In photography and image processing, color balance is the global adjustment of the intensities of the colors. An important goal of this adjustment is to specific colors – particularly neutral colors – correctly. Hence, the method is sometimes called gray balance, neutral balance. Color balance changes the mixture of colors in an image and is used for color correction. Generalized versions of color balance are used to correct colors other than neutrals or to change them for effect. Image data acquired by sensors – either film or electronic image sensors – must be transformed from the values to new values that are appropriate for color reproduction or display. In film photography, color balance is achieved by using color correction filters over the lights or on the camera lens. It is particularly important that neutral colors in a scene appear neutral in the reproduction, most digital cameras have means to select color correction based on the type of scene lighting, using either manual lighting selection, automatic white balance, or custom white balance.
The algorithms for these processes perform generalized chromatic adaptation, many methods exist for color balancing. Setting a button on a camera is a way for the user to indicate to the processor the nature of the scene lighting, another option on some cameras is a button which one may press when the camera is pointed at a gray card or other neutral colored object. This captures an image of the ambient light, which enables a digital camera to set the color balance for that light. There is a literature on how one might estimate the ambient lighting from the camera data. A variety of algorithms have been proposed, and the quality of these has been debated, a few examples and examination of the references therein will lead the reader to many others. Examples are Retinex, a neural network or a Bayesian method. Color balancing an image not only the neutrals, but other colors as well. An image that is not color balanced is said to have a color cast, Color balancing may be thought in terms of removing this color cast.
Color balance is related to color constancy. Algorithms and techniques used to color constancy are frequently used for color balancing
Factors considered may include unusual lighting distribution, variations within a camera system, non-standard processing, or intended underexposure or overexposure. Cinematographers may apply exposure compensation for changes in angle or film speed. Most DSLR cameras have a display whereby the photographer can set the camera to either over or under expose the subject by up to three f-stops in 1/3rd stop intervals. Each number on the scale represents one f-stop, decreasing the exposure by one f-stop will halve the amount of light reaching the sensor, the dots in between the numbers represent 1/3rd of an f-stop. In photography, some cameras include exposure compensation as a feature to allow the user to adjust the automatically calculated exposure, camera exposure compensation is commonly stated in terms of EV units,1 EV is equal to one exposure step, corresponding to a doubling of exposure. Exposure can be adjusted by changing either the lens f-number or the exposure time, if the mode is aperture priority, exposure compensation changes the exposure time, if the mode is shutter priority, the f-number is changed.
If a flash is being used, some cameras will adjust it as well, the earliest reflected-light exposure meters were wide-angle, averaging types, measuring the average scene luminance. When measuring a scene with atypical distribution of light and dark elements, or an element that is lighter or darker than a middle tone. For example, a scene with predominantly light tones often will be underexposed and that both scenes require the same exposure, regardless of the meter indication, becomes obvious from a scene that includes both a white horse and a black horse. A photographer usually can recognize the difference between a horse and a black horse, a meter usually cannot. When metering a white horse, a photographer can apply exposure compensation so that the horse is rendered as white. Many modern cameras incorporate metering systems that measure scene contrast as well as average luminance, in scenes with very unusual lighting, these metering systems sometimes cannot match the judgment of a skilled photographer, so exposure compensation still may be needed.
An early application of compensation was the Zone System developed by Ansel Adams. Developed for black-and-white film, the Zone System divided luminance into 11 zones, with Zone 0 representing pure black, the meter indication would place whatever was metered on Zone V, a medium gray. The meter indication, remains Zone V, the Zone System is a very specialized form of exposure compensation, and is used most effectively when metering individual scene elements, such as a sunlit rock or the bark of a tree in shade. Many cameras incorporate narrow-angle spot meters to facilitate such measurements, because of the limited tonal range, an exposure compensation range of ±2 EV is often sufficient for using the Zone System with color film and digital sensors. Exposure value Exposure index Light meter Zone System Exposure bracketing Auto Exposure Bracketing
Film speed is the measure of a photographic films sensitivity to light, determined by sensitometry and measured on various numerical scales, the most recent being the ISO system. A closely related ISO system is used to measure the sensitivity of digital imaging systems, highly sensitive films are correspondingly termed fast films. In both digital and film photography, the reduction of exposure corresponding to use of higher sensitivities generally leads to reduced image quality, in short, the higher the sensitivity, the grainier the image will be. Ultimately sensitivity is limited by the efficiency of the film or sensor. The speed of the emulsion was expressed in degrees Warnerke corresponding with the last number visible on the plate after development. Each number represented an increase of 1/3 in speed, typical speeds were between 10° and 25° Warnerke at the time. The concept, was built upon in 1900 by Henry Chapman Jones in the development of his plate tester. In their system, speed numbers were inversely proportional to the exposure required, for example, an emulsion rated at 250 H&D would require ten times the exposure of an emulsion rated at 2500 H&D.
The methods to determine the sensitivity were modified in 1925, the H&D system was officially accepted as a standard in the former Soviet Union from 1928 until September 1951, when it was superseded by GOST 2817-50. The Scheinergrade system was devised by the German astronomer Julius Scheiner in 1894 originally as a method of comparing the speeds of plates used for astronomical photography, Scheiners system rated the speed of a plate by the least exposure to produce a visible darkening upon development. ≈2 The system was extended to cover larger ranges and some of its practical shortcomings were addressed by the Austrian scientist Josef Maria Eder. Scheiners system was abandoned in Germany, when the standardized DIN system was introduced in 1934. In various forms, it continued to be in use in other countries for some time. The DIN system, officially DIN standard 4512 by Deutsches Institut für Normung, was published in January 1934, International Congress of Photography held in Dresden from August 3 to 8,1931.
The DIN system was inspired by Scheiners system, but the sensitivities were represented as the base 10 logarithm of the sensitivity multiplied by 10, similar to decibels. Thus an increase of 20° represented an increase in sensitivity. ≈3 /10 As in the Scheiner system, speeds were expressed in degrees, originally the sensitivity was written as a fraction with tenths, where the resultant value 1.8 represented the relative base 10 logarithm of the speed. Tenths were abandoned with DIN4512, 1957-11, and the example above would be written as 18° DIN, the degree symbol was finally dropped with DIN4512, 1961-10
Contrast is the difference in luminance or colour that makes an object distinguishable. In visual perception of the world, contrast is determined by the difference in the color and brightness of the object. The human visual system is sensitive to contrast than absolute luminance. The maximum contrast of an image is the contrast ratio or dynamic range, the human contrast sensitivity function shows a typical band-pass filter shape peaking at around 4 cycles per degree with sensitivity dropping off either side of the peak. The high-frequency cut-off represents the optical limitations of the systems ability to resolve detail and is typically about 60 cycles per degree. The high-frequency cut-off is related to the density of the retinal photoreceptor cells. The low frequency drop-off is due to lateral inhibition within the ganglion cells. A typical retinal ganglion cell presents a centre region with either excitation or inhibition, one experimental phenomenon is the inhibition of blue in the periphery if blue light is displayed against white, leading to a yellow surrounding.
The yellow is derived from the inhibition of blue on the surroundings by the center, since white minus blue is red and green, this mixes to become yellow. For example, in the case of computer displays, contrast depends on the properties of the picture source or file. For some screens the angle between the surface and the observers line of sight is important. There are many definitions of contrast. Some include color, others do not, travnikova laments, Such a multiplicity of notions of contrast is extremely inconvenient. It complicates the solution of many applied problems and makes it difficult to compare the results published by different authors, various definitions of contrast are used in different situations. Here, luminance contrast is used as an example, but the formulas can be applied to other physical quantities, in many cases, the definitions of contrast represent a ratio of the type Luminance difference Average luminance. The rationale behind this is that a difference is negligible if the average luminance is high.
Below, some definitions are given. Weber contrast is defined as I − I b I b, with I and I b representing the luminance of the features, the measure is referred to as Weber fraction, since it is the term that is constant in Webers Law
In photography, the term acutance describes a subjective perception of sharpness that is related to the edge contrast of an image. Acutance is related to the amplitude of the derivative of brightness with respect to space, due to the nature of the human visual system, an image with higher acutance appears sharper even though an increase in acutance does not increase real resolution. Historically, acutance was enhanced chemically during development of a negative, in the example image, two light gray lines were drawn on a gray background. As the transition is instantaneous, the line is as sharp as can be represented at this resolution, acutance in the left line was artificially increased by adding a one-pixel-wide darker border on the outside of the line and a one-pixel-wide brighter border on the inside of the line. The actual sharpness of the image is unchanged, but the apparent sharpness is increased because of the greater acutance. In this somewhat overdone example most viewers will be able to see the borders separately from the line, several image processing techniques, such as unsharp masking, can increase the acutance in real images.
Low-pass filtering and resampling often cause overshoot, which increases acutance, but can reduce absolute gradient and resampling can cause clipping and ringing artifacts. An example is bicubic interpolation, widely used in processing for resizing images. Thus the acutance of an image is a vector field, coarse grain or noise can, like sharpening filters, increase acutance, hence increasing the perception of sharpness, even though they degrade the signal-to-noise ratio
Colorfulness or saturation in colorimetry and color theory refers to the perceived intensity of a specific color. Colorfulness is the visual sensation according to which the color of an area appears to be more or less chromatic. Chroma is the relative to the brightness of a similarly illuminated area that appears to be white or highly transmitting. Therefore, chroma should not be confused with colorfulness, saturation is the colorfulness of a color relative to its own brightness. A highly colorful stimulus is vivid and intense, while a less colorful stimulus appears more muted, with no colorfulness at all, a color is a “neutral” gray. Any color can be described using three color appearance parameters — colorfulness and hue, saturation is one of three coordinates in the HSL and HSV color spaces. The saturation of a color is determined by a combination of light intensity, the purest color is achieved by using just one wavelength at a high intensity, such as in laser light. If the intensity drops, as a result the saturation drops, to desaturate a color of given intensity in a subtractive system, one can add white, gray, or the hues complement.
CIELUV The chroma normalized by the lightness, s u v = C u v ∗ L ∗ =132 +2 where is the chromaticity of the white point, and chroma is defined below. Nevertheless, this provides a reasonable predictor of saturation. S a b = C a b ∗ C a b ∗2 + L ∗2100 % where Sab is the saturation, L* the lightness and C*ab is the chroma of the color. CIECAM02 The square root of the colorfulness divided by the brightness, M is proportional to the chroma C, thus the CIECAM02 definition bears some similarity to the CIELUV definition. An important difference is that the CIECAM02 model accounts for the conditions through the parameter FL. Different color spaces, such as CIELAB or CIELUV may be used, the naïve definition of saturation does not specify its response function. However, both color spaces are nonlinear in terms of perceived color differences. It is possible—and sometimes desirable—to define a quantity that is linearized in term of the psychovisual perception. The transformation of to is given by, C a b ∗ = a ∗2 + b ∗2 h a b = arctan b ∗ a ∗ and analogously for CIE L*C*h.
The chroma in the CIE L*C*h and CIE L*C*h coordinates has the advantage of being more psychovisually linear, and therefore, chroma in CIE1976 L*a*b* and L*u*v* color spaces is very much different from the traditional sense of saturation
A color space is a specific organization of colors. In combination with physical device profiling, it allows for reproducible representations of color, for example, Adobe RGB and sRGB are two different absolute color spaces, both based on the RGB color model. When defining a color space, the reference standard is the CIELAB or CIEXYZ color spaces. For example, although several specific color spaces are based on the RGB color model, colors can be created in printing with color spaces based on the CMYK color model, using the subtractive primary colors of pigment. The resulting 3-D space provides a position for every possible color that can be created by combining those three pigments. Colors can be created on computer monitors with color spaces based on the RGB color model, a three-dimensional representation would assign each of the three colors to the X, Y, and Z axes. Note that colors generated on given monitor will be limited by the medium, such as the phosphor or filters. Another way of creating colors on a monitor is with an HSL or HSV color space, based on hue, with such a space, the variables are assigned to cylindrical coordinates.
Many color spaces can be represented as three-dimensional values in this manner, but some have more, or fewer dimensions, Color space conversion is the translation of the representation of a color from one basis to another. The RGB color model is implemented in different ways, depending on the capabilities of the system used, by far the most common general-used incarnation as of 2006 is the 24-bit implementation, with 8 bits, or 256 discrete levels of color per channel. Any color space based on such a 24-bit RGB model is limited to a range of 256×256×256 ≈16.7 million colors. Some implementations use 16 bits per component for 48 bits total and this is especially important when working with wide-gamut color spaces, or when a large number of digital filtering algorithms are used consecutively. The same principle applies for any color space based on the color model. CIE1931 XYZ color space was one of the first attempts to produce a space based on measurements of human color perception. The CIERGB color space is a companion of CIE XYZ.
Additional derivatives of CIE XYZ include the CIELUV, CIEUVW, RGB uses additive color mixing, because it describes what kind of light needs to be emitted to produce a given color. RGB stores individual values for red and blue, RGBA is RGB with an additional channel, alpha, to indicate transparency. Common color spaces based on the RGB model include sRGB, Adobe RGB, ProPhoto RGB, scRGB, one starts with a white substrate, and uses ink to subtract color from white to create an image
Sony Corporation is a Japanese multinational conglomerate corporation that is headquartered in Kōnan, Tokyo. Its diversified business includes consumer and professional electronics, entertainment, the company is one of the leading manufacturers of electronic products for the consumer and professional markets. Sony was ranked 116th on the 2015 list of Fortune Global 500 and these make Sony one of the most comprehensive entertainment companies in the world. The group consists of Sony Corporation, Sony Pictures Entertainment, Sony Interactive Entertainment, Sony Music Entertainment, Sony Financial Holdings and others. Sony is among the Semiconductor sales leaders by year and as of 2013, the companys current slogan is BE MOVED. Their former slogans were make. believe, like. no. other, Sony has a weak tie to the SMFG keiretsu, the successor to the Mitsui keiretsu. Sony began in the wake of World War II, in 1946, Masaru Ibuka started an electronics shop in a department store building in Tokyo. The company had $530 in capital and a total of eight employees, in the following year he was joined by his colleague, Akio Morita, and they founded a company called Tokyo Tsushin Kogyo 東京通信工業.
The company built Japans first tape recorder, called the Type-G, in 1958 the company changed its name to Sony. When Tokyo Tsushin Kogyo was looking for a name to use to market themselves, they strongly considered using their initials. The primary reason they did not is that the railway company Tokyo Kyuko was known as TTK, the company occasionally used the acronym Totsuko in Japan, but during his visit to the United States, Morita discovered that Americans had trouble pronouncing that name. Another early name that was tried out for a while was Tokyo Teletech until Akio Morita discovered that there was an American company already using Teletech as a brand name, the name Sony was chosen for the brand as a mix of two words. One was the Latin word sonus, which is the root of sonic and sound, and the other was sonny, a common slang term used in 1950s America to call a boy. In the 1950s Japan sonny boys, was a word into Japanese which connoted smart and presentable young men. The first Sony-branded product, the TR-55 transistor radio, appeared in 1955, at the time of the change, it was extremely unusual for a Japanese company to use Roman letters to spell its name instead of writing it in kanji.
The move was not without opposition, TTKs principal bank at the time and they pushed for a name such as Sony Electronic Industries, or Sony Teletech. Akio Morita was firm, however, as he did not want the company tied to any particular industry. Eventually, both Ibuka and Mitsui Banks chairman gave their approval, according to Schiffer, Sonys TR-63 radio cracked open the U. S. market and launched the new industry of consumer microelectronics
In photography, the metering mode refers to the way in which a camera determines the exposure. Cameras generally allow the user to select between spot, center-weighted average, or multi-zone metering modes, various metering modes are provided to allow the user to select the most appropriate one for use in a variety of lighting conditions. With spot metering, the camera will only measure a small area of the scene. This will by default be the centre of the scene. The user can select a different off-centre spot, or to recompose by moving the camera after metering. The first spot meter was built by Arthur James Dalladay, editor of The British Journal of Photography in about 1935, a few models support a Multi-Spot mode which allows multiple spot meter readings to be taken of a scene that are averaged. Some cameras, the OM-4 and T90 included, support metering of highlight, spot metering is very accurate and is not influenced by other areas in the frame. It is commonly used to very high contrast scenes.
The area around the back and hairline will become over-exposed, spot metering is a method upon which the Zone System depends. In many cases the camera will over or underexpose, when using the spot mode, modern cameras tend to find the correct exposure precisely. In complex light situations though, professional photographers tend to switch to manual mode, another example of spot metering usage would be when photographing the moon. Due to the dark nature of the scene, other metering methods tend to overexpose the moon. Spot metering will allow for more detail to be out in the moon while underexposing the rest of the scene. More commonly, spot metering is used in photography, where the brightly lit actors stand before a dark or even black curtain or scrim. Spot metering only considers the actors in this case, while ignoring the overall darkness of the scene, in this system, the meter concentrates between 60 to 80 percent of the sensitivity towards the central part of the viewfinder. The balance is feathered out towards the edges, some cameras will allow the user to adjust the weight/balance of the central portion to the peripheral one.
When moving the point off center the camera will proceed as above. Although promoted as a feature, center-weighted metering was originally a consequence of the meter cell reading from the screen of SLR cameras
The focal length of an optical system is a measure of how strongly the system converges or diverges light. For an optical system in air, it is the distance over which initially collimated rays are brought to a focus. A system with a focal length has greater optical power than one with a long focal length. For a thin lens in air, the length is the distance from the center of the lens to the principal foci of the lens. For a converging lens, the length is positive, and is the distance at which a beam of collimated light will be focused to a single spot. For a diverging lens, the length is negative, and is the distance to the point from which a collimated beam appears to be diverging after passing through the lens. The focal length of a lens can be easily measured by using it to form an image of a distant light source on a screen. The lens is moved until an image is formed on the screen. In this case 1/u is negligible, and the length is given by f ≈ v. Back focal length or back focal distance is the distance from the vertex of the last optical surface of the system to the focal point.
For an optical system in air, the focal length gives the distance from the front. If the surrounding medium is not air, the distance is multiplied by the index of the medium. Some authors call these distances the front/rear focal lengths, distinguishing them from the front/rear focal distances, defined above. In general, the length or EFL is the value that describes the ability of the optical system to focus light. The other parameters are used in determining where an image will be formed for an object position. The quantity 1/f is known as the power of the lens. The corresponding front focal distance is, FFD = f, in the sign convention used here, the value of R1 will be positive if the first lens surface is convex, and negative if it is concave. The value of R2 is negative if the surface is convex
The f-number of an optical system such as a camera lens is the ratio of the systems focal length to the diameter of the entrance pupil. It is a number that is a quantitative measure of lens speed. It is known as the ratio, f-ratio, f-stop. The f-number is commonly indicated using a hooked f with the format f/N, the f-number N or f# is given by, N = f D where f is the focal length, and D is the diameter of the entrance pupil. It is customary to write f-numbers preceded by f/, which forms a mathematical expression of the pupil diameter in terms of f and N. Ignoring differences in light transmission efficiency, a lens with a greater f-number projects darker images, the brightness of the projected image relative to the brightness of the scene in the lenss field of view decreases with the square of the f-number. Doubling the f-number decreases the brightness by a factor of four. To maintain the same photographic exposure when doubling the f-number, the time would need to be four times as long. Most lenses have a diaphragm, which changes the size of the aperture stop.
The entrance pupil diameter is not necessarily equal to the aperture stop diameter, a 100 mm focal length f/4 lens has an entrance pupil diameter of 25 mm. A200 mm focal length f/4 lens has a pupil diameter of 50 mm. The 200 mm lenss entrance pupil has four times the area of the 100 mm lenss entrance pupil, a T-stop is an f-number adjusted to account for light transmission efficiency. The word stop is sometimes confusing due to its multiple meanings, a stop can be a physical object, an opaque part of an optical system that blocks certain rays. In photography, stops are a used to quantify ratios of light or exposure. The one-stop unit is known as the EV unit. On a camera, the setting is traditionally adjusted in discrete steps. Each stop is marked with its corresponding f-number, and represents a halving of the light intensity from the previous stop. This corresponds to a decrease of the pupil and aperture diameters by a factor of 1/2 or about 0.7071, each element in the sequence is one stop lower than the element to its left, and one stop higher than the element to its right
Culture of Austria
Austrian culture has largely been influenced by its past and present neighbours, Poland, Germany and Bohemia. Vienna, the city of Austria has long been an important centre of musical innovation. Composers of the 18th and 19th centuries were drawn to the city by the patronage of the Habsburgs, Wolfgang Amadeus Mozart, Ludwig van Beethoven, and Johann Strauss, Jr. among others, were associated with the city. During the Baroque period and Hungarian folk forms influenced Austrian music, viennas status began its rise as a cultural center in the early 16th century, and was focused around instruments including the lute. During the 18th century, the classical-music era dominated European classical music, the Musikverein in Vienna is considered to be one of the three finest concert halls in the world and was opened on January 6,1870. Since 1939, the famous Vienna New Years Concert of the Vienna Philharmonic is broadcast from its Golden Hall to an audience of one billion in 44 countries. The members of the Vienna Philharmonic, which is considered one of the finest orchestras in the world, are chosen from the orchestra of the Vienna State Opera.
The Vienna Philharmonic can trace its origins to 1842, when Otto Nicolai formed the Philharmonische Academie and this orchestra took all its decisions by a democratic vote of all its members, and these are principles still held today. The Vienna State Opera, in German called Staatsoper, is one of the most important opera companies in the world. It employs over 1000 people, and in 2008, the operating budget of the Staatsoper was 100 million Euros with slightly more than 50% coming in the form of a state subsidy. It is venue for the Vienna Opera Ball, an event that takes place on the Thursday preceding Ash Wednesday, the Opera Ball was first held 1936, and has seen up to 12,000 visitors. 180 pairs are opening the ball officially, before the command Alles Walzer, the Vienna Boys Choir is one of the best known boys choirs in the world. Palais Augarten serves as space and boarding school for the boys of the choir. The most popular form of modern Austrian folk music is Viennese Schrammelmusik, which is played with an accordion, modern performers include Roland Neuwirth, Karl Hodina, and Edi Reiser.
Yodeling is a type of singing that was developed in the Alps. In Austria, it was called juchazn and featured the use of both nonlexical syllables and yells that were used to communicate across mountains, Austrian folk dancing is mostly associated with Schuhplattler, Ländler, Polka, or Waltz. However, there are other dances, such as Zwiefacher, Kontratänze, the ländler is a folk dance of uncertain origin. Known as a song under several names for a long period, it became known as Landl ob der Enns