Sniffing Out Danger

Airport security just got a bit of a boost with the development of a new smart system that can help find explosives-carrying terrorists. The system uses electronic "noses" that can sense the smell of explosives, process the data, and correlate the information with the way an individual moves. In other words, the new smart nose can track down suspected terrorists.

Chemical Noses

By now, terrorists know that there will be security cameras in a crowded airport terminal, but they're not expecting that chemical noses will be hidden inside the walls of the terminal. These sensors sound an alarm when terrorists with chemical explosives on them pass by. The alarm alerts security guards who make a notation on their monitoring equipment. While the guard can't pinpoint the individual carrying the explosives, the network of sensors will begin the process of narrowing down the suspects until a terrorist's identity is confirmed.

A prototype for just this type of security system has been developed by German researchers at the Fraunhofer Institute for Communication, Information Processing, and Ergonomics FKIE, located in Wachtberg, Germany. The researchers call the system HAMLeT, an acronym for Hazardous Material Localization and Person Tracking. FKIE Department head Dr. Wolfgang Koch says that, "HAMLeT will alert security personnel to suspicious individuals."

The new smart system employs a network of smell sensors that have a high sensitivity and can find and follow the trail of explosives. The sensor chips contain oscillating crystals. As the electronic sensors catch the smell of the chemical molecules, the frequency of the oscillation changes and adapts. The change in frequency is specific to the type of substance sensed by the electronic noses.

Scent Sense

A second component of this system can fuse data so that the path of the explosives is tracked and the carrier found. Yet another network of sensors is required to follow the route of the individual and for this aspect of the system, researchers have brought laser scanners into play. "HAMLeT's real achievement is its ability to collate all the data and convert it into a clear and accurate overall picture," notes Koch. The data fusion is accomplished through algorithms that can generate an image of crowd flow and connect a certain scent with a specific person.

The researchers put on a successful demonstration of the HAMLeT system for the German Armed Forces, in which the FKIE managed to hunt down five explosives-carrying "terrorists" in a simulation. At present, the scientists are refining the algorithms used by the prototype so as to cut back on the rate of false alarms.