China has begun rolling out new software capable of recognising people simply by the way that they walk.
The " recognition" technology, developed by Chinese artificial intelligence firm Watrix, is capable of identifying individuals from the shape and movement of their silhouette from up to 50 metres away, even if their face is hidden.
The system is currently being used by police in Beijing and Shanghai and adds to the country's formidable surveillance network that includes an estimated 170 million CCTV cameras.
The software can be used on footage from standard surveillance cameras, however it does not currently work in real-time. Instead, the footage is analysed once it is recorded, which takes approximately 10 minutes.
"You don't need people's cooperation for us to be able to recognise their identity," Watrix CEO Huang Yongzhen said.
"Gait analysis can't be fooled by simply limping, walking with splayed feet or hunching over, because we're analysing all the features of the entire body."
Previous surveillance initiatives include a so-called "spy bird" programme that uses dove-like drones to monitor populations from the skies.
China is also in the process of introducing a controversial "social credit system", aimed at reinforcing the idea that "keeping trust is glorious and breaking trust is disgraceful", according to a government document.
Set to be fully operational by 2020, the programme ranks citizens by their behaviour – such as parking violations and jaywalking – in order to determine who is most worthy of the best social housing and schooling for their children.