Credit: Christine Daniloff/MIT

An illustration of Wi-Vi, a technology that "sees" people through walls. 

A project developed by MIT’s Computer Science and Artificial Intelligence Laboratory has the potential to subvert common assumptions about privacy in the physical environment. Electrical engineering professor Dina Katabi and her research team have created a system called "Wi-Vi"—short for Wireless Vision and based on the acronym for Wireless Fidelity (Wi-Fi)—to enable vision through walls, closed doors, and other opaque building surfaces. In particular, the system is designed to track the presence and movements of people in buildings.

The system tracks Wi-Fi signals that penetrate walls and other physical obstructions, locating people by tracking reflections and eliminating information related to inanimate objects. "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," said professor Katabi in an MIT press release. "So 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… So, if [a] person moves behind the wall, all reflections from static objects are cancelled out, and the only thing registered by the device is the moving human."

Katabi and her team anticipate the use of Wi-Vi by first responders in rescue missions, in addition to security and gaming applications. Not surprisingly, the technology has detractors who fear a significant loss of personal privacy, adding further "Big Brother" capabilities to governments and private organizations that currently monitor networks of security cameras. The technology's importance in saving lives during post-disaster emergencies may trump these concerns, however. Moreover, in the inevitable escalation of technological complexity, tools that block Wi-Vi tracking in high-security environments—and perhaps even family homes—will likewise be developed in response.

Blaine Brownell, AIA, is a regularly featured columnist whose stories appear on this website each week. His views and conclusions are not necessarily those of ARCHITECT magazine nor of the American Institute of Architects.