Terahertz Imagery Progresses

ke4roh writes "Since Slashdot last discussed terahertz imaging, the European Space Agency's Star Tiger project has taken terahertz images of a human hand. Some of the pictures show just how useful the imagery might be for peering through walls and such - one of the images is through a 15mm pad of paper." The EE Times has another story.

Comments

It's passive.

[dark-nl]

The picture of the hand, at least, was taken using just the rays the hand emits naturally.

Re:Can see through clothing...

[bm_luethke]

The night vision glasses only worked on white clothing. It enabled both the thermal imaging and light gathering source open at the same time. This had the affect of taking the normal light image (so they looked like a person) plus the underlying form (the thermal imaging portion). Looked like a 3D model with only a single texture apllied to the model (I.E. all flesh tone, not, ummm, other colors (at work, nothing more will make it through the censors :) ). While not truly see through, it did look pretty good :P

It's not actually THz...

[JRHelgeson]

The article actually states that the camera is imaging at the 0.2THz to 0.3THz - which means that they're operating at 200-300GHz.

Thats like Intel stating they broke the Gigahertz barrier when they reached 300 MHz processor speeds (or rather 0.3GHz).

Re:Good to see some constuctive devices being made

[jratcliffe]

There are already systems that can see through walls, using UWB. Not _exactly_ the same thing, but pretty cool, nonetheless: http://www.businessweek.com/technology/content/oct 2002/tc20021017_4359.htm

Conservative SCOTUS ruled against thermal imaging

[Artifice_Eternity]

It's possible that Ashcroft will seek the use of this and other types of remote imaging technology in the future. But for now, he can't use them without a warrant.

Surprisingly, the Supreme Court ruled last year -- in an opinion written by Scalia (conservative) and joined by Souter (moderate) and Thomas (conservative), as well as Ginsburg and Breyer (both liberal) -- that the use of thermal imaging to detect marijuana grow lamps inside a house was illegal:

The District Court [had previously] ruled that the thermal imaging device "is a non-intrusive device which emits no rays or beams and shows a crude visual image of the heat being radiated from the outside of the house"; it "did not show any people or activity within the walls of the structure" it "cannot penetrate walls or windows to reveal conversations or human activities"; and "(n)o intimate details of the home were observed."

The Court of Appeals initially reversed this ruling, but reversed itself, ruling that Kyllo has shown no expectation of privacy because he had made no attempt to conceal the heat escaping from his home, and even if he had, there was no reasonable expectation of privacy because the imager "did not expose any intimate details of Kyllo's life," only "amorphous 'hot spots' on the roof and exterior wall."

The U. S. Supreme Court reversed the decision of the Court of Appeals. Justice Scalia's decision pointed out that the Fourth Amendment provides that "(t)he right of the people to be secure in their persons, houses, papers, and effects, against unreason able searches and seizures shall not be violated." It cited a 1961 ruling, Silverman v. United States, ruling, "At the very core" of the Fourth Amendment "stands the right of a man to retreat into his own home and there be free from unreasonable governmental intrusion." It held that with few exceptions, the question whether a warrantless search of a home is reasonable and hence constitutional must be answered no.

The decision discussed at length the change in technology availing the government of visual surveillance, and the historic tie of visual surveillance to trespass. However, the court observed, visual surveillance has been historically lawful, because the eye cannot be guilty of trespass. The decision referred back to the 1986 Ciraolo case where the Supreme Court ruled that aerial surveillance with the naked eye was permissible without a search warrant, even if the police were looking at plants growing within the back yard, which known legally as being within the "curtilage" of the home.

In his discussion of the effect of the evolution of technology on privacy rights, Justice Scalia stated that technology enabling human flight has uncovered portions of the house and its curtilage that once were private. But, he held, the Kyllo case had to confront the limits on the power of technology to shrink the realm of guaranteed privacy.

What the court concluded is that a search is permissible without a search warrant if the surveillance was normally available to the public without additional technology. Thus, looking down from an airplane is permissible, but using an eavesdropping device is not.

The distinction that "off-the-wall observations" could be permissible while "through the wall" surveillance could be impermissible would lead to a trap as technology advances. The court held that any other approach "would leave the homeowner at the mercy of advancing technology-including imaging technology that could discern all human activity in the home."

It looks to me like terahertz imaging would fall under this ruling, and thus be illegal without a warrant. For now, anyway...

Astronomy that can be done with this?

[dpp]

that's cool. What sort of astrnomy can be done with this?

I work for an observatory that uses these wavelengths to do astronomy. At these wavelengths you're mostly looking at the cold material in the universe --- stuff like interstellar gas, dust, and so on.

Re:seems bogus

[JBark]

I believe they failed to metion infrared, because infrared is usually considered part of the light spectrum, hence the terms "infrared light" and "ultra-violet light".

Re:Thermal imaging

[t_little]

Sounds like thermal imaging on steroids

It is thermal imaging. Terahertz waves are at the low end of the far-infrared region of the spectrum. They are produced by thermal radiation of all objects warmer than liquid helium temperature.

Terahertz in the U.S.

[oil]

There's a small company in Ann Arbor, Michigan that has a commercial terahertz imaging device called the T-Ray 2000. Check it out. http://www.picometrix.com/t-ray/index.html