EV3000-D manual
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is prohibited. ©2008 United Vision solutions, Co., Specifications are subject to change. Check website:
www.unitedvisionsolutions.com
Appendix B
Glossary
Atmospheric Attenuation
– The amount of radiated IR energy that is absorbed by the atmosphere. It is a function
of the temperature and humidity, particles in the air (i.e. fog, smoke, smog, etc.) and wavelength, among other factors.
CCIR -
Video standard for monochrome, 50 field/sec interlaced video output (i.e. European standard black and white
video).
Critical Dimension –
The dimension of a target used in calculating the DRI performance. It is a function of length,
width and height, as well as what face of the target is presented to the imager.
DRI (Detection-Recognition-Identification)
– A method of characterizing the range performance of a thermal
imager according to a standard set of criteria using a standard atmospheric model, and a target of alternating black
and white stripe (cycles) at different temperatures.
Detection –
The minimum distance at which an imager can reproduce a single cycle (black/white stripe) of a target.
Typically used to represent the distance at which the imager can first detect a given target (i.e. a hot blob). In addition
to the imager, the detection range is also a function of the target size and temperature difference from the background.
Field of View (FOV)
– The area in space that is seen by the lens of a thermal imager. Usually expressed in degrees,
and specified for both horizontal and vertical dimensions. The FOV is a characteristic of the lens.
FLIR 92
– A set of standards defined by the Night Vision Laboratories for calculating DRI information.
F-Number
– Focal Length/Diameter of Lens (same as in a visible lens). A lower F-number means that more IR
radiation passes through, but the lens is larger.
Focal Plane Array (FPA)
– An integrated circuit with a two dimensional matrix of detector elements
that sits in the focal plane of the thermal imager. An imager that uses an FPA is referred to as a “staring”
imager because the entire array stares at the scene to collect IR energy to make an image.
Hyperfocal Distance
– The distance beyond which all objects are in focus when an imagers’ focus adjust
is set to infinity.
Infrared Imager
– An Instrument that collects infrared energy and produces a video image where the
gray scale values correspond to differences in temperature.
Indium Antimonide (InSB)
– Semiconductor material used in the fabrication of a cooled FPA.
Typically pronounced “Inns-Bee”, these detectors must be cooled to 77°K to operate.
Identification –
The distance at which an imager can resolve six cycles across a given target. Used to
describe the distance at which a target can be clearly identified (in the case of a truck, the ability to
discriminate between a T-72 and a Humvee). In addition to the imager, the recognition range is also a
function of the target size and temperature difference from the background.
Infrared (IR) –
The portion of the electromagnetic spectrum located just above visible light. The
infrared spectrum extends from just above red (0.7 micron) to about 12 micron.
