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Foot-lambert
A foot-lambert or footlambert (fL, sometimes fl or ft-L) is a unit of luminance in United States customary units and some other unit systems. A foot-lambert equals 1/π or 0.3183 candela per square foot, or 3.426 candela per square meter (the corresponding SI unit). The foot-lambert is named after Johann Heinrich Lambert (1728–1777), a Swiss-German mathematician, physicist and astronomer. It is rarely used by electrical and lighting engineers, who prefer the candela per square foot or candela per square meter units. The luminance of a perfect Lambertian diffuse reflecting surface in foot-lamberts is equal to the incident illuminance in foot-candles. For real diffuse reflectors, the ratio of luminance to illuminance in these units is roughly equal to the reflectance of the surface. Mathematically, :L_\mathrm v = E_\mathrm v \times R, where :L_\mathrm v is the luminance, in foot-lamberts, :E_\mathrm v is the illuminance, in foot-candles, and :R is the reflectivity, expressed as a f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luminance
Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through, is emitted from, or is reflected from a particular area, and falls within a given solid angle. The procedure for conversion from spectral radiance to luminance is standardized by the CIE and ISO. Brightness is the term for the ''subjective'' impression of the ''objective'' luminance measurement standard (see for the importance of this contrast). The SI unit for luminance is candela per square metre (cd/m2). A non-SI term for the same unit is the nit. The unit in the Centimetre–gram–second system of units (CGS) (which predated the SI system) is the stilb, which is equal to one candela per square centimetre or 10 kcd/m2. Description Luminance is often used to characterize emission or reflection from flat, diffuse surfaces. Luminance levels indicate how much luminous power could be det ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bril (unit)
The bril is an old, non- SI, unit of luminance. The SI unit of luminance is the candela per square metre. Unit conversions See also * Photometry (optics) Photometry is a branch of optics that deals with measuring light Light, visible light, or visible radiation is electromagnetic radiation that can be visual perception, perceived by the human eye. Visible light spans the visible spectr ... Units of luminance Centimetre–gram–second system of units {{optics-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Candela Per Square Meter
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 cd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lambert (unit)
The lambert (symbol L) is a non- SI metric unit of luminance named for Johann Heinrich Lambert (1728–1777), a Swiss mathematician, physicist and astronomer. A related unit of luminance, the foot-lambert, is used in the lighting, cinema and flight simulation industries. The SI unit is the candela per square metre (cd/m2). Definition 1 lambert (L) = \frac candela per square centimetre (0.3183 cd/cm2) or \frac cd m−2 See also Other units of luminance: * Apostilb (asb) * Blondel (blondel) * Bril Bril is a surname. Notable people with the surname include: * Ben Bril, Dutch boxer *Joel Bril, pen name of Joel Löwe * Matthaeus Bril, Flemish painter *Paul Bril Paul Bril (1554 – 7 October 1626) was a Southern Netherlands, Flemish painter ... (bril) * Nit (nit) * Stilb (sb) * Skot (sk) References {{reflist "Lighting Design Glossary: Luminance" at ''Schorsch Lighting Design Knowledgebase'' Units of luminance Non-SI metric units ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nit (unit)
NiT, NIT, or Nits may refer to: Education * Namgyal Institute of Tibetology, Sikkim, India * Narula Institute of Technology, West Bengal, India * National Institutes of Technology, India * Naval Institute of Technology, Biliran, Philippines * Nippon Institute of Technology, Japan * Northern Institute of Technology Management, Germany * Babol Noshirvani University of Technology, Iran Science and technology * Nit, the egg case of a head louse * Nit (unit), of luminance * Nat (unit) The natural unit of information (symbol: nat), sometimes also nit or nepit, is a unit of information or information entropy, based on natural logarithms and powers of e (mathematical constant), ''e'', rather than the powers of 2 and binary loga ... or nit, natural unit of information * Network Investigative Technique, computer malware used by the FBI Other uses * National Invitational Tournament (NIT), American college basketball tournament * Nature, Intentions, Time, Special Instructi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skot (unit)
Skot (symbol: sk) is an old and deprecated measurement unit of luminance, used for self-luminous objects (''dark luminance''). The term comes from Greek , meaning "darkness". Overview The skot to measure the dark luminance () was introduced in 1940 by the (, LiTG) out of a necessity to describe the luminance of self-luminous objects, which differed so much from that of other objects that it was impractical to describe it using commonly used luminance values. Conversion factors for so called "scotopic stilb" () depend on the spectral distribution of the light and were therefore redefined in 1948 by the International Commission on Illumination (, IBK) for a specific color temperature of 2042 K or 2046 K, the temperature of solidification of platinum. Before 1948, the definition was based on a temperature of 2360 K as emitted by a wolfram-vacuum lamp. At this temperature, 1 sk = 10−3 asb. The maximum allowed value is 10 skot to avoid the uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blondel (unit)
Blondel may refer to: * Apostilb, an old unit of luminance * Blondel (surname) * Blondel de Nesle (c. 1155 – 1202), French trouvère, or poet * Jean-François Blondel (1683–1756), French architect * Maurice Blondel (1861–1949), French philosopher * Vincent Blondel (born 1965), Belgian applied mathematician * Amazing Blondel, an English progressive folk band ** Blondel (album), ''Blondel'' (album), a 1973 album by the band * Blondel (musical), ''Blondel'' (musical), a rock opera See also * Blondell, a surname and given name * Blondeau, a French surname * Blondin (other) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apostilb
The apostilb is an obsolete unit of luminance. The SI unit of luminance is the candela per square metre (cd/m2). In 1942 Parry Moon proposed to rename the apostilb the blondel, after the French physicist André Blondel André-Eugène Blondel (28 August 1863 – 15 November 1938) was a French engineer and physicist. He is the inventor of the electromechanical oscillograph and a system of photometric units of measurement. Life Blondel was born in Chaumont, Ha .... The symbol for the apostilb is asb. The apostilb is defined in terms of another unit of luminance, the stilb (sb): :1 asb = 1/ ⋅ 10−4 sb : asb = 1 cd/m2 Table of SI photometry quantities for reference See also Other units of luminance: * Lambert (L) * Skot (sk) * Bril (bril) * Nit (nit) * Foot-lambert (fL) References {{reflist Units of luminance Centimetre–gram–second system of units ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stilb (unit)
The stilb (sb) is the CGS unit of luminance for objects that are not self-luminous. It is equal to one candela per square centimeter or 104 nits (candelas per square meter). The name was coined by the French physicist André Blondel around 1920. It comes from the Greek word (), meaning 'to glitter'. It was in common use in Europe up to World War I. In North America self-explanatory terms such as candle per square inch and candle per square meter were more common. The unit has since largely been replaced by the SI unit: candela per square meter 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 .... The current national standard for SI in the United States discourages the use of the stilb.IEEE/ASTM SI 10-2002. ''American National Standard for Use of the International System of Units (SI ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nit (unit)
NiT, NIT, or Nits may refer to: Education * Namgyal Institute of Tibetology, Sikkim, India * Narula Institute of Technology, West Bengal, India * National Institutes of Technology, India * Naval Institute of Technology, Biliran, Philippines * Nippon Institute of Technology, Japan * Northern Institute of Technology Management, Germany * Babol Noshirvani University of Technology, Iran Science and technology * Nit, the egg case of a head louse * Nit (unit), of luminance * Nat (unit) The natural unit of information (symbol: nat), sometimes also nit or nepit, is a unit of information or information entropy, based on natural logarithms and powers of e (mathematical constant), ''e'', rather than the powers of 2 and binary loga ... or nit, natural unit of information * Network Investigative Technique, computer malware used by the FBI Other uses * National Invitational Tournament (NIT), American college basketball tournament * Nature, Intentions, Time, Special Instructi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joint Aviation Authorities
The Joint Aviation Authorities (JAA) was an associated body of the European Civil Aviation Conference representing the civil aviation regulatory authorities of a number of European States who had agreed to co-operate in developing and implementing common safety regulatory standards and procedures. It was not a regulatory body, regulation being achieved through the member authorities. It was in existence from 1970 until disbanded in 2009. Its headquarters were located in Hoofddorp near Schiphol airport in Netherlands. JAA issued the Joint Aviation Requirements (JAR), intended to establish minimum requirements for air safety. In implementing the so-called FUJA Report, JAA entered into a new phase as of 1 January 2007. In this new phase the former "JAA" became "JAA T" (Transition). JAA T consisted of a Liaison Office (JAA LO) and a Training Office (JAA TO). The offices of JAA LO were located in the premises of the European Union Aviation Safety Agency (EA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Federal Aviation Administration
The Federal Aviation Administration (FAA) is a Federal government of the United States, U.S. federal government agency within the United States Department of Transportation, U.S. Department of Transportation that regulates civil aviation in the United States and surrounding international waters. Its powers include air traffic control, certification of personnel and aircraft, setting standards for airports, and protection of U.S. assets during the launch or re-entry of commercial space vehicles. Powers over neighboring international waters were delegated to the FAA by authority of the International Civil Aviation Organization. The FAA was created in as the Federal Aviation Agency, replacing the Civil Aeronautics Administration (United States), Civil Aeronautics Administration (CAA). In 1967, the FAA became part of the newly formed U.S. Department of Transportation and was renamed the Federal Aviation Administration. Major functions The FAA's roles include: *Regulating U.S. co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
