Back in 1998
came out with a camcorder
, that under certain lighting conditions (not to mention only in daylight
) with the use of the camcorder's infrared
sensor (called NightShot iirc
) and a black and white IR
, lets you see through a layer of relatively cool clothing to the warm bodies underneath.
The cameras that could do this cost from around $700 to $2000 US. The funniest part of the entire story is that when this hit the news, all 400 thousand of them were sold within one week. Sony said they weren't going to recall them or publicize this use because they weren't that kind of company. Pretty predictable statement since A) It spread by word of mouth and news stories anyway so they didn't need to publicize anything about it and B) Sex is consistently the single biggest consumer magnet EVER.
My friend actually bought one, and went to the beach one day to try it out. He showed me the tape, and it worked pretty well. The people looked like they weren't wearing anything, and the only hint of clothing was a green glow where a bathing suit was. He sold the $1,200 camera on Ebay for $3,000 (See reason B above).
http://www.kaya-optics.com is a site dealing specifically with IR photographic technology along these same lines.