EM 1110-2-2907
1 October 2003
ETC
Earth-terrain camera.
Evaporative cooling
Temperature drop caused by evaporation of water from a moist
surface.
Exitance
The radiant flux.
F
False color image
A color image where parts of the non-visible EM spectrum are
expressed as one or more of the red, green, and blue components, so
that the colors produced by the Earth's surface do not correspond to
normal visual experience. Also called a false-color composite (FCC).
The most commonly seen false-color images display the very-near
infrared as red, red as green, and green as blue.
False color photograph
Another term for IR color photograph.
Far range
The portion of a radar image farthest from the aircraft or spacecraft
flight path.
Fiducial Marks
A set of four marks located in the corners or edge-centered, or both, of
a photographic image. These marks are exposed within the camera
onto the original film and are used to define the frame of reference for
spatial measurements on aerial photographs. Opposite fiducial marks
connected, intersect at approximately the image center of the aerial
photograph.
Film
Light-sensitive photographic emulsion and its base.
Film speed
Measure of the sensitivity of photographic film to light. Larger numbers
indicate higher sensitivity.
Film Types
Photographic products for use in image interpretation are commonly
generated from the following film types:
Black-and-White Panchromatic (B&W): This film primarily
consists of a black-and-white negative material with a
sensitivity range comparable to that of the human eye. It has
good contrast and resolution with low graininess and a wide
exposure range.
Black-and-White Infrared (BIR): With some exceptions, this film
is sensitive to the spectral region encompassing 0.4
micrometers to 0.9 micrometers. It is sometimes referred to as
near-infrared film because it utilizes only a narrow portion of the
total infrared spectrum (0.7 micrometers to 0.9 micrometers).
Conventional Color: This film contains three emulsion layers
that are sensitive to blue, green, and red (the three primary
colors of the visible spectrum). This film replicates colors as
seen by the human eye and is commonly referred to as normal
or natural color. Color film is a valuable image interpretation
tool because the human eye can discern a greater variety of
color tones than gray tones.
Color Infrared (CIR): This film, originally referred to as
camouflage-detection film because of its warfare applications,
differs from conventional color film because its emulsion layers
are sensitive to green, red, and near-infrared radiation (0.5
micrometers to 0.9 micrometers). Used with a yellow filter to
absorb the blue light, this film provides sharp images and
penetrates haze at high altitudes. Color-infrared film also is
referred to as false-color film.
Filter, digital
Mathematical procedure for modifying values of numerical data.
Filter, optical
A material that, by absorption or reflection, selectivity modifies the
radiation transmitted through an optical system.
Glossary-11
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