1 - NGA

ke chert-A chart showing prevalence of ice,
usually with reference 10 nav’@ble walerways.
Ice aurvelllanca producte-Plolllrrg charts,
repcrt forms, and other cworfucts used for the
collection and dksemina!ion of ice posftion
information.
MIL-HDBK-850
Icad.bar sspparatua-An apparalus ~or
meeeurtw Ilnaar distance wilh great precision
and acwrecy, and consisting assantialty of a
Sfaal bar which is maintained et a constant
tert?peratura by being surrourtdm with melting
Isa. The bar is rectangular in cross section, and
IS carried In a Y-shapad trough which is Iillad
with matting ke and mounted on a car which
rneves on a track. Bar lengths are observed wiih
micrometer microscopes mou M ed on S!able
supfmrfs. Also called Woodward base-llne
measuring apparatus.
Ideal Eartts-See aqulllbrlum theory.
kdeal sea level-The theoretical sea surlace
whuh is everywhere normal to the plumb line.
Referance of all depth soundings to this level
would rqaka them all comparable.
Ideniltlcatlon poetrs-Peats of wood or other
suitable rrkmerfal, appropriately marked and
inacrfbed, and placad near survey stations 10 aid
In their recovery and identification, AISO called
supplemental poata for aurvay
monumants.
Idla pendulum—A working pendulum placed
In the recalver in advance 01 its being used, so
Ihal It may assume the same temperature as
the dummy pendulum.
Image corrolatlon—The matching of position
and physkal characteristics betwaen imagery of
the same geographic area horn dillarersl types
of aenaore, between sensor imagery and a data
base, or between two images frem the same
aansor.
Imaae dagradatlon—[photometry) The
reduction of the Inherent optimum Imaging
polential of individual sensor systems caused by
emr In sensor operations or pmcesslng
pMCt?dUrJS. Raducliorsa In quality caused by
unavoidable facfom; i a., atmospherics, srmw
125
cover, ate., are net asaocialad with the term.
Image dlrastlon—A term used 10 describe the
image orientation 0! a photographic negative or
positive relative to the positbrr of the emulsion.
See also emulalon-to-basa; emulalon-toemulalon;
right-reading; wrong-reading.
Imaga dlatortlon-Any shift In’ the posllion of
an Imega on a photograph which alla’s the
perspective charactetistica of the photograph.
Causes of image distortion hStJds lens
aberration, dMerantial ahritiage of flfm or papar,
and motion 01 the film or camera.
Imaga enhancement—Any of aavaral
processes that might improve the interpretation
quality of an Image. Such processes include
contrast improvement, greatar resolution,
special Iillering, etc.
Image motion compensation (lMC)-
(JCS) Movement Intentionally Imparted to film at
such a rate as to mmpansate for the fonvard
motion of an eir or space vehicle when
photographing ground objects.
Image motion companaatlon dlatotilon—
In a panoramic camera system, the
displacement of images of ground points Irom
their expectad cylindrical poslticn causect by the
translation 01 the lens or negative wrfaca (a
motion usad to wmpensale for Image motion
during exposure time).
Imaga motion ?actore-Those factors
wherein the Image MotIon varies directly wfth the
aircraft ground speed and lens focal length and
inversely with the anitucle,
Imege motion—lhe smearfng or blurring of
imagery on an aerial ptretcgraph bacauaa ot the
relative movement of the camera with raspecf to
the ground.
Image plane—See photograph plane.
Image point-(photogrammetry) Image on a
photograph mrrespcmding to a definite object
on the ground.
Image procasal ng—Encompasses all the
various operations that can be applied to
photographic or image data. These Include, but