Recent technological advancements have allowed drones to use WiFi signals to see through walls.
The University of California Santa Barbara research team were able to create three-dimensional images of the objects that were behind a brick wall in a series of experiments with a pair of drones.
The two drones simultaneously work together to transmit data. They would each fly around four sided walls of a brick building conducting scans.
A single drone is responsible for the transmition of a continuous Wi-Fi signal, while the other, on the opposite side of the house, measures its power after it passes through.
By circumnavigating the house several times, the drones can produce incredibly high-resolution and accurate 3D images of the objects inside the walls.
Yasamin Mostofi, a professor of electrical and computer engineering at USB, stated that, “Our proposed approach has enabled unmanned aerial vehicles to image details through walls in 3D with only Wi-Fi signals. This approach utilises only Wi-Fi RSSI [received signal strength indicator] measurements, does not require any prior measurements in the area of interest and does not need objects to move to be imaged."
Such advanced techniques could have applications for search-and-rescue, archaeology or monitoring unstable buildings. Real life implications for what would otherwise be an impossible scenario.
Dated technology has already been able to use Wi-Fi signals to create 3D images, including in one recent paper from the Technical University of Munich.
“Of course, this raises privacy questions,” said Friedemann Reinhard, the leader of that project. “After all, to a certain degree even encrypted signals transmit an image of their surroundings to the outside world. However, it is rather unlikely that this process will be used for the view into foreign bedrooms in the near future. For that, you would need to go around the building with a large antenna, which would hardly go unnoticed.”
It's expected the military could benefit as well from these technological achievements, with the ability to conduct safe covert reconnaissance missions.
FreeSense, a software developed by Chinese researchers, is able to accurately identify individuals based on their body shape and the way they walk. Combined with the drones, this could be a powerful tool.
Mostofi stated it could be a long time before such technologies are available in your home however, stating, “Enabling 3D through-wall imaging of real areas is considerably more challenging due to the considerable increase in the number of unknowns.”
In real world scenarios there are millions of signals constantly bouncing around so in a residential neighborhood or business application there would be great interference.