How do Chinese police catch criminals with facial-recognition sunglasses?

In China, the police are now wearing sunglasses equipped with facial-recognition technology to catch criminal suspects. 

Transport police in Zhengzhou, central China, were given the cutting-edge gadgets in 2018 to screen passengers and spot suspects in crowds at train stations.

A camera connected to the smartphone-like shades would allow the officers to take mugshots of the individual in question and compare them to a database back at headquarters.

Transport police in Zhengzhou, central China were given the cutting-edge gadgets in February to screen passengers and spot suspects in crowds at train stations

The system would then bring up the suspect's personal information including name, ethnicity, gender and address. All the information would be transferred back to the officer's glasses.

The glasses can also tell officers whether or not the targets are on the run from the law, the address of any hotel they are staying at and information related to their internet usage.

This is part of China's efforts to build a digital surveillance system that uses a variety of biometric data - from photos and iris scans to fingerprints - to keep close tabs on the movements of its 1.4 billion population.

The technology has since allowed police in Zhengzhou to nab seven suspects.

They were accused of crimes ranging from human trafficking to hit-and-runs. 

Another 26 people were caught using fake IDs, according to the state-owned People's Daily, quoting the city's police department. 

The facial recognition sunglasses system was expanded to Beijing in March as well, particularly at highway checkpoints on the city's outskirts.

The smart glasses can pick up facial features and car registration plates, and match them in real-time with a 'blacklist' of suspects, according to Reuters.

The rapid development of the technology has triggered a demand for commercial applications as well, with gyms, restaurants and even public toilets getting in on the facial recognition game.