On Mon, Mar 22, 2004 at 11:46:27AM -0800, Steve Schear wrote: > There are purported to be devices using ultra wideband RF and microwave > frequencies and millimeter wave active or passive devices to do > this. Resolution of the microwave devices should be even lower than the IR
No, active devices should be able to image down to mm and better (T-ray). Ultrawideband is good for a portable radar to penetrate wood/plaster (maybe even brick and concrete, if not too thick), and pick up breathing and heartbeat signatures, as it can resolve time domain very well. Penetration depth depends on the wavelength: red penetrates deeper than blue, NIR even deeper (it's being used to diagnose early stages of skin melanoma, you look really mottled in NIR, try it; apparently it's being used for transcranial infrared oxytometry and even stimulation), microwaves and T-ray are cm to dm. T-ray could augment x-Ray, since capable of instant portable imaging without requiring ionizing radiation. > and perhaps suitable only for determining occupant location, for example > prior to breaking down the door during a SWAT raid. Millimeter waves are If it's a wooden door I don't see why you can't resolve limbs and even individual digits with active imaging. > emitted by warm bodies, such as own own, and can be used to passively see > thorough clothing. Not sure if passive devices would work through walls > due to attenuation, but active devices probably could. This is very likely. -- Eugen* Leitl <a href="http://leitl.org";>leitl</a> ______________________________________________________________ ICBM: 48.07078, 11.61144 http://www.leitl.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE http://moleculardevices.org http://nanomachines.net
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