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luminance
A Wisdom Archive on luminance

luminance A selection of articles related to luminance

luminance, Luminance, Luminance - Definition, Radiance, Lambertian reflectance, Diffuse reflection

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ARTICLES RELATED TO luminance

luminance: Encyclopedia II - YIQ - Formula

This formula approximates the conversion from the RGB color space to YIQ. R, G and B are defined on a scale from zero to one: or using matrices Two things to note: The top row is identical to that of the YUV color space If then . In other words, the top row coefficients sum to unity and the last two rows sum to zero. ...

See also:

YIQ, YIQ - Formula

Read more here: » YIQ: Encyclopedia II - YIQ - Formula

luminance: Encyclopedia II - Frequency modulation - Applications in radio

Edwin Armstrong presented his paper: "A Method of Reducing Disturbances in Radio Signaling by a System of Frequency Modulation", which first described FM radio, before the New York section of the Institute of Radio Engineers on November 6, 1935. Frequency modulation requires a wider bandwidth than amplitude modulation by an equivalent modulating signal, but this also makes the signal more robust against interference. Frequency modulation is also more robust against simple signal amplitude fading phenomena. As a result, FM was chosen a ...

See also:

Frequency modulation, Frequency modulation - Applications in radio, Frequency modulation - Theory, Frequency modulation - Modulation Index

Read more here: » Frequency modulation: Encyclopedia II - Frequency modulation - Applications in radio

luminance: Encyclopedia II - Component video - Analogue component video

Most component video systems are variations of the red, green and blue signals that make up a television image. The simplest type, RGB, consists of the three discrete red, green and blue signals sent down three coaxial cables. This type is commonly used in Europe through SCART connectors, in the form of RGB plus composite sync, i.e. four of the wires in a SCART cable are used for the video signal (excluding ground wires). Outside Europe and Australasia, it is generally used for comp ...

See also:

Component video, Component video - Analogue component video, Component video - Digital component video

Read more here: » Component video: Encyclopedia II - Component video - Analogue component video

luminance: Encyclopedia II - Sampling frequency - Sampling theorem

The Nyquist-Shannon sampling theorem states that the sampling frequency has to be greater than twice the Nyquist frequency or, equivalently, twice the bandwidth of the signal being sampled. If a signal has a bandwidth of 100 Hz then to avoid aliasing the sampling frequency must be greater than 200 Hz. In other words, the sampling frequency must be at least twice the maximum frequency component of the signal. Otherwise, the origi ...

See also:

Sampling frequency, Sampling frequency - Sampling theorem, Sampling frequency - Oversampling, Sampling frequency - Audio, Sampling frequency - Video systems, Sampling frequency - External link

Read more here: » Sampling frequency: Encyclopedia II - Sampling frequency - Sampling theorem

luminance: Encyclopedia II - Weighting filter - Audio applications

In each field of audio measurement, special units are used to indicate a weighted measurement as opposed to a basic physical measurement of energy level. For sound, the unit is the phon (1 kHz equivalent level). Weighting filter - Loudness measurements. In the measurement of loudness, for example, an A-weighting filter is commonly used to emphasise frequencies around 3–6 kHz where the human ear is most sensitive, while attenuating very high and very low frequencies to which the ear is insensitive. The ai ...

See also:

Weighting filter, Weighting filter - Audio applications, Weighting filter - Loudness measurements, Weighting filter - Telecommunications, Weighting filter - Environmental noise measurement, Weighting filter - Audio reproduction and broadcasting equipment, Weighting filter - Other applications of weighting

Read more here: » Weighting filter: Encyclopedia II - Weighting filter - Audio applications

luminance: Encyclopedia II - Charge-coupled device - Applications

CCDs containing grids of pixels are used in digital cameras, optical scanners and video cameras as light-sensing devices. They commonly respond to 70% of the incident light (meaning a quantum efficiency of about 70%,) making them more efficient than photographic film, which captures only about 2% of the incident light. As a result CCDs were rapidly adopted by astronomers. An image is projected by a lens on the capacitor array, causing each capacitor to accumulate an electric charge proportional to the light intensity at that location. ...

See also:

Charge-coupled device, Charge-coupled device - History, Charge-coupled device - Applications, Charge-coupled device - Color cameras, Charge-coupled device - Competing technologies

Read more here: » Charge-coupled device: Encyclopedia II - Charge-coupled device - Applications

luminance: Encyclopedia II - NTSC - Technical details

NTSC - Refresh rate. The NTSC format—or more correctly the M format; see broadcast television systems—consists of 29.97 interlaced frames of video per second. Each frame consists of 486 lines out of a total of 525 (the rest are used for sync, vertical retrace, and other data such as captioning). The NTSC system interlaces its scanlines, drawing odd-numbered scanlines in odd-numbered fields and even-numbered scanlines in even-numbered fields, yielding a nearly flicker-free image at its approximately 59. ...

See also:

NTSC, NTSC - History, NTSC - Technical details, NTSC - Refresh rate, NTSC - Color encoding, NTSC - Transmission modulation scheme, NTSC - Quality problems, NTSC - Variants of NTSC, NTSC - History of the NTSC signal, NTSC - The current state of NTSC III, NTSC - Vertical Interval Reference, NTSC - Countries and territories that use NTSC, NTSC - North America, NTSC - Central America and the Caribbean, NTSC - South America, NTSC - Asia, NTSC - The Pacific, NTSC - Indian Ocean, NTSC - Middle East

Read more here: » NTSC: Encyclopedia II - NTSC - Technical details

luminance: Encyclopedia II - S-Video - Connector

Today, S-Video signals are generally connected using 4-pin mini-DIN connectors using a 75 ohm termination impedance. Apart from the impedance requirement, these connectors are identical to ones used for the now-obsolete Apple Desktop Bus; ADB cables can be used for S-Video transfer if no other cable is available, but picture quality may not be as good, and there is a risk of damage to unshielded cathode ra ...

See also:

S-Video, S-Video - Overview, S-Video - Connector, S-Video - Usage

Read more here: » S-Video: Encyclopedia II - S-Video - Connector

luminance: Encyclopedia II - Gamma correction - Terminology

The names of the various quantities are somewhat confusing. The term intensity refers strictly to the amount of light that is emitted per unit of time and per unit of surface, in units of lux. Note, however, that in many fields of science this quantity is called luminous emittance, as opposed to luminous intensity, which is a different quantity. Luminance, can mean several things even within the context of video: Luminance is the apparent brightness of an object, taking into account the wavelength-dependent sensiti ...

See also:

Gamma correction, Gamma correction - Terminology, Gamma correction - A simple monitor test

Read more here: » Gamma correction: Encyclopedia II - Gamma correction - Terminology

luminance: Encyclopedia II - Projection screen - Home theater screens and gain

One of the most often quoted properties in a home theater screen is the gain. This is a measure of reflectivity of light compared to a screen coated with titanium dioxide, when the measurement is taken for light targeted and reflected perpendicular to the screen. Titanium oxide is a bright white colour, but greater gains can be accomplished with materials that reflect more of the light parallel to projection axis and less off-axis. Frequently quoted gain levels of various materials range from 0.8 of light grey matte screens to 2.5 of ...

See also:

Projection screen, Projection screen - Screens by installation type, Projection screen - Home theater screens and gain, Projection screen - Screen geometry and optics, Projection screen - Image brightness and contrast

Read more here: » Projection screen: Encyclopedia II - Projection screen - Home theater screens and gain

luminance: Encyclopedia II - Opponent process - History

The opponent color theory was first proposed by Ewald Hering in 1872 (Hering, 1964). He thought that the colors red, yellow, green, and blue are special in that any other color can be described as a mix of them, and that they exist in opposite pairs. That is, either red or green is perceived and never greenish-red. (Note that although yellow is a mixture of red and green in the RGB color theory, the eye does not perceive it as such.) In 1957 Leo Hurvich and Dorothea Jameson provided quantitative data for Hering's co ...

See also:

Opponent process, Opponent process - History

Read more here: » Opponent process: Encyclopedia II - Opponent process - History

luminance: Encyclopedia II - MPEG-2 - Video coding simplified

MPEG-2 is for the generic coding of moving pictures and associated audio and creates a video stream out of three types of frame data (intra frames, forward predictive frames and bidirectional predicted frames) that can be arranged in a specified order called the GOP structure (GOP = Group Of Pictures - see below). (Actually, the standard itself does not define or use the term GOP, except in the name of a syntax structure called a GOP header — however, users of MPEG-2 have found that the GOP concept he ...

See also:

MPEG-2, MPEG-2 - The standard, MPEG-2 - Video coding simplified, MPEG-2 - Audio encoding, MPEG-2 - Profiles and Levels, MPEG-2 - DVD, MPEG-2 - DVB, MPEG-2 - ATSC, MPEG-2 - ISO/IEC 13818, MPEG-2 - Patent holders

Read more here: » MPEG-2: Encyclopedia II - MPEG-2 - Video coding simplified

luminance: Encyclopedia II - Binocular rivalry - Early theories of binocular rivalry

Various theories were proposed to account for binocular rivalry. Porta and Dutour took it as evidence for an ancient theory of visual perception that has come to be known as suppression theory. Its essential idea is that, despite having two eyes, we see only one of everything (known as singleness of vision) because we see with one eye at a time. According to this theory, we do not normally notice the alternations between the two eyes because their images are too similar. By making the images very different, Porta and Dutour argued, this natu ...

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Binocular rivalry, Binocular rivalry - Types of binocular rivalry, Binocular rivalry - Why binocular rivalry is interesting, Binocular rivalry - History of binocular rivalry, Binocular rivalry - Early theories of binocular rivalry, Binocular rivalry - Empirical studies of binocular rivalry: B. B. Breese 1899 1909

Read more here: » Binocular rivalry: Encyclopedia II - Binocular rivalry - Early theories of binocular rivalry

luminance: Encyclopedia II - YUV - Luminance/chrominance systems in general

The primary advantages of luminance/chrominance systems such as YUV, and its relatives YIQ and YDbDr, are that they remain compatible with black and white analog television (largely due to the work of Georges Valensi). The Y channel saves nearly all the data recorded by black and white cameras, so it produces a signal suitable for playback on old monochrome displays. In this case, the U and V are simply discarded. If displaying color, all three cha ...

See also:

YUV, YUV - Luminance/chrominance systems in general, YUV - Types of sampling

Read more here: » YUV: Encyclopedia II - YUV - Luminance/chrominance systems in general

luminance: Encyclopedia II - Y - Codes for computing

In Unicode the capital Y is codepoint U+0059 and the lowercase y is U+0079. The ASCII code for capital Y is 89 and for lowercase y is 121; or in binary 01011001 and 01111001, correspondingly. The EBCDIC code for capital Y is 232 and for lowercase y is 168. The numeric character references in HTML and XML are "Y" and "y" for upper and lower case respectively. ...

See also:

Y, Y - Codes for computing, Y - Meanings of Y

Read more here: » Y: Encyclopedia II - Y - Codes for computing

luminance: Encyclopedia II - SÉCAM - History

Work on SÉCAM began in 1956. The technology was ready by the end of the fifties, but this was too soon for a wide introduction. Initially, a version of SÉCAM for the then French 819-line television standard was devised and tested, but not introduced. Following a pan-European agreement to introduce colour TV only in 625 lines, France had to start the conversion by switching over to a 625-line television standard, which happened at the beginning of the 1960s with the ...

See also:

SÉCAM, SÉCAM - Technical details, SÉCAM - History, SÉCAM - Why SÉCAM in France?, SÉCAM - Why SÉCAM elsewhere?, SÉCAM - SÉCAM varieties, SÉCAM - Problems with the standard, SÉCAM - Facetious interpretations of the SÉCAM acronym, SÉCAM - Countries and territories that use or have used SÉCAM

Read more here: » SÉCAM: Encyclopedia II - SÉCAM - History

luminance: Encyclopedia II - NTSC - Countries and territories that use NTSC

NTSC - North America. Canada Mexico United States NTSC - Central America and the Caribbean. Antigua and Barbuda Aruba Bahamas Barbados Belize Bermuda British Virgin Islands Cayman Islands Costa Rica Cuba Dominica Dominican Republic El Salvador Guatemala Grenada Honduras Jamaica Leeward Islan ...

See also:

NTSC, NTSC - History, NTSC - Technical details, NTSC - Refresh rate, NTSC - Color encoding, NTSC - Transmission modulation scheme, NTSC - Quality problems, NTSC - Variants of NTSC, NTSC - History of the NTSC signal, NTSC - The current state of NTSC III, NTSC - Vertical Interval Reference, NTSC - Countries and territories that use NTSC, NTSC - North America, NTSC - Central America and the Caribbean, NTSC - South America, NTSC - Asia, NTSC - The Pacific, NTSC - Indian Ocean, NTSC - Middle East

Read more here: » NTSC: Encyclopedia II - NTSC - Countries and territories that use NTSC

luminance: Encyclopedia II - NTSC - Vertical Interval Reference

The standard NTSC video image contains some lines (lines 1-21 of each field) which are not visible; all are beyond the edge of the viewable image, but only lines 1-9 are used for the vertical-sync and equalizing pulses. The remaining lines were deliberately blanked in the original NTSC specification to provide time for the electron beam in CRT-based screens to return to the top of the display. VIR (or Vertical Interval Reference), widely adopted in the 1980's, attempts to correct some of the color problems with NTSC video by adding st ...

See also:

NTSC, NTSC - History, NTSC - Technical details, NTSC - Refresh rate, NTSC - Color encoding, NTSC - Transmission modulation scheme, NTSC - Quality problems, NTSC - Variants of NTSC, NTSC - History of the NTSC signal, NTSC - The current state of NTSC III, NTSC - Vertical Interval Reference, NTSC - Countries and territories that use NTSC, NTSC - North America, NTSC - Central America and the Caribbean, NTSC - South America, NTSC - Asia, NTSC - The Pacific, NTSC - Indian Ocean, NTSC - Middle East

Read more here: » NTSC: Encyclopedia II - NTSC - Vertical Interval Reference

luminance: Encyclopedia II - NTSC - The current state of NTSC III

The North American analog transmission chain is strictly NTSC III now. Many NTSC II devices feed into existing transmission chains, with NTSC III compatibility being achieved by signal processing in the digital domain. Typical terrestrial TV transmitters or cable company distribution units send out NTSC III signals, especially if the originating signal comes from a TVRO or ATSC source. All free-to-air analog satcom transmissions are NTSC III. Video scrambling systems such as VideoCipher cannot achieve full NTSC III c ...

See also:

NTSC, NTSC - History, NTSC - Technical details, NTSC - Refresh rate, NTSC - Color encoding, NTSC - Transmission modulation scheme, NTSC - Quality problems, NTSC - Variants of NTSC, NTSC - History of the NTSC signal, NTSC - The current state of NTSC III, NTSC - Vertical Interval Reference, NTSC - Countries and territories that use NTSC, NTSC - North America, NTSC - Central America and the Caribbean, NTSC - South America, NTSC - Asia, NTSC - The Pacific, NTSC - Indian Ocean, NTSC - Middle East

Read more here: » NTSC: Encyclopedia II - NTSC - The current state of NTSC III

luminance: Encyclopedia II - NTSC - Variants of NTSC

Unlike PAL, with its many and varied underlying broadcast television systems in use throughout the world, NTSC color encoding is invariably used with broadcast system M, giving NTSC-M. Britain once contemplated introducing a 405-line NTSC-A system on top of its old black-and-white television system, but the proposal was eventually scrapped in favor of the incompatible PAL-I. Only Japan's variant "NTSC-J" is very slightly different: in Japan, black level and blanking level of the signal are identical, as they are in PAL, while in Ameri ...

See also:

NTSC, NTSC - History, NTSC - Technical details, NTSC - Refresh rate, NTSC - Color encoding, NTSC - Transmission modulation scheme, NTSC - Quality problems, NTSC - Variants of NTSC, NTSC - History of the NTSC signal, NTSC - The current state of NTSC III, NTSC - Vertical Interval Reference, NTSC - Countries and territories that use NTSC, NTSC - North America, NTSC - Central America and the Caribbean, NTSC - South America, NTSC - Asia, NTSC - The Pacific, NTSC - Indian Ocean, NTSC - Middle East

Read more here: » NTSC: Encyclopedia II - NTSC - Variants of NTSC

luminance: Encyclopedia II - S-VHS - S-VHS vs ED-Beta

Shortly after the announcement of S-VHS, Sony responded with an announcement of Extended Definition Betamax (ED-ßeta.) S-VHS was JVC's next generation video format designed to dominate the competing SuperBeta format (which already offered better-than-VHS quality.) Not to be outdone, Sony developed ED-Beta as their next generation competitor to S-VHS. In terms of video performance, ED-Beta offered even greater luminance bandwidth than S-VHS: 500 horizontal picture elements vs S-VHS's 400, putting ED-Beta nearly on par wi ...

See also:

S-VHS, S-VHS - Technical details, S-VHS - Shadow of VHS, S-VHS - S-VHS vs ED-Beta, S-VHS - Home Use

Read more here: » S-VHS: Encyclopedia II - S-VHS - S-VHS vs ED-Beta

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