US buys in to QinetiQ's millimetre wave technology

Human is a warmer

Simplest thing: place the object against the skin, so that it gets warmed by the body. Cover with thermal vest.

Hot water bottles would work

The technology works by 'reflecting' the cold microwave radiation from the sky, so covering something metallic with something rubber would stop it being seen. However, the technology claims to be able to detect explosive material under clothes, so the 'reflection' difference between your skin and the rubber coating could possibly be detected - but might not be such a strong signal.

I saw a talk several years ago about a study in Japan which tried a similar idea for detecting drugs in envelopes in the postal system. A Terahertz (millimetre wave) scanner was used to detect powders and to classify the types of material detected but the engineers found that a small amount to tinfoil-lining reflects the radiation and hence foils the scanner (as well as keeping the drugs fresh). The upshot is that if everybody wore tin foil hats or huge comedy metal buttons it would be a nightmare for the human observer to see anything above the clutter!

Don't be confused by the terms hot and cold

I don't think they are referring to thermal radiation. Like a radioactive emitter might be described as "hot" even if its not actually hot in the thermal sense.

Can we get a "story dumbed down" picture ?

It's radar, not IR.

I don't know why the press release is talking about "cold" vs "hot", but "hard" vs "soft" might be a better characterisation of what mm wave radar can distinguish between. Maybe there's an IR element to assist in differentiation.

Keeping a water bottle at body temperature is a non-trivial task, but I'm sure they'll scan for *anomalous* temperatures rather than cooler ones. People with therapeutic heatpacks may come in for closer inspection...

Ok, a new slant...

A pistol inside a silicon breast implant.

Sorted.

It's an interesting idea...

...but surely if the idea is to remove the "human" element it's not going to be 100% fool proof? For the programers and developers to get this to work, they'll have to consider virtually all the problems they want to stop and then make sure that it doesn't generate too many false positivies.

'Cold' radiation

Black body radiation gives a radiation curve for a given temperature of item. This curve has a very long tail toward the high frequency end of the spectrum, so humans and knives and whatnot should emit some microwave radiation. The question is whether you'd actually be able to sense a 10K temperature difference at a wavelength like that. It should theoretically be possible to determine the temperature of an object with just 2 different wavelength's radiation strength, so if this thing does any sort of spread spectrum operation, they could actually tell you just how cool your knife is.

The apparent passive nature of the thing (I didn't read any more details than were in this article) should make interference from buttons and the foil hats mostly irrelevant.

And thermal jackets shouldn't block too much microwave radiation.

If this deal is anywhere near as sensisive as some infared cameras are, then it'll give the added side affect of being able to see certain dangly bits of flesh through articles of clothing. Say pants, for instance.

Mass scanning.

This sort of tech could, eventually, mean that everybody is getting some check. And machines could replace expensive staff.

I see plenty of reports which suggest that TSA, and some other, security is not very competent. If the false positives are no worse than the current system, it could be a big improvement.

But with the sort of idiocy that hassles a five0year-ild because their name matches a watchlist, I don't see mucyh hope for this tech improving anything.

Wait... this might be a good thing...

Everyone seems to be wondering why they don't just have humans doing the job. It is possible that these systems don't work well. Maybe they just won the government officials over with the "cool new gadget" factor. But let's assume for the moment that they do work pretty well. The reasons for deploying them are privacy, speed, and cost. They don't need to do invasive searches of every person to find hidden items. The ability to avoid searching large numbers of people allows many more people to pass through a given checkpoint in the same amount of time. The machines avoid requiring people to stop at the checkpoints for long periods of time. Also, since one machine can do the job of many humans, it can save money in the long run (depending on the cost of the machines and maintenance). Metal detectors have the same advantages, which is why they have been in widespread use for a long time.