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Photometria
''Photometria'' is a book on the measurement of light by Johann Heinrich Lambert published in 1760.Lambert, Johann Heinrich, Photometria, sive de mensura et gradibus luminis, colorum et umbrae', Augsburg: Eberhard Klett, 1760. It established a complete system of photometric quantities and principles; using them to measure the optical properties of materials, quantify aspects of vision, and calculate illumination. Content of ''Photometria'' Written in Latin, the title of the book is a word Lambert devised from the Greek: φῶς, φωτος (transliterated phôs, photos) = light, and μετρια (transliterated metria) = measure. Lambert’s word has found its way into European languages as photometry, photometrie, and fotometria. ''Photometria'' was the first work to accurately identify most fundamental photometric concepts, assemble them into a coherent system of photometric quantities, define these quantities with a precision sufficient for mathematical statements, and build f ... [...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] |
David DiLaura
David L. DiLaura (Boulder, Colorado) is an American engineer, educator and pioneer in lighting calculation software. He received his Bachelor of Science in physics from Wayne State University in Detroit in 1970, after which he worked for 10 years as an illuminating engineer at the architectural engineering firm of Smith, Hinchman & Grylls. During this time he was also visiting lecturer in illuminating engineering at the University of Colorado at Boulder, where he taught for the first time in 1972. In 1981 he founded Lighting Technologies, Inc. in Boulder, Colorado, where he directed the development of Lumen Micro. At the same time he was appointed Associate Professor Adjunct of Architectural Engineering in the College of Engineering at University of Colorado, and established its lighting education program. He was appointed Senior Instructor at University of Colorado in January 1994, and gave up daily management responsibilities at Lighting Technologies. He was Professor and A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lambert's Cosine Law
In optics, Lambert's cosine law says that the radiant intensity or luminous intensity observed from an ideal diffusely reflecting surface or ideal diffuse radiator is directly proportional to the cosine of the angle ''θ'' between the direction of the incident light and the surface normal; I = I0cos(''θ'').RCA Electro-Optics Handbook, p.18 ffModern Optical Engineering, Warren J. Smith, McGraw-Hill, p. 228, 256 The law is also known as the cosine emission law or Lambert's emission law. It is named after Johann Heinrich Lambert, from his ''Photometria'', published in 1760. A surface which obeys Lambert's law is said to be ''Lambertian'', and exhibits Lambertian reflectance. Such a surface has the same radiance when viewed from any angle. This means, for example, that to the human eye it has the same apparent brightness (or luminance). It has the same radiance because, although the emitted power from a given area element is reduced by the cosine of the emission angle, the so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beer–Lambert Law
The Beer–Lambert law, also known as Beer's law, the Lambert–Beer law, or the Beer–Lambert–Bouguer law relates the attenuation of light to the properties of the material through which the light is travelling. The law is commonly applied to chemical analysis measurements and used in understanding attenuation in physical optics, for photons, neutrons, or rarefied gases. In mathematical physics, this law arises as a solution of the BGK equation. History The law was discovered by Pierre Bouguer before 1729, while looking at red wine, during a brief vacation in Alentejo, Portugal. It is often attributed to Johann Heinrich Lambert, who cited Bouguer's ''Essai d'optique sur la gradation de la lumière'' (Claude Jombert, Paris, 1729) – and even quoted from it – in his ''Photometria'' in 1760. Lambert's law stated that the loss of light intensity when it propagates in a medium is directly proportional to intensity and path length. Much later, the German scientist Augus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lambertian Reflectance
Lambertian reflectance is the property that defines an ideal "matte" or diffusely reflecting surface. The apparent brightness of a Lambertian surface to an observer is the same regardless of the observer's angle of view. More technically, the surface's luminance is isotropic, and the luminous intensity obeys Lambert's cosine law. Lambertian reflectance is named after Johann Heinrich Lambert, who introduced the concept of perfect diffusion in his 1760 book ''Photometria''. Examples Unfinished wood exhibits roughly Lambertian reflectance, but wood finished with a glossy coat of polyurethane does not, since the glossy coating creates specular highlights. Though not all rough surfaces are Lambertian, this is often a good approximation, and is frequently used when the characteristics of the surface are unknown. Spectralon is a material which is designed to exhibit an almost perfect Lambertian reflectance. Use in computer graphics In computer graphics, Lambertian reflection is often ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1760 In Science
The year 1760 in science and technology involved some significant events. Chemistry * Louis Claude Cadet de Gassicourt investigates inks based on cobalt salts and isolates cacodyl from cobalt mineral containing arsenic, pioneering work in organometallic chemistry. Geology * John Michell suggests earthquakes are caused by one layer of rocks rubbing against another. Medicine * April 30 – Swiss mathematician Daniel Bernoulli presents a paper at the French Academy of Sciences in Paris in which "a mathematical model was used for the first time to study the population dynamics of infectious disease." * Samuel-Auguste Tissot publishes ''L'Onanisme'' in Lausanne, a treatise on the supposed ill-effects of masturbation. Physics * Johann Heinrich Lambert publishes ''Photometria'', a pioneering work in photometry, including a formulation of the Beer–Lambert law on light absorption and the introduction of the albedo as a reflection coefficient. Events * Mathematician Leonhard Euler beg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Metrology
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviolet, and infrared light. Because light is an electromagnetic wave, other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves exhibit similar properties. Most optical phenomena can be accounted for by using the classical electromagnetic description of light. Complete electromagnetic descriptions of light are, however, often difficult to apply in practice. Practical optics is usually done using simplified models. The most common of these, geometric optics, treats light as a collection of rays that travel in straight lines and bend when they pass through or reflect from surfaces. Physical optics is a more comprehensive model of light, which includes wave effects such as diffraction and interference that cannot be acc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1760 Books
Year 176 ( CLXXVI) was a leap year starting on Sunday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Proculus and Aper (or, less frequently, year 929 ''Ab urbe condita''). The denomination 176 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. Events By place Roman Empire * November 27 – Emperor Marcus Aurelius grants his son Commodus the rank of ''Imperator'', and makes him Supreme Commander of the Roman legions. * December 23 – Marcus Aurelius and Commodus enter Rome after a campaign north of the Alps, and receive a triumph for their victories over the Germanic tribes. * The Equestrian Statue of Marcus Aurelius is made. It is now kept at Museo Capitolini in Rome (approximate date). Births * Fa Zheng, Chinese nobleman and adviser (d. 220) * Liu Bian, Chinese emperor of the Han Dynasty ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Printing And The Mind Of Man
''Printing and the Mind of Man'' is a book first published in 1967 and based on an exhibition in 1963. ''PMM'', as it is usually abbreviated, is regarded as a standard bibliographical reference, and offers a survey of the impact of printed books on the development of western civilization. The book developed from an exhibition put on at two locations to coincide with the 1963 International Printing Machinery and Allied Trades Exhibition (IPEX). At the behest of typographer Stanley Morison it was decided to put together an exhibition of the contribution printing had made to the enlargement of human knowledge. A display at Earls Court concentrated on the technical side of printing, while a display at the British Museum looked more at fine printing. However, both displays had the quite novel intention of promoting the study of books for their role in advancing factual knowledge, rather than for their aesthetics. Ian Fleming, who lent 40 books from his library, was among the private co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Graphics (computer Science)
Computer graphics is a sub-field of computer science which studies methods for digitally synthesizing and manipulating visual content. Although the term often refers to the study of three-dimensional computer graphics, it also encompasses two-dimensional graphics and image processing. The individuals who serve as professional designers for computers graphics are known as "Graphics Programmers", who often are computer programmers with skills in computer graphics design. Overview Computer graphics studies the aesthetic manipulation of visual and geometric information using computational techniques. It focuses on the ''mathematical'' and ''computational'' foundations of image generation and processing rather than purely aesthetic issues. Computer graphics is often differentiated from the field of visualization, although the two fields have many similarities. Connected studies include: * Applied mathematics * Computational geometry * Computational topology * Computer vision ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Additive Color
Additive color or additive mixing is a property of a color model that predicts the appearance of colors made by coincident component lights, i.e. the perceived color can be predicted by summing the numeric representations of the component colors. Modern formulations of Grassmann's laws describe the additivity in the color perception of light mixtures in terms of algebraic equations. Additive color predicts perception and not any sort of change in the photons of light themselves. These predictions are only applicable in the limited scope of color matching experiments where viewers match small patches of uniform color isolated against a grey or black background. Additive color models are applied in the design and testing of electronic displays that are used to render realistic images containing diverse sets of color using phosphors that emit light of a limited set of primary colors. Examination with a sufficiently powerful magnifying lens will reveal that each pixel in CRT, L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
