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f.number—See ralatlve aperture.
la-l. (imagery) The emulsbn side of a
negative or faycul plate, or the prfrrting surface
of a pfafe. 2. (topology) A two-dimensional
to@ogical enfffy defined as an undivided are
surrounded by topological edges represeming
all or part of the extent of a feature or of an
attributed area.
tacslmllo chart-see modlflsrd facttlmlle
chart.
lrsctorad tranaparancy—A system of radar
simulation which ufifizea a pair of phonographic
ima9e6 on a glass pfate or plates to store
topographic and radar reflection data. The data
are scanned by e ffylng-spot scanner cathoderay
lube, and the density of the images is read
by two photomulfiifier tubes. The hvo planar
dimensions of the two imagea are the x- and y-
&lmenaiorra of the topography and reflectance
data respectively. The dansifies of the
reflectance images ara used to store fhe intrinsic
strength of radar target rallectance. The images
are identical in their x- end y-values but
separated in one dimension by me optical
spacing of the dual readout syslem. Also called
land mass elmuialor plete.
factory acceptance test (FAT)-A formal
test of the system under pmwrament in the
manufacturers envfmnmerrf In order to verify
succeesfut pmducfion of hardware or Software.
Recipient personnel witness lhe test to verify
requirements and successful product generation
before the system is shipped lo the recipiant.
FAF block—A block of 1024 by 1024 pixels of
image data. See also fast access fOrMal.
fafflng tfda-See ebb tide.
fallln#—The distance by which e rarulom line
falls to fhe right or left of a comer on whch the
tnse line IS too cbse. Usually the dhectbn of
falling fa expressed m cardinal.
falee bearing—The difference befween the
true bearlno and the back bearinc! caused by
the mnve~ence of maridiana, -
fafae See Infrared.
MIL-HDBK-850
F
false eesting-A value assigned to the orl@
of castings, in a grid cmrdinate system, to avoid
the inmnvenience of using negative
coordinates. See also grkt coordlnataa.
falaa fix p~fSablllty-A stallsticat value or
ratio which reflects the likelihood of a fafSe
match ocasm”ng between Weeforsd digilal
cartographic data and data or Imagery acquired
by electronic aerial sensor eystama. See also
Imege corralatlon; terrain contour
matchkrg (TERCOM); terrain corralatlon.
false horlzor+A line resembling the visible
horfzon, but above or bafow ft.
falsa norfhlng-A value assigned fo the origin
of norfhh’rgs, in a grid coordinate system, to
avoid the inconvenience of uairsg negalive
coordinate. Sae also grid coordfnatea.
falsa orlgln-(JCS) A fixed polm to the south
and west of a grid zone from which grid
distances are measured eastward and
northward, See aleo grid orlg in.
felee paraltax--(JCS) The apParent vetil=l
displacamerrt of an object from its true posifiirr
when viewed stereoscopically, due to movement
ot the object ifseff as well as to change in the
poinl of Observation.
false atere*An Imaginary Impression of
aleraoscopic relief. See also paeudoacopfc
sferao.
fan camera photography—(JCS]
Phonography taken simultaneously by an
assembly of three or more cameras,
systematically installed at fised angles refatfve to
each other so as to provide wide lateral
coverage with overkpplng images. See also
trlcemera photography.
fan camara%(JCS) An assembly of three or
more cameras systematically disposed at fixed
angies relafive to each othar so as to provide
wide lateral coverage with overlapping Imagas.
fasf acceea formaf (FAF)-A filing scheme
for breaking digital imagerf into smaller chunks
of data. See also FAF block.
fathogram—A graphic rsmrd of depth
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