Smiths Detection has launched a millimetre-wave security scanner that can display real-time moving images of a person being scanned and detect small, non-metallic objects hidden in clothing.

Devices that offer mm-wave video imagery are already on the market but they use mechanical scanning with a mobile element — either lenses or optics — to gather the mm-wave information from the scene.

Smiths' 'eqo' steered array imager, so named because it detects mm-wave echoes, uses what the company claims is revolutionary scanning technology, with electronic lenses that are reconfigured throughout the operation to carry out the scan. It takes the form of a security portal: the person to be scanned enters it then stands in a 'scan zone' in front of an imaging panel.

Rory Doyle, Smiths product manager for mm-wave imagers, said: 'At the core of the technology is a large array of antennas, which we configure to focus on different points on the scene. We do that reconfiguration very rapidly — many millions of times per second — to cover the large volume scanning area in front of a flat panel of these solid-state antennas. We gather that mm-wave information and turn it into an image.'

Eqo uses an active mm-wave detection system. Passive systems pick up the mm-wave heat energy emitted by the body, which is used as a background reference point. Lightweight materials, including light clothing, appear transparent. If there is an object on the person, the system detects the different mm-wave energy output level.

With an active system such as eqo, mm-wave is transmitted into the detection area to boost the level of energy overall, give a better return and a more detailed image. The different signal given by objects against the background signal from the body allows the scanners to detect even non-metallic items that may pose a risk, such as ceramics and plastics.

'Different imagers use different mm-wave frequencies to offer different characteristics,' said Doyle.

'The frequency range we work in is a good compromise between current commercially available technology and optimum detection capability.'

Because eqo electronically scans the scene rapidly and produces a live video-style output, the moving image offers security officials extra information. 'We get a lot of extra cues in terms of detection of materials from the movement of the person and objects on them in the image,' said Doyle. 'This enhances the technical benefits with an operational aspect that gives us a very good detection capability.'

Smiths previously made a passive imager that gave a similar video-style output but eqo's active system offers an improved refresh rate, a smoother moving image and better resolution.

Doyle said one of the biggest challenges in developing it was dispensing with the mechanical moving parts to change to an all-electronic scanning system. It also generates large amounts of data, which needs to be gathered and processed in real time to turn into a meaningful image.

In common with other scanners that allow operators to see through clothing, eqo scanning poses privacy issues. Alongside technical solutions such as face blurring, the main safeguards when in use would be operational.

'We would never show a mm-wave image in the location where the person is being screened,' said Doyle. 'The images are typically viewed remotely and, if there's something that needs to be followed up, that information is relayed over a wireless or verbal link to an attendant operator to carry out a search or clear the person being screened. The scanning data is never saved in an operational environment, so the image is discarded once the person has been cleared.'

Doyle argued that scanning technology is considered less of an invasion of privacy than being patted down by security operatives. He said that in trials in the US, given the option between going through a scanner using an early version of the technology or being frisked, 90 per cent of people chose to be scanned.

A pre-sale release of the eqo system is now being evaluated by Smiths customers and is being demonstrated at security shows. 'The technology's proven, we have a few items to finish off in terms of product level of availability, then eqo should be on the market in the second quarter of this year,' said Doyle.

The initial application for eqo would be as a security portal in airports but Smiths anticipates a wider market with the increase in security checkpoints in areas such as building security, critical infrastructure and mass transit.

Doyle said future versions could be integrated with sensor technology to allow detection of other threat objects or materials, combined with more sophisticated imaging.

Berenice Baker