We’ve become accustomed to tapping and swiping our smartphones, but what if you could control devices in your home or office with gestures made from wherever you’re standing? WiSee, a technology developed by University of Washington computer scientists, can recognize gestures by analyzing how specific body motions disrupt Wi-Fi signals — no special sensors or cameras are necessary. The overall effect is a lot like the Xbox Kinect, which relies on cameras and thus works only in a single room.
“This is repurposing wireless signals that already exist in new ways,” said lead researcher Shyam Gollakota, a UW assistant professor of computer science and engineering. “You can actually use wireless for gesture recognition without needing to deploy more sensors.”
The UW researchers created a special receiver that listens to the Wi-Fi signals from all the devices in the home, and looks at the minute Doppler shifts and multi-path distortions that result from human movement within the environment. Using the MIMO (multiple-input and multiple-output) technology inherent to 802.11n, WiSee can differentiate among up to five people within the space. Since you wouldn’t want random movements to be interpreted as gestures, WiSee requires a trigger gesture, after which it watches only that person, presumably until a timer elapses or someone else takes control. The trigger gesture could also serve as a password of sorts. At the moment, only a single device can be controlled at a time, though the researchers are looking at how to control multiple devices simultaneously.
In testing in a two-bedroom apartment and an office environment, WiSee was able to identify nine whole-body gestures with an average accuracy rate of 94 percent (the accuracy rate for random guesses is only 11 percent). False positives — unintentional movements that were interpreted as gestures — happened roughly 2.5 times per hour when two gestural repetitions were required; increasing the necessary repetitions to four essentially eliminated false positives (0.07 events per hour). See “Whole-Home Gesture Recognition Using Wireless Signals” (PDF) for the full paper.
Although WiSee’s proof-of-concept requires a special receiver, the researchers say that the necessary technology could be embedded in consumer-level wireless access points. Also, the paper and demo video say nothing about how WiSee controls things like music volume, television station, and the like — although such hand-waving (hah!) is understandable in a proof-of-concept, a real-world system would have to come up with a coherent method of controlling a potentially wide variety of devices and applications. That’s not impossible, but it is a non-trivial problem.