Alternative Power sources - IR film, was: How to use FLIR infrared ...

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IR film, was: How to use FLIR infrared ...

danny burstein

2007-11-11, 1:25 pm

>>
....[color=darkred]
>Hey, that is a market niche for somebody to exploit- have some company
>that makes store-brand disposables do a production run of ones loaded
>with IR film, package them with instructions and a prepaid processing
>envelope, and sell them in the insulation and weatherstripping aisles at
>the big-box stores. (If anybody out there makes a go of that, I want a
>cut of the profits...)

>I can see it now- thousands of DIYs out there at midnight in winter
>coats, taking pictures of there houses, while the neighbors call in
>prowler reports... :^/

Afraid it ain't that simple. "Infrared" sensitive film
is NOT picking up the "heat" (term used a bit loosely)
emissions/reflections that you're looking for.

These products record the "near infra-red" part
of the spectrum. To get the termperature numbers,
you'd have to get to "far infra-red".

"Near infra-red" is the part of the spectrum that's
just beyond the regular "red" in the rainbow.

You might have heard the screams about five years
ago when Sony's camcorders, when in "nightshot"
mode, could "see through clothing". THe reality
is that the sensors could pck up "near infra-red".

Many materials that look "black" are really very, very,
dark red - letting a teensy bit of visible red
through (so small it looks blackish) but a modest
amount of near infra-red. So these cameras could
kind of, in some instances, maybe... look "through"
those fabrics - if they were thin enough.

--
_____________________________________________________
Knowledge may be power, but communications is the key
dannyb@panix.com
[to foil spammers, my address has been double rot-13 encoded]

Neon John

2007-11-11, 5:25 pm

On Sun, 11 Nov 2007 17:14:45 +0000 (UTC), danny burstein <dannyb@panix.com> wrote:

>You might have heard the screams about five years
>ago when Sony's camcorders, when in "nightshot"
>mode, could "see through clothing". THe reality
>is that the sensors could pck up "near infra-red".
>
>Many materials that look "black" are really very, very,
>dark red - letting a teensy bit of visible red
>through (so small it looks blackish) but a modest
>amount of near infra-red. So these cameras could
>kind of, in some instances, maybe... look "through"
>those fabrics - if they were thin enough.

That camera and any other with the IR cut filter removed and a low pass optical
filter installed work (quite well, actually) to image through clothes for the simple
reason that many fabrics are transparent to shortwave IR. The camera doesn't image
body heat. It images reflected IR that passes through the cloth. Cotton and wool
are essentially opaque. Light synthetics like rayon are transparent.

John
--
John De Armond
See my website for my current email address
http://www.neon-john.com
http://www.johndearmond.com <-- best little blog on the net!
Tellico Plains, Occupied TN
I love cats ... they taste just like chicken.

Trygve Lillefosse

2007-11-11, 8:25 pm

On Sun, 11 Nov 2007 15:12:18 -0500, Neon John <no@never.com> wrote:

>On Sun, 11 Nov 2007 17:14:45 +0000 (UTC), danny burstein <dannyb@panix.com> wrote:
>
>
>
>That camera and any other with the IR cut filter removed and a low pass optical
>filter installed work (quite well, actually) to image through clothes for the simple
>reason that many fabrics are transparent to shortwave IR. The camera doesn't image
>body heat. It images reflected IR that passes through the cloth. Cotton and wool
>are essentially opaque. Light synthetics like rayon are transparent.

Just have to add that you can get a tan with a T-shirt on, it only
takes quite a bit longer than without.

--
SEE YA !!!
Trygve Lillefosse
AKA - Malawi, The Fisher King

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