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Lambert (unit)
The lambert (symbol L, la or Lb) 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 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. The symbol for the apostilb i ... (asb) * Blondel (blondel) * Bril (bril) * Nit (nit) * Stilb (sb) * Skot (sk) {{SI light units References "Lighting Design Glossary: Luminance" at ''Schorsch Lighting Design Knowledgebase'' Units of luminance Non-SI ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metric Units
Metric units are units based on the metre, gram or second and decimal (power of ten) multiples or sub-multiples of these. The most widely used examples are the units of the International System of Units (SI). By extension they include units of electromagnetism from the CGS and SI units systems, and other units for which use of SI prefixes has become the norm. Other unit systems using metric units include: * International System of Electrical and Magnetic Units * Metre–tonne–second (MTS) system of units * MKS system of units (metre, kilogram, second) Metric units that are part of the SI The first group of metric units are those that are at present defined as units within the International System of Units (SI). In its most restrictive interpretation, this is what may be meant when the term ''metric unit'' is used. The SI defines 30 named units and associated symbols: * The unit one (1) is the unit of a quantity of dimension one. * The second (s) is the unit of time. * The ... [...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. 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 detected by the human eye looking at a particular surface from a particular angle of view. Luminance is thus an i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johann Heinrich Lambert
Johann Heinrich Lambert (, ''Jean-Henri Lambert'' in French; 26 or 28 August 1728 – 25 September 1777) was a polymath from the Republic of Mulhouse, generally referred to as either Swiss or French, who made important contributions to the subjects of mathematics, physics (particularly optics), philosophy, astronomy and map projections. Biography Lambert was born in 1728 into a Huguenot family in the city of Mulhouse (now in Alsace, France), at that time a city-state allied to Switzerland. Some sources give 26 August as his birth date and others 28 August. Leaving school at 12, he continued to study in his free time while undertaking a series of jobs. These included assistant to his father (a tailor), a clerk at a nearby iron works, a private tutor, secretary to the editor of ''Basler Zeitung'' and, at the age of 20, private tutor to the sons of Count Salis in Chur. Travelling Europe with his charges (1756–1758) allowed him to meet established mathematicians in the German ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
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] |
Candela
The candela ( or ; symbol: cd) is the unit of luminous intensity in the International System of Units (SI). It measures luminous power per unit solid angle emitted by a light source in a particular direction. Luminous intensity is analogous to radiant intensity, but instead of simply adding up the contributions of every wavelength of light in the source's spectrum, the contribution of each wavelength is weighted by the standard luminosity function (a model of the sensitivity of the human eye to different wavelengths). A common wax candle emits light with a luminous intensity of roughly one candela. If emission in some directions is blocked by an opaque barrier, the emission would still be approximately one candela in the directions that are not obscured. The word ''candela'' is Latin for ''candle''. The old name "candle" is still sometimes used, as in ''foot-candle'' and the modern definition of ''candlepower''. Definition The 26th General Conference on Weights and Measures (C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Square Centimetre
The square metre ( international spelling as used by the International Bureau of Weights and Measures) or square meter (American spelling) is the unit of area in the International System of Units (SI) with symbol m2. It is the area of a square with sides one metre in length. Adding and subtracting SI prefixes creates multiples and submultiples; however, as the unit is exponentiated, the quantities grow exponentially by the corresponding power of 10. For example, 1 kilometre is 103 (one thousand) times the length of 1 metre, but 1 square kilometre is (103)2 (106, one million) times the area of 1 square metre, and 1 cubic kilometre is (103)3 (109, one billion) cubic metres. SI prefixes applied The square metre may be used with all SI prefixes used with the metre. Unicode characters Unicode has several characters used to represent metric area units, but these are for compatibility with East Asian character encodings and are meant to be used in new documents. * * * * ... [...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. The symbol for the apostilb is asb. The apostilb is defined in terms of another unit of luminance, the Stilb (unit), stilb (sb): :1 asb = 1/ ⋅ 10−4 sb : asb = 1 cd/m2 See also Other units of luminance: * Lambert (unit), Lambert (L) * Skot (unit), Skot (sk) * Bril (unit), Bril (bril) * Nit (unit), Nit (nit) * Foot-lambert (fL) References {{reflist Units of luminance Centimetre–gram–second system of units ... [...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] |
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 the science of the measurement of light, in terms of its perceived brightness to the human eye. It is distinct from radiometry, which is the science of measurement of radiant energy (including light) in terms of absolute power. ... Units of luminance Centimetre–gram–second system of units {{optics-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nit (unit)
NiT, NIT or Nits may refer to: Education * 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) or nit, natural unit of information * Network Investigative Technique, computer malware used by the FBI Other uses * National Invitation Tournament, for US men's college basketball * Nagpur Improvement Trust, India * Nits (band), a Dutch musical group * ''National Indigenous Times'', indigenous Australian affairs newspaper * Negative income tax * Neith or Nit, ancient Egyptian goddess * Norfolk International Terminals, facility of the Virginia Port Authority, US * Notice inviting tenders, Indian equivalent of invitation to tender An invitation t ... [...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] |
