Facial recognition performed on a crowd on a city street.
Trismegist san/Shutterstock.com

Today it’s easy to recognize faces from camera footage taken in public. Whenever you leave the house, your movements can be tracked whenever a camera sees your face! Luckily, there are some ways to avoid this—at least for now.

How Is Public Facial Recognition Possible?

Thanks to a branch of computer science called “machine vision“, it’s possible to create software algorithms that quickly match a face in a photo or video to one on file. Since modern cameras are so good and computers are incredibly fast, this can be done in real-time, even in large crowds.

Wait, how do they have a photo to match your face? Well, if you’ve ever put a photo of yourself on social media or a friend has tagged you in one of their photos, then it’s simple to scrape the internet for photos that have already been identified. Most likely by you!

The technology is so good, that you can pretty much assume that whenever you’re in sight of a camera in public, there’s a chance that your face could be tagged and logged. It’s a scary thought, but we also use this technology for more mundane uses every day.

You Already Use Facial Recognition

When you use a Snapchat filter that puts a funny mustache on your face, that’s the same type of technology used in facial recognition in public. The same goes for biometric unlocking on your phone. Apple’s Face ID uses sophisticated algorithms and depth-sensing cameras to match your face with the data on file, making sure that no one else can use the phone.

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The point is that facial recognition technology isn’t good or bad, it all depends on how it’s used. Concerns about public facial recognition are mainly based on private and government surveillance using the technology.

Most existing privacy laws around the world say that you can be filmed when in public, as long as there isn’t a reasonable expectation of privacy. If that weren’t the case, the paparazzi couldn’t do business, after all. Unfortunately, those laws could not foresee that mass-tracking of people could be done by simply pointing a camera at them.

Wear a Mask

The simplest way to avoid getting your face scanned in public is to wear a mask. At the time of writing, plenty of people are already doing this with face masks worn for pandemic reasons, which is why biometric face unlocking doesn’t work when you have one on. It is possible to get identify a face with a mask on that only covers half the face, but it’s much harder to do it using, for example, public security cameras.

A full mask is more foolproof, but many parts of the world have anti-mask laws that may make this impractical.

Hats, Sunglasses, Makeup, T-shirts, and Hair

A person wearing a mask, hoodie, and sunglasses.
Alejandro Ivan Suarez/Shutterstock.com

A wide-brimmed hat makes it harder for cameras mounted above to see your face. Sunglasses, especially when worn with a face mask, is another effective method to stop your face from being scanned, and shouldn’t run afoul of mask laws.

There’s also a new style of makeup that’s designed specifically to confuse machine vision systems trying to recognize your face.

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Another clever hack that’s been discovered is the practice of wearing clothing with printed faces . While this doesn’t stop your face from being scanned, it can make the system scan the wrong face.

You can also obscure your face with long hair (or a wig) to make it harder for facial recognition systems. Although obviously, it makes it hard to see where you’re going!

Specialized Privacy Glasses

These are all passive ways to prevent facial recognition systems from getting a good look at you, but there are ways to actively interfere with facial recognition as well. One interesting idea is to use special privacy glasses that can detect when a camera is looking at you and then blind them without damaging anyone’s equipment.

One company, Reflectacles, makes a variety of these glasses that are aimed at defeating different types of facial recognition. They do this with infrared-blocking lenses and reflective frames that blind the camera.

Historical Facial Recognition

One worrying aspect of facial recognition is that it can be applied to old footage. So, assuming the fidelity is good enough, footage from the past can be run through a facial recognition system and your movements can be tracked after the fact. Unfortunately, you’ve probably been captured by hundreds of cameras over the years and there’s no way to prevent that from being analyzed. It is however a good cautionary tale about how future technologies can unravel privacy retroactively.

Recognition Technology Is Advancing

While most of the ways to defeat facial recognition in public here still work, the technology is advancing quickly. As the algorithms get smarter, many of these mitigations aren’t going to be effective anymore. For example, the “dazzle” makeup method has already been defeated.

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Already, it may not even be necessary to see someone’s face to ID them. For example, gait recognition technology can analyze the way someone moves and walks and match them to a record. So you could look at footage of a protest, where people are often fully masked, and then find them when they are in public again by matching their unique gait.

The future advancement of public biometrics like these means that it’s probably more effective to outlaw the use of such technologies to breach privacy, rather than trying to directly defeat the tech in the wild.

Pushback Against Facial Recognition Technology

Public awareness and dissatisfaction with facial recognition have already led to it being halted in some cases. For example, Microsoft has banned police from using its facial recognition technology and will not sell it to them. In Canada, facial recognition using Clearview AI has been declared illegal. Facebook is also shutting down its facial recognition plans after a public outcry.

More US states are passing laws restricting government use of face recognition technology, too.

 

Profile Photo for Sydney Butler Sydney Butler
Sydney Butler has over 20 years of experience as a freelance PC technician and system builder. He's worked for more than a decade in user education and spends his time explaining technology to professional, educational, and mainstream audiences. His interests include VR, PC, Mac, gaming, 3D printing, consumer electronics, the web, and privacy. He holds a Master of Arts degree in Research Psychology with a focus on Cyberpsychology in particular.
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