- Industry: Aerospace
- Number of terms: 16933
- Number of blossaries: 2
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The Executive Branch agency of the United States government, responsible for the nation's civilian space program and aeronautics and aerospace research.
Any one of a group of operations which improves the interpretability of an image or the detectability of targets or categories in the image. These operations, in the case of Landsat images, include: contrast stretch, edge enhancement, spatial filtering, noise suppression, image smoothing, and sharpening of image detail (often called pan-sharpening).
Industry:Aerospace
Any quantity of a problem that is not an independent variable. More specifically, a term which distinguishes, from dependent variables, quantities which are constants or which may be assigned more or less arbitrary values for purposes of the problem at hand. In computing, parameters passed to a function subroutine are more normally called arguments.
Industry:Aerospace
Any systematic arrangement of meridians and parallels portraying the curved surface of a sphere or spheroid upon a plane.
Industry:Aerospace
Any tabular statement of the assigned places of a celestial body (including a manmade satellite) for regular intervals. Ephemeris data help to characterize the conditions under which remote sensing data are collected and may be used to correct the sensor data prior to analysis.
Industry:Aerospace
Any technique that condenses the available data so as to make data storage or transmission more efficient. Data compression can be lossy in which some amount of information (data) is lost or lossless in which no information (data) is lost.
Industry:Aerospace
Any unwanted disturbance affecting a measurement (as of a frequency band), especially that which degrades the information-bearing quality of the data of interest. Noise determines the precision with which a radiometric measurement can be made. The standard deviation of a measurement is a common method for defining noise. Noise includes systematic or random sources. Systematic noise is constant or modelable with time and includes coherent noise, scan-correlated-shift, banding and striping and others, which reduce the ability to extract information from images. Systematic noise is potentially reducible with ground processing. Random noise, or white noise, is not correctable, but the uncertainty of estimates of the mean value can be reduced by multiple measurements, which are subject only to random noise. The potential degradation of signal from variations in the analog reference signal from space are reduced by using analog-to-digital converters and then adding error correction code to the digital signal to allow the exact original digital number to be recovered in ground processing even if it was degraded in transit. Also see banding, coherent noise, background noise, scan-correlated-shift and signal-to-noise ratio.
Industry:Aerospace
As used on Landsat 1 and 2, a camera system which operated by shuttering three independent cameras simultaneously, each sensing a different spectral band in the range of 0.48 to 0.83 µm. The RBV system for Landsat 3 contained two identical cameras, which operated in the spectral band from 0.50 to 0.75 µm. The cameras were aliened to view adjacent nominal 99 by 99 km square ground scenes with a 15 km sidelap yielding 183 by 99 km scene pairs. Two successive scene pairs nominally overlapped an MSS scene.
Industry:Aerospace
Auxiliary; accessory. in remote sensing, ancillary data are secondary data, pertaining to the area or classes of interest, such as topographic, demographic, or climatological data. Ancillary data may be digitized and used in conjunction with the primary remote sensing data.
Industry:Aerospace
Calibration equations to convert unitless values from an optical satellite imager in Digitals Numbers (DNs) to engineering or scientific units such as at-satellite radiance or spectral radiance. Radiance is power (energy per unit time) per unit area per unit solid angle, in units such as watts per steradian per square meter (W sr-1 m-2). Spectral radiance is radiance per unit wavelength, in units such as watts per steradian per square meter per micron (W sr-1 m-2 mm-1) for a specific spectral band-pass. The coefficients for such calibration equations are normally developed by laboratory tests of the instrument prior to launch with reference to sources that are traceable to National Institute of Science and Technology (NIST) radiance standards. Also see NIST traceability. .
Industry:Aerospace
Computer files of fixed parameters used in the ground processing system to convert raw uncalibrated bits from a spacecraft imager to radiometrically calibrated, artifact-reduced and geometrically-referenced or re-sampled products. For example, the USGS Landsat Ground Processing System (LGPS) at EROS Data Center uses the current version of the Calibration Parameter File (CPF) to convert input Level-0R in its archive to radiometrically corrected Level-1Rs and radiometrically and systematically corrected Level-1Gs or topographically corrected (Level-1G terrain) products. Each CPF is stamped with applicability dates associated with the date of acquisition of the imagery being processed. The Image Assessment System (IAS) updates the CPF as necessary.
Industry:Aerospace
