EM 1110-2-2907
1 October 2003
Luminance
Quantitative measure of the intensity of light from a source.
M
Mach band
An optical illusion of dark and light fringes within adjacent areas of
contrasted tone. It is a psychophysiological phenomenon, which aids
human detection of boundaries or edges.
Median filter
A spatial filter, which substitutes the median value of DN from
surrounding pixels for that recorded at an individual pixel. It is useful for
removing random noise.
Mercator Projection
Mercator is a conformal map projection, that is, it preserves angular
relationships. Mercator was designed and is recommended for
navigational use and is the standard for marine charts. Mercator is
often and inappropriately used as a world map projection in atlases and
for wall charts where it presents a misleading view of the world because
of the excessive distortion of area in the higher latitude areas.
Mercury
U.S. program of one-man, earth-orbiting spacecraft in 1962 and 1963.
Region of the electromagnetic spectrum in the wavelength range of 0.1
to 30 cm.
Mid-infrared (MIR)
The range of EM wavelengths from 8 to 14 m dominated by emission
of thermally generated radiation from materials; also known as thermal
Mie scattering
The scattering of EM energy by particles in the atmosphere with
comparable dimensions to the wavelength involved.
Minimum ground
Minimum distance on the ground between two targets at which they can
separation
be resolved on an image.
Minus-blue photographs
Black-and-white photographs acquired using a filter that removes blue
wavelengths to produce higher spatial resolution.
Mixed pixel
A pixel whose DN represents the average energy reflected or emitted
by several types of surface present within the area that it represents on
the ground; sometimes called a mixel.
Modular optoelectric
An along-track scanner carried on the Space Shuttle that recorded two
multispectral scanner
bands of data.
(MOMS)
Modulate
To vary the frequency, phase, or amplitude of electromagnetic waves.
Modulation transfer
A method of describing spatial resolution.
function (MTF)
MOMS
Modular optoelectric multispectral scanner.
MOS-1
Marine Observation Satellite, launched by Japan in 1987.
Mosaic
Composite image or photograph made by piecing together individual
images or photographs covering adjacent areas.
MSS
Multispectral scanner system of Landsat that acquires images of four
wavelength bands in the visible and reflected IR regions.
Multiband camera
System that simultaneously acquires photographs of the same scene at
different wavelengths.
Multispectral classification
Identification of terrain categories by digital processing of data acquired
by multispectral scanners.
Multispectral scanner
Scanner system that simultaneously acquires images of the same
scene at different wavelengths.
N
NAD27--North American
NAD27 is defined with an initial point at Meads Ranch, Kansas, and by
Datum of 1927
the parameters of the Clarke 1866 ellipsoid. The location of features on
USGS topographic maps, including the definition of 7.5-minute
quadrangle corners, are referenced to the NAD27.
Glossary-19
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