Terahertz Imaging:Another Way to See Through Walls

311Stylee writes: "Wow. I've never even heard of this before, but it looks genuine with a writeup on MSNBC and Space.com . Existing technology is used to measure sea temperatures through clouds via satellite, but newer cameras could be used in a huge array of applications because of their ability to see through walls, clothing, smoke and clouds. Google gets 546 hits on T-rays, inlcuding one from AT+T Bell Labs."

Comments

Beware Sony Owners Instead...

[Chasing Amy]

> So tell me why the government wants to see through my clothes?

Interestingly enough, people can already see through your clothes--at least, if you're wearing something fairly diaphanous or skintight already, like a swimsuit, or very light-colored clothing. And all they need is an older Sony video camera with NightShot before they put special filters on to prevent the trick from working, or a newer model with modifications...

Does anyone else recall the breif hysteria when Sony video camera owners realized that using NightShot during the day allowed them to record an image that saw partly through swimsuits and light clothes, and that became public? News broadcasts were definitely playing it up. Sony immediately announced that future video cameras would ship with filters to prevent such imagery...

IIRC, the problem (or "bonus") was that the IR light emitted by NightShot would travel through thin or light-colored clothing before being either reflected or re-emitted (can't recall exactly how it works...), so that when captured by the lens during daylight capturing, it let one "see" through some clothing.

There is in fact a whole genre of Internet pr0n dedicated to capturing unsuspecting females in swimsuits or thin white clothing with such cameras. The films have a greenish tinge, like looking through some Night Vision goggles, but do indeed show body outlines, nipples, pubic hair, etc.

Now, if that can be done with a HandyCam for a few hundred dollars, you know the government with its budget can get a lot more sophisticated and see a lot more clearly...

Re:Not Visible, microwaves

[dpp]

These wavelengths have the rather ungainly "millimeter and submillimeter" label. There's "far-infrared" at about 100 microns, and this regime runs from there out to, well, about a millimeter. :-)

I am an astronomer who works with submillimeter wavelengths at the James Clerk Maxwell Telescope (JCMT). In this regime, we're really at the boundary between optics and radio. You can almost think of it as the boundary between whether you treat light as a wave or as a particle.

Some of our astronomical instruments are radio-style "heterodyne" receivers which treat the light as a wave and produce spectral line information (telling you what molecules are out there and what they're doing). It's a bit like sweeping a radio dial through a range of frequencies and marking the signal strength of all the stations.

Other detectors treat the light much more as a particle, just measuring the total amount of radiation falling onto a pixel. On the JCMT we have such an instrument called SCUBA (the Submillimeter Common User Bolometer Array). They're analogous to the CCDs used at optical and infrared wavelengths. I'm guessing that the work mentioned in the article refers to detectors of this type, but I could of course be wrong. :-)