OKI (TOKYO:6703) has developed an ambient voice suppressor (AVS) technology that accurately extracts voice periods and suppresses noise, and a compact sound source separation (SSS) microphone module based on this technology. Achieving significant improvements in separating and extracting the speaker's voice from surrounding noise, the AVS technology makes possible stress-free communications via smartphones and other mobile devices in noisy environments, such as exhibition halls, inside vehicles, train stations, and so on.

Smartphones have grown increasingly popular in recent years and are often used in hands-free for teleconferencing or other purposes, as well as for ordinary phone calls. When a mobile phone is used for hands-free calls in noisy public locations, the phone's microphone might pick up surrounding voices and background noise, generating howling or degrading speech communication quality.

"To counter these problems, OKI has developed AVS technology based on many years of research on sound source separation.^1" says Takeshi Kamijoh, General Manager of Research and Development Center at OKI. "AVS technology uses multiple microphones to suppress surrounding voices and background noise. In the verification test using a newly-developed compact SSS microphone module in which AVS is embedded, we confirmed that the technology provides improved clarity in noisy environments (bus terminals and train platforms)."

OKI plans to promote the use of compact SSS microphone modules and sound source separation software featuring the AVS technology in information communication devices and continue to develop for further applications.

Some developments related to AVS were based on the joint development with Professor Tetsunori Kobayashi, Waseda University.

Features of the compact SSS microphone module incorporating AVS
1. Improved voice call quality
The technology improves the clarity of the speaker's voice by suppressing background noise and surrounding voices in noisy environments. Sound diffraction occurred by hands-free conversations under extremely noisy conditions often generates howling. The AVS suppresses diffracted sound components, which eliminate howling and ensure clear voice communication.

The AVS technology can improve not only mobile devices like smartphones, but also various other products with voice communication functions such as intercoms and videoconferencing systems, etc. The compact SSS microphone module is also suitable for ATMs, ticket-vending machines, and other technology incorporating voice communication functions.

2. Preventing speech recognition system from false recognition
Many of today's smartphones and car-mounted navigation systems have voice search functions with speech recognition technologies. In noisy locations, these functions might erroneously respond to not the user-speaker's voice but others. Under these conditions, the compact SSS microphone module suppresses surrounding voices and prevents the speech recognition system from false recognition.

[Glossary]
¹ Sound source separation
A technology that extracts just the target sound source from a mixed sound including multiple-source sounds and various background noises.

About OKI Electric Industry (OKI)
Founded in 1881, OKI Electric Industry is Japan's leading telecommunications manufacturer in the Info-telecom field. Headquartered in Tokyo, Japan, OKI provides top-quality products, technologies, and solutions to customers through its info-telecom systems and printer operations. Its various business divisions function synergistically to bring to market exciting new products and technologies that meet a wide range of customer needs in various sectors. Visit OKI's global website at http://www.oki.com/.

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