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Troland
The troland (symbol Td), named after Leonard T. Troland, is a unit of ''conventional retinal illuminance''. It is meant as a method for correcting photometric measurements of luminance values impinging on the human eye by scaling them by the effective pupil size. It is equal to retinal illuminance produced by a surface whose luminance is one nit when the apparent area of the entrance pupil of the eye is 1 square millimeter. The troland unit was proposed in 1916 by Leonard T. Troland, who called it a photon. The troland typically refers to the ordinary or photopic troland, which is defined in terms of the photopic luminance: : \mathrm = \mathrm \times \mathrm , where ''L'' is the photopic luminance in cd m−2 and ''p'' is pupil area in mm2. A scotopic troland is also sometimes defined: : \mathrm = \mathrm \times \mathrm , where ''L′'' is the scotopic luminance in cd m−2 and ''p'' is pupil area in mm2. Although named "retinal illuminance" (and originally named "p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Troland Research Awards
The Troland Research Awards are an annual prize given by the United States National Academy of Sciences to two researchers (preferably 45 years of age or younger) in recognition of psychological research on the relationship between consciousness and the physical world. The areas where these award funds are to be spent include but are not limited to areas of experimental psychology, the topics of sensation, perception, motivation, emotion, learning, memory, cognition, language, and action. The award preference is given to experimental work with a quantitative approach or experimental research seeking physiological explanations. Recipients SourceNAS* Michael J. Frank (2021) ::For his groundbreaking discoveries in our understanding of learning, valuation, and cognitive control. * Nicole C. Rust (2021) ::For her fundamental contributions to the understanding of how the cortex makes use of complex visual information to guide intelligent behavior. * Michael C. Frank (2020) ::For his w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leonard T
Leonard or ''Leo'' is a common English masculine given name and a surname. The given name and surname originate from the Old High German ''Leonhard'' containing the prefix ''levon'' ("lion") from the Greek Λέων ("lion") through the Latin '' Leo,'' and the suffix ''hardu'' ("brave" or "hardy"). The name has come to mean "lion strength", "lion-strong", or "lion-hearted". Leonard was the name of a Saint in the Middle Ages period, known as the patron saint of prisoners. Leonard is also an Irish origin surname, from the Gaelic ''O'Leannain'' also found as O'Leonard, but often was anglicised to just Leonard, consisting of the prefix ''O'' ("descendant of") and the suffix ''Leannan'' ("lover"). The oldest public records of the surname appear in 1272 in Huntingdonshire, England, and in 1479 in Ulm, Germany. Variations The name has variants in other languages: * Leen, Leendert, Lenard (Dutch) * Lehnertz, Lehnert (Luxembourgish) * Len (English) * :hu:Lénárd (Hungarian) * Lenart ( ... [...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] |
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] |
Human Eye
The human eye is a sensory organ, part of the sensory nervous system, that reacts to visible light and allows humans to use visual information for various purposes including seeing things, keeping balance, and maintaining circadian rhythm. The eye can be considered as a living optical device. It is approximately spherical in shape, with its outer layers, such as the outermost, white part of the eye (the sclera) and one of its inner layers (the pigmented choroid) keeping the eye essentially light tight except on the eye's optic axis. In order, along the optic axis, the optical components consist of a first lens (the cornea—the clear part of the eye) that accomplishes most of the focussing of light from the outside world; then an aperture (the pupil) in a diaphragm (the iris—the coloured part of the eye) that controls the amount of light entering the interior of the eye; then another lens (the crystalline lens) that accomplishes the remaining focussing of light into ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pupil
The pupil is a black hole located in the center of the iris of the eye that allows light to strike the retina.Cassin, B. and Solomon, S. (1990) ''Dictionary of Eye Terminology''. Gainesville, Florida: Triad Publishing Company. It appears black because light rays entering the pupil are either absorbed by the tissues inside the eye directly, or absorbed after diffuse reflections within the eye that mostly miss exiting the narrow pupil. The term "pupil" was coined by Gerard of Cremona. In humans, the pupil is round, but its shape varies between species; some cats, reptiles, and foxes have vertical slit pupils, goats have horizontally oriented pupils, and some catfish have annular types. In optical terms, the anatomical pupil is the eye's aperture and the iris is the aperture stop. The image of the pupil as seen from outside the eye is the entrance pupil, which does not exactly correspond to the location and size of the physical pupil because it is magnified by the cornea. On the ... [...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] |
Photopic
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] |
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 Metre
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] |
Scotopic
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 amacrin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vision
Vision, Visions, or The Vision may refer to: Perception Optical perception * Visual perception, the sense of sight * Visual system, the physical mechanism of eyesight * Computer vision, a field dealing with how computers can be made to gain understanding from digital images or videos * Machine vision, technology for imaging-based automatic inspection Perception of the future * Foresight (psychology), in business, the ability to envisage future market trends and plan accordingly * Goal, a desired result ** Vision statement, a declaration of objectives to guide decision-making Other perceptions * Vision (spirituality), a supernatural experience that conveys a revelation * Hallucination, a perception of something that does not exist Arts and media Events * Visions (convention), a science fiction event * Vision Festival, a New York City art festival Film and television * "The Vision", episode of '' Alcoa Presents: One Step Beyond'' * ''The Vision'' (film), 1998 British televisi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
