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Multispectral Image
Multispectral imaging captures image data within specific wavelength ranges across the electromagnetic spectrum. The wavelengths may be separated by filters or detected with the use of instruments that are sensitive to particular wavelengths, including light from frequencies beyond the visible light range (i.e. infrared and ultraviolet). It can allow extraction of additional information the human eye fails to capture with its visible receptors for red, green and blue. It was originally developed for military target identification and reconnaissance. Early space-based imaging platforms incorporated multispectral imaging technology to map details of the Earth related to coastal boundaries, vegetation, and landforms. Multispectral imaging has also found use in document and painting analysis. Multispectral imaging measures light in a small number (typically 3 to 15) of spectral bands. ''Hyperspectral imaging'' is a special case of spectral imaging where often hundreds of conti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NASA SDO Multispectral View Of The Sun, September 2011
The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States's civil list of government space agencies, space program, aeronautics research and outer space, space research. National Aeronautics and Space Act, Established in 1958, it succeeded the National Advisory Committee for Aeronautics (NACA) to give the American space development effort a distinct civilian orientation, emphasizing peaceful applications in space science. It has since led most of America's space exploration programs, including Project Mercury, Project Gemini, the 1968–1972 Apollo program missions, the Skylab space station, and the Space Shuttle. Currently, NASA supports the International Space Station (ISS) along with the Commercial Crew Program and oversees the development of the Orion (spacecraft), Orion spacecraft and the Sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectral Signature
Spectral signature is the variation of reflectance or emittance of a material with respect to wavelengths (i.e., reflectance/emittance as a function of wavelength). The spectral signature of stars indicates the composition of the stellar atmosphere. The spectral signature of an object is a function of the incidental EM wavelength and material interaction with that section of the electromagnetic spectrum. The measurements can be made with various instruments, including a task specific spectrometer, although the most common method is separation of the red, green, blue and near infrared portion of the EM spectrum as acquired by digital cameras. Calibrating spectral signatures under specific illumination are collected in order to apply a correction to airborne or satellite imagery digital images. The user of one kind of spectroscope looks through it at a tube of ionized gas. The user sees specific lines of colour falling on a graduated scale. Each substance will have its own uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scattering
In physics, scattering is a wide range of physical processes where moving particles or radiation of some form, such as light or sound, are forced to deviate from a straight trajectory by localized non-uniformities (including particles and radiation) in the medium through which they pass. In conventional use, this also includes deviation of reflected radiation from the angle predicted by the law of reflection. Reflections of radiation that undergo scattering are often called ''diffuse reflections'' and unscattered reflections are called ''specular'' (mirror-like) reflections. Originally, the term was confined to light scattering (going back at least as far as Isaac Newton in the 17th century). As more "ray"-like phenomena were discovered, the idea of scattering was extended to them, so that William Herschel could refer to the scattering of "heat rays" (not then recognized as electromagnetic in nature) in 1800. John Tyndall, a pioneer in light scattering research, noted the connecti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infrared Signature
Infrared signature, as used by defense scientists and the military, is the appearance of objects to infrared sensors. An infrared signature depends on many factors, including the shape and size of the object, temperature, and emissivity, reflection of external sources ( earthshine, sunshine, skyshine) from the object's surface, the background against which it is viewed and the waveband of the detecting sensor. As such there is no all-encompassing definition of infrared signature nor any trivial means of measuring it. For example, the infrared signature of a truck viewed against a field will vary significantly with changing weather, time of day and engine loading. Two fairly successful examples of defining the infrared signature of an object are the apparent temperature difference at the sensor and the contrast radiant intensity (CRI) definitions. Apparent temperature difference The apparent temperature difference method of defining infrared signature gives the physical temperat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emissivity
The emissivity of the surface of a material is its effectiveness in emitting energy as thermal radiation. Thermal radiation is electromagnetic radiation that most commonly includes both visible radiation (light) and infrared radiation, which is not visible to human eyes. A portion of the thermal radiation from very hot objects (see photograph) is easily visible to the eye. The emissivity of a surface depends on its chemical composition and geometrical structure. Quantitatively, it is the ratio of the thermal radiation from a surface to the radiation from an black body, ideal black surface at the same temperature as given by the Stefan–Boltzmann law. (A comparison with Planck's law is used if one is concerned with particular wavelengths of thermal radiation.) The ratio varies from 0 to 1. The surface of a perfect black body (with an emissivity of 1) emits thermal radiation at the rate of approximately 448 watts per square metre (W/m) at a room temperature of . Objects have emi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermography
Infrared thermography (IRT), thermal video or thermal imaging, is a process where a thermal camera captures and creates an image of an object by using infrared radiation emitted from the object in a process, which are examples of infrared imaging science. Thermographic cameras usually detect radiation in the long-infrared range of the electromagnetic spectrum (roughly 9,000–14,000 nanometers or 9–14 μm) and produce images of that radiation, called thermograms. Since infrared radiation is emitted by all objects with a temperature above absolute zero according to the black body radiation law, thermography makes it possible to see one's environment with or without visible illumination. The amount of radiation emitted by an object increases with temperature; therefore, thermography allows one to see variations in temperature. When viewed through a thermal imaging camera, warm objects stand out well against cooler backgrounds; humans and other warm-blooded animals becom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Focal-plane Array Testing
Focal plane array testing is a specialized field of Test Engineering, test engineering. Staring array, Focal plane array (FPA) imaging devices are used in missile guidance sensors, infrared astronomy, manufacturing inspection, and thermal imaging. Focal plane array testing is the process of validation and verification, verifying and validating that these devices function correctly. Focal plane arrays are complex to develop, in some cases the fabrication process may have more than 150 steps, testing of these devices must ensure that each step has the desired result. The actual test methodology used for testing focal plane arrays differs depending on the type of device. However, the types of tests usually fall into one of the following categories: diagnostic, performance, statistical, system simulation, or end-to-end simulation. Government oversight of testing The development and testing military technology such as FPAs is concentrated in the space and defense industries. As a r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Army Research Laboratory
The U.S. Army Combat Capabilities Development Command Army Research Laboratory (DEVCOM ARL) is the foundational research laboratory for the United States Army under the United States Army Futures Command (AFC). DEVCOM ARL conducts intramural and extramural research guided by 11 Army competencies: Biological and Biotechnology Sciences; Humans in Complex Systems; Photonics, Electronics, and Quantum Sciences; Electromagnetic Spectrum Sciences; Mechanical Sciences; Sciences of Extreme Materials; Energy Sciences; Military Information Sciences; Terminal Effects; Network, Cyber, and Computational Sciences; and Weapons Sciences. The laboratory was established in 1992 to unify the activities of the seven corporate laboratories of the U.S. Army Laboratory Command (LABCOM) as well as consolidate other Army research elements to form a centralized laboratory. The seven corporate laboratories that merged were the Atmospheric Sciences Laboratory (ASL), the Ballistic Research Laboratory (BRL), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opticks (Software)
Opticks is a remote sensing application that supports imagery, video (motion imagery), synthetic aperture radar (SAR), multi-spectral, hyper-spectral, and other types of remote sensing data. Opticks supports processing remote sensing video in the same manner as it supports imagery, which differentiates it from other remote sensing applications. Opticks was initially developed by Ball Aerospace & Technologies Corp. and other organizations for the United States Intelligence Community. Ball Aerospace open sourced Opticks hoping to increase the demand for remote sensing data and broaden the features available in existing remote sensing software. The Opticks software and its extensions are developed by over twenty different organizations, and over two hundred users are registered users at http://opticks.org. Future planned enhancements include adding the ability to ingest and visualize lidar data, as well as a three-dimensional (3-D) visualization capability. Opticks can also be us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Geospatial-Intelligence Agency
The National Geospatial-Intelligence Agency (NGA) is a combat support agency within the United States Department of Defense whose primary mission is collecting, analyzing, and distributing geospatial intelligence (GEOINT) to support national security. Founded in 1996 as the National Imagery and Mapping Agency (NIMA), it changed names in 2003. It is a member of the United States Intelligence Community. NGA headquarters, also known as NGA Campus East or NCE, is located at Fort Belvoir North Area in Springfield, Virginia. At , it is the third-largest government building in the Washington metropolitan area after the Pentagon and the Ronald Reagan Building and International Trade Center, Ronald Reagan Building. The agency also operates NGA Campus West, or NCW, in St. Louis, Missouri, and support and liaison offices worldwide. NGA also helps respond to natural and manmade disasters, helps with security planning for major events such as the Olympic Games, disseminates maritime safety ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
K-means Clustering
''k''-means clustering is a method of vector quantization, originally from signal processing, that aims to partition of a set, partition ''n'' observations into ''k'' clusters in which each observation belongs to the cluster (statistics), cluster with the nearest mean (cluster centers or cluster centroid), serving as a prototype of the cluster. This results in a partitioning of the data space into Voronoi cells. ''k''-means clustering minimizes within-cluster variances (squared Euclidean distances), but not regular Euclidean distances, which would be the more difficult Weber problem: the mean optimizes squared errors, whereas only the geometric median minimizes Euclidean distances. For instance, better Euclidean solutions can be found using k-medians clustering, ''k''-medians and k-medoids, ''k''-medoids. The problem is computationally difficult (NP-hardness, NP-hard); however, efficient heuristic algorithms converge quickly to a local optimum. These are usually similar to the ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unsupervised Classification
Unsupervised learning is a framework in machine learning where, in contrast to supervised learning, algorithms learn patterns exclusively from unlabeled data. Other frameworks in the spectrum of supervisions include weak- or semi-supervision, where a small portion of the data is tagged, and self-supervision. Some researchers consider self-supervised learning a form of unsupervised learning. Conceptually, unsupervised learning divides into the aspects of data, training, algorithm, and downstream applications. Typically, the dataset is harvested cheaply "in the wild", such as massive text corpus obtained by web crawling, with only minor filtering (such as Common Crawl). This compares favorably to supervised learning, where the dataset (such as the ImageNet1000) is typically constructed manually, which is much more expensive. There were algorithms designed specifically for unsupervised learning, such as clustering algorithms like k-means, dimensionality reduction techniques like ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
