The URLs [1] [2] describe the content. I thought [1] was interesting but not answering your question. [2] Answers your question, and shows black and white and thermal pictures.
[EDIT] I stand corrected, [2] is unrelated. My bad! Here's some good sources as alternative.
"MIT turns Wi-Fi Into Indoor GPS
New tech from CSAIL lab lets one Wi-Fi device locate another to within centimeters" [3]
"RF-Capture: Capturing the Human Figure
Through a Wall
It can know who the person behind a wall is.
It can trace a person's handwriting in air from behind a wall.
It can determine how a person behind a wall is moving." [4]
[1] https://www.medgadget.com/2014/06/mits-wifi-system-detects-p... (June 2014)
[2] https://hackaday.io/project/5452-wifi-thermal-camera (2015)
[EDIT] I stand corrected, [2] is unrelated. My bad! Here's some good sources as alternative.
"MIT turns Wi-Fi Into Indoor GPS New tech from CSAIL lab lets one Wi-Fi device locate another to within centimeters" [3]
"RF-Capture: Capturing the Human Figure Through a Wall
It can know who the person behind a wall is. It can trace a person's handwriting in air from behind a wall. It can determine how a person behind a wall is moving." [4]
They also contain further resources.
[3] https://spectrum.ieee.org/tech-talk/telecom/wireless/mit-tur...
[4] http://rfcapture.csail.mit.edu/