Finally, I am assuming that IR film acts in a fashion similar to the
real-time sensors.
I think that's where the trouble starts, Chris.
The basic operation of ANY sensing medium depends on a differential
in energy levels. Chemistry-based film of all kinds, including IR, is
carefully designed so that it does not self-expose (well, too much)
if placed on the dashboard of a closed-up car in the sun all day.
Thus it cannot be used to sense hot objects, or it would be
impossible to economically ship and store.
The sort of detectors you referred to are artificially cooled during
operation so there is sufficient differential between their ambient
condition and the condition they are detecting. A detector that is at
20 degrees C simply doesn't have enough energy differential to detect
human skin that is only at 30 degrees C.
Those "night vision" goggles you see in the movies and TV? They
contain IR illuminators. In effect, they shine invisible near-IR
light on the scene, and then detect its reflection. They DO NOT sense
the heat of human bodies.
Well, gotta go. UPS just delivered a package that is sitting in the
sun on my porch, smoking as though there were dry ice inside -- it
must be that new thermal IR film I ordered... hope I can expose it
before my body temperature does... :-)
--
: Jan Steinman <mailto:Jan@xxxxxxxxxxxxxx>
: Bytesmiths <http://www.bytesmiths.com>
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