Yitu Technology, based in Shanghai, China has developed and employed an artificial intelligence (A.I.) algorithm called Dragonfly Eye that uses facial recognition technology capable of identifying 2 billion people in seconds. Zhu Long, CEO of Yitu Technologies, told the South China Morning Post, "Our machines can very easily recognise you among at least 2 billion people in a matter of seconds, which would have been unbelievable just three years ago." Dragonfly Eye is presently used by 150 municipal public security systems and 20 provincial public security departments across the country of China. Dragonfly Eye was initially employed on the Shanghai Metro in Shanghai, China, during January of this year. Local police authorities credit Dragonfly Eye with aiding in the arrest of 576 suspects on the Shanghai Metro in the first three months of using the facial recognition system.

Zhu Long, co-founder and CEO of Yitu Technology, has his identity checked at the company's headquarters in the Hongqiao business district in Shanghai. "Our machines can very easily recognise you among at least 2 billion people in a matter of seconds," says chief executive and Yitu co-founder Zhu Long, "which would have been unbelievable just three years ago." Its platform is also in service with more than 20 provincial public security departments, and is used as part of more than 150 municipal public security systems across the country, and Dragonfly Eye has already proved its worth. On its very first day of operation on the Shanghai Metro, in January, the system identified a wanted man when he entered a station. After matching his face against the database, Dragonfly Eye sent his photo to a policeman, who made an arrest.

A smart surveillance system that can identify criminals among a database of 2 billion faces within seconds has been revealed in China. The system connects to millions of CCTV cameras and uses artificial intelligence to pick out targets. Known as'Dragonfly Eye', it has already been used in Shanghai to track down hundreds of wanted criminals, reports suggest. A smart surveillance system (pictured) that can scan 2 billion faces within seconds has been revealed in China. The system has been helping Shanghai's police force track down criminals in a city with more than 24 million inhabitants.

The lifts rising to Yitu Technology's headquarters have no buttons. The pass cards of the staff and visitors stepping into the elevators that service floors 23 and 25 of a newly built sky scraper in Shanghai's Hongqiao business district are read automatically – no swipe required – and each passenger is deposited at their specified floor. The only way to beat the system and alight at a different floor is to wait for someone who does have access and jump out alongside them. Or, if this were a sci-fi thriller, you'd set off the fire alarms and take the stairs while everyone else was evacuating. But even in that scenario you'd be caught: Yitu's cameras record everyone coming into the building and tracks them inside.