|
ITU-R BT.1886
ITU-R BT.1886 is the reference EOTF of SDR-TV. It is a gamma 2.4 transfer function (a power law with a 2.4 exponent) considered as a satisfactory approximation of the response characteristic of CRT to electrical signal. It has been standardized by ITU in March 2011. It is used for Rec. 709 ( HD-TV) and Rec. 2020 ( UHD-TV). Definition BT.1886 EOTF is as follows: L = a (\max V+b),0^ where * L is the screen luminance, in cd/m2. * V is the input video signal level, in the range \left , 1 \right/math>. * \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 screen luminance for black, in cd/m2. According to ITU, for a better match, L_B can be set to 0.1 for moderate black level settings (e.g. 0.1 cd/m2) or to 0 for lower black levels (e.g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EOTF
Images and videos use specific transfer functions to describe 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 a 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 composition 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. 709 and Rec. 2020: Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard-dynamic-range Video
Standard-dynamic-range video (SDR video) is a video technology which represents light intensity based on the brightness, 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 cd/m2, a black level around 0.1 cd/m2 and Rec.709 / sRGB color gamut. It uses the 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 (HDR video), a new technology that was developed in the 2010s to overcome SDR's limits. Technical details Transfer function Conventional gamma curves: * Opto-electronic transfer function (OETF): ** Rec. 601 (analog video signals in SD-TV digital video form) ** Rec. 709 ( HD-TV) ** Rec. 2020 ( UHD-TV) ** sRGB ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma Correction
Gamma correction or gamma is a Nonlinearity, nonlinear operation used to encode and decode Relative luminance, luminance or CIE 1931 color space#Tristimulus values, tristimulus values in video or still image systems. Gamma correction is, in the simplest cases, defined by the following Power law, 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), un ... [...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 relative change in the other quantity proportional to the change raised to a constant exponent: one quantity varies as a power of another. The change is independent of the initial size of those quantities. For instance, the area of a square has a power law relationship with the length of its side, since if the length is doubled, the area is multiplied by 2, while if the length is tripled, the area is multiplied by 3, and so on. Empirical examples The distributions of a wide variety of physical, biological, and human-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, cloud sizes, the foraging pattern of various species, the sizes of activity patterns of neuronal populations, the frequencies of words ... [...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 on an oscilloscope, a Film frame, frame of video on an Analog television, analog television set (TV), Digital imaging, digital raster graphics on a computer monitor, or other phenomena like radar targets. A CRT in a TV is commonly called a picture tube. CRTs have also been Williams tube, 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 TVs and computer monitors, the entire front area of the tube is scanned repeatedly and systematically in a fixed pattern called a raster scan, raster. In color devices, an image is produced by con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Telecommunication Union
The International Telecommunication Union (ITU)In the other common languages of the ITU: * * is a list of specialized agencies of the United Nations, specialized agency of the United Nations responsible for many matters related to information and communications technology, information and communication technologies. It was established on 17 May 1865 as the International Telegraph Union, the first formal and permanent international organization. The organization significantly predates the UN, making it the oldest UN agency. Doreen Bogdan-Martin is the Secretary-General of ITU, the first woman to serve as its head. The ITU was initially aimed at helping connect Telegraphy, 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 cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High-definition Television
High-definition television (HDTV) describes a television or video system which provides a substantially higher image resolution than the previous generation of technologies. The term has been used since at least 1933; in more recent times, it refers to the generation following standard-definition television (SDTV). It is the standard video format used in most broadcasts: Terrestrial television, terrestrial broadcast television, cable television, satellite television. Formats HDTV may be transmitted in various formats: * 720p (): 921,600 pixels * 1080i () interlaced scan: 1,036,800 pixels (≈1.04Mpx). * 1080p () progressive scan: 2,073,600 pixels (≈2.07Mpx). ** Some countries also use a non-standard CTA resolution, such as : 777,600 pixels (≈0.78Mpx) per field or 1,555,200 pixels (≈1.56Mpx) per frame When transmitted at two megapixels per frame, HDTV provides about five times as many pixels as SD (standard-definition television). The increased resolution provides for a cl ... [...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 resolution#Resolutions, 4K UHD and 8K resolution#Resolutions, 8K UHD, which are two digital video formats with an Aspect ratio (image), 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 display aspect ratio, 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. Fr ... [...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 deprecated 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 display A liquid-crystal display (LCD) is a flat-panel display or other Electro-optic modulator, electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers to display information. Liq ...s have luminances of 200 to 300 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transfer Functions In Imaging
Images and videos use specific transfer functions to describe 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 a 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 composition 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. 709 and Rec. 2020: Th ... [...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 elected Director of the Bureau is Mario Maniewicz; he was first elected by t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transfer Functions
Transfer may refer to: Arts and media *Transfer (2010 film), ''Transfer'' (2010 film), a German science-fiction movie directed by Damir Lukacevic and starring Zana Marjanović *Transfer (1966 film), ''Transfer'' (1966 film), a short film * Transfer (journal), ''Transfer'' (journal), in management studies *"A Transfer", a 1995 television episode of ''Neon Genesis Evangelion'' *The Transfer (Smash), "The Transfer" (''Smash''), a 2013 television episode *''The Transfer'', a novel by Silvano Ceccherini * "Transfer", a song by Five for Fighting from the 2010 album ''Slice (album), Slice'' 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
