| dc.description.abstract | The purpose of this research is to develop a software-based simulation platform for hearing aid. In this thesis, the main focus was on the microphone processing strategy for hearing aid. This study provides a software-based simulation platform for hearing aid, as an assistive tool, for the hearing impaired and clinician to experience hearing aid function and choose appropriate hearing aid. The platform contains microphone strategy, noise reduction, and wide dynamic range compression (WDRC). In this study, microphone processing strategies from four different hearing aid companies were simulated based on the patent literature of GN ReSound (Canta), Sonic Inovation (Natura), Siemens (Aktiengesellschaft), and Oticon (Syncro) to allow users to experience different hearing aid company’’s strategies. Through subjective quality evaluation (waveform, spectrogram, listening) as well as objective quality evaluation (average SNR, log-spectral distance) to assess the microphone strategy, noise reduction strategy combining with microphone strategy of noise elimination performance. For comparison purpose, another commonly used microphones strategy, known as Griffiths-Jim Beamformer Algorithm, was also simulated. In the subjective evaluation, we found that the speech waveform and formant frequencies of the speech spectrogram become clear, and the the voice quality by listening to the sound was better. In addition, through the objective assessment, we found that microphone processing strategies from four hearing-aid companies have effectively enhanced the microphone signal to noise ratio of 4 to 6 dB and the Griffiths-Jim Beamformer strategy improved microphone signal 3 to 4 dB. Furthere improvements of SNRs were shown after we combined four microphone processing strategies and the Griffiths-Jim Beamformer microphone strategy with respective noise reduction strategies from different companies, and the WDRC.
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