A new technology developed at Duke University uses metamaterials and compressive sensing to determine the direction of a sound and extract it from the surrounding background noise. Once miniaturized, the device could have applications in hearing aids, cochlear implants, and ultrasound medical sensors.
The proof-of-concept device resembles a thick, plastic, pie-shaped honeycomb split into dozens of slices. The depth of the honeycomb openings varies from hole to hole. Each slice of the honeycomb "pie" has a unique pattern.
The cavities distort a sound wave as it approaches the device. The distortion has a specific signature depending on what particular slice has been passed over. After being picked up by a microphone on the other side, the sound is transmitted to a computer that is able to separate the jumble of noises based on the unique distortions.
The researchers tested their invention in multiple trials by simultaneously sending three identical sounds at the sensor from three different directions. The technology was able to distinguish between the sounds with a 96.7 percent accuracy rate.
While the prototype is six inches wide, the researchers believe it could be scaled down and incorporated into medical imaging tools. The device could also improve the sound fidelity and increase functionalities for applications like hearing aids and cochlear implants.
