Scientists in Germany have demonstrated a startling new form of surveillance: identifying people using nothing more than ordinary WiFi signals. By analyzing how radio waves bounce around a room, researchers can effectively “see” and recognize individuals — even if they are not carrying a device and even if their phone is turned off.
How do they identify a particular person though? I get you could see people as present or not or moving around the room, but it’s insane that they would be able to tell facial features etc.
You can initiate identification post visual contact or before loss of visual contact. As long as tracking is good the identification info can be propagated
The wavelength of a 5 Ghz wifi signal (the highest frequency in common use for wifi) is a little under 6 cm. So as a crude measure, it’s not going to resolve spatial features much smaller than that with much reliability.
I think as a person moves about the waves would get a clearer picture.
A paper from around a decade ago talked about using WiFi to identify key strokes so with large data models we have today I would assume they could get pretty good fidelity on a person. Maybe not enough for “beyond a reasonable doubt” but probably enough where your WiFi company is selling your data on what you do at home
Height and build alone would narrow it down significantly.