EM 1110-2-2907
1 October 2003
Histogram
A means of expressing the frequency of occurrence of values in a data
set within a series of equal ranges or bins, the height of each bin
representing the frequency at which values in the data set fall within the
chosen range. A cumulative histogram expresses the frequency of all
values falling within a bin and lower in the range. A smooth curve
derived mathematically from a histogram is termed the probability
density function (PDF).
HORIZONTAL
Transmission of microwaves so that the electric lines of force are
horizontal, while the magnetic lines of force are vertical.
HRPT--High Resolution
HRPT data are full resolution image data transmitted to a ground
Picture Transmission
station as they are collected. The average instantaneous field-of-view
of 1.4 milliradians yields a HRPT ground resolution of approximately 1.1
km at the satellite nadir from the nominal orbit altitude of 833 km (517
mi).
HRV--High Resolution
The HRV instrument is a multispectral radiometer designed for SPOT
Visible Imaging
spacecraft. The HRV instrument provides for high-resolution imaging in
Instrument
the visible and near-infrared portions of the electromagnetic spectrum.
The first three SPOT satellites carry twin HRVs that operate in a
number of viewing configurations and in different spectral modes. Some
of those viewing configurations and spectral modes include one HRV
only operating in a dual spectral mode (i.e., in both panchromatic mode
and multispectral mode); two HRVs operating in the twin-viewing
configuration (i.e., one HRV in panchromatic mode and one HRV in
multispectral mode); and two HRVs operating independently of each
other (i.e., not in twin-viewing configuration).
Hue
In the IHS system, represents the dominant wavelength of a color.
HYDROLOGY
Scientific study of the waters of the Earth, especially with relation to the
effects of precipitation and evaporation upon the occurrence and
character of ground water.
HYPSOGRAPHY
The scientific study of the Earth's topologic configuration above sea
level, especially the measurement and mapping of land elevation.
I
IFOV
Instantaneous field of view.
IHS
Intensity, hue, and saturation system of colors.
Image
Pictorial representation of a scene recorded by a remote sensing
system. Although image is a general term, it is commonly restricted to
representations acquired by non-photographic methods.
Image dissection
The breaking down of a continuous scene into discrete spatial
elements, either by the receptors on the retina, or in the process of
capturing the image artificially.
Image striping
A defect produced in line scanner and push-broom imaging devices
produced by the non-uniform response of a single detector, or amongst
a bank of detectors. In a line-scan image the stripes are perpendicular
to flight direction, but parallel to it in a push-broom image.
Image swath
See ground swath.
Incidence angle
In radar, the angle formed between an imaginary line normal to the
surface and another connecting the antenna and the target.
Incident energy
Electromagnetic radiation impinging on a surface.
Glossary-15
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