Google can catch shoulder surfers peeking at your phone

google shoulder surfers smartphone alert shopping cafe

Imagine you’re in town waiting for a friend. With time to kill before they arrive, you do what most people do and get your smartphone out. You might flick through your Twitter timeline, check Facebook, open Instagram, or tap out a message on WhatsApp. You fail to notice the stranger standing right behind you, looking at your display.

Would you like your phone to be able flag such an occurrence with an on-screen message along the lines of, “There’s someone else looking at your display,” or perhaps something more direct, like, “Hey! Stop looking at my phone right now, creep!” though such harsh words may admittedly cause an unwanted public altercation.

It turns out that researchers at Google have been developing such a privacy-focused feature, and have now posted a video demonstrating how it works.

The feature uses the front-facing camera to scan the faces of anyone looking toward the phone. If the software spots someone it doesn’t recognize, it flashes up the message: “Stranger is looking alert!”

In Google’s recently posted demonstration video (below) spotted by Quartz, the researchers have had a bit of fun by adding a stream of Snapchat-inspired rainbow-colored vomit coming from the stranger’s mouth.

According to the video’s introduction, it seems like this may be more of an experimental project, or possibly the seed of an idea that could one day be offered as an option on our phones.

The feature is set to be presented at next week’s Neural Information Processing Systems conference in Long Beach, California, by Google researchers Hee Jung Ryu and Florian Schroff.

The technology can work for a range of “lighting conditions and head poses,” according to the researchers’ notes, and recognizes a face in two milliseconds, so you’ll know pretty darn quick if someone is peering over your shoulder.

A feature like this would come in handy if you’re in a busy place and you’re reading or writing personal messages, or if you’d simply prefer to keep your smartphone display to yourself.

It might work better in some situations than others, though. On a crowded train, for example, a fellow passenger may just glance at your screen simply because it’s human nature to do so. That could result in the alert popping up with annoying regularity, in which case it would prove more useful if it showed after a few seconds once the technology determined that the shoulder surfer is taking a long, lingering look rather than a fleeting one.

With facial recognition technology already well developed and front-facing camera technology improving all the time, we imagine such a feature could be added to most smartphones with little effort, though whether shoulder surfing is enough of a problem that users would find it useful is another question entirely.