The ability to passively track people within a given space is every retailer's dream (and every conspiracy theorist's nightmare). Those dreams recently took a step closer to reality with the debut of a new people-tracking system from MIT.

Unveiled at MIT's Computer Science and Artificial Laboratory (CSAIL), the system works much like Microsoft's popular Kinect motion-tracking accessory in that both systems are capable of following a human target's location throughout a room without the need for the subject to hold a transmitter. The Kinect is currently far more precise that MIT's prototype, able to track multiple targets and even read lips from across a room, but the MIT device has the advantage of being able to track people on the other side of walls.

The MIT system utilizes three radio antennas pointed at a wall and spaced about a meter apart. In this case, the wall is an interior one dividing the two MIT offices where the system was developed. The system uses these antennas to triangulate the position of a single subject on the other side of the wall, displaying their location as a red dot on the system's monitor to within just 10 cm.

This is especially impressive since, as MIT Ph.D candidate, Fadel Adib, explained to IT World, "What we're doing here is localization through a wall without requiring you to hold any transmitter or receiver [and] simply by using reflections off a human body. What is impressive is that our accuracy is higher than even state of the art Wi-Fi localization."

The system does have a number of hurdles to clear before researchers can hope to bring the technology to market, the first of which is the system's inability to track more than one person as more than a single point in space. Currently researchers must stand at least a meter outside of either room to prevent interference. Oddly, multiple subjects can stand in the monitored room, they just have to stand very still so as not to confuse the machine. The team hopes to improve the system's tracking ability to handle multiple targets and display them at least as silhouettes, as current Kinects do, within the next few software iterations. The table-top sized device will also, of course, have to be shrunk and optimized for mass production.

The MIT researchers believe that a commercial version of the technology could find a home in retail establishments where they could track how many people stop for how long at which displays or in senior care facilities where they would track residents and alert staff if anyone falls down or stops moving for an extended period. "We now have an initial algorithm that can tell us if a person is just standing and breathing," Adib said. And in the home, it could theoretically be utilized as a security monitor. Just better hope that only one guy breaks in. [PC World - IT World]