TERRORISTS who try to infiltrate American embassies may soon be up against a 3D scanner that sees through their clothes and can spot any concealed weapons, even if they are not made of metal. The scanners may also replace strip-searches in prisons and could eventually be used in airports to catch drug smugglers.
Researchers at Pacific Northwest National Laboratory in Richland, Washington, who developed the scanner, originally hoped that it could replace X-ray scanners and metal detectors at airports. But while the millimetre-band waves it uses have none of the health risks associated with ionising radiation such as X-rays, the image produced by the scanner proved all too revealing, so the plan was dropped following concerns that airline passengers would object to security staff seeing them naked.
Despite the increased concern about security, 鈥渁irports will not be the first application鈥�, says Greg Koller, of Pacific Northwest. They are more likely to be used in embassies, where security guards already frisk people for concealed weapons. They could also replace strip-searches in prisons. In these places, says Koller, the scanner is likely to be a less objectionable option. 鈥淧rivacy is not an issue here,鈥� he points out.
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The 3D Body Holo Scanner, as it is known, uses two sources of 鈥渕illimetre-band鈥� radio waves with a wavelength of around one centimetre to produce a 3D image. The electromagnetic waves pass through clothes but bounce off flesh and other items, everything from pens to knives and plastic explosives. An array of sensors picks up the reflections, which are then analysed by computer software to generate a 3D image. People walk into the scanner, pause for a couple of seconds, before being given the all-clear, or not.
Last month SafeView, a new company based in California, was set up to exploit the technology. 鈥淐ommercialisation steps are expected to produce good products sometime next year,鈥� says Mike Lyons, SafeView鈥檚 chairman.
To safeguard people鈥檚 modesty, Pacific Northwest has tried to refine the image-generating software. The aim is to extract the vital images, such as guns, and superimpose them on a generic sexless mannequin. 鈥淲e鈥檝e made some progress in doing this,鈥� says Koller. 鈥淚t all depends on what you鈥檇 want to use it for. I鈥檇 say we鈥檙e about three-quarters of the way there.鈥�
But the crucial difference may be the change in public opinion since the attacks on the World Trade Center on 11 September last year. 鈥淭he increased interest in security is likely to speed up the process for commercialising this technology,鈥� says Koller.
The 3D scanner is initially likely to cost around $100,000, which is roughly twice the price of an airport X-ray scanner. While some X-ray devices are currently being developed that will be capable of picking out plastic objects, the resolution of the millimetre-wave scanner is significantly better, and it鈥檚 faster, says Lyons. Also the fact that it generates a 3D image should make it easier to spot anything suspicious. 鈥淎lgorithms that are looking for anomalies caused by plastic explosives, contraband and weapons can work much better because they get multiple views of the threats from different angles,鈥� says Lyons.