Understanding Infrared Thermography Reading 3

Instruments used for these applications evolved from military programs based
on the need to detect and identify tactical targets through atmosphere in the
dark and in bad weather. For this reason, they generally operate in the 8 to 12
μm spectral window where the atmosphere has very little absorption.
Exceptions to this generality are infrared seeking and homing sensors that
are sensitive to specific target emission signatures. such as rocket engine
plumes. These instruments usually operate somewhere in the 3 to 5 μm
region. The same qualitative instruments can be readily adapted to fire
detection applications. From the ground or the air, they provide the capability
of detecting incipient fires and unextinguished portions of forest fires. The 8 to
12 μm spectral region over which they operate also provides improved
visibility (less absorption loss) through smoke and fog.
Charlie Chong/ Fion Zhang