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

[Michael Mol]

On 1/28/2010 7:12 PM, john-thomas richards wrote:
> On Thu, Jan 28, 2010 at 06:03:26PM -0500, Michael Mol wrote:
>> 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...
>
> Seriously?  Wow.  You are conversant in more technical fields than I
> could *list*.

I'll take that as a compliment, but working with thermovision IR cameras 
in C++ on Windows is my day job. Everything else is a hobby. :)