Environmental noise reduction based on speech/non-speech identification for hearing aids

We proposed a very practical and useful noise reduction system that has wide application for hearing impaired persons, such as a sound-gathering system at a lecture hall or conference room. The system uses two basic technologies, a speech/non-speech identification process and a new noise reduction process. A speech/non-speech identification process uses four characteristics of the time and frequency domains of the input signal. In the noise reduction process, frequency weighting function is used for basic spectral subtraction and a loss control algorithm. Various kinds of environmental noise were reduced by this system, which showed excellent performance. Noise is further reduced by using a multi-microphone system as an acoustic noise suppressor. The results of intelligibility tests using persons with hearing loss show excellent noise reduction