[GRLUG] OFF TOPIC - Speaking of Infrared...

[Michael Mol]

On 1/28/2010 4:18 PM, Benjamin Flanders wrote:
> I think there are different wavelengths for IR.  What this simple
> camera trick will show is hi-frequency IR not the low frequency IR
> emanating from warm objects.  You would be able to see in the dark
> with this and an ir l.e.d. but you wouldn't have predator vision.

Warm objects emit some energy on a large range of wavelengths, 
approximating* the blackbody curve, including both near-IR and far-IR 
frequencies.

The chief problem with "darkvision" as it applies to passive near-IR is 
that there is a lot of ambient near-IR radiation that's not related to 
warm bodies.

In short, your warm body radiation in the near-IR will be there, but 
largely drowned out by the ambient near-IR radiation.**

* I'll avoid going into a discussion of emissivity changing things away 
from the ideal curve.

** I'll also avoid going into a discussion of how thermovision cameras 
work, unless people actually want to hear...