German device can sniff out terrorists from crowd

Hundreds of people hurry through a long airport corridor. Among them are two terrorists, who've blended themselves in the crowd. They are carrying small amounts of chemicals in their jacket pockets -- these chemicals are individual components for an explosive similar to what Nigerian terror suspect Abdulmutallab had tried ignite in an American plane last month.

While security cameras in the airport capture the two men's 'suspicious movements', sensors hidden in the corridor wall 'sniff out'  the smell of explosives with the two men.

As the men walk in, the sensors send off alarm signals alerting the security personnel about 'some' suspicious passengers. They note the alert on the monitoring equipment, however this is insufficient for them to track down to the two men.

But the sensor network helps them do this.

The sensors correlate the 'suspicious' movements of the men from the cameras with the 'smell' of the chemicals and track the two men into the airport till they are arrested.

The above scenario was a mock drill conducted by Germany's armed forces and researchers for a new intelligence system that can help identify terrorists carrying explosives, or even small amounts individual chemicals in any part of the body.

The new intelligence system, if proven foolproof under all circumstances, could prove to be a breakthrough in tracking militants who may be carrying small amounts of chemicals at airports.

The failed US plane plot sent warning signals to all countries on how terrorists could dodge security checks to sneak chemicals into airports.

These sensitive electronic 'noses' can take over the role of sniffer dogs at airport to not only capture the smell of explosives, but also process the acquired data, correlate it with individuals' movements and ultimately track down the suspects.

Researchers at Germany's Fraunhofer Institute for Communication, Information Processing and Ergonomics in Wachtberg have built a prototype security system called

HAMLeT, which stands for Hazardous Material Localisation and Person Tracking, which can alert security personnel about suspicious men.

"HAMLeT will alert security personnel about suspicious individuals," said Head of the Department Dr Wolfgang Koch from the FKIE.

At a recent mock drill carried out by the German Armed Forces, researchers at the FKIE proved the system's ability to track down five 'terrorists' carrying hidden explosives, said sources from the institute.

The system involves a network of highly sensitive smell sensors, which can follow an explosive's trail for a long distance.

The sensor chips contain oscillating crystals, and each time the crystals capture chemical molecules in the environment, their oscillation frequency changes. The degree of frequency change is different for different substances.

While, another component in the system -- the sensor's data fusion function -- traces the explosive's path and ferrets out the carrier.

A second sensor network is helps track the suspect's path, and German researchers used laser scanners for this purpose.

"HAMLeT's real achievement is its ability to collate all data and convert it into a clear and accurate overall picture," said Koch.

The data fusion system comprises complex algorithms, which allow HAMLeT to build up a precise image of pedestrian flows and connect a particular smell with a specific individual.

The scientists are now working to refine the prototype's algorithms to reduce the false alarm rates.

Image: A passenger is checked by security personnel at the main terminal of Frankfurt's airport | Photograph: Ralph Orlowski / Reuters