Face masks usually break facial recognition: Study
Plus what to do if you use facial recognition on your phone.
Face masks play a vital role in limiting the spread of coronavirus, but wearing them has one downside: facial recognition systems, such as Face ID on the iPhone, generally can't handle them.
A new US study reaffirms that wearing a face mask can reduce the effectiveness of face recognition systems by as much as 50%.
The study, from the National Institute of Standards and Technology (NIST), examined 89 commercial face recognition systems and tested their ability to recognise faces which had been digitally supplemented with one of nine mask designs.
"Algorithm accuracy with masked faces declined substantially across the board," the NIST summary of the study noted. "Using unmasked images, the most accurate algorithms fail to authenticate a person about 0.3% of the time. Masked images raised even these top algorithms' failure rate to about 5%, while many otherwise competent algorithms failed between 20% to 50% of the time."
The study also found that the shape and colour of a mask can make a big difference. Round masks didn't interfere with recognition as much as oblongs or other shapes. Darker masks also seemed harder to recognise, though NIST says further research is needed in this area.
The lesson? If you're a keen Face ID user, a pale coloured round mask might work out better than something with a complex darker design.
The result isn't surprising. Facial recognition systems rely on a variety of signals, including the angles of the face and the shape of the mouth and nose. Wearing a face mask obscures all of those. While some systems can cope with people wearing glasses, masks present a bigger challenge.
Facial recognition is widely used for security and validation purposes, including the SmartGate system used for border control in Australia. In the (currently unlikely) event that you're heading overseas, any mask would need to be removed before using SmartGate.
Can I still use facial recognition on my phone?
Facial recognition is a popular choice for unlocking smart phones, supported on both iPhone and Android models. Looking at your phone is less hassle than using a fingerprint or entering a passcode.
However, since recognition technology can't currently cope with face masks, you'll need to use a different authentication method when you're out and about wearing a mask. Switch to fingerprint recognition or a passcode instead. While you could remove your mask, that's frankly a recipe for unnecessary face touching.
iOS 13.5, Apple's most recent operating system update, includes tweaks designed for people wearing face masks. The update doesn't change the recognition algorithm, but makes it easier to switch to using your passcode instead.
If Face ID fails and calculates a mask might be the reason, the passcode option will now appear immediately, rather than requiring several attempts. You can also swipe up from the login screen to bring up the passcode login screen.
As face masks look set to become the new normal, research into their effectiveness and impact continues. One recent Australian study confirmed that multi-layer masks are more effective in blocking the spread of droplets.
Want more help with masks? Check out our overview of face masks, how to choose the best one, what doctors recommend when using them, the rules that apply in Australia and our regularly-updated guide on where to buy masks.
