Robots can use Wi-Fi for x-ray vision.

Receiving a Wi-Fi signal through a couple of thick walls is often a headache, but researchers are trying to extract the best from the weakness of the signal, writes The Verge. By measuring signal strength, researchers at the University of California, Santa Barbara have figured out a way to use Wi-Fi to see through walls.

Their method works when there are two autonomous robots moving around an unknown structure, while one sends a signal to another. As a result, robots will be able to collect enough data about where the signal is strong and where it is weak to build a two-dimensional picture of what they are looking at.

In the video, researchers use a hollow square of bricks with a pillar in the middle as an example of how this can work. At first, robots perceive the pole as an entire wall, but as the scanning continues, it becomes clear that there is empty space around the column.
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The final image of robots is certainly far from clear, but accurate enough to get a pretty good understanding of the structure. And while the video shows the movement of robots in a very organized way around a simple object, the researchers suggest that a more random route may allow them to also work effectively where there are obstacles to their movement.