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CIE 1964 Color Space
The CIE 1964 (''U''*, ''V''*, ''W''*) color space, also known as CIEUVW, is based on the CIE 1960 UCS: :U^*=13W^*(u-u_0), \quad V^*=13W^*(v-v_0), \quad W^*=25Y^\frac13-17 where is the white point and ''Y'' is the luminous tristimulus value of the object. The asterisks in the exponent indicates that the variable represent a more perceptually uniform color space than its predecessor (compare with CIELAB). Wyszecki invented the UVW color space in order to be able to calculate color differences without having to hold the luminance constant. He defined a lightness index ''W''* by simplifying expressions suggested earlier by Ladd and Pinney, and Glasser ''et al.''. The chromaticity components ''U''* and ''V''* are defined such that the white point maps to the origin, as in Adams chromatic valence color spaces. This arrangement has the benefit of being able to express the loci of chromaticities with constant saturation simply as for a constant ''C''. Furthermore, the chromaticity axe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CIE 1960 Color Space
The CIE 1960 color space ("CIE 1960 UCS", variously expanded ''Uniform Color Space'', ''Uniform Color Scale'', ''Uniform Chromaticity Scale'', ''Uniform Chromaticity Space'') is another name for the chromaticity space devised by David MacAdam. The CIE 1960 UCS does not define a luminance or lightness component, but the ''Y'' tristimulus value of the XYZ color space or a lightness index similar to ''W''* of the CIE 1964 color space are sometimes used. Today, the CIE 1960 UCS is mostly used to calculate correlated color temperature, where the isothermal lines are perpendicular to the Planckian locus. As a uniform chromaticity space, it has been superseded by the CIE 1976 UCS. Background Judd determined that a more uniform color space could be found by a simple projective transformation of the CIEXYZ tristimulus values: : \begin ''R'' \\ ''G'' \\ ''B'' \end = \begin 3.1956 & 2.4478 & -0.1434 \\ -2.5455 & 7.0492 & 0.9963 \\ 0.0000 & 0.0000 & 1.0000 \end \begin X \\ Y \\ Z ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wiley Interscience
John Wiley & Sons, Inc., commonly known as Wiley (), is an American multinational publishing company founded in 1807 that focuses on academic publishing and instructional materials. The company produces books, journals, and encyclopedias, in print and electronically, as well as online products and services, training materials, and educational materials for undergraduate, graduate, and continuing education students. History The company was established in 1807 when Charles Wiley opened a print shop in Manhattan. The company was the publisher of 19th century American literary figures like James Fenimore Cooper, Washington Irving, Herman Melville, and Edgar Allan Poe, as well as of legal, religious, and other non-fiction titles. The firm took its current name in 1865. Wiley later shifted its focus to scientific, technical, and engineering subject areas, abandoning its literary interests. Wiley's son John (born in Flatbush, New York, October 4, 1808; died in East Orange, New Jers ... [...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 wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tristimulus Value
The CIE 1931 color spaces are the first defined quantitative links between distributions of wavelengths in the electromagnetic visible spectrum, and physiologically perceived colors in human color vision. The mathematical relationships that define these color spaces are essential tools for color management, important when dealing with color inks, illuminated displays, and recording devices such as digital cameras. The system was designed in 1931 by the ''"Commission Internationale de l'éclairage"'', known in English as the International Commission on Illumination. The CIE 1931 RGB color space and CIE 1931 XYZ color space were created by the International Commission on Illumination (CIE) in 1931. They resulted from a series of experiments done in the late 1920s by William David Wright using ten observers and John Guild using seven observers. The experimental results were combined into the specification of the CIE RGB color space, from which the CIE XYZ color space was derived. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color Difference
In color science, color difference or color distance is the separation between two colors. This metric allows quantified examination of a notion that formerly could only be described with adjectives. Quantification of these properties is of great importance to those whose work is color-critical. Common definitions make use of the Euclidean distance in a device-independent color space. Euclidean sRGB As most definitions of color difference are distances within a color space, the standard means of determining distances is the Euclidean distance. If one presently has an RGB (red, green, blue) tuple and wishes to find the color difference, computationally one of the easiest is to consider ''R'', ''G'', ''B'' linear dimensions defining the color space. \text = \sqrt. When the result should be computationally simple as well, it is often acceptable to remove the square root and simply use \text^2 = (R_2 - R_1)^2 + (G_2 - G_1)^2 + (B_2 - B_1)^2. This will work in cases when ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CIELAB
The CIELAB color space, also referred to as ''L*a*b*'' , is a color space defined by the International Commission on Illumination (abbreviated CIE) in 1976. (Referring to CIELAB as "Lab" without asterisks should be avoided to prevent confusion with Hunter Lab). It expresses color as three values: ''L*'' for perceptual lightness and ''a*'' and ''b*'' for the four unique colors of human vision: red, green, blue and yellow. CIELAB was intended as a perceptually uniform space, where a given numerical change corresponds to a similar perceived change in color. While the LAB space is not truly perceptually uniform, it nevertheless is useful in industry for detecting small differences in color. Like the CIEXYZ space it derives from, CIELAB color space is a device-independent, "standard observer" model. The colors it defines are not relative to any particular device such as a computer monitor or a printer, but instead relate to the CIE standard observer which is an averaging of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luminance (relative)
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 an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lightness (color)
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] |
Institute Of Radio Engineers
The Institute of Radio Engineers (IRE) was a professional organization which existed from 1912 until December 31, 1962. On January 1, 1963, it merged with the American Institute of Electrical Engineers (AIEE) to form the Institute of Electrical and Electronics Engineers (IEEE). Founding Following several attempts to form a technical organization of wireless practitioners in 1908–1912, the Institute of Radio Engineers (IRE) was finally established in 1912 in New York City. Among its founding organizations were the Society of Wireless Telegraph Engineers (SWTE) and the Wireless Institute (TWI). At the time, the dominant organization of electrical engineers was the American Institute of Electrical Engineers (AIEE). Many of the founding members of IRE considered AIEE too conservative and too focused on electric power. Moreover, the founders of the IRE sought to establish an international organization (unlike the “American” AIEE), and adopted a tradition of electing som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
JOSA
The ''Journal of the Optical Society of America'' is a peer-reviewed scientific journal of optics, published by Optica. It was established in 1917 and in 1984 was split into two parts, A and B. ''Journal of the Optical Society of America A'' Part A covers various topics in optics, vision, and image science. The editor-in-chief is Olga Korotkova (University of Miami, USA). ''Journal of the Optical Society of America B'' Part B covers various topics in the field of optical physics, such as guided waves, laser spectroscopy, nonlinear optics, quantum optics, lasers, organic and polymer materials for optics, and ultrafast phenomena In optics, an ultrashort pulse, also known as an ultrafast event, is an electromagnetic pulse whose time duration is of the order of a picosecond (10−12 second) or less. Such pulses have a broadband optical spectrum, and can be created by .... The editor-in-chief is Kurt Busch ( Humboldt University of Berlin, Germany). References {{reflist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adams Chromatic Valence Color Space
Adams chromatic valence color spaces are a class of color spaces suggested by Elliot Quincy Adams. Two important Adams chromatic valence spaces are CIELUV and Hunter Lab. Chromatic value/valence spaces are notable for incorporating the opponent process model and the empirically-determined 2½ factor in the red/green vs. blue/yellow chromaticity components (such as in CIELAB). Chromatic value In 1942, Adams suggested chromatic ''value'' color spaces. Chromatic value, or ''chromance'', refers to the intensity of the opponent process responses and is derived from Adams' theory of color vision. A chromatic value space consists of three components: * V_Y, the Munsell–Sloan–Godlove value function: V_Y^2 = 1.4742Y - 0.004743 Y^2; * V_X - V_Y, the red–green chromaticity dimension, where V_X is the value function applied to (y_n/x_n)X instead of ''Y''; * V_Z - V_Y, the blue–yellow chromaticity dimension, where V_Z is the value function applied to (y_n/z_n)Z instead of ''Y''. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euclidean Distance
In mathematics, the Euclidean distance between two points in Euclidean space is the length of a line segment between the two points. It can be calculated from the Cartesian coordinates of the points using the Pythagorean theorem, therefore occasionally being called the Pythagorean distance. These names come from the ancient Greek mathematicians Euclid and Pythagoras, although Euclid did not represent distances as numbers, and the connection from the Pythagorean theorem to distance calculation was not made until the 18th century. The distance between two objects that are not points is usually defined to be the smallest distance among pairs of points from the two objects. Formulas are known for computing distances between different types of objects, such as the distance from a point to a line. In advanced mathematics, the concept of distance has been generalized to abstract metric spaces, and other distances than Euclidean have been studied. In some applications in statistics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
