> Come to think of it, I think I have heard of remote temp. sensors using
> laser beams. Maybe they use a red laser beam to measure distance and
> reflectivity (surface nature) and then use these factors to correct the
> reading from the pyro sensor.

The laser beam is simply a pointing tool.
Since the device is averaging the field of view, a design goal is to keep
the field as narrow as possible. So that makes it important to point it in
the right direction. If you miss, you get the wrong answer.
Also, the reflectivity for visible light isn't the same as the emissivity
in IR. Even the emissivity for a particular surface may not be constant
over a wide temperature range. One of those things where the real world
spoils a good  law of physics.

Steve.