Your face is becoming your key to accessing your money, your devices and passing through security checks. Unlike a fingerprint, your face can be scanned from a distance without your knowledge. Here’s how it's done.

Your face is measured at more than 80 "nodal points", and the span between them is then used to create a long unique number called a faceprint.
Tap or click a feature to see what the system measures.

The iPhone shines a grid of 30,000 infrared dots on a face and makes a crude 3D model.

Other systems use infrared images to achieve facial recognition. Infrared is not affected by shadow in the visible light spectrum.

Here's how it's done at greater distances. Security systems scan the image for faces.

Facial features are isolated, and if the image isn't infrared the colour is taken out.

The system then re-orients the facial features to allow standard measurement.

The measurements are made into a faceprint...

..then the faceprint is compared to a database of faceprints. The error rate can be as low as 0.8 per cent, but has matched incorrectly in the past.