Glasses use sonar, AI to interpret upper body poses in 3D

A variation of sonar technology – in miniature form, developed by Cornell University researchers – is proving a game-changer in wearable body-sensing technology.

PoseSonic consists of off-the-shelf eyeglasses outfitted with micro sonar that can track the wearer’s upper body movements in 3D through a combination of inaudible soundwaves and artificial intelligence. With further development, researchers believe it could enhance augmented reality and virtual reality and track detailed physical and behavioral data for personal health.

“We’re the first research group using inaudible acoustics and AI to track body poses through a wearable device,” said Cheng Zhang, assistant professor of information science. “By integrating cutting-edge AI into low-power, low-cost and privacy-conscious acoustic sensing systems, we use less instrumentation on the body, which is more practical, and battery performance is significantly better for everyday use.”

PoseSonic has two pairs of tiny microphones and speakers – each about the diameter of a pencil – attached to the hinges of eyeglasses. The speakers emit inaudible soundwaves that bounce off the upper body and back up to the microphones, generating an echo profile image. This image is then fed into PoseSonic’s machine learning algorithm, which estimates the body pose with near-perfect accuracy. And unlike other data-driven, wearable pose-tracking systems, PoseSonic functions well without an initial training session with the user, the researchers said.

The system can estimate body movements made at nine body joints, including the shoulders, elbows, wrists, hips and nose, which is useful to estimate head positioning, researchers said.

The technology is a major step up from existing wearable devices that often require a mini video camera, which isn’t always practical. Current wearables with video cameras also require significant battery power, the researchers said. Acoustic sensing requires minimal power – 10 times less than a wearable camera. Because of this, the technology makes for a much smaller and unobtrusive wearable, researchers said.

Further, they added, there’s much less privacy risk with sonar.

“A wearable video camera poses privacy risks for anyone in the wearer’s vicinity,” said Saif Mahmud, a doctoral student in the field of information science. “Our solution: Let’s put a little inaudible acoustic field around us that can track our body’s movement while also respecting other people’s privacy.”

This research is supported by the National Science Foundation.

For additional information, see this Cornell Chronicle story.

Cornell University has dedicated television and audio studios available for media interviews.

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