‘Wireless radiation could be used to surveil people without their knowledge or consent, even if they aren’t wearing a “smart” device or holding a cellphone, according to the authors of a new study.

The study authors — engineering faculty members with the Institute for Systems and Computer Engineering, Technology and Science at the University of Porto, Portugal —  posted their report Jan. 24 on the Cornell University open-access research website, arXiv.

The study showcases hardware the authors designed that leveraged ambient wireless radiofrequency (RF) radiation to detect and render a visual image of human activity — such as waving a hand or a person’s breathing rate — with over 90% accuracy.

Their design involved a thin programmable surface — a Reconfigurable Intelligent Surface (RIS) — that communicates with computers and artificial intelligence (AI).

RIS can manipulate and steer Wi-Fi signals in controlled ways, explained Fariha Husain, manager of Children’s Health Defense’s (CHD) Electromagnetic Radiation (EMR) & Wireless Program. “By adjusting how radio waves reflect off this surface, the researchers were able to enhance signal-sensitivity and improve their ability to detect subtle human movements.”

Husain said:

“RIS panels can be strategically placed to optimize wireless signal reflection and steering and may take any shape or be integrated into objects. Indoors, they can be mounted on walls, ceilings or furniture.

“Outdoors and in urban areas, they can be installed on offices, airports, shopping centers, lampposts and advertising billboards. Additionally, RIS panels will enable smart city surveillance by tracking pedestrian and vehicle movement.”