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Mesopic
Mesopic vision, sometimes also called twilight vision, is a combination of photopic and scotopic vision under low-light (but not necessarily dark) conditions. Mesopic levels range approximately from 0.01 to 3.0 cd/m2 in luminance. Most nighttime outdoor and street lighting conditions are in the mesopic range. Human eyes respond to certain light levels differently. This is because under high light levels typical during daytime (photopic vision), the eye uses cones to process light. Under very low light levels, corresponding to moonless nights without artificial lighting (scotopic vision), the eye uses rods to process light. At many nighttime levels, a combination of both cones and rods supports vision. Photopic vision facilitates excellent color perception, whereas colors are barely perceptible under scotopic vision. Mesopic vision falls between these two extremes. In most nighttime environments, enough ambient light prevents true scotopic vision. In the words of Duco Sch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Purkinje Effect
The Purkinje effect (; sometimes called the Purkinje shift, often incorrectly pronounced ) is the tendency for the peak luminance sensitivity of the eye to shift toward the blue end of the color spectrum at low illumination levels as part of dark adaptation. In consequence, reds will appear darker relative to other colors as light levels decrease. The effect is named after the Czech anatomist Jan Evangelista Purkyně. While the effect is often described from the perspective of the human eye, it is well established in a number of animals under the same name to describe the general shifting of spectral sensitivity due to pooling of rod and cone output signals as a part of dark/light adaptation. This effect introduces a difference in color contrast under different levels of illumination. For instance, in bright sunlight, geranium flowers appear bright red against the dull green of their leaves, or adjacent blue flowers, but in the same scene viewed at dusk, the contrast is rever ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photopic Vision
Photopic vision is the vision of the eye under well-lit conditions (luminance levels from 10 to 108 cd/m2). In humans and many other animals, photopic vision allows color perception, mediated by cone cells, and a significantly higher visual acuity and temporal resolution than available with scotopic vision. The human eye uses three types of cones to sense light in three bands of color. The biological pigments of the cones have maximum absorption values at wavelengths of about 420 nm (blue), 534 nm (bluish-green), and 564 nm (yellowish-green). Their sensitivity ranges overlap to provide vision throughout the visible spectrum. The maximum efficacy is 683 lm/W at a wavelength of 555 nm (green). By definition, light at a frequency of hertz has a luminous efficacy of 683 lm/W. The wavelengths for when a person is in photopic vary with the intensity of light. For the blue-green region (500 nm), 50% of the light reaches the image point of the retina. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primary Color
A set (mathematics), set of primary colors or primary colours (see American and British English spelling differences#-our, -or, spelling differences) consists of colorants or colored lights that can be mixed in varying amounts to produce a gamut of colors. This is the essential method used to create the perception of a broad range of colors in, e.g., electronic displays, color printing, and paintings. Perceptions associated with a given combination of primary colors can be predicted by an appropriate mixing model (e.g., additive mixing, additive, subtractive mixing, subtractive) that reflects the physics of how light interacts with physical media, and ultimately the retina. Primary colors can also be conceptual (not necessarily real), either as additive mathematical elements of a color space or as irreducible phenomenological categories in domains such as psychology and Philosophy of color, philosophy. Color space primaries are precisely defined and empirically rooted in psychop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color Vision
Color vision, a feature of visual perception, is an ability to perceive differences between light composed of different wavelengths (i.e., different spectral power distributions) independently of light intensity. Color perception is a part of the larger visual system and is mediated by a complex process between neurons that begins with differential stimulation of different types of photoreceptors by light entering the eye. Those photoreceptors then emit outputs that are propagated through many layers of neurons and then ultimately to the brain. Color vision is found in many animals and is mediated by similar underlying mechanisms with common types of biological molecules and a complex history of evolution in different animal taxa. In primates, color vision may have evolved under selective pressure for a variety of visual tasks including the foraging for nutritious young leaves, ripe fruit, and flowers, as well as detecting predator camouflage and emotional states in other pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scotopic Vision
In the study of human visual perception, scotopic vision (or scotopia) is the vision of the eye under low-light conditions. The term comes from Greek ''skotos'', meaning "darkness", and ''-opia'', meaning "a condition of sight". In the human eye, cone cells are nonfunctional in low visible light. Scotopic vision is produced exclusively through rod cells, which are most sensitive to wavelengths of around 498 nm (blue-green) and are insensitive to wavelengths longer than about 640 nm (red-orange). This condition is called the Purkinje effect. Retinal circuitry Of the two types of photoreceptor cells in the retina, rods dominate scotopic vision. This is caused by increased sensitivity of the photopigment molecule expressed in rods, as opposed to that in cones. Rods signal light increments to rod bipolar cells, which, unlike most bipolar cell types, do not form direct connections with retinal ganglion cells - the output neuron of the retina. Instead, two types of amacri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. In modern photometry, the radiant power at each wavelength is weighted by a luminosity function that models human brightness sensitivity. Typically, this weighting function is the photopic sensitivity function, although the scotopic function or other functions may also be applied in the same way. Photometry and the eye The human eye is not equally sensitive to all wavelengths of visible light. Photometry attempts to account for this by weighting the measured power at each wavelength with a factor that represents how sensitive the eye is at that wavelength. The standardized model of the eye's response to light as a function of wavelength is given by the luminosity function. The eye has different responses as a function of wavelength when it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airport
An airport is an aerodrome with extended facilities, mostly for commercial air transport. Airports usually consists of a landing area, which comprises an aerially accessible open space including at least one operationally active surface such as a runway for a plane to take off and to land or a helipad, and often includes adjacent utility buildings such as control towers, hangars and terminals, to maintain and monitor aircraft. Larger airports may have airport aprons, taxiway bridges, air traffic control centres, passenger facilities such as restaurants and lounges, and emergency services. In some countries, the US in particular, airports also typically have one or more fixed-base operators, serving general aviation. Operating airports is extremely complicated, with a complex system of aircraft support services, passenger services, and aircraft control services contained within the operation. Thus airports can be major employers, as well as important hubs for tourism ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blue-green
Blue-green is the color that is between green and blue. It belongs to the cyan family of colors. Variations Cyan (aqua) Cyan, also called aqua, is the blue-green color that is between blue and green on a modern RGB color wheel. The modern RGB color wheel replaced the traditional old-fashioned RYB color wheel because it is possible to display much brighter and more saturated colors using the primary and secondary colors of the RGB color wheel. In the terminology of color theory, RGB color space has a much larger color gamut than RYB color space. The first recorded use of ''cyan'' as a color name in English was in 1879. Turquoise The color turquoise, a representation of the color of the semi-precious stone turquoise. The first recorded use of ''turquoise'' as a color name in English was in 1573. The color "turquoise" is a light tone of blue-green. Green-blue Green-blue was a Crayola crayon color from 1958 to 1990. Bondi Blue Bondi blue is a color belo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chartreuse (color)
Chartreuse (, , ), also known as yellow-green, is a color between yellow and green. It was named because of its resemblance to the green color of a French liqueur called '' green chartreuse'', introduced in 1764. Similarly, ''chartreuse yellow'' is a yellow color mixed with a small amount of green; it was named because of its resemblance to the color of another French liqueur called '' yellow chartreuse'', introduced in 1838. Shades of chartreuse History and etymology The French word ''chartreuse'' means "charterhouse". The monasteries of the monks of the Carthusian order, of which the first one was established in 1082 by Saint Bruno, are called charter houses because they were chartered—and given generous material support—by the Duke of Burgundy, known as Philip the Bold, when he took over the area in 1378. Philip the Bold's elaborately decorated tomb was initially installed at a Carthusian charterhouse when he died in 1404. These monks started producing Chartreuse lique ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Available Light
In photography and cinematography, available light (also called ambient light or practical light) refers to any ''available'' source of light that is not explicitly supplied by the photographer for the purpose of taking pictures. The term usually refers to light sources in the surrounding environment that are present naturally (e.g. sunlight, moonlight, starlight, etc.) or artificial lighting that are already pre-existing (e.g. street lights, room lights, etc.). It generally excludes flashes, although arguably flash lighting provided by other photographers shooting simultaneously in the same space could be considered available light. Light sources that affect the scene and are included in the actual frame are called practical light sources, or simply practicals. Use of available light is an important factor in candid photography in order not to disturb the subjects. The use of available light may pose a challenge for a photographer. The brightness and direction of the light ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Springer Science+Business Media
Springer Science+Business Media, commonly known as Springer, is a German multinational publishing company of books, e-books and peer-reviewed journals in science, humanities, technical and medical (STM) publishing. Originally founded in 1842 in Berlin, it expanded internationally in the 1960s, and through mergers in the 1990s and a sale to venture capitalists it fused with Wolters Kluwer and eventually became part of Springer Nature in 2015. Springer has major offices in Berlin, Heidelberg, Dordrecht, and New York City. History Julius Springer founded Springer-Verlag in Berlin in 1842 and his son Ferdinand Springer grew it from a small firm of 4 employees into Germany's then second largest academic publisher with 65 staff in 1872.Chronology ". Springer Science+Business Media. In 1964, Springer expanded its business internationally, o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color Blindness
Color blindness or color vision deficiency (CVD) is the decreased ability to color vision, see color or differences in color. It can impair tasks such as selecting ripe fruit, choosing clothing, and reading traffic lights. Color blindness may make some academic activities more difficult. However, issues are generally minor, and the colorblind automatically develop adaptations and coping mechanisms. People with achromatopsia, total color blindness (achromatopsia) may also be Hemeralopia, uncomfortable in bright environments and have visual impairment, decreased visual acuity. The most common cause of color blindness is an Heredity, inherited problem or variation in the functionality of one or more of the three classes of cone cells in the retina, which mediate color vision. The most common form is caused by a genetic disorder called congenital red–green color blindness. Males are more likely to be color blind than females, because the genes responsible for the most common for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
