11
Camera and Technology Overview (cont’d)
Most objects that you see are not radiating visible light but
instead, are reflecting light radiated from another source.
Most objects have to be heated to extreme temperatures before
they radiate energy in the visible light spectrum. However,
energy in the infrared range is being
radiated by all objects
that are above absolute zero (-459F). Hence, everything has a
thermal signature, regardless of light conditions.
As the frequency of electromagnetic energy increases, the
length of the waves decreases. Infrared shares many of the
properties of visible light, but its different wavelength has
several other unique characteristics. For instance, materials
that are opaque to visible light may be transparent to infrared,
and vice–versa. Infrared is less subject to scattering and
absorption by smoke, smog, or dust than visible light, and
infrared cannot be seen by the human eye.
Different objects give off varying amounts of infrared,
depending on the temperature of the object and also on a
characteristic called emissivity.. Heavy rain, fog, and other
environmental conditions may degrade infrared imagery, but
an infrared thermal imager will still penetrate these obscurants
better than the human eye, or other night vision technologies.
The Thermal-Eye 250D infrared detecting system
distinguishes between very small differences in thermal
(infrared) radiation, converts it to electrical signals, amplifies
those differences, and reproduces them correspondingly in the
visible light (video) range. Powerful advantages are achieved
in being able to turn a pitch black night into a black and white
TV image of the scene. As your infrared knowledge and
experience grows, further applications will develop as you
recognize heat clues beyond the naked eye in both day and
night conditions.
Summary of Contents for 3261607 Thermal-Eye 250D
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