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From: chidsey@smoke.brl.mil (Irving Chidsey)
Newsgroups: sci.research,sci.electronics,sci.physics,sci.environment
Subject: Re: Infrared detection of wildlife
Keywords: infrared,detection,research,elephant
Message-ID: <14589@smoke.brl.mil>
Date: 27 Nov 90 16:44:03 GMT
References: <2492@cod.NOSC.MIL> <1990Nov27.133123.5370@mlb.semi.harris.com>
Followup-To: sci.research
Organization: U.S. Army Ballistic Research Laboratory, APG, MD.
Lines: 39

In article <1990Nov27.133123.5370@mlb.semi.harris.com> jws@thumper.mlb.semi.harris.com (James W. Swonger) writes:
<
< If the background temperature is going to be high (like tropical) then
<it will be harder to see the elephants - not much thermal contrast. For
<your test, be sure to pick a hot night so you don't end up with a system
<which only works at the zoo.
<
< Night vision systems based on image intensification or with an active IR
<illuminator and operated by a spotter would probably be effective but I
<don't think a passive IR, automated system would.
<
< Some CCTV cameras may have enough sensitivity in the IR band to be useful
<with some modifications. If you can get a CCD camera and put a thermoelectric
<cooler on the back of the CCD you can push the thermal noise down. Then with an
<IR filter you have a cheapie mid-IR vision system (you will still probably want
<an IR illuminator for optional use).


	The real kicker is "under the canopy".  I don't think IR will work
as it will be blocked by the leaves in the canopy.  To penetrate the canopy,
you will need something with a wavelength much longer than the typical length
of the leaves in the canopy.  

	Radar may work.  The reflectivity of elephants is probably lousy,
but at reasonable ranges you may be able to find elephants by looking for
the height difference.  If they are running, you may be able to use a
motion detection mode to separate the elephant return from the ground
clutter and the foliage clutter.

	The other effect that might get thru the canapy is sound.  But then
you need a quiet platform, a balloon or dirigible, not a light plane or a
helicopter.  Sounds like an interesting project.

	                                                Irv
-- 
I do not have signature authority.  I am not authorized to sign anything.
I am not authorized to commit the BRL, the DOA, the DOD, or the US Government
to anything, not even by implication.
			Irving L. Chidsey  <chidsey@brl.mil>