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Rec. 2020
ITU-R Recommendation BT.2020, more commonly known by the abbreviations Rec. 2020 or BT.2020, defines various aspects of ultra-high-definition television (UHDTV) with standard dynamic range (SDR) and wide color gamut (WCG), including picture resolutions, frame rates with progressive scan, bit depths, color primaries, RGB and luma-chroma color representations, chroma subsamplings, and an opto-electronic transfer function. The first version of Rec. 2020 was posted on the International Telecommunication Union (ITU) website on August 23, 2012, and two further editions have been published since then. Rec. 2020 is extended for high-dynamic-range (HDR) by Rec. 2100, which uses the same color primaries as Rec. 2020. Technical details Resolution Rec. 2020 defines two standard image formats of 3840 × 2160 ("4K") and 7680 × 4320 ("8K"). These both have an aspect ratio of 16:9 and use square pixels. Frame rate Rec. 2020 s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CIE 1931 Color Space
In 1931, the International Commission on Illumination (CIE) published the CIE 1931 color spaces which define the relationship between the visible spectrum and human color vision. The CIE color spaces are mathematical models that comprise a "standard observer", which is a static idealization of the color vision of a normal human. A useful application of the CIEXYZ colorspace is that a mixture of two colors in some proportion lies on the straight line between those two colors. One disadvantage is that it is not perceptually uniform. This disadvantage is remedied in subsequent color models such as CIELUV and CIELAB, but these and modern color models still use the CIE 1931 color spaces as a foundation. The CIE (from the French name " Commission Internationale de l'éclairage" - International Commission on Illumination) developed and maintains many of the standards in use today relating to colorimetry. The CIE color spaces were created using data from a series of experiments, where ... [...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] |
Wavelength
In physics and mathematics, wavelength or spatial period of a wave or periodic function is the distance over which the wave's shape repeats. In other words, it is the distance between consecutive corresponding points of the same ''phase (waves), phase'' on the wave, such as two adjacent crests, troughs, or zero crossings. Wavelength is a characteristic of both traveling waves and standing waves, as well as other spatial wave patterns. The multiplicative inverse, inverse of the wavelength is called the ''spatial frequency''. Wavelength is commonly designated by the Greek letter lambda (''λ''). For a modulated wave, ''wavelength'' may refer to the carrier wavelength of the signal. The term ''wavelength'' may also apply to the repeating envelope (mathematics), envelope of modulated waves or waves formed by Interference (wave propagation), interference of several sinusoids. Assuming a sinusoidal wave moving at a fixed phase velocity, wave speed, wavelength is inversely proportion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primary Color
Primary colors are colorants or colored lights that can be mixed in varying amounts to produce a gamut of colors. This is the essential method used to create the perception of a broad range of colors in, e.g., electronic displays, color printing, and paintings. Perceptions associated with a given combination of primary colors can be predicted by an appropriate mixing model (e.g., additive, subtractive) that uses the physics of how light interacts with physical media, and ultimately the retina to be able to accurately display the intended colors. The most common color mixing models are the additive primary colors (red, green, blue) and the subtractive primary colors (cyan, magenta, yellow). Red, yellow and blue are also commonly taught as primary colors (usually in the context of subtractive color mixing as opposed to additive color mixing), despite some criticism due to its lack of scientific basis. Primary colors can also be conceptual (not necessarily real), either as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
White Point
A white point (often referred to as reference white or target white in technical documents) is a set of tristimulus values or chromaticity coordinates that serve to define the color "white" in image capture, encoding, or reproduction. Depending on the application, different definitions of white are needed to give acceptable results. For example, photographs taken indoors may be lit by incandescent lights, which are relatively orange compared to daylight. Defining "white" as daylight will give unacceptable results when attempting to color-correct a photograph taken with incandescent lighting. Illuminants An illuminant is characterized by its relative spectral power distribution (SPD). The white point of an illuminant is the chromaticity of a white object under the illuminant, and can be specified by chromaticity coordinates, such as the ''x'', ''y'' coordinates on the CIE 1931 chromaticity diagram (hence the use of the relative SPD and not the absolute SPD, because the white ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color Space
A color space is a specific organization of colors. In combination with color profiling supported by various physical devices, it supports reproducible representations of colorwhether such representation entails an analog or a digital representation. A color space may be arbitrary, i.e. with physically realized colors assigned to a set of physical color swatches with corresponding assigned color names (including discrete numbers infor examplethe Pantone collection), or structured with mathematical rigor (as with the NCS System, Adobe RGB and sRGB). A "color space" is a useful conceptual tool for understanding the color capabilities of a particular device or digital file. When trying to reproduce color on another device, color spaces can show whether shadow/highlight detail and color saturation can be retained, and by how much either will be compromised. A "color model" is an abstract mathematical model describing the way colors can be represented as tuples of numbers (e. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RGB Color Space
RGB color spaces are a category of additive colorimetric color spaces specifying part of its absolute color space definition using the RGB color model. RGB color spaces are commonly found describing the mapping of the RGB color model to human perceivable color, but some RGB color spaces use imaginary (non-real-world) primaries and thus can not be displayed directly. Like any color space, while the specifications in this category use the RGB color model to describe their space, it is not mandatory to use that model to signal pixel color values. Broadcast TV color spaces like NTSC, PAL, Rec. 709, Rec. 2020 additionally describe a translation from RGB to YCbCr and that is how they are usually signalled for transmission, but an image can be stored as either RGB or YCbCr. This demonstrates using the singular term "RGB color space" can be misleading, since a chosen color space or signalled colour can be described by any appropriate color model. However the singular can be seen in spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Level
Video black level is defined as the level of brightness at the darkest (black) part of a visual image or the level of brightness at which no light is emitted from a screen, resulting in a pure black screen. Video displays generally need to be calibrated so that the displayed black is true to the black information in the video signal. If the black level is not correctly adjusted, visual information in a video signal could be displayed as black, or black information could be displayed as above black information (gray). The voltage of the black level varies across different television standards. PAL sets the black level the same as the blanking level, while NTSC sets the black level approximately 54 mV above the blanking level In video technology, blanking level is the level of the composite video signal during the front and back porches of the video signal. The composite video signal is actually the video information superimposed on blanking. The total level of the com .... ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pixel
In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a Raster graphics, raster image, or the smallest addressable element in a dot matrix display device. In most digital display devices, pixels are the smallest element that can be manipulated through software. Each pixel is a Sampling (signal processing), sample of an original image; more samples typically provide more accurate representations of the original. The Intensity (physics), intensity of each pixel is variable. In color imaging systems, a color is typically represented by three or four component intensities such as RGB color model, red, green, and blue, or CMYK color model, cyan, magenta, yellow, and black. In some contexts (such as descriptions of camera sensors), ''pixel'' refers to a single scalar element of a multi-component representation (called a ''photosite'' in the camera sensor context, although ''wikt:sensel, sensel'' is sometimes used), while in yet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aspect Ratio (image)
The aspect ratio of an image is the ratio of its width to its height. It is expressed as two numbers separated by a colon, in the format width:height. Common aspect ratios are 1.85:1 and 2.39:1 in cinematography, 4:3 and 16:9 in television, and 3:2 in still photography and 1:1: Used for square images, often seen on social media platforms like Instagram, 21:9: An ultrawide aspect ratio popular for gaming and desktop monitors. Some common examples The common film aspect ratios used in cinemas are 1.85:1 and 2.39:1.The 2.39:1 ratio is commonly labeled 2.40:1, e.g., in the American Society of Cinematographers' ''American Cinematographer Manual'' (Many widescreen films before the 1970 Society of Motion Picture and Television Engineers, SMPTE revision used 2.35:1). Two common videography, videographic aspect ratios are 4:3 (1.:1), the universal video format of the 20th century, and 16:9 (1.:1), universal for high-definition television and European digital television. Other cinematic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
8K Resolution
8K resolution refers to an image or display resolution with a width of approximately 8,000 pixels. 8K UHD () is the highest resolution defined in the Rec. 2020 ( UHDTV) standard. 8K display resolution is the successor to 4K resolution. TV manufacturers pushed to make 4K a new standard by 2017. At CES 2012, the first prototype 8K TVs were unveiled by Japanese electronics corporation Sharp. The feasibility of a fast transition to this new standard is questionable in view of the absence of broadcasting resources. In 2018, Strategy Analytics predicted that 8K-ready devices will still only account for 3% of UHD TVs by 2023 with global sales of 11 million units a year. However, TV manufacturers remain optimistic as the 4K market grew much faster than expected, with actual sales exceeding projections nearly six-fold in 2016. In 2013, a transmission network's capability to carry HDTV resolution was limited by internet speeds and relied on satellite broadcast to transmit the high ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
