U Ideas of General Interest --April 2001University of Illinois at Urbana-Champaign
Contact: James E. Kloeppel, Physical Sciences Editor (217) 244-1073; [email protected]
TECHNOLOGYLicense agreement signed to commercialize intelligent hearing aid
CHAMPAIGN, Ill. --For someone with partial hearing loss, picking out a voice in a crowded social gathering can be hard, even with the help of a hearing aid. That's about to change in a revolutionary way.
Scientists at the University of Illinois recently signed an exclusive licensing agreement with Phonak Inc., a leading manufacturer of technologically advanced hearing aids, to commercialize an intelligent hearing aid system. The new hearing-aid technology will be able to spatially separate sounds and process them in a way much like the human brain. A key feature of the new system is its ability to integrate signals from each ear so that a listener can focus on a desired voice while canceling out background noise.
The concept for the intelligent hearing aid was developed by a team of 12 researchers at the university's Beckman Institute for Advanced Science and Technology. Professors from the departments of physiology, electrical and computer engineering, and speech and hearing science contributed to the work.
"Today's state-of-the-art hearing aids can select a voice in a crowd by applying highly directive microphones," said Albert Feng, a UI professor of molecular and integrative physiology and leader of the Beckman team. "However, these devices cannot effectively differentiate between background noise and the desired conversation when the sources are in close proximity, causing confusion in noisy environments."
By allowing the wearer to focus on a single conversation without excessive interference, the intelligent hearing aid will represent a significant improvement over conventional systems, Feng said.
The intelligent hearing aid prototype consists of a pair of miniature microphones, a processor, an amplifier and two earpieces. At the heart of the system is what is called a Binaurally based Intelligent Auditory Processor, which filters the sounds and transmits only the desired voice to the amplifier. The processor works by comparing signals from the microphones and detecting subtle differences in their time of arrival -- much like the process that occurs in the human brain.
"Normal hearing exploits the fact that we have two ears," said Doug Jones, a UI professor of electrical and computer engineering and a member of the Beckman team. "Our brains utilize both the time of arrival and the intensity of impinging sound waves to perform spatial processing and filtering. This allows us to focus our attention in the direction of the desired sounds and ignore the rest."
To perform this process artificially, the researchers developed an efficient algorithm capable of extracting the desired speech signal in the presence of multiple interfering sounds. Using the algorithm, they built a prototype that works in real time and performs very well in noisy environments.
"The algorithm mimics the biological system to perform auditory scene analysis and to reproduce how the brain selects and filters information," Jones said. "By pointing the microphones at the desired source, we can capture the intended signal and filter out all others."
Phonak engineers and UI researchers are now working to package the prototype into a miniature, self-contained system. Phonak is headquartered in Stafa, Switzerland.
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