You can tell a lot of things from the way someone walks.
Chinese artificial intelligence start-up Watrix says its software can identify a person from 50 metres away - even if they have covered their face or have their back to a camera - making it more than a match for Sherlock Holmes.
Known as gait recognition, the technology works by analysing thousands of metrics about a person's walk, from body contour to the angle of arm movement to whether a person has a toe-in or toe-out gait, to then build a database.
"With facial recognition people need to look into a camera - co-operation is not needed for them to be recognised [by our technology]," said Huang Yongzhen, co-founder and chief executive of Watrix, in an interview in Beijing. Features like this have given Watrix an edge in catching runaway criminals, who tend to avoid surveillance, said Huang.