Schneier - Facial Recognition for People Wearing Masks

The Chinese facial recognition company Hanwang claims it can recognize people wearing masks:

The company now says its masked facial recognition program has reached 95 percent accuracy in lab tests, and even claims that it is more accurate in real life, where its cameras take multiple photos of a person if the first attempt to identify them fails.

[...]

Counter-intuitively, training facial recognition algorithms to recognize masked faces involves throwing data away. A team at the University of Bradford published a study last year showing they could train a facial recognition program to accurately recognize half-faces by deleting parts of the photos they used to train the software.

When a facial recognition program tries to recognize a person, it takes a photo of the person to be identified, and reduces it down to a bundle, or vector, of numbers that describes the relative positions of features on the face.

[...]

Hanwang's system works for masked faces by trying to guess what all the faces in its existing database of photographs would look like if they were masked.

from Schneier on Security https://www.schneier.com/blog/archives/2020/03/facial_recognit_3.html