Dina Katabi, a professor in MIT’s Department of Electrical Engineering and Computer Science, and graduate student Fadel Adib, used low-power Wi-Fi signals to track human movement behind walls. These researchers have created a new system that could be used in future electronic devices to potentially give people X-ray vision.
The system is radically different from previous efforts, which have used expensive radar technology. Dina Katabi’s system, known as Wi-Vi,(Wi-Fi and Vision) transmits a low-power Wi-Fi signal that reflects off of people and can therefore be used to locate and track them.
Katabi said in a press release; “We wanted to create a device that is low-power, portable and simple enough for anyone to use, to give people the ability to see through walls and closed doors…We had to come up with a technology that could cancel out all these other reflections, and keep only those from the moving human body.”
The newly designed system uses two antennas to transmit the signal and a single receiver to read the waves that return. The signal from the second antenna is the inverse signal of the first one, allowing the two signals to interfere with each other and cancel out. This allows only reflections that change between the two signals, such as reflections from moving objects, to reach the receiver.
“So, if the person moves behind a wall, all reflections from static objects are cancelled out, and the only thing registered by the device is the moving human,” Adib explained.
The researchers strongly believe that this new technology, the Wi-Vi system, can be utilized to aid search-and-rescue teams in finding trapped survivors during natural disasters. It could also be used to help police officers locate criminals hiding in buildings and also help them avoid walking into an ambush.
