Sense of security

Technology originally developed for space communication projects may soon be used by UK security forces to detect concealed weapons at airports or railway stations.

The Tadar sensing system, which takes its name from the Brazilian Tadarida bat, is designed to detect metallic and non-metallic objects hidden beneath clothing. It uses 3mm-wavelength technology that can see through clothing, but is completely harmless to people, according to its Irish developer, Farran Technology.

The company designed the technology for use by ESA in advanced astronomy and radio communications, as its high signal bandwidth is ideal for inter-satellite communications. This was coupled with Farran’s scanning technology to design the Tadar system.

It works by measuring the a person’s radiated body heat by scanning them against a temperature- controlled background panel. The presence of any object hidden between the clothes and the body blocks the body’s natural energy and the thermal contrast provides a high-resolution image of the object.

Even materials that conventional metal detectors cannot see, such as plastic explosives, can be identified. This is because each type of material has its own frequency response and produces its own unique image — like a fingerprint. A metallic object will block 100 per cent of the body’s heat, whereas something made from plastic will block considerably less.

Tony McEnroe, Farran’s managing director, said the system has a number of advantages over competing technologies, such as terahertz or X-ray imaging.

‘Tadar is much further on in terms of commercialisation than any terahertz technology,’ he said. ‘It also does not have the health implications of other technologies because it is completely passive and just measures the body’s energy. ‘Competing technologies, such as terahertz, would have to radiate the person first. With X-ray you are actually ionising the person so that definitely has health implications.’

The system refreshes the image up to 10 times per second, speeding up the monitoring process. At present the system relies on a manual operator checking the screen for suspicious objects. In the future, however, Tadar will use integrated recognition algorithms to monitor the images and pick out suspicious objects.

The sensors have been prototyped over the past two years and Farran plans to demonstrate the product to the DTI early in the New Year, with the first units expected to be in use by the end of 2006.