“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.”
The tech is even far older than the article. I remember seeing this being demo'd at least a decade ago. Though, it looks like the fidelity has improved significantly from the early proof-of-concept videos that were floating around for a while.