Rio de Janeiro will deploy facial recognition cameras during its carnival

Facial recognition is increasingly used as way to access your money and your devices. When it comes to policing, it could soon mean the difference between freedom and imprisonment. Faces can be scanned at a distance, generating a code as unique as your fingerprints. This is created by measuring the distance between various points, like the width of a person's nose, distance between the eyes and length of the jawline. Facial recognition systems check more than 80 points of comparison, known as'nodal points', combining them to build a person's faceprint.