Thursday, March 08, 2007

A More Modest Security Scanner

At the Physics of Sex blog, we're huge supporters of freedom and tolerance. But part of ensuring those prescious commodities includes protecting personal privacy. Recently, some airports have installed backscatter x-ray scanners that see through clothing, revealing weapons in the very rare case that someone tries sneaking something on board, while giving security staff a gander at the most intimate details of the bodies of terrorists and innocents alike. You can see some examples in this Google image search. In addition, although the risk is low, you have to get at least a small x-ray dose to suffer the indignity.

Tomorrow morning at the APS March Meeting in Denver, Panu Helisto of the Finnish research company VTT will describe a new imaging system that measures some of the heat-radiation your body emits all the time. It is inherently unable to reveal personal details because it simply lacks resolution to produce a picture of anything smaller than several inches across. And yet it measures terahertz radiation (a type of radiation that's somewhere between infrared light and radio waves) that passes through all but the heaviest clothing, to provide enough detail to pick out the shapes of most knives, guns, and other dangerous stuff. Check out the pictures here that Helisto and colleagues at VTT and NIST made with a microbolometer. The shot on the right is a microbolometer image of the guy in the photo on the left. Looks like he's packin' some heat.

The system will be built of detectors called microbolometers that heat up and change electrical properties when light radiation is focused on them. They were initially developed as parts of antennas for imaging faint radiation from space. A bolometer-based radio antenna measured echoes of the Big Bang that started the universe running, and earned a Nobel Prize for Arno Penzias and Robert Wilson in 1978.

Coincidentally, their antenna lacked resolution to produce pictures of small objects like Uranus, and Helisto's system lacks resolution to reveal details of your a. . .

I'm not going to say it, but I bet you can figure out what I was going to type. I'm not being modest, it's just too lousy a joke. (Feel free to use it though, if you need a bad joke for the pub.)

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