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White Light Scanner
A white light scanner (WLS) is a device for performing surface height measurements of an object using coherence scanning interferometry ( CSI) with spectrally-broadband, "white light" illumination. Different configurations of scanning interferometer may be used to measure macroscopic objects with surface profiles measuring in the centimeter range, to microscopic objects with surface profiles measuring in the micrometer range. For large-scale non-interferometric measurement systems, see structured-light 3D scanner. Description Vertical scanning interferometry is an example of low-coherence interferometry, which exploits the low coherence of white light. Interference will only be achieved when the path length delays of the interferometer are matched within the coherence time of the light source. VSI monitors the fringe contrast rather than the shape of the fringes. Fig. 2 illustrates a Twyman–Green interferometer set up for white light scanning of a macroscopic object. Lig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nepenthes Khasiana Lunate Cells
''Nepenthes'' () is a genus of carnivorous plants, also known as tropical pitcher plants, or monkey cups, in the monotypic family Nepenthaceae. The genus includes about 170 species, and numerous natural and many cultivated hybrids. They are mostly liana-forming plants of the Old World tropics, ranging from South China, Indonesia, Malaysia, and the Philippines; westward to Madagascar (two species) and the Seychelles (one); southward to Australia (four) and New Caledonia (one); and northward to India (one) and Sri Lanka (one). The greatest diversity occurs on Borneo, Sumatra, and the Philippines, with many endemic species. Many are plants of hot, humid, lowland areas, but the majority are tropical montane plants, receiving warm days but cool to cold, humid nights year round. A few are considered tropical alpine, with cool days and nights near freezing. The name "monkey cups" refers to the fact that monkeys were once thought to drink rainwater from the pitchers. Description ''N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
White Light Interferometric Microscope
White is the lightest color and is achromatic (having no hue). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully reflect and scatter all the visible wavelengths of light. White on television and computer screens is created by a mixture of red, blue, and green light. The color white can be given with white pigments, especially titanium dioxide. In ancient Egypt and ancient Rome, priestesses wore white as a symbol of purity, and Romans wore white togas as symbols of citizenship. In the Middle Ages and Renaissance a white unicorn symbolized chastity, and a white lamb sacrifice and purity. It was the royal color of the kings of France, and of the monarchist movement that opposed the Bolsheviks during the Russian Civil War (1917–1922). Greek and Roman temples were faced with white marble, and beginning in the 18th century, with the advent of neoclassical architecture, white became the most common color of new churches ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raw Data
Raw data, also known as primary data, are ''data'' (e.g., numbers, instrument readings, figures, etc.) collected from a source. In the context of examinations, the raw data might be described as a raw score (after test scores). If a scientist sets up a computerized thermometer which records the temperature of a chemical mixture in a test tube every minute, the list of temperature readings for every minute, as printed out on a spreadsheet or viewed on a computer screen are "raw data". Raw data have not been subjected to processing, "cleaning" by researchers to remove outliers, obvious instrument reading errors or data entry errors, or any analysis (e.g., determining central tendency aspects such as the average or median result). As well, raw data have not been subject to any other manipulation by a software program or a human researcher, analyst or technician. They are also referred to as ''primary'' data. Raw data is a relative term (see data), because even once raw data hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refractive Index
In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium. The refractive index determines how much the path of light is bent, or refracted, when entering a material. This is described by Snell's law of refraction, , where ''θ''1 and ''θ''2 are the angle of incidence and angle of refraction, respectively, of a ray crossing the interface between two media with refractive indices ''n''1 and ''n''2. The refractive indices also determine the amount of light that is reflected when reaching the interface, as well as the critical angle for total internal reflection, their intensity ( Fresnel's equations) and Brewster's angle. The refractive index can be seen as the factor by which the speed and the wavelength of the radiation are reduced with respect to their vacuum values: the speed of light in a medium is , and similarly the wavelength in that medium is , where ''Π... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fourier Transform
A Fourier transform (FT) is a mathematical transform that decomposes functions into frequency components, which are represented by the output of the transform as a function of frequency. Most commonly functions of time or space are transformed, which will output a function depending on temporal frequency or spatial frequency respectively. That process is also called ''analysis''. An example application would be decomposing the waveform of a musical chord into terms of the intensity of its constituent pitches. The term ''Fourier transform'' refers to both the frequency domain representation and the mathematical operation that associates the frequency domain representation to a function of space or time. The Fourier transform of a function is a complex-valued function representing the complex sinusoids that comprise the original function. For each frequency, the magnitude (absolute value) of the complex value represents the amplitude of a constituent complex sinusoid with that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Field Of View
The field of view (FoV) is the extent of the observable world that is seen at any given moment. In the case of optical instruments or sensors it is a solid angle through which a detector is sensitive to electromagnetic radiation. Humans and animals In the context of human and primate vision, the term "field of view" is typically only used in the sense of a restriction to what is visible by external apparatus, like when wearing spectacles or virtual reality goggles. Note that eye movements are allowed in the definition but do not change the field of view when understood this way. If the analogy of the eye's retina working as a sensor is drawn upon, the corresponding concept in human (and much of animal vision) is the visual field. It is defined as "the number of degrees of visual angle during stable fixation of the eyes".Strasburger, Hans; Pöppel, Ernst (2002). Visual Field. In G. Adelman & B.H. Smith (Eds): ''Encyclopedia of Neuroscience''; 3rd edition, on CD-ROM. El ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Path Length
In optics, optical path length (OPL, denoted ''Λ'' in equations), also known as optical length or optical distance, is the product of the geometric length of the optical path followed by light and the refractive index of homogeneous medium through which a light ray propagates; for inhomogeneous optical media, the product above is generalized as a path integral as part of the ray tracing procedure. A difference in OPL between two paths is often called the optical path difference (OPD). OPL and OPD are important because they determine the phase of the light and governs interference and diffraction of light as it propagates. Formulation In a medium of constant refractive index, ''n'', the OPL for a path of geometrical length ''s'' is just :\mathrm = n s .\, If the refractive index varies along the path, the OPL is given by a line integral :\mathrm = \int_C n \mathrm d s,\quad where ''n'' is the local refractive index as a function of distance along the path ''C''. An electroma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reference Beam
A reference beam is a laser beam used to read and write holograms. It is one of two laser beams used to create a hologram. In order to read a hologram out, some aspects of the reference beam (namely its angle of incidence, beam profile and wavelength) must be reproduced exactly as when it was used to write the hologram. As a result, usually reference beams are Gaussian beams or spherical wave The (two-way) wave equation is a second-order linear partial differential equation for the description of waves or standing wave fields — as they occur in classical physics — such as mechanical waves (e.g. water waves, sound waves and seis ... beams (beams that radiate from a single point) which are fairly easy to reproduce. The other beam used to write a hologram is the signal beam or object beam. Holography {{optics-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signal Beam
A signal beam or object beam is one of at least two laser beams used to write holograms. The signal beam is the beam that carries the information to be stored in the hologram. In the case of a holographic picture, this beam is reflected off the object being recorded, into the media. In the case of holographic data storage, the beam has some kind information encoded into it (for instance, it can be sent through a transparency or a spatial light modulator). The other beam necessary to write a hologram is the reference beam A reference beam is a laser beam used to read and write holograms. It is one of two laser beams used to create a hologram. In order to read a hologram out, some aspects of the reference beam (namely its angle of incidence, beam profile and wavel .... Holography Laser applications {{Tech-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cartesian Coordinate System
A Cartesian coordinate system (, ) in a plane is a coordinate system that specifies each point uniquely by a pair of numerical coordinates, which are the signed distances to the point from two fixed perpendicular oriented lines, measured in the same unit of length. Each reference coordinate line is called a ''coordinate axis'' or just ''axis'' (plural ''axes'') of the system, and the point where they meet is its ''origin'', at ordered pair . The coordinates can also be defined as the positions of the perpendicular projections of the point onto the two axes, expressed as signed distances from the origin. One can use the same principle to specify the position of any point in three-dimensional space by three Cartesian coordinates, its signed distances to three mutually perpendicular planes (or, equivalently, by its perpendicular projection onto three mutually perpendicular lines). In general, ''n'' Cartesian coordinates (an element of real ''n''-space) specify the point in an ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Metrology
Surface metrology is the measurement of small-scale features on surfaces, and is a branch of metrology. Surface primary form, surface fractality, and surface finish (including surface roughness) are the parameters most commonly associated with the field. It is important to many disciplines and is mostly known for the machining of precision parts and assemblies which contain mating surfaces or which must operate with high internal pressures. Surface finish may be measured in two ways: ''contact'' and ''non-contact'' methods. Contact methods involve dragging a measurement stylus across the surface; these instruments are called profilometers. Non-contact methods include: interferometry, digital holography, confocal microscopy, focus variation, structured light, electrical capacitance, electron microscopy, photogrammetry annon-contact profilometers Overview The most common method is to use a diamond stylus profilometer. The stylus is run perpendicular to the lay of the surface. The p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coherence Scanning Interferometry
Coherence scanning interferometry (CSI) is any of a class of optical surface measurement methods wherein the localization of interference fringes during a scan of optical path length provides a means to determine surface characteristics such as topography, transparent film structure, and optical properties. CSI is currently the most common interference microscopy technique for areal surface topography measurement. The term "CSI" was adopted by the International Organization for Standardization (ISO). The technique encompasses but is not limited to instruments that use spectrally broadband, visible sources ( white light) to achieve interference fringe localization. CSI uses either fringe localization alone or in combination with interference fringe In physics, interference is a phenomenon in which two waves combine by adding their displacement together at every single point in space and time, to form a resultant wave of greater, lower, or the same amplitude. Constructive a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
