Sniffing Out the Bad Guys

After Richard Reid’s bumbling 2001 attempt to destroy a commercial aircraft in-flight by detonating explosives hidden in his shoe, political satirist Bill Maher speculated on Reid having waged a drunken bet with his friends that he could cause Americans to have to take off their shoes before boarding planes - and suggested that we should be grateful that Reid had chosen shoes rather than underwear. Of course, on Christmas Day of 2009, Maher’s satire proved prophetic, and the impracticality of conducting a visual search of every piece of attire of every passenger boarding every plane became glaringly apparent.

It could be that what the TSA really needs - rather than a line of naked passengers at the security gates - is a shot of German ingenuity. Researchers at Fraunhofer-Gesellschaft have developed a network of electronic sniffing devices that can not only smell explosive chemicals hidden on a person, but identify the carrier even as he moves through a crowd. The new intelligent system uses a network of “chemical noses” to capture the smell of the explosives, then the system processes the acquired data, correlates it with the individual’s movements, and ultimately tracks him down.

Researchers at the Fraunhofer Institute for Communication, Information Processing and Ergonomics (FKIE) in Wachtberg have built such a prototype security system and named it HAMLeT (Hazardous Material Localization and Person Tracking). “HAMLeT will alert security personnel to suspicious individuals,” says FKIE department head Dr. Wolfgang Koch. The sensor data fusion process employs complex algorithms which allow HAMLeT to build up a precise image of pedestrian flows and connect a particular smell with a specific individual. “HAMLeT’s real achievement is its ability to collate all the data and convert it into a clear and accurate overall picture.”

In a trial involving the German Armed Forces, researchers at the FKIE proved the system’s ability to track down five mock terrorists carrying hidden explosives, but the scientists admit that the system currently has a tendency to produce false positives, rendering it too cumbersome to yet deploy. But with some refinement of the algorithms and perhaps the incorporation of ever-improving face-recognition technology, systems like this could become commonplace anywhere large crowds gather, from airports to sports stadiums.