Chinese scientists develop mini-camera to scan crowds for potential suicide bombers

Chinese scientists are developing a mini-camera to scan crowds for highly stressed individuals, offering law-enforcement officers a potential tool to spot would-be suicide bombers.

But the technology has raised concerns over its implications for individual privacy and potential abuse by government agencies.

Stress has a range of effects on the body. It can register as changes in heart rate, facial expression and body temperature, which scientists can already monitor from a distance. But the readings are not always reliable. For example, with enough practice, a person can learn to control their heartbeat.

That's why Chen Tong , an associate professor of electronic information engineering at Southwest University in Chongqing looked at another indicator - the level of blood oxygenation. Using hyperspectral imaging, which examines information across the electromagnetic spectrum, Chen and his research team have developed a "stress sensor" that measures the amount of oxygen in blood across exposed areas of a body, such as the face. "The higher the mental stress, the higher the blood oxygenation," he said.

Chen's research comes amid heightened fears over security on the mainland after a series of deadly attacks in public places. According to the authorities, the assailants ranged from knife-wielding religious extremists going on rampages in train stations to distraught citizens setting fire to crowded buses.

"They all looked and behaved as ordinary people but their level of mental stress must have been extremely high before they launched their attacks. Our technology can detect such people, so law enforcement officers can take precautions and prevent these tragedies," Chen said.