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.