Paying with your face

Face-detecting systems will soon be regularly used to authorise payments, provide access to buildings and track down criminals and terrorists.

Face recognition might transform everything from policing to the way people interact every day with banks, stores, and transportation services.

Already governments in some countries are using software to identify suspected criminals in video from surveillance cameras.

The technology has taken off in China because of the country's attitudes toward surveillance and privacy. Unlike countries such as the United States, China has a large centralised database of ID card photos.

Facial recognition has existed for decades, but only now is it accurate enough to be used in secure financial transactions. The new versions use deep learning, an artificial-intelligence technique that is especially effective for image recognition because it makes a computer zero in on the facial features that will most reliably identify a person.