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Value (colorimetry)
Lightness is a visual perception of the luminance (L) of an object. It is often judged relative to a similarly lit object. In colorimetry and color appearance models, lightness is a prediction of how an illuminated color will appear to a standard observer. While luminance is a linear measurement of light, lightness is a linear prediction of the human perception of that light. This is because human vision's lightness perception is non-linear relative to light. Doubling the quantity of light does not result in a doubling in perceived lightness, only a modest increase. The symbol for perceptual lightness is usually either J as used in CIECAM02 or L^* as used in CIELAB and CIELUV. L^* ("Lstar") is not to be confused with L as used for luminance. In some color ordering systems such as Munsell color system, Munsell, Lightness is referenced as value. Chiaroscuro and Tenebrism both take advantage of dramatic contrasts of value to heighten drama in art. Artists may also employ shading ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Poynton
Charles A. Poynton is a Canadian technical consultant and writer based in Toronto. He gives seminars on digital video systems and has written two books, ''A Technical Introduction to Digital Video'' (Wiley, 1996; ) and ''Digital Video and HDTV: Algorithms and Interfaces'' (Morgan Kaufmann, 2003; ). He is currently a columnist at Spectracal.com. Poynton is a Fellow of SMPTE, and was awarded the David Sarnoff Gold Medal in 1993 for his work to "integrate video technology with computing and communications". He is a popular teacher of seminars and travels widely for this purpose. In 1981, he founded Poynton Vector Corporation to design and build digital television processing equipment for NASA's Johnson Space Center. From 1985 to 1995, this equipment converted the field-sequential color television signal from the Space Shuttle to NTSC The first American standard for analog television broadcast was developed by National Television System Committee (NTSC)National Television Syst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harry John McNicholas
Harry may refer to: TV shows * ''Harry'' (American TV series), a 1987 American comedy series starring Alan Arkin * ''Harry'' (British TV series), a 1993 BBC drama that ran for two seasons * ''Harry'' (talk show), a 2016 American daytime talk show hosted by Harry Connick Jr. People and fictional characters *Harry (given name), a list of people and fictional characters with the given name *Harry (surname), a list of people with the surname *Dirty Harry (musician) (born 1982), British rock singer who has also used the stage name Harry *Harry Potter (character), the main protagonist in a Harry Potter fictional series by J. K. Rowling Other uses *Harry (derogatory term), derogatory term used in Norway * ''Harry'' (album), a 1969 album by Harry Nilsson *The tunnel used in the Stalag Luft III escape ("The Great Escape") of World War II * ''Harry'' (newspaper), an underground newspaper in Baltimore, Maryland See also *Harrying (laying waste), may refer to the following historical events ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kasson S
{{disambig, geo, surname ...
Kasson may refer to: People * Burt Z. Kasson (1877–1943), New York politician * John A. Kasson (1822–1910), Iowa politician and lawyer * Kasson Crooker, electronic music composer from Boston, Massachusetts Places in the United States * Kasson, Indiana * Kasson, Minnesota * Kasson, West Virginia * Kasson Brook, Pennsylvania * Kasson Township, Michigan Kasson Township ( ) is a civil township of Leelanau County in the U.S. state of Michigan. The population was 1,647 as of the 2020 census. A small portion of the township is included in the Sleeping Bear Dunes National Lakeshore. History Kasso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irwin G
Irwin may refer to: Places ;United States * Irwin, California * Irwin, Idaho * Irwin, Illinois * Irwin, Iowa * Irwin, Nebraska * Irwin, Ohio * Irwin, Pennsylvania * Irwin, South Carolina * Irwin County, Georgia * Irwin Township, Venango County, Pennsylvania * Fort Irwin, California ;Australia * Shire of Irwin, Western Australia People * Irwin (given name) * Irwin (surname) Fruit * Irwin (mango), a mango variety from Florida Other uses * IRWIN, a painting collective that is a member of Neue Slowenische Kunst * Irwin 41, an American sailboat design * Irwin Toy, a Canadian toy manufacturer and distributor * Irwin Industrial Tools, a subsidiary of Stanley Black & Decker * Irwin Magnetic Systems, a computer storage manufacturer See also * Earvin * Ervin (other) * Ervine * Erving (other) * Erwan * Erwin (other) * Irmin (other) * Irvin * Irvine (other) * Irving (other) Irving may refer to: People *Irving (name), including a l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lightness Approximations
Lightness is a visual perception of the luminance (L) of an object. It is often judged relative to a similarly lit object. In colorimetry and color appearance models, lightness is a prediction of how an illuminated color will appear to a standard observer. While luminance is a linear measurement of light, lightness is a linear prediction of the human perception of that light. This is because human vision's lightness perception is non-linear relative to light. Doubling the quantity of light does not result in a doubling in perceived lightness, only a modest increase. The symbol for perceptual lightness is usually either J as used in CIECAM02 or L^* as used in CIELAB and CIELUV. L^* ("Lstar") is not to be confused with L as used for luminance. In some color ordering systems such as Munsell, Lightness is referenced as value. Chiaroscuro and Tenebrism both take advantage of dramatic contrasts of value to heighten drama in art. Artists may also employ shading, subtle manipulatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffuser (optics)
In optics, a diffuser (also called a light diffuser or optical diffuser) is any material that diffuses or scatters light in some manner to transmit soft light. Diffused light can be easily obtained by reflecting light from a white surface, while more compact diffusers may use translucent material, including ground glass, teflon, opal glass, and greyed glass. Types Perfect reflecting diffuser A perfect (reflecting) diffuser (PRD) is a theoretical perfectly white surface with Lambertian reflectance (its brightness appears the same from any angle of view). It does not absorb light, giving back 100% of the light it receives. Reflective diffusers can be easily characterised by scatterometers.{{cite web, url=http://www.zebraoptical.com/roughnessviascatterometry.html, title=Page Title, website=www.zebraoptical.com Diffractive diffuser/homogenizer A diffractive diffuser is a kind of diffractive optical element (DOE) that exploits the principles of diffraction and refraction. It uses d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnesium Oxide
Magnesium oxide ( Mg O), or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium (see also oxide). It has an empirical formula of MgO and consists of a lattice of Mg2+ ions and O2− ions held together by ionic bonding. Magnesium hydroxide forms in the presence of water (MgO + H2O → Mg(OH)2), but it can be reversed by heating it to remove moisture. Magnesium oxide was historically known as magnesia alba (literally, the white mineral from Magnesia), to differentiate it from ''magnesia negra'', a black mineral containing what is now known as manganese. Related oxides While "magnesium oxide" normally refers to MgO, the compound magnesium peroxide MgO2 is also known. According to evolutionary crystal structure prediction, MgO2 is thermodynamically stable at pressures above 116 GPa (gigapascals), and a semiconducting suboxide Mg3O2 is thermodynamically stable above 500 GPa. Because of its stability, MgO is used as a model sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stevens's Power Law
Stevens' power law is an empirical relationship in psychophysics between an increased intensity or strength in a physical stimulus and the perceived magnitude increase in the sensation created by the stimulus. It is often considered to supersede the Weber–Fechner law, which is based on a logarithmic relationship between stimulus and sensation, because the power law describes a wider range of sensory comparisons, down to zero intensity. The theory is named after psychophysicist Stanley Smith Stevens (1906–1973). Although the idea of a power law had been suggested by 19th-century researchers, Stevens is credited with reviving the law and publishing a body of psychophysical data to support it in 1957. The general form of the law is :\psi(I) = k I ^a, where ''I'' is the intensity or strength of the stimulus in physical units (energy, weight, pressure, mixture proportions, etc.), ψ(''I'') is the magnitude of the sensation evoked by the stimulus, ''a'' is an exponent that depend ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albert Henry Munsell
Albert Henry Munsell (January 6, 1858 – June 28, 1918) was an American painter, teacher of art, and the inventor of the Munsell color system. He was born in Boston, Massachusetts, attended and served on the faculty of Massachusetts Normal Art School, and died in nearby Brookline. As a painter, he was noted for seascapes and portraits. Munsell is famous for inventing the Munsell color system, an early attempt at creating an accurate system for numerically describing colors. He wrote three books about it: ''A Color Notation'' (1905), ''Atlas of the Munsell Color System'' (1915) and one published posthumously, ''A Grammar of Color: Arrangements of Strathmore Papers in a Variety of Printed Color Combinations According to The Munsell Color System'' (1921). The Munsell color order system has gained international acceptance and has served as the foundation for many color order systems, including CIELAB. In 1917, he founded the Munsell Color Company. Biography Albert Henry Munsel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weber–Fechner Law
The Weber–Fechner laws are two related hypotheses in the field of psychophysics, known as Weber's law and Fechner's law. Both laws relate to human perception, more specifically the relation between the actual change in a physical stimulus and the perceived change. This includes stimuli to all senses: vision, hearing, taste, touch, and smell. Weber states that, "the minimum increase of stimulus which will produce a perceptible increase of sensation is proportional to the pre-existent stimulus," while Fechner's law is an inference from Weber's law (with additional assumptions) which states that the intensity of our sensation increases as the logarithm of an increase in energy rather than as rapidly as the increase. History and formulation of the laws Both Weber's law and Fechner's law were formulated by Gustav Theodor Fechner (1801–1887). They were first published in 1860 in the work ''Elemente der Psychophysik'' (''Elements of Psychophysics''). This publication was th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relative Luminance
Relative luminance Y follows the photometric definition of luminance L including spectral weighting for human vision, but while luminance L is a measure of light in units such as cd/m^2, Relative luminance Y values are normalized as 0.0 to 1.0 (or 1 to 100), with 1.0 (or 100) being a theoretical perfect reflector of 100% reference white. Like the photometric definition, it is related to the luminous flux density in a particular direction, which is radiant flux density weighted by the luminous efficiency function (''λ'') of the CIE Standard Observer. The use of relative values is useful in color or appearance models that describe perception relative to the eye's adaptation state and a reference white. For example, in prepress for print media, the absolute luminance of light reflecting off the print depends on the specific illumination, but a color appearance model using relative luminance can predict the appearance by referencing the given light source. Relative luminance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
