Wi-Fi has freed us from wires, delivering increasingly speedy connectivity to every corner of our homes and workplaces. Wi-Fi can do more than beam data back and forth, though. Scientists from Carnegie Mellon University have shown that an off-the-self Wi-Fi router can not only tell where you are in a room, but it can also determine your body position.
The team didn’t have to spend big to get the hardware for this experiment. All they needed was a pair of entry-level routers that cost about $30 apiece. The routers were set up at opposite ends of a room, and a computer measured 2.4GHz signal transmission between the access points.
The data output from this setup is not the image you see above — for that, researchers had to turn to an AI model called DensePose that estimates body position from 2D photos. The key was applying the model to “feature maps” built from the recorded Wi-Fi signals. After training, the AI can turn that data into the 3D mesh representations you see in the sample images. When superimposed over photographs, the estimation of body position can be eerily accurate.
According to the study (published on the pre-print arXiv server), using Wi-Fi antennas could be much cheaper compared with regular RGB cameras or LIDAR if you need to track people around a space. The researchers use the example of home healthcare, which sometimes requires continuous monitoring of elderly or disabled patients. However, this system still relies on AI to interpret the radio waves, and the environment can impact how those waves travel. The model in the experiment was trained on a single environment, and it’s unclear how easy it would be to adapt that to general surveillance. It also gets confused when there are more than three people in the path of wireless signals or when people are standing in unusual poses the AI hasn’t seen before.
On one level, this technology feels like a privacy nightmare, even if it’s hard to adapt to new surroundings. The cost is so low, and people walking around bathed in wireless signals would never know you’re mapping their movements. However, the team points out this could actually be a boon to privacy. Cameras capture identifiable images, but Wi-Fi signals only generate a human-shaped mesh. This could lead to more privacy-conscious ways to monitor a room for unauthorized entry. You wouldn’t know who’s there, but you could tell where they are and (roughly) what they’re doing.
Now read:
- The FCC Opens Up Spectrum for Faster 6GHz Wi-Fi
- Researchers Build Creepy Drones That Can ‘See’ Other Wi-Fi Devices Through Walls
- MIT Created 2D Material to Convert Wi-Fi into Power
from ExtremeTechExtremeTech https://ift.tt/PHAy3F2
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