“We developed a deep neural network that maps the phase and amplitude of WiFi signals to UV coordinates within 24 human regions. The results of the study reveal that our model can estimate the dense pose of multiple subjects, with comparable performance to image-based approaches, by utilizing WiFi signals as the only input.”
I heard that they can analyze window glass to get audio recordings because as a slow moving liquid, vibrations in the air leave an imprint on the glass.
The "glass is a liquid" thing is a myth. The reason why old windows tended to be thicker at the bottom (which is usually the cited reason for this myth) is because windowpane making techniques weren't very good and so they would always have one thicker side. The builders would naturally install the pane with that side on the bottom because it was more stable. Glass doesn't "flow" over time, it's a solid crystallineamorphous material.
They bounce a laser off the glass and can hear what's happening in the room by capturing the vibrations of the glass. I seem to remember the US embassy was caught spying on the Canadian Prime Minister using this technique.
MIT used a high speed camera to reconstruct sound vibrations from objects behind soundproof glass, such as a bag of chips, water in a glass, and a plant. That was in 2014.
Yep I have read that sensitive buildings are now built with a hallway ringing the building and offices further inside, so the rooms where classified things are discussed don't have windows accessible by outside lasers.
Yes that's possible and it has some years but there's some conditions. The glass needs to have a sticker onto it for the trick AFAIK is to reflect a laser or infrared light onto it and track the less than milimétric vibrations of it and depending on where is the sticker and how big is the window it affects the quality of the recording.
Given this wifi trick I think it would have to do with signals not passing through water clearly or some thing on the likes and more over it should need some specific equipment to pull out the trick, I don't imagine you could just hack a router and patch surveillance in the firmware.