A Laser Can Now Use a Keyhole to See Inside a Closed Room

As we descend into a world like the one in Minority Report, it becomes clear that technology is getting too smart. There are clothes that can track where you go and drones that monitor how close you are to others. Now, in an extra creepy technological turn, researchers at Stanford say they can see into a closed room using a laser beam. However, there are tricks to avoid detection by this keyhole laser.

Gizmodo reported on this new “non-line-of-sight” (or NLOS) technique. Its creators refer to it as “keyhole imaging” for short. As its name implies, Keyhole imaging requires a room to have an open keyhole or another tiny hole to work. But if that’s available, the method can reveal completely concealed objects… As long as they’re moving.

An animation of an object shooting a laser into a closed room through a keyhole.

Stanford Computational Imaging Lab

In the video above, the researchers outline how keyhole imaging works. In essence, the researchers use a laser beam coupled with a photon collector (i.e., a camera) to track objects inside a closed room. As the laser beam shoots into a room, it bounces off the walls. This light eventually returns to the photon collector. Depending on how it returns to the photon collector, it presents different arrival signatures. Very much like radar. Or, more appropriately, LiDAR.

There are serious limitations to keyhole imaging, including the fact that target objects can’t be stationary. Much like the T. rex from Jurassic Park, keyhole imagining can only see things that are moving. It seems that the computer algorithms that decipher the light patterns detected by the photon collector need an object to move in order to present an arrival distribution pattern that’s strong enough to observe.

An animation of an object shooting a laser into a closed room that contains a person.

Stanford Computational Imaging Lab

Regardless of the drawbacks, keyhole imagining could be promising for more practical technology. This seems to be the goal of this keyhole laser anyway. For example, the researchers note this tech could be used for autonomous cars or robotic vision. Which, incredibly, already is an everyday technology at this point.

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