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ITU-R BT.1886
ITU-R BT.1886 is the reference EOTF of Standard-dynamic-range video, SDR-TV. It is a Gamma correction, gamma 2.4 transfer function (a power law with a 2.4 exponent) considered as a satisfactory approximation of the response characteristic of Cathode-ray tube, CRT to electrical signal. It has been standardized by International Telecommunication Union, ITU in March 2011. It is used for Rec. 709 (High-definition television, HD-TV) and Rec. 2020 (Ultra-high-definition television, UHD-TV). Definition BT.1886 EOTF is as follows: L = a (\max[(V+b),0])^ where * L is the screen luminance, in Candela per square metre, cd/m2. * V is the input video signal level, in the range \left[0, 1 \right]. * \gamma is the exponent of the power function and equal to 2.4 * a = (^ - ^)^ is the variable for user gain (legacy “contrast” control) * b = \frac is the variable for user black level lift (legacy “brightness” control) * L_W is the screen luminance for white, in cd/m2. * L_B is the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EOTF
This article is about the transfer functions used in pictures and videos and describing the relationship between electrical signal, scene light and displayed light. Definition The opto-electronic transfer function (OETF) is the transfer function having the scene light as input and converting into the picture or video signal as output. This is typically done within a camera. The electro-optical transfer function (EOTF) is the transfer function having the picture or video signal as input and converting it into the linear light output of the display. This is done within the display device. The opto-optical transfer function (OOTF) is the transfer function having the scene light as input and the displayed light as output. The OOTF is the result of the OETF and the EOTF and is usually non-linear. List of transfer functions Linear * Raw formats *Some OETF and EOTF have an initial linear portion followed by a non-linear part (e.g. sRGB and Rec.709). Gamma * Rec. 601, Rec. 7 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard-dynamic-range Video
Standard-dynamic-range (SDR) video is a video technology which represents light intensity based on the brightness, Contrast (vision), contrast and color characteristics and limitations of a cathode ray tube (CRT) display. SDR video is able to represent a video or picture's colors with a maximum luminance around 100 Candela per square metre, cd/m2, a black level around 0.1 Candela per square metre, cd/m2 and Rec. 709, Rec.709 / sRGB Gamut, color gamut. It uses the Gamma correction, gamma curve as its electro-optical transfer function. The first CRT television sets were manufactured in 1934 and the first color CRT television sets were manufactured in 1954. The term "standard-dynamic-range video" was adopted to distinguish SDR video from high-dynamic-range video, a new technology that was developed in the 2010s to overcome SDR's limits. Technical details Transfer function Conventional Gamma correction, gamma curves: * Opto-electronic transfer function (OETF): ** Rec. 601 (analog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma Correction
Gamma correction or gamma is a nonlinear operation used to encode and decode luminance or tristimulus values in video or still image systems. Gamma correction is, in the simplest cases, defined by the following power-law expression: : V_\text = A V_\text^\gamma, where the non-negative real input value V_\text is raised to the power \gamma and multiplied by the constant ''A'' to get the output value V_\text. In the common case of , inputs and outputs are typically in the range 0–1. A gamma value \gamma 1 is called a ''decoding gamma'', and the application of the expansive power-law nonlinearity is called gamma expansion. Explanation Gamma encoding of images is used to optimize the usage of bits when encoding an image, or bandwidth used to transport an image, by taking advantage of the non-linear manner in which humans perceive light and color. The human perception of brightness ( lightness), under common illumination conditions (neither pitch black nor blindingly bright), fol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power Law
In statistics, a power law is a Function (mathematics), functional relationship between two quantities, where a Relative change and difference, relative change in one quantity results in a proportional relative change in the other quantity, independent of the initial size of those quantities: one quantity varies as a Exponentiation, power of another. For instance, considering the area of a square in terms of the length of its side, if the length is doubled, the area is multiplied by a factor of four. Empirical examples The distributions of a wide variety of physical, biological, and man-made phenomena approximately follow a power law over a wide range of magnitudes: these include the sizes of craters on the moon and of solar flares, the foraging pattern of various species, the sizes of activity patterns of neuronal populations, the frequencies of words in most languages, frequencies of family names, the species richness in clades of organisms, the sizes of power outages, volcanic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cathode-ray Tube
A cathode-ray tube (CRT) is a vacuum tube containing one or more electron guns, which emit electron beams that are manipulated to display images on a phosphorescent screen. The images may represent electrical waveforms (oscilloscope), pictures (television set, computer monitor), radar targets, or other phenomena. A CRT on a television set is commonly called a picture tube. CRTs have also been used as memory devices, in which case the screen is not intended to be visible to an observer. The term ''cathode ray'' was used to describe electron beams when they were first discovered, before it was understood that what was emitted from the cathode was a beam of electrons. In CRT television sets and computer monitors, the entire front area of the tube is scanned repeatedly and systematically in a fixed pattern called a raster. In color devices, an image is produced by controlling the intensity of each of three electron beams, one for each additive primary color (red, green, and blue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Telecommunication Union
The International Telecommunication Union is a specialized agency of the United Nations responsible for many matters related to information and communication technologies. It was established on 17 May 1865 as the International Telegraph Union, making it the oldest UN agency. The ITU was initially aimed at helping connect telegraphic networks between countries, with its mandate consistently broadening with the advent of new communications technologies; it adopted its current name in 1932 to reflect its expanded responsibilities over radio and the telephone. On 15 November 1947, the ITU entered into an agreement with the newly created United Nations to become a specialized agency within the UN system, which formally entered into force on 1 January 1949. The ITU promotes the shared global use of the radio spectrum, facilitates international cooperation in assigning satellite orbits, assists in developing and coordinating worldwide technical standards, and works to improve tele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High-definition Television
High-definition television (HD or HDTV) describes a television system which provides a substantially higher image resolution than the previous generation of technologies. The term has been used since 1936; in more recent times, it refers to the generation following standard-definition television (SDTV), often abbreviated to HDTV or HD-TV. It is the current de facto standard video format used in most broadcasts: terrestrial broadcast television, cable television, satellite television and Blu-ray Discs. Formats HDTV may be transmitted in various formats: * 720p (1280 horizontal pixels × 720 lines): 921,600 pixels * 1080i (1920×1080) interlaced scan: 1,036,800 pixels (~1.04 MP). * 1080p (1920×1080) progressive scan: 2,073,600 pixels (~2.07 MP). ** Some countries also use a non-standard CEA resolution, such as 1440×1080i: 777,600 pixels (~0.78 MP) per field or 1,555,200 pixels (~1.56 MP) per frame When transmitted at two megapixels per frame, HDTV provides about five times ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultra-high-definition Television
Ultra-high-definition television (also known as Ultra HD television, Ultra HD, UHDTV, UHD and Super Hi-Vision) today includes 4K UHD and 8K UHD, which are two digital video formats with an aspect ratio of 16:9. These were first proposed by NHK Science & Technology Research Laboratories and later defined and approved by the International Telecommunication Union (ITU). The Consumer Electronics Association announced on October 17, 2012, that "Ultra High Definition", or "Ultra HD", would be used for displays that have an aspect ratio of 16:9 or wider and at least one digital input capable of carrying and presenting native video at a minimum resolution of . In 2015, the Ultra HD Forum was created to bring together the end-to-end video production ecosystem to ensure interoperability and produce industry guidelines so that adoption of ultra-high-definition television could accelerate. From just 30 in Q3 2015, the forum published a list up to 55 commercial services available aroun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Candela Per Square Metre
The candela per square metre (symbol: cd/m2) is the unit of luminance in the International System of Units (SI). The unit is based on the candela, the SI unit of luminous intensity, and the square metre, the SI unit of area. The nit (symbol: nt) is a non-SI name also used for this unit (1 nt = 1 cd/m2). The term ''nit'' is believed to come from the Latin word , "to shine". As a measure of light emitted per unit area, this unit is frequently used to specify the brightness of a display device. The sRGB spec for monitors targets . Typically, monitors calibrated for SDR broadcast or studio color grading should have a brightness of . Most consumer desktop liquid crystal displays have luminances of 200 to 300 cd/m2. HDR displays range from 450 to above 1600 cd/m2. Comparison with other units of luminance One candela per square metre is equal to: *10−4 stilbs (the CGS unit of luminance) *π×10−4 lamberts *π apostilbs *0.292 foot-lamberts *π×103 skots ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transfer Functions In Imaging
This article is about the Transfer function, transfer functions used in Image, pictures and Video, videos and describing the relationship between Signal, electrical signal, scene light and displayed light. Definition The opto-electronic transfer function (OETF) is the transfer function having the scene light as input and converting into the picture or video signal as output. This is typically done within a camera. The electro-optical transfer function (EOTF) is the transfer function having the picture or video signal as input and converting it into the linear light output of the display. This is done within the display device. The opto-optical transfer function (OOTF) is the transfer function having the scene light as input and the displayed light as output. The OOTF is the result of the OETF and the EOTF and is usually non-Linear function (calculus), linear. List of transfer functions Linear function (calculus), Linear * RAW format, Raw formats *Some OETF and EOTF have an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ITU-R Recommendations
The ITU Radiocommunication Sector (ITU-R) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU) and is responsible for radio communications. Its role is to manage the international radio-frequency spectrum and satellite orbit resources and to develop standards for radiocommunication systems with the objective of ensuring the effective use of the spectrum. ITU is required, according to its constitution, to allocate spectrum and register frequency allocation, orbital positions and other parameters of satellites, “in order to avoid harmful interference between radio stations of different countries”. The international spectrum management system is therefore based on regulatory procedures for frequency coordination, notification and registration. ITU-R has a permanent secretariat, the Radiocommunication Bureau, based at the ITU HQ in Geneva, Switzerland. The electeDirector of the Bureauis Mr. Mario Maniewicz; he was first elected by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transfer Functions
Transfer may refer to: Arts and media * ''Transfer'' (2010 film), a German science-fiction movie directed by Damir Lukacevic and starring Zana Marjanović * ''Transfer'' (1966 film), a short film * ''Transfer'' (journal), in management studies * "The Transfer" (''Smash''), a television episode *''The Transfer'', a novel by Silvano Ceccherini Finance * Transfer payment, a redistribution of income and wealth by means of the government making a payment * Balance transfer, transfer of the balance (either of money or credit) in an account to another account * Money transfer (other) ** Wire transfer, an international expedited bank-to-bank funds transfer Science and technology Learning and psychology * Transfer (propaganda), a method of psychological manipulation * Knowledge transfer, within organizations * Language transfer, in which native-language grammar and pronunciation influence the learning and use of a second language * Transfer of learning, in education Mathematic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
