Wireless radio signals can be used to monitor a person’s precise movements through a solid wall, thanks to artificial intelligence. The technology could help us monitor people for health and safety less intrusively—but it also raises a range of security and privacy issues.

X-ray visionary: Dina Katabi, a researcher at MIT, has been developing technology for detecting people and their movements behind a solid wall using radio waves. The approach relies on cutting-edge machine learning to interpret the signals.

Stick figures: Katabi and her students trained an AI system using radio signals and video footage of people moving around. This made it possible to generate stick figures showing what people were doing behind a wall. The system, called RF-Pose, can also distinguish between different people reliably. Here’s their research paper.

Nothing to hide: One idea is to use the system to monitor those who might be at risk of a fall—a sick or elderly person, say. But it isn’t hard to imagine how such a system could be used for surveillance. Speaking at a recent conference, Katabi said her group is taking steps to ensure that the data is only collected with consent and is anonymized. She also suggested that technical countermeasures could be taken to block monitoring.