Technology is everywhere, and pretty soon you won’t be able to hide from it.
Researchers at the Massachusetts Institute of Technology (MIT) Computer Science and Artificial Intelligence Lab are developing 3D motion-tracking technology that can see through walls.
The system, WiTrack, senses the motion of a person through radio signals reflecting off their body to pinpoint location and movement. The system uses one antenna to transmit signals and three antennas to receive signals. A geometric model of a person’s location is built by the signals between antennas, using reflections off a person’s body to calculate the distance between the antennas and the person.
WiTrack stemmed from a previous MIT project, WiVi. WiVi was a system developed by Dina Katabi, a professor of computer science, and Fadel Adib, a graduate student, that detected humans through walls using WiFi signals. The problem with WiVi was that it didn’t provide exact locations. Based on WiVi, Adib and Katabi developed WiTrack in collaboration with Rob Miller, a professor of computer science and engineering, and Zach Kabelac, a graduate student. In comparison to WiVi, WiTrack is able to locate motion with significantly higher accuracy.
“Because of the limited bandwidth, you cannot get very high location accuracy using WiFi signals,” said Adib. “WiTrack transmits a very low-power radio signal, 100x smaller than WiFi and 1,000x smaller than what your cellphone can transmit. But the signal is structured in a particular way to measure the time from when the signal was transmitted until the reflections come back. WiTrack has a geometric model that maps reflection delays to the exact location of the person. The model can also eliminate reflections off walls and furniture to allow us to focus on tracking human motion.”
With WiTrack, a whole new form of gaming and virtual reality could be possible.
“Today, if you are playing a game with the Xbox Kinect or Nintendo Wii, you have to stand right in front of your gaming console, which limits the types of games you can play,” said Katabi. “Imagine playing an interactive video game that transforms your entire home into a virtual world. The game console tracks you as you run down real hallways away from video game enemies, or as you hide from other players behind couches and walls. This is what WiTrack can bring to video gaming.”