Near-Earth Object Program Office for NASA, as of 2013, it has found 95% of asteroids that are a kilometer or more in diameter that cross Earths orbit. JPL was early to employ women mathematicians, in the 1940s and 1950s, using mechanical calculators, women in an all-female computations group performed trajectory calculations. In 1961, JPL hired Dana Ulery as their first woman engineer to work alongside male engineers as part of the Ranger and Mariner mission tracking teams, when founded, JPLs site was a rocky flood-plain just outside the city limits of Pasadena. Almost all of the 177 acres of the U. S, the city of La Cañada Flintridge, California was incorporated in 1976, well after JPL attained international recognition with a Pasadena address
13.
Space probe
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A space probe is a robotic spacecraft that does not orbit the Earth, but, instead, explores further into outer space. A space probe may approach the Moon, travel through space, flyby, orbit, or land on other planetary bodies. Approximately fifteen missions are currently operational, once a probe has left the vicinity of Earth, its trajectory will likely take it along an orbit around the Sun similar to the Earths orbit. To reach another planet, the simplest practical method is a Hohmann transfer orbit, more complex techniques, such as gravitational slingshots, can be more fuel-efficient, though they may require the probe to spend more time in transit. Some high Delta-V missions can only be performed, within the limits of modern propulsion, a technique using very little propulsion, but requiring a considerable amount of time, is to follow a trajectory on the Interplanetary Transport Network. First man-made object to land on the Moon, or any other extra terrestrial surface. First mission to photograph the far side of the Moon, launched in 1959, first robotic sample return probe from the Moon. It was sent to the Moon on November 10,1970, first successful in-place analysis of another planet. It may have also been the first space probe to impact the surface of another planet, the Venera 7 probe was the first spacecraft to successfully soft land on another planet and to transmit data from there back to Earth. Upon its arrival at Mars on November 13,1971, Mariner 9 became the first space probe to orbit around another planet. Although, the spacecraft failed shortly after landing, the Mars Exploration Rovers, Spirit and Opportunity surface and geology, and searched for clues to past water activity on Mars. They were each launched in 2003 and landed in 2004, communication with Spirit stopped on sol 2210. JPL continued to attempt to regain contact until May 24,2011, Opportunity arrived at Endeavour crater on 9 August 2011, at a landmark called Spirit Point named after its rover twin, after traversing 13 miles from Victoria crater, over a three-year period. As of January 26,2016, Opportunity has lasted for more than twelve years on Mars — although the rovers were intended to last only three months. The first dedicated missions to a comet, in this case and they dropped landers and balloons at Venus before their rendezvous with Halleys Comet. This Japanese probe was the first non-US, non-Soviet interplanetary probe, a second Japanese probe, it made ultraviolet wavelength observations of the comet. The first space probe to penetrate a comets coma and take images of its nucleus. First solar wind sample return probe from sun-earth L1, first sample return probe from a comet tail
14.
Palo Alto, California
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Palo Alto is a charter city located in the northwest corner of Santa Clara County, California, in the San Francisco Bay Area of the United States. The city shares its borders with East Palo Alto, Mountain View, Los Altos, Los Altos Hills, Stanford, Portola Valley and it is named after a coast redwood tree called El Palo Alto. Palo Alto was established by Leland Stanford Sr. when he founded Stanford University, following the death of his son and it has also served as an incubator to several other high-technology companies such as Google, Facebook, Logitech, Intuit, Pinterest, and PayPal. As of the 2010 census, the total resident population is 64,403. Palo Alto is one of the most expensive cities in the United States, the recorded history of Palo Alto dates back to 1769, when Gaspar de Portolá noted an Ohlone settlement. This remains an area of known Indian mounds, a plaque at Middlefield Road and Embarcadero Road commemorates the area. The city got its name from a tall coast redwood tree, named El Palo Alto, a plaque there recounts the story of the Portolà expedition, a 63-man, 200-horse expedition from San Diego to Monterey from November 7–11,1769. The group overshot Monterey in the fog and when they reached modern-day Pacifica, they ascended Sweeney Ridge, thinking the bay was too wide to cross, the group retraced their journey to Monterey, never becoming aware of the Golden Gate entrance to the Bay. Located south of the San Francisquito Creek, west of todays I-280, in 1835, Rafael Soto and family settled near the San Francisquito Creek near Newell and Middlefield, selling goods to travelers. Rafael Soto died in 1839, but his wife, Maria Antonia Mesa, was granted Rancho Rinconada del Arroyo de San Francisquito in 1841, in 1839, their daughter María Luisa Soto married John Coppinger, who was the grantee of Rancho Cañada de Raymundo. Rancho Cañada de Raymundo was West of San Francisquito Creek, and began at Alambique Creek, the border of Rancho Corte de Madera. Bear Gulch Creek flowed on his land in Portola Valley, the rancho also abutted Buelnas grant near Skyline Boulevard and Matadero Creek. Upon Coppingers death, Maria inherited it and later married a visiting boat captain, Greer owned a home on the site that is now Town & Country Village on Embarcadero and El Camino Real. Greer Avenue and Court are named for him, to the west of Rafael Soto, near El Camino and following the Creek, was Rancho San Francisquito granted in 1839 to Antonio Buelna and wife Maria Concepcion. To the south of the Sotos, the brothers Secundino and Teodoro Robles in 1849 bought Rancho Rincon de San Francisquito from José Peña, where the Joness house was, then east down Arastradero Rd. to the north property line of Alta Mesa Memorial Park and Terman Park. The property then went along the bay to the Embarcadero, a boundary in the day, then up to the Stanford University gates, up Galvez. The grant was bounded on the south by Mariano Castros Rancho Pastoria de las Borregas grant across San Antonio Road, thats the Robles Rancho, about 80% of Palo Alto and Stanford University. It was whittled down by 1863 through courts to 6,981 acres, stories say their grand hacienda was built on the former meager adobe of José Peña near Ferne off San Antonio Road, midway between Middlefield and Alma Street
15.
Variety (magazine)
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Variety is a weekly American entertainment trade magazine and website owned by Penske Media Corporation. The last daily printed edition was put out on March 19,2013, Variety originally reported on theater and vaudeville. Variety has been published since December 16,1905, when it was launched by Sime Silverman as a weekly periodical covering vaudeville with its headquarters in New York City, on January 19,1907, Variety published what is considered the first film review in history. In 1933, Sime Silverman launched Daily Variety, based in Hollywood, Sime Silverman had passed on the editorship of the Weekly Variety to Abel Green as his replacement in 1931, he remained as publisher until his death in 1933 soon after launching the Daily. His son Sidne Silverman, known as Skigie, succeeded him as publisher of both publications, both Sidne and his wife, stage actress Marie Saxon, died of tuberculosis. Their only son Syd Silverman, born 1932, was the heir to what was then Variety Inc. Young Syds legal guardian Harold Erichs oversaw Variety Inc. until 1956, after that date Syd Silverman was publisher of both the Weekly Variety in New York and the Daily Variety in Hollywood, until the sale of both papers in 1987 to the Cahners Corp. In L. A. the Daily was edited by Tom Pryor from 1959 until 1988, for twenty years its editor-in-chief was Peter Bart, originally only of the weekly New York edition, with Michael Silverman running the Daily in Hollywood. Bart had worked previously at Paramount Pictures and The New York Times, in April 2009, Bart moved to the position of vice president and editorial director, characterized online as Boffo No More, Bart Up and Out at Variety. From mid 2009 to 2013, Timothy M. Gray oversaw the publication as Editor-in-Chief, after over 30 years of various reporter, in October 2014, Eller and Wallenstein were upped to Co-Editors in Chief, with Littleton continuing to oversee the trades television coverage. This dissemination comes in the form of columns, news stories, images, video, Cahners Publishing purchased Variety from the Silverman family in 1987. On December 7,1988, Barts predecessor, Roger Watkins, proposed, upon its launch, the new-look Variety measured one inch shorter with a washed-out color on the front. In October 2012, Reed Business Information, the periodicals owner, PMC is the owner of Deadline. com, which since the 2007–2008 Writers Guild of America strike has been considered Varietys largest competitor in online showbiz news. In October,2012, Jay Penske announced that the paywall would come down, the print publication would stay. A significant portion of the advertising revenue comes during the film-award season leading up to the Academy Awards. During this Awards Season, large numbers of colorful, full-page For Your Consideration advertisements inflate the size of Variety to double or triple its usual page count, paid circulation for the weekly Variety magazine in 2013 was 40,000. Each copy of each Variety issue is read by an average of three people, with a total readership of 120,000. Variety. com has 17 million unique monthly visitors, Variety is a weekly entertainment publication with a broad coverage of movies, television, theater, music and technology, written for entertainment executives
16.
Paul Gottlieb Nipkow
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Paul Julius Gottlieb Nipkow was a German technician and inventor. He invented the Nipkow disk, one of the first successful technologies for television transmission, hundreds of stations experimented with television broadcasting using the Nipkow system in the 1920s and 1930s, until it was superseded by all-electronic systems in the 1940s. Nipkow was born in Lauenburg in the Prussian province of Pomerania, while at school in neighbouring Neustadt, in the province of West Prussia, Nipkow experimented in telephony and the transmission of moving pictures. After graduation, he went to Berlin in order to study science and he studied physiological optics with Hermann von Helmholtz, and electro-physics with Adolf Slaby. While still a student he conceived the idea of using a disk, to divide a picture into a mosaic of points. Accounts of its invention state that the idea came to him while sitting alone at home with an oil lamp on Christmas Eve,1883, alexander Bain had transmitted images telegraphically in the 1840s but the Nipkow disk improved the encoding process. He applied to the patent office in Berlin for a patent covering an electric telescope for the electric reproduction of illuminating objects. This was granted on 15 January 1885, retroactive to January 6,1884 and it is not known whether Nipkow ever attempted a practical realization of this disk but one may assume that he himself never constructed one. The patent lapsed after 15 years owing to lack of interest, Nipkow took up a position as a designer at an institute in Berlin-Buchloh and did not continue work on the broadcasting of pictures. The first television broadcasts used an optical-mechanical picture scanning method, the method that Nipkow had helped create with his disk, Nipkow recounted his first sight of television at a Berlin radio show in 1928, the televisions stood in dark cells. Hundreds stood and waited patiently for the moment at which they would see television for the first time, I waited among them, growing ever more nervous. Now for the first time I would see what I had devised 45 years ago, finally I reached the front row, a dark cloth was pushed to the side, and I saw before me a flickering image, not easy to discern. The system demonstrated was from John Logie Bairds Baird Television Company and he became honorary president of the television council of the Imperial Broadcasting Chamber. German inventors and discoverers History of television Works by or about Paul Gottlieb Nipkow at Internet Archive The Television System of Paul Nipkow
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Electronics World
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Electronics World is a technical magazine in electronics and RF engineering aimed at professional design engineers. It is produced monthly in print and digital formats and it encompasses a range of issues in the electronics and RF industry, from design through to product implementation. The features are contributed by engineers and academics in the electronics industry, the Marconi Company published the first issue of the journal The Marconigraph in April 1911. This monthly magazine was the first significant journal dedicated to wireless communication, in April 1913, after two years and 24 issues, The Marconigraph was superseded by The Wireless World. An Illustrated Monthly Magazine for all interested in Wireless Telegraphy and Telephony as its first issue was sold on news-stands, with the same issue, publication frequency of Wireless World became weekly. A similar series was published after 1945 utilising the then ubiquitous EF50 RF pentode amplifier valve, with the outbreak of World War II and the expected shortages of paper and other resources, the publication reverted to being monthly, a frequency that it still retains to this day. The title was changed in September 1984 to Electronics and Wireless World, a sister publication was Wireless Engineer which was more of a learned journal than a popular magazine, featuring high quality, technical articles. In October 1945 Wireless World published what became a famous article by Arthur C. Clarke which foresaw the coming of communications satellites in synchronous orbit around the Earth. In his Wireless World article Clarke suggested that three satellites placed in the equatorial orbit at an altitude of 36,000 km, spaced 120 degrees apart. In 1962 NASA launched Telstar 1, the first communications satellite, Telstar 1 lasted only six months, but this paved the way for modern-day communications-there are nearly 900 active satellites in orbit today of which some two-thirds are communications satellites. Clarkes article, Extra-Terrestrial Relays, was Electronic World readers most asked for article to re-print in the centenary edition. The article was featured in the BBCs The Genius of Invention programme broadcast on 7 February 2013. For decades, Wireless World was a place where pioneers in audio, in 1952 it made the first public announcement of the Baxandall tone control circuit, a design now employed in millions of hi-fi systems including amplifiers and effects for musical instruments. In 1955 it published the design of the popular Mullard 5-10 audio amplifier using two EL84 power pentodes in ultra-linear push-pull configuration, in 1975/6 Wireless World published the design of a decoder of broadcast TV Teletext information before the first commercial decoder became available. Later it published regular columns of brief Circuit Ideas, in the August to December 1967 editions a series, Wireless World Digital Computer by Brian Crank, was published. It described how to build a simple binary computer at home. It was constructed entirely from reject transistors, and was intended for teaching the principles of computer operation. In 1977 a series of articles was published based on the design of the NASCOM1 computer, in 1979 they published a design by John Adams for a dual-processor desktop computer which included a novel high-level programming language
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IBM Personal Computer
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The IBM Personal Computer, commonly known as the IBM PC, is the original version and progenitor of the IBM PC compatible hardware platform. It is IBM model number 5150, and was introduced on August 12,1981 and it was created by a team of engineers and designers under the direction of Don Estridge of the IBM Entry Systems Division in Boca Raton, Florida. IBM compatible became an important criterion for sales growth, only the Apple Macintosh family kept significant market share without compatibility with the IBM personal computer, International Business Machines, one of the worlds largest companies, had a 62% share of the mainframe computer market in 1981. Its share of the computer market, however, had declined from 60% in 1970 to 32% in 1980. In 1979 BusinessWeek asked, Is IBM just another stodgy, mature company, by 1981 its stock price had declined by 22%. IBMs earnings for the first half the year grew by 5. 3%—one third of the inflation rate—while those of minicomputer maker Digital Equipment Corporation grew by more than 35%. B. M, No longer dominates the computer business. IBM wished to avoid the outcome with the new personal computer industry, dominated by the Commodore PET, Atari 8-bit family, Apple II, Tandy Corporations TRS-80. With $150 million in sales by 1979 and projected growth of more than 40% in the early 1980s. The Japanese project, codenamed Go, ended before the 1981 release of the American-designed IBM PC codenamed Chess, whether IBM had waited too long to enter an industry in which Apple and others were already successful was unclear. An observer stated that IBM bringing out a computer would be like teaching an elephant to tap dance. Successful microcomputer company Vector Graphics fiscal 1980 revenue was $12 million, the company only sold through its internal sales force, had no experience with resellers or retail stores, and did not introduce the first product designed to work with non-IBM equipment until 1980. Another observer claimed that IBM made decisions so slowly that, when tested, as with other large computer companies, its new products typically required about four to five years for development. IBM had to learn how to develop, mass-produce. The potential importance to microcomputers of a company so prestigious, that a saying in American companies stated No one ever got fired for buying IBM, was nonetheless clear. InfoWorld, which described itself as The Newsweekly for Microcomputer Users, stated that for my grandmother, is far and away the media star, not because of its features, but because it exists at all. When the number eight company in the Fortune 500 enters the field, the influence of a personal computer made by a company whose name has literally come to mean computer to most of the world is hard to contemplate. The editorial acknowledged that some factions in our industry have looked upon IBM as the enemy, desktop sized programmable calculators by Hewlett Packard had evolved into the HP9830 BASIC language computer by 1972. In 1972–1973 a team led by Dr. SCAMP emulated an IBM1130 minicomputer to run APL\1130, in 1973 APL was generally available only on mainframe computers, and most desktop sized microcomputers such as the Wang 2200 or HP9800 offered only BASIC
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Pixie
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Pixies are mythical creatures of folklore, considered to be particularly concentrated in the high moorland areas around Devon and Cornwall, suggesting some Celtic origin for the belief and name. Akin to the Irish and Scottish Aos Sí, pixies are believed to inhabit ancient underground ancestor sites such as circles, barrows, dolmens. Sometimes their eyes are described as being pointed upwards at the temple ends and these, however, are Victorian era conventions and not part of the older mythology. In modern use, the term can be synonymous with fairies or sprites, however, in folklore there is a traditional enmity, even war, between the two races. The origin of the name pixie is uncertain, some have speculated that it comes from the Swedish dialectal pyske meaning wee little fairy. The term Pobel Vian is often used to refer to them collectively, in west Penwith, the area of late survival of the Cornish language, spriggans are distinguished from pixies by their malevolent nature. Closely associated with tin mining in Cornwall are the subterranean ancestral knockers, Pixie mythology is believed to pre-date Christian presence in Britain. In the Christian era they were said to be the souls of children who had died un-baptised. These children would change their appearance to pixies once their clothing was placed in clay pots used in their earthly lives as toys. By 1869 some were suggesting that the name pixie was a remnant of Pictic tribes who used to paint and tattoo their skin blue. This suggestion is still met in contemporary writing, but there is no proven connection, the earliest published version of The Three Little Pigs story is from Dartmoor in 1853 and has three little pixies in place of the pigs. Until the advent of modern fiction, pixie mythology was localised to Britain. Some have noted similarities to northern fairies, Germanic and Scandinavian elves, before the mid-19th century, pixies and fairies were taken seriously in much of Cornwall and Devon. Books devoted to the beliefs of the peasantry are filled with incidents of pixie manifestations. Some locales are named for the associated with them. In Devon, near Challacombe, a group of rocks are named for the said to dwell there. At Trevose Head in Cornwall 600 pixies were said to have gathered dancing and laughing in a circle that had appeared upon the turf until one of their number, named Omfra, in some areas belief in pixies and fairies as real beings persists. In the legends associated with Dartmoor, pixies are said to themselves as a bundle of rags to lure children into their play
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Norman McLaren
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Norman McLaren, CC CQ was a Scottish/Canadian animator, director and producer known for his work for the National Film Board of Canada. He was a pioneer in a number of areas of animation and filmmaking, including animation, drawn-on-film animation, visual music, abstract film, pixilation. McLaren was born in Stirling, Scotland and studied set design at the Glasgow School of Art and his early experiments with film and animation included actually scratching and painting the film stock itself, as he did not have ready access to a camera. His earliest extant film, Seven Till Five, a day in the life of an art school was influenced by Eisenstein and displays a strongly formalist attitude. McLaren used pixilation effects, superimpositions and animation not only to display the staging of an art school ball and his two early films won prizes at the Scottish Amateur Film Festival, where fellow Scot and future NFB founder John Grierson was a judge. Grierson, who was at that head of the UK General Post Office film unit, saw another of his movies at an amateur film festival. He hired McLaren for the GPO after his studies, following a stint as cameraman on Defence of Madrid, Ivor Montagu’s documentary on the Spanish Civil War. McLaren worked at the GPO from 1936 to 1939, making four films including, Book Bargain, Mony a Pickle and Love on the Wing, McLaren then moved to New York City in 1939, just as World War II was about to begin in Europe. With a grant from the Solomon Guggenheim Foundation, he worked in New York until 1941, making four drawn-on-film animated works, Boogie-Doodle, along with Dots, Loops and Stars and Stripes. At the invitation of Grierson, he moved to Canada in 1941 to work for the National Film Board, to open an animation studio, upon McLarens arrival in Canada, Grierson asked him to direct a promotional film reminding Canadians to mail their Christmas cards early, Mail Early. He then worked on animated shorts as well as maps for Allied propaganda documentary films, followed by his War Bonds campaign films, V for Victory,5 for 4, Hen Hop and Dollar Dance. McLaren trained these emerging animators, who would all work on cartoons, animated cards, studio A, the NFBs first animation studio, formally came into existence as of January 1943, with McLaren as its head. During his work for the NFB, McLaren created his most famous film, Neighbours, which has won various awards around the world, including the Canadian Film Award and the Academy Award. Besides the brilliant combination of visuals and sound, the film has a strong social message against violence. In his early period in Canada, McLaren spent considerable time developing the department of the board. In addition to film, McLaren worked with UNESCO in the 1950s and 1960s on programs to teach film and animation techniques in China and his five part Animated Motion shorts, produced in the late 1970s, are an excellent example of instruction on the basics of film animation. McLaren is remembered for his experiments with image and sound as he developed a number of groundbreaking techniques for combining and synchronizing animation with music, the National Film Board honoured McLaren by naming its Montreal head office building the Norman McLaren Building. The Montreal borough of Saint-Laurent, which is home to the NFB, has also honoured McLaren by naming a borough district after him, in 2006, he was the subject of a short animated documentary McLarens Negatives
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Grant Munro (filmmaker)
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Grant Munro, OC is a Canadian animator, filmmaker and actor. He was born in Winnipeg, Manitoba and he has one sister and a brother. Brian Munro spent his life in the Canadian Forces, serving with Princess Patricias Canadian Light Infantry. Of note, he received the Presidential Unit Citation for the Battle of Kapyong in the Korean War. Grant Munro was educated at the Robert H. Smith school, Queenston school, and Gordon Bell High, before attending the Musgrove School of Art and the Winnipeg School of Art. Earning an honor diploma from the Ontario College of Art in 1944, he joined the National Film Board, Canadas public film producer. His work as an animator first won note during 1945, setting the songs My Darling Clementine and he went on to collaborate with McLaren on the films Two Bagatelles, Seven Surprizes, Christmas Cracker and Canon. In the 1970s, Munros focus shifted to documentaries and he also directed See You in the Funny Papers, which examined the life and work of cartoonist Lynn Johnston. Munro retired from the National Film Board in 1988, the 1962 short Christmas Cracker was nominated for an Academy Award and won a Golden Gate Award. Canon won the Canadian Film Award for Best Arts and Experimental, on June 20,2007 Concordia University awarded Munro an honorary doctorate in recognition of his legacy for generations of filmmakers. On October 10,2008, Grant Munro was made an Officer in the Order of Canada by Governor General Michaëlle Jean, the backgrounder to the award read as follows, Grant Munro is a pioneering animator and filmmaker. One of the earliest and longest-serving members of the National Film Board of Canada, as well, he was involved in making several award-winning films and has been an inspiring role model and dedicated mentor to several generations of young filmmakers. A frequent collaborator with Norman McLaren, Munro brought a wicked wit and sublime grace to the art
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Digital camera
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A digital camera or digicam is a camera that produces digital images that can be stored in a computer, displayed on a screen and printed. Most cameras sold today are digital, and digital cameras are incorporated into many devices ranging from PDAs, Digital and movie cameras share an optical system, typically using a lens with a variable diaphragm to focus light onto an image pickup device. The diaphragm and shutter admit the correct amount of light to the imager, just as with film, however, unlike film cameras, digital cameras can display images on a screen immediately after being recorded, and store and delete images from memory. Many digital cameras can also record moving videos with sound, some digital cameras can crop and stitch pictures and perform other elementary image editing. The history of the camera began with Eugene F. Lally of the Jet Propulsion Laboratory. His 1961 idea was to take pictures of the planets and stars while travelling through space to give information about the astronauts position, unfortunately, as with Texas Instruments employee Willis Adcocks filmless camera in 1972, the technology had yet to catch up with the concept. Steven Sasson as an engineer at Eastman Kodak invented and built the first electronic camera using a charge-coupled device image sensor in 1975, earlier ones used a camera tube, later ones digitized the signal. Early uses were military and scientific, followed by medical. In the mid to late 1990s digital cameras became common among consumers, by the mid-2000s digital cameras had largely replaced film cameras, and higher-end cell phones had an integrated digital camera. By the beginning of the 2010s, almost all smartphones had a digital camera. The two major types of image sensor are CCD and CMOS. A CCD sensor has one amplifier for all the pixels, while each pixel in a CMOS active-pixel sensor has its own amplifier, compared to CCDs, CMOS sensors use less power. Cameras with a small sensor use a back-side-illuminated CMOS sensor, overall final image quality is more dependent on the image processing capability of the camera, than on sensor type. The resolution of a camera is often limited by the image sensor that turns light into that discrete signals. The brighter the image at a point on the sensor. Depending on the structure of the sensor, a color filter array may be used. The number of pixels in the sensor determines the cameras pixel count, in a typical sensor, the pixel count is the product of the number of rows and the number of columns. For example, a 1,000 by 1,000 pixel sensor would have 1,000,000 pixels, final quality of an image depends on all optical transformations in the chain of producing the image
23.
Dots per inch
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Dots per inch is a measure of spatial printing or video dot density, in particular the number of individual dots that can be placed in a line within the span of 1 inch. Monitors do not have dots, but do have pixels, the related concept for monitors. Many resources, including the Android developer guide, use the terms DPI and PPI interchangeably, old CRT type video displays were almost universally rated in dot pitch, which refers to the spacing between the sub-pixel red, green and blue dots which made up the pixels themselves. Monitor manufacturers used the term dot trio pitch, the measurement of the distance between the centers of adjacent groups of three dots/rectangles/squares on the CRT screen. Monitors commonly used dot pitches of 0.39,0.33,0.32,0.29,0.27,0.25, LCD monitors have a trio of sub pixels, which are more easily measured. This is caused by the spreading of ink on the surface of the media, up to a point, printers with higher DPI produce clearer and more detailed output. A printer does not necessarily have a single DPI measurement, it is dependent on print mode, the range of DPI supported by a printer is most dependent on the print head technology it uses. A dot matrix printer, for example, applies ink via tiny rods striking an ink ribbon, an inkjet printer sprays ink through tiny nozzles, and is typically capable of 300–720 DPI. A laser printer applies toner through an electrostatic charge. The DP measurement of a printer often needs to be higher than the pixels per inch measurement of a video display in order to produce similar-quality output. This is due to the range of colors for each dot typically available on a printer. Higher-end inkjet printers can offer 5,6 or 7 ink colors giving 32,64 or 128 possible tones per dot location, contrast this to a standard sRGB monitor where each pixel produces 256 intensities of light in each of three channels. While some color printers can produce variable drop volumes at each dot position, and may use additional ink-color channels and this dithered printing process could require a region of four to six dots in order to faithfully reproduce the color in a single pixel. Fittingly,600 dpi is now the output resolution of entry-level laser printers and some utility inkjet printers, with 1200/1440. In printing, DPI refers to the resolution of a printer or imagesetter. DPI refers to the dot density of an image when it is reproduced as a real physical entity. A digitally stored image has no inherent physical dimensions, measured in inches or centimeters, some digital file formats record a DPI value, or more commonly a PPI value, which is to be used when printing the image. This number lets the printer or software know the size of the image, or in the case of scanned images
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Pixel density
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Horizontal and vertical density are usually the same, as most devices have square pixels, but differ on devices that have non-square pixels. PPI can also describe the resolution, in pixels, of an image file, the unit is not square centimeters—a 100×100 pixel image printed in a 1 cm square has a resolution of 100 pixels per centimeter. Used this way, the measurement is meaningful when printing an image and it has become commonplace to refer to PPI as DPI, even though PPI refers to input resolution. Industry standard, good quality photographs usually require 330 pixels per inch, at 100% size and this delivers a quality factor of 2, which is optimum. The lowest acceptable quality factor is considered 1.5, which equates to printing a 225 ppi image using a 150 lpi screen onto coated paper, screen frequency is determined by the type of paper the image is printed on. An absorbent paper surface, uncoated recycled paper for instance, lets ink droplets spread —so requires a more open printing screen, input resolution can therefore be reduced to minimize file size without loss in quality, as long as the quality factor of 2 is maintained. This is easily determined by doubling the line frequency, for example, printing on an uncoated paper stock often limits printing screen frequency to no more than 120 lpi, therefore, a quality factor of 2 is achieved with images of 240 ppi. The PPI of a display is related to the size of the display in inches. This measurement is referred to as dots per inch, though that measurement more accurately refers to the resolution of a computer printer. This figure is determined by dividing the width of the area in pixels by the width of the display area in inches. It is possible for a display to have different horizontal and vertical PPI measurements, the dot pitch of a computer display determines the absolute limit of possible pixel density. In January 2008, Kopin Corporation announced a 0.44 inch SVGA LCD with a density of 2272 PPI. In 2011 they followed this up with a 3760 DPI0. 21” diagonal VGA colour display, the manufacturer says they designed the LCD to be optically magnified, as in high-resolution eyewear devices. Holography applications demand even greater density, as higher pixel density produces a larger image size. Spatial light modulators can reduce pixel pitch to 2.5 μm, some observations indicate that the unaided human generally cant differentiate detail beyond 300 PPI. However, this figure depends both on the distance between viewer and image, and the visual acuity. The human eye also responds in a different way to a bright, high pixel density display technologies would make supersampled antialiasing obsolete, enable true WYSIWYG graphics and, potentially enable a practical “paperless office” era. For perspective, such a device at 15 inch screen size would have to more than four Full HD screens
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Image resolution
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Image resolution is the detail an image holds. The term applies to digital images, film images. Higher resolution means more image detail, image resolution can be measured in various ways. Resolution quantifies how close lines can be to other and still be visibly resolved. Resolution units can be tied to physical sizes, to the size of a picture. Line pairs are used instead of lines, a line pair comprises a dark line. A line is either a line or a light line. A resolution of 10 lines per millimeter means 5 dark lines alternating with 5 light lines, photographic lens and film resolution are most often quoted in line pairs per millimeter. The resolution of digital cameras can be described in different ways. Resolution is the capability of the sensor to observe or measure the smallest object clearly with distinct boundaries, there is a difference between the resolution and a pixel. A pixel is actually a unit of the digital Resolution depends upon the size of the pixel, usually, with any given lens setting, the smaller the size of the pixel, the higher the resolution will be and the clearer the object in the image will be. Images having smaller pixel sizes might consist of more pixels, the number of pixels correlates to the amount of information within the image. An image of N pixels height by M pixels wide can have any less than N lines per picture height. Other conventions include describing pixels per unit or pixels per area unit. None of these pixel resolutions are true resolutions, but they are referred to as such. Below is an illustration of how the image might appear at different pixel resolutions. An image that is 2048 pixels in width and 1536 pixels in height has a total of 2048×1536 =3,145,728 pixels or 3.1 megapixels, one could refer to it as 2048 by 1536 or a 3. 1-megapixel image. Or, you can think of it as a low quality image if printed at about 28.5 inches wide
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Video Graphics Array
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Video Graphics Array is the display hardware first introduced with the IBM PS/2 line of computers in 1987. Today, the VGA analog interface is used for high definition video, including resolutions of 1080p, while the transmission bandwidth of VGA is high enough to support even higher resolution playback, there can be picture quality degradation depending on cable quality and length. How discernible this degradation is depends on the individuals eyesight and the display, though it is noticeable when switching to. The VGA supports both All Points Addressable graphics modes, and alphanumeric text modes, the other color modes defaulted to standard EGA or CGA compatible palettes, but could still be redefined if desired using VGA-specific programming. g. 400×600 or 360×480, and thin pixels,16 colors and the 70 Hz refresh rate with e. g. 736×410 mode. Its single-chip implementation allowed the VGA to be placed directly on a PC′s motherboard with a minimum of difficulty, since it only required video memory, timing crystals, the original VGA specifications are as follows,256 KB Video RAM 16-color and 256-color paletted display modes. 262, 144-color global palette Selectable 25.175 MHz or 28.322 MHz master pixel clock Usual line rate fixed at 31, compatibility is almost full at BIOS level, but even at register level, a very high value of compatibility is reached. The formula for the VGA horizontal frequency is thus ×525 kHz =4500 ÷143 kHz ≈31.4685 kHz, All other frequencies used by the VGA card are derived from this value by integer multiplication or division. Since the exactness of quartz oscillators is limited, real cards will have higher or lower frequency. All derived VGA timings can be varied widely by software that bypasses the VGA firmware interface and communicates directly with the VGA hardware, the use of other timings may in fact damage such monitors and thus was usually avoided by software publishers. For the most common VGA mode, the timings are. The figures shown in this image may be inaccurate and not match the above table exactly. The same general layout applies, merely at a lower frequency and these timings are the same in the higher frequency mode, but all pixel counts are correspondingly multiplied by 9/8ths – thus,720 active pixels,900 total per line, and a 54 pixel back porch. The monitor is triggered into synchronising at the higher frame rate by use of a positive-polarity VSync pulse. Depending on manufacturer, the details of active period and front/back porch widths, particularly in the horizontal domain. 640×400 @70 Hz is traditionally the video used for booting most VGA-compatible x86 personal computers which show a graphical boot screen. 640×480 @60 Hz is the default Windows graphics mode, up to Windows 2000 and it remains an option in XP and later versions via the boot menu low resolution video option and per-application compatibility mode settings. 320×200 @70 Hz is the most common mode for VGA-era PC games, using exactly the same timings as the 640×400 mode, the actual timings vary slightly from the defined standard
27.
JPEG
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JPEG is a commonly used method of lossy compression for digital images, particularly for those images produced by digital photography. The degree of compression can be adjusted, allowing a selectable tradeoff between size and image quality. JPEG typically achieves 10,1 compression with little loss in image quality. JPEG compression is used in a number of file formats. These format variations are not distinguished, and are simply called JPEG. The term JPEG is an initialism/acronym for the Joint Photographic Experts Group, the MIME media type for JPEG is image/jpeg, except in older Internet Explorer versions, which provides a MIME type of image/pjpeg when uploading JPEG images. JPEG files usually have an extension of. jpg or. jpeg. JPEG/JFIF supports a maximum size of 65, 535×65,535 pixels. JPEG stands for Joint Photographic Experts Group, the name of the committee created the JPEG standard. The Joint stood for ISO TC97 WG8 and CCITT SGVIII, in 1987 ISO TC97 became ISO/IEC JTC1 and in 1992 CCITT became ITU-T. Currently on the JTC1 side JPEG is one of two sub-groups of ISO/IEC Joint Technical Committee 1, Subcommittee 29, Working Group 1 – titled as Coding of still pictures, on the ITU-T side ITU-T SG16 is the respective body. The original JPEG group was organized in 1986, issuing the first JPEG standard in 1992, which was approved in September 1992 as ITU-T Recommendation T.81 and in 1994 as ISO/IEC 10918-1. The JPEG standard specifies the codec, which defines how an image is compressed into a stream of bytes and decompressed back into an image, the Exif and JFIF standards define the commonly used file formats for interchange of JPEG-compressed images. JPEG standards are formally named as Information technology – Digital compression, ISO/IEC10918 consists of the following parts, Ecma International TR/98 specifies the JPEG File Interchange Format, the first edition was published in June 2009. The JPEG compression algorithm is at its best on photographs and paintings of scenes with smooth variations of tone. For web usage, where the amount of used for an image is important. JPEG/Exif is also the most common format saved by digital cameras, on the other hand, JPEG may not be as well suited for line drawings and other textual or iconic graphics, where the sharp contrasts between adjacent pixels can cause noticeable artifacts. Such images may be saved in a lossless graphics format such as TIFF, GIF, PNG
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Bijection
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In mathematical terms, a bijective function f, X → Y is a one-to-one and onto mapping of a set X to a set Y. A bijection from the set X to the set Y has a function from Y to X. If X and Y are finite sets, then the existence of a means they have the same number of elements. For infinite sets the picture is complicated, leading to the concept of cardinal number. A bijective function from a set to itself is called a permutation. Bijective functions are essential to many areas of including the definitions of isomorphism, homeomorphism, diffeomorphism, permutation group. Satisfying properties and means that a bijection is a function with domain X and it is more common to see properties and written as a single statement, Every element of X is paired with exactly one element of Y. Functions which satisfy property are said to be onto Y and are called surjections, Functions which satisfy property are said to be one-to-one functions and are called injections. With this terminology, a bijection is a function which is both a surjection and an injection, or using words, a bijection is a function which is both one-to-one and onto. Consider the batting line-up of a baseball or cricket team, the set X will be the players on the team and the set Y will be the positions in the batting order The pairing is given by which player is in what position in this order. Property is satisfied since each player is somewhere in the list, property is satisfied since no player bats in two positions in the order. Property says that for each position in the order, there is some player batting in that position, in a classroom there are a certain number of seats. A bunch of students enter the room and the instructor asks them all to be seated. After a quick look around the room, the instructor declares that there is a bijection between the set of students and the set of seats, where each student is paired with the seat they are sitting in. The instructor was able to conclude there were just as many seats as there were students. For any set X, the identity function 1X, X → X, the function f, R → R, f = 2x +1 is bijective, since for each y there is a unique x = /2 such that f = y. In more generality, any linear function over the reals, f, R → R, f = ax + b is a bijection, each real number y is obtained from the real number x = /a. The function f, R →, given by f = arctan is bijective since each real x is paired with exactly one angle y in the interval so that tan = x
29.
Bitmap
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In computing, a bitmap is a mapping from some domain to bits, that is, values which are zero or one. It is also called a bit array or bitmap index, in computer graphics, when the domain is a rectangle a bitmap gives a way to store a binary image, that is, an image in which each pixel is either black or white. The more general term refers to a map of pixels. Often bitmap is used for this as well, in some contexts, the term bitmap implies one bit per pixel, while pixmap is used for images with multiple bits per pixel. A bitmap is a type of organization or image file format used to store digital images. The term bitmap comes from the computer programming terminology, meaning just a map of bits, now, along with pixmap, it commonly refers to the similar concept of a spatially mapped array of pixels. Raster images in general may be referred to as bitmaps or pixmaps, whether synthetic or photographic, besides BMP, other file formats that store literal bitmaps include InterLeaved Bitmap, Portable Bitmap, X Bitmap, and Wireless Application Protocol Bitmap. Similarly, most other file formats, such as JPEG, TIFF, PNG, and GIF, also store bitmap images. In typical uncompressed bitmaps, image pixels are stored with a color depth of 1,4,8,16,24,32,48. Pixels of 8 bits and fewer can represent either grayscale or indexed color. An alpha channel may be stored in a bitmap, where it is similar to a grayscale bitmap, or in a fourth channel that, for example. The bits representing the bitmap pixels may be packed or unpacked, depending on the color depth, a pixel in the picture will occupy at least n/8 bytes, where n is the bit depth. In the formula above, header size and color palette size, due to effects of row padding to align each row start to a storage unit boundary such as a word, additional bytes may be needed. They called these device-independent bitmaps or DIBs, and the format for them is called DIB file format or BMP file format. According to Microsoft support, A device-independent bitmap is a used to define device-independent bitmaps in various color resolutions. The main purpose of DIBs is to allow bitmaps to be moved from one device to another, a DIB is an external format, in contrast to a device-dependent bitmap, which appears in the system as a bitmap object. A DIB is normally transported in metafiles, BMP files, here, device independent refers to the format, or storage arrangement, and should not be confused with device-independent color. The X Window System uses a similar XBM format for black-and-white images, numerous other uncompressed bitmap file formats are in use, though most not widely
30.
Raster scan
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A raster scan, or raster scanning, is the rectangular pattern of image capture and reconstruction in television. By analogy, the term is used for graphics, the pattern of image storage. The word raster comes from the Latin word rastrum, which is derived from radere, see also rastrum, the pattern left by the lines of a rake, when drawn straight, resembles the parallel lines of a raster, this line-by-line scanning is what creates a raster. It is a process of covering the area progressively, one line at a time. Although often a great deal faster, it is similar in the sense to how ones gaze travels when one reads lines of text. In a raster scan, an image is subdivided into a sequence of known as scan lines. This ordering of pixels by rows is known as raster order, analog television has discrete scan lines, but does not have discrete pixels – it instead varies the signal continuously over the scan line. Thus, while the number of lines is unambiguously defined. In raster scanning, the beam sweeps horizontally left-to-right at a rate, then blanks and rapidly moves back to the left. During this time, the position is also steadily increasing, but much more slowly – there is one vertical sweep per image frame. The resulting tilt in the lines is very small, and is dwarfed in effect by screen convexity. As discussed above, this not exactly happen, the vertical sweep continues at a steady rate over a scan line. Steady-rate sweep is done, instead of a stairstep of advancing every row, because steps are hard to implement technically, the resulting tilt is compensated in most CRTs by the tilt and parallelogram adjustments, which impose a small vertical deflection as the beam sweeps across the screen. When properly adjusted, this deflection exactly cancels the downward slope of the scanlines, the horizontal retrace, in turn, slants smoothly downward as the tilt deflection is removed, theres no jump at either end of the retrace. In detail, scanning of CRTs is performed by magnetic deflection, rapidly changing the deflection requires a voltage spike to be applied to the yoke, and the deflection can only react as fast as the inductance and spike magnitude permit. This happens during the blanking interval, in electronics, these movements of the beam are called sweeps, and the circuits that create the currents for the deflection yoke are called the sweep circuits. These create a wave, steady movement across the screen, then a typically rapid move back to the other side. A linear change in current would swing the beams at a constant rate angularly, Computer printers create their images basically by raster scanning
31.
Halftone
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Halftone is the reprographic technique that simulates continuous tone imagery through the use of dots, varying either in size or in spacing, thus generating a gradient-like effect. Halftone can also be used to specifically to the image that is produced by this process. This reproduction relies on an optical illusion, the tiny halftone dots are blended into smooth tones by the human eye. At a microscopic level, developed black-and-white photographic film also consists of two colors, and not an infinite range of continuous tones. The semi-opaque property of ink allows halftone dots of different colors to create another optical effect—full-color imagery, william Fox Talbot is credited with the idea of halftone printing. In a 1852 patent he suggested using photographic screens or veils in connection with an intaglio process. Several different kinds of screens were proposed during the following decades, one of the well known attempts was by Stephen H. Horgan while working for the New York Daily Graphic. The first printed photograph was an image of Steinway Hall in Manhattan published on December 2,1873, the Graphic then published the first reproduction of a photograph with a full tonal range in a newspaper on March 4,1880 with a crude halftone screen. The first truly successful commercial method was patented by Frederic Ives of Philadelphia in 1881, although he found a way of breaking up the image into dots of varying sizes, he did not make use of a screen. In 1882, the German Georg Meisenbach patented a process in England. His invention was based on the ideas of Berchtold and Swan. He used single lined screens which were turned during exposure to produce cross-lined effects and he was the first to achieve any commercial success with relief halftones. Shortly afterwards, Ives, this time in collaboration with Louis and Max Levy, improved the process further with the invention, the relief halftone process proved almost immediately to be a success. The use of blocks in popular journals became regular during the early 1890s. The development of printing methods for lithography appears to have followed a largely independent path. In the 1860s, A. Hoen & Co. focused on methods allowing artists to manipulate the tones of hand-worked printing stones, by the 1880s, Hoen was working on halftone methods that could be used in conjunction with either hand-worked or photolithographic stones. The most common method of creating screens—amplitude modulation—produces a regular grid of dots that vary in size, the other method of creating screens—frequency modulation—is used in a process also known as stochastic screening. Both modulation methods are named by analogy with the use of the terms in telecommunications, the resolution of a halftone screen is measured in lines per inch
32.
Regular grid
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A regular grid is a tessellation of n-dimensional Euclidean space by congruent parallelotopes. Grids of this appear on graph paper and may be used in finite element analysis as well as finite volume methods. Since the derivatives of field variables can be expressed as finite differences. Unstructured grids offer more flexibility than structured grids and hence are very useful in finite element, a Cartesian grid is a special case where the elements are unit squares or unit cubes, and the vertices are integer points. A rectilinear grid is a tessellation by rectangles or parallelepipeds that are not, in general, the cells may still be indexed by integers as above, but the mapping from indexes to vertex coordinates is less uniform than in a regular grid. An example of a grid that is not regular appears on logarithmic scale graph paper. Cartesian coordinate system Integer point Unstructured grid
33.
Convolution
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It has applications that include probability, statistics, computer vision, natural language processing, image and signal processing, engineering, and differential equations. The convolution can be defined for functions on other than Euclidean space. For example, periodic functions, such as the discrete-time Fourier transform, can be defined on a circle, a discrete convolution can be defined for functions on the set of integers. Computing the inverse of the operation is known as deconvolution. The convolution of f and g is written f∗g, using an asterisk or star and it is defined as the integral of the product of the two functions after one is reversed and shifted. As such, it is a kind of integral transform. While the symbol t is used above, it need not represent the time domain, but in that context, the convolution formula can be described as a weighted average of the function f at the moment t where the weighting is given by g simply shifted by amount t. As t changes, the weighting function emphasizes different parts of the input function, for the multi-dimensional formulation of convolution, see Domain of definition. A primarily engineering convention that one sees is, f ∗ g = d e f ∫ − ∞ ∞ f g d τ ⏟. For instance, ƒ*g is equivalent to, but ƒ*g is in fact equivalent to, Convolution describes the output of an important class of operations known as linear time-invariant. See LTI system theory for a derivation of convolution as the result of LTI constraints, in terms of the Fourier transforms of the input and output of an LTI operation, no new frequency components are created. The existing ones are only modified, in other words, the output transform is the pointwise product of the input transform with a third transform. See Convolution theorem for a derivation of that property of convolution, conversely, convolution can be derived as the inverse Fourier transform of the pointwise product of two Fourier transforms. One of the earliest uses of the convolution integral appeared in DAlemberts derivation of Taylors theorem in Recherches sur différents points importants du système du monde, soon thereafter, convolution operations appear in the works of Pierre Simon Laplace, Jean-Baptiste Joseph Fourier, Siméon Denis Poisson, and others. The term itself did not come into use until the 1950s or 60s. Prior to that it was known as faltung, composition product, superposition integral. Yet it appears as early as 1903, though the definition is rather unfamiliar in older uses, the operation, ∫0 t φ ψ d s,0 ≤ t < ∞, is a particular case of composition products considered by the Italian mathematician Vito Volterra in 1913. The summation is called a summation of the function f
34.
ClearType
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ClearType is Microsofts implementation of subpixel rendering technology in rendering text in a font system. ClearType attempts to improve the appearance of text on certain types of display screens by sacrificing color fidelity for additional intensity variation. This trade-off is asserted to work well on LCD flat panel monitors, ClearType was first announced at the November 1998 COMDEX exhibition. The technology was first introduced in software in January 2000 as a feature of Microsoft Reader. ClearType was significantly changed with the introduction of DirectWrite in Windows 7, Word 2013 stopped using ClearType, because There is a problem with ClearType, it depends critically on the color of the background pixels. ClearType uses spatial anti-aliasing at the level to reduce visible artifacts on such displays when text is rendered, making the text appear smoother. ClearType also uses very heavy font hinting to force the font to fit into the pixel grid and this increases edge contrast and readability of small fonts at the expense of font rendering fidelity and has been criticized by graphic designers for making different fonts look similar. Like most other types of subpixel rendering, ClearType involves a compromise, the compromise can improve text appearance when luminance detail is more important than chrominance. Only user and system applications render the application of ClearType, ClearType does not alter other graphic display elements. For example, ClearType enhancement renders text on the screen in Microsoft Word, in theory, the method can enhance the anti-aliasing of any digital image. ClearType is not used when printing text, most printers already use such small pixels that aliasing is rarely a problem, and they dont have the addressable fixed subpixels ClearType requires. Nor does ClearType affect text stored in files, ClearType only applies any processing to the text while it is being rendered onto the screen. ClearType was invented in the Microsoft e-Books team by Bert Keely and it was then analyzed by researchers in the company, and signal processing expert John Platt designed an improved version of the algorithm. Dick Brass, a Vice President at Microsoft from 1997 to 2004, however, actual display hardware usually implements each pixel as a group of three adjacent, independent subpixels, each of which displays a different primary color. Thus, on a computer display, each pixel is actually composed of separate red, green. For example, if a flat-panel display is examined under a magnifying glass, if the computer controlling the display knows the exact position and color of all the subpixels on the screen, it can take advantage of this to improve the apparent resolution in certain situations. For example, if a line with a width smaller than a full pixel must be rendered. If the line passes through the leftmost portion of the pixel, only the red subpixel is lit, if it passes through the rightmost portion of the pixel, only the blue subpixel is lit
35.
Subpixel rendering
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A single pixel on a colour subpixelated display is made of several colour primaries, typically three coloured elements—ordered either as blue, green, and red, or as red, green, and blue. These pixel components, sometimes called subpixels, appear as a colour to the human eye because of blurring by the optics. The components are easily visible, however, when viewed with a magnifying glass. Over a certain threshold the colours in the subpixels are not visible. Subpixel rendering is better suited to some display technologies than others, the technology is well-suited to LCDs and other technologies where each logical pixel corresponds directly to three or more independent coloured subpixels, but less so for CRTs. In a CRT the light from the pixel components often spreads across pixels, if a designer knew precisely about the displays electron beams and aperture grille, subpixel rendering might have some advantage. But the properties of the CRT components, coupled with the alignment variations that are part of the production process, the technique should have good application to organic light emitting diodes and other display technologies that organize pixels the same way as LCDs. The origin of subpixel rendering as used today remains controversial, Apple, then IBM, and finally Microsoft patented various implementations with certain technical differences owing to the different purposes their technologies were intended for. It is sometimes claimed that the Apple II, introduced in 1977 and this shows that both Microsoft and the patent examiner who granted the patents were aware of this prior art. The bytes that comprise the Apple II high-resolution screen buffer contain seven visible bits, each pixel, since it is represented by a single bit, is either on or off, there are no bits within the pixel itself for specifying colour or brightness. Two lit pixels next to each other are always white, regardless of whether the pair is even/odd or odd/even, however, this approximation is what most programmers of the time would have in mind while working with the Apples high-resolution mode. If a diagonal line were only one wide, it would appear alternately purple. The flag bit in each byte affects colour by shifting pixels half a pixel-width to the right and this half-pixel shift was exploited by some graphics software, such as HRCG, an Apple utility that displayed text using the high-resolution graphics mode, to smooth diagonals. Although it did not provide a way to address subpixels individually, it did allow positioning of pixels at fractional pixel locations, however, this technique is not related to LCD subpixel rendering as described in this article. Microsoft announced their subpixel rendering technology, called ClearType, at COMDEX in 1998, it was made available in Windows XP. Note that subpixel rendering per se is prior art, using a different colour filter thus easily circumvents Microsofts patent claims, SubLCD is another open source subpixel rendering method that claims it does not infringe existing patents, and promises to remain unpatented. David Turner was however skeptical of SubLCDs authors claims, Unfortunately, I, as the FreeType author, the reason is precisely the very vague patent claims described previously. To me, there is a chance, that these claims also cover the SubLCD technique
36.
Bayer filter
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A Bayer filter mosaic is a color filter array for arranging RGB color filters on a square grid of photosensors. Its particular arrangement of color filters is used in most single-chip digital image used in digital cameras, camcorders. The filter pattern is 50% green, 25% red and 25% blue, hence is also called RGBG, GRGB and it is named after its inventor, Bryce Bayer of Eastman Kodak. Bayer is also known for his recursively defined matrix used in ordered dithering, Bryce Bayers patent in 1976 called the green photosensors luminance-sensitive elements and the red and blue ones chrominance-sensitive elements. He used twice as many elements as red or blue to mimic the physiology of the human eye. The luminance perception of the human retina uses M and L cone cells combined, during daylight vision and these elements are referred to as sensor elements, sensels, pixel sensors, or simply pixels, sample values sensed by them, after interpolation, become image pixels. At the time Bayer registered his patent, he proposed to use a cyan-magenta-yellow combination. This arrangement was unpractical at the time because the necessary dyes did not exist, the big advantage of the new CMY dyes is that they have an improved light absorption characteristic, that is, their quantum efficiency is higher. The raw output of Bayer-filter cameras is referred to as a Bayer pattern image, since each pixel is filtered to record only one of three colors, the data from each pixel cannot fully specify each of the red, green, and blue values on its own. To obtain an image, various demosaicing algorithms can be used to interpolate a set of complete red, green. These algorithms make use of the pixels of the corresponding colors to estimate the values for a particular pixel. Different algorithms requiring various amounts of computing power result in varying-quality final images and this can be done in-camera, producing a JPEG or TIFF image, or outside the camera using the raw data directly from the sensor. Demosaicing can be performed in different ways, simple methods interpolate the color value of the pixels of the same color in the neighborhood. For example, once the chip has been exposed to an image, a pixel with a green filter provides an exact measurement of the green component. The red and blue components for this pixel are obtained from the neighbors, for a green pixel, two red neighbors can be interpolated to yield the red value, also two blue pixels can be interpolated to yield the blue value. Because of this, other demosaicing methods attempt to identify high-contrast edges and only interpolate along these edges, therefore, the green channel is interpolated at first then the red and afterwards the blue channel, so that the color ratio red-green respective blue-green are constant. There are other methods that make different assumptions about the image content, images with small-scale detail close to the resolution limit of the digital sensor can be a problem to the demosaicing algorithm, producing a result which is not looking like the model. Typically this artifact manifests itself along edges, where abrupt or unnatural shifts in color occur as a result of misinterpolating across, rather than along, for preventing and removing this false coloring various methods exist
37.
Nyquist rate
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In signal processing, the Nyquist rate, named after Harry Nyquist, is twice the bandwidth of a bandlimited function or a bandlimited channel. When a continuous function, x, is sampled at a constant rate, fs samples/second, but only one of them is bandlimited to ½ fs cycles/second, which means that its Fourier transform, X, is 0 for all |f| ≥ ½ fs. The mathematical algorithms that are used to recreate a continuous function from samples create arbitrarily good approximations to this theoretical. It follows that if the function, x, is bandlimited to ½ fs. In terms of a functions own bandwidth, as depicted above, and 2B is called the Nyquist rate for functions with bandwidth B. When the Nyquist criterion is not met, a condition called aliasing occurs, in most cases, the differences are viewed as distortion. Figure 2 depicts a type of function called baseband or lowpass, because its range of significant energy is [0. When instead, the range is, for some A > B, it is called bandpass. One way to do that is frequency-mixing the bandpass function down to the frequency range, one of the possible reasons is to reduce the Nyquist rate for more efficient storage. For a more general discussion, see bandpass sampling, long before Harry Nyquist had his name associated with sampling, the term Nyquist rate was used differently, with a meaning closer to what Nyquist actually studied. This rate is referred to as signaling at the Nyquist rate. According to the OED, Blacks statement regarding 2B may be the origin of the term Nyquist rate, Nyquists famous 1928 paper was a study on how many pulses could be transmitted per second, and recovered, through a channel of limited bandwidth. Signaling at the Nyquist rate meant putting as many code pulses through a channel as its bandwidth would allow. Shannon used Nyquists approach when he proved the theorem in 1948
38.
Pixel aspect ratio
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Pixel aspect ratio is a mathematical ratio that describes how the width of a pixel in a digital image compares to the height of that pixel. Most digital imaging systems display an image as a grid of tiny, Pixel Aspect Ratio describes this difference. Use of pixel aspect ratio mostly involves pictures pertaining to standard-definition television, most other imaging systems, including those that comply with SMPTE standards and practices, use square pixels. In digital images, there is a distinction with the Storage Aspect Ratio, if an image is displayed with square pixels, then these ratios agree, if not, then non-square, rectangular pixels are used, and these ratios disagree. The aspect ratio of the pixels themselves is known as the Pixel Aspect Ratio – for square pixels this is 1,1 – and these are related by the identity, SAR × PAR = DAR. For example, a 640 ×480 VGA image has a SAR of 640/480 =4,3, by contrast, a 720 ×576 D-1 PAL image has a SAR of 720/576 =5,4, but is displayed on a 4,3 display. In analog images such as there is no notion of pixel, nor notion of SAR or PAR. Today they arise also in transcoding between resolutions with different SARs, actual displays do not generally have non-square pixels, though digital sensors might, they are rather a mathematical abstraction used in resampling images to convert between resolutions. However, by a sampling rate, the effective horizontal resolution can be determined by the sampling theorem. Also, the resolution may be rounded, third, analog video signals are interlaced – each image is sent as two fields, each with half the lines. Thus pixels are either twice as tall as they would be without interlacing, Video is presented as a sequential series of images called video frames. Historically, video frames were created and recorded in analog form, as digital display technology, digital broadcast technology, and digital video compression evolved separately, it resulted in video frame differences that must be addressed using Pixel Aspect Ratio. Digital video frames are defined as a grid of pixels used to present each sequential image. The horizontal component is defined by pixels, and is known as a video line, the vertical component is defined by the number of lines, as in 480 lines. Such standards define an image as an array of well-defined horizontal Lines, well-defined vertical Line Duration, however, there is not a standard-definition television standard that properly defines image edges or explicitly demands a certain number of picture elements per line. As a result of becoming powerful enough to serve as video editing tools, video digital-to-analog converters. To convert analog video lines into a series of square pixels, the luma sampling rate for 480i pictures was 12 3⁄11 MHz and for 576i pictures was 14 3⁄4 MHz. The term pixel aspect ratio was first coined when ITU-R BT.601 specified that standard-definition television pictures are made of lines of exactly 720 non-square pixels and it designated 177,160 for 480i or 1035,1132 for 576i
39.
Anamorphic widescreen
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Anamorphic widescreen is a process by which a comparatively wide widescreen image is vertically expanded to fit into a storage medium with a narrower aspect ratio. Compatible play-back equipment can then recompress the vertical dimension to show the original widescreen image, the technique originally comes from cinema. A film would be framed and recorded as widescreen, but the picture would be squashed together using a specially crafted concave lens to fit into non-widescreen 1.37,1 aspect ratio film. This film can then be printed and manipulated like any other 1.37,1 film stock, an anamorphic lens on the projector in the cinema corrects the picture by performing exactly the opposite distortion, returning it to its original width and its widescreen aspect ratio. The anamorphic lens on the projector is a specially crafted convex lens that corrects the picture so that the images on the screen look normal, similar operations are performed electronically to allow widescreen material to be stored on formats or broadcast on systems that assume a non-widescreen aspect ratio. Many commercial cinematic presentations are recorded on standard 35 mm ~4,3 aspect ratio film, another anamorphic lens on the movie theatre projector ultimately corrects the picture. Other movies are made using the simpler technique, which involves both filming and projecting without any expensive special lenses. The movie is produced in 1.375 format, and then the image is simply cropped in post-production to fit the desired aspect ratio of 1.85,1 or 1.66,1 or whatever is desired. The anamorphic encoding on DVD is related to the filming technique only by name. For instance, Star Wars was filmed in 2.35,1 ratio using a camera lens. Since it is a film, when encoded on a widescreen-format DVD the studio would almost certainly use the anamorphic encoding process. Monty Python and the Holy Grail was filmed in 1.85,1 ratio without using a lens on the camera. However, since it is also a film, when encoded on a widescreen-format DVD the studio would probably use the anamorphic encoding process. As a sidenote, if a purely non-widescreen version of the analog-anamorphic Star Wars were to be released on DVD, a DVD labeled as Widescreen Anamorphic contains video that has the same frame size in pixels as traditional fullscreen video, but uses wider pixels. The shape of the pixels is called pixel aspect ratio and is encoded in the stream for a DVD player to correctly identify the proportions of the video. If an anamorphic DVD video is played on standard 4,3 television without adjustment, if not so labeled, the DVD is intended for a 4,3 display, and will be letterboxed or panned and scanned. There has been no clear standardization for companies to follow regarding the advertisement of anamorphically enhanced widescreen DVDs, some companies, such as Universal and Disney, include the aspect ratio of the movie. Below are how various companies advertise their anamorphic DVD movies on their packaging, Anchor Bay, Enhanced for 16,9 TVs, artisan Entertainment,16,9 Fullscreen Version or Enhanced for 16,9 Television
40.
Rec. 601
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It includes methods of encoding 525-line 60 Hz and 625-line 50 Hz signals, both with an active region covering 720 luminance samples and 360 chrominance samples per line. The color encoding system is known as YCbCr 4,2,2, the standard has been revised several times in its history. Its edition 7, referred to as BT. 601-7, was approved in March 2011 and was published in October 2011. The Rec.601 signal can be regarded as if it is a digitally encoded analog component video signal, regardless of the frame rate, the luminance sampling frequency is 13.5 MHz. The samples are uniformly quantized using 8 or 10 bit PCM codes in the YCbCr domain, for each 8 bit luminance sample, the nominal value to represent black is 16 and the value for white is 235. Eight-bit code values from 1 through 15 provide footroom, and can be used to accommodate transient signal content such as filter undershoots, similarly, code values 236 through 254 provide headroom and can be used to accommodate transient signal content such as filter overshoots. The values 0 and 255 are used to encode the sync pulses and are forbidden within the picture area. The Cb and Cr samples are unsigned and use the value 128 to encode the neutral color difference value, as used when encoding a white, slightly different primaries are specified for the 625 line and 525 line systems. Rec.601 defines a nonlinear transfer function which is linear near 0 and then transfers to a gamma curve for the rest of the light intensity range. E = {4.500 L L <0.0181.099 L0.45 −0.099 L ≥0.018 The CCIR received a 1982–83 Technology,709, the corresponding standard for high-definition television Rec. 2020, ITU-R Recommendation for ultra-high-definition television ITU-R BT.656, ITU-R Recommendation for parallel and serial transmission formats for BT.601 video Pixel aspect ratio
41.
Graphical user interface
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GUIs were introduced in reaction to the perceived steep learning curve of command-line interfaces, which require commands to be typed on a computer keyboard. The actions in a GUI are usually performed through direct manipulation of the graphical elements, beyond computers, GUIs are used in many handheld mobile devices such as MP3 players, portable media players, gaming devices, smartphones and smaller household, office and industrial controls. Designing the visual composition and temporal behavior of a GUI is an important part of application programming in the area of human–computer interaction. Its goal is to enhance the efficiency and ease of use for the logical design of a stored program. Methods of user-centered design are used to ensure that the language introduced in the design is well-tailored to the tasks. The visible graphical interface features of an application are sometimes referred to as chrome or GUI, typically, users interact with information by manipulating visual widgets that allow for interactions appropriate to the kind of data they hold. The widgets of an interface are selected to support the actions necessary to achieve the goals of users. A model–view–controller allows a structure in which the interface is independent from and indirectly linked to application functions. This allows users to select or design a different skin at will, good user interface design relates to users more, and to system architecture less. Large widgets, such as windows, usually provide a frame or container for the main presentation content such as a web page, smaller ones usually act as a user-input tool. A GUI may be designed for the requirements of a market as application-specific graphical user interfaces. By the 1990s, cell phones and handheld game systems also employed application specific touchscreen GUIs, newer automobiles use GUIs in their navigation systems and multimedia centers, or navigation multimedia center combinations. Sample graphical desktop environments A GUI uses a combination of technologies and devices to provide a platform that users can interact with, a series of elements conforming a visual language have evolved to represent information stored in computers. This makes it easier for people with few computer skills to work with, the most common combination of such elements in GUIs is the windows, icons, menus, pointer paradigm, especially in personal computers. The WIMP style of interaction uses a virtual device to represent the position of a pointing device, most often a mouse. Available commands are compiled together in menus, and actions are performed making gestures with the pointing device, a window manager facilitates the interactions between windows, applications, and the windowing system. The windowing system handles hardware devices such as pointing devices, graphics hardware, window managers and other software combine to simulate the desktop environment with varying degrees of realism. Smaller mobile devices such as personal assistants and smartphones typically use the WIMP elements with different unifying metaphors, due to constraints in space
