Efficacy of a Wiener Filter Based Technique for Speech Enhancement in Hearing Aids

Abstract

Hearing aid is the most fundamental technology employed towards rehabilitation of persons with sensory neuralhearing impairment. Hearing in noise is still a matter of major concern for many hearing aid users and thus continues to be achallenging issue for the hearing aid designers. Several techniques are being currently used to enhance the speech at thehearing aid output. Most of these techniques, when implemented, result in reduction of intelligibility of the speech signal. Thusthe dissatisfaction of the hearing aid user towards comprehending the desired speech amidst noise is prevailing. MultichannelWiener Filter is widely implemented in binaural hearing aid technology for noise reduction. In this study, Wiener filter basednoise reduction approach is experimented for a single microphone based hearing aid set up. This method checks the status ofthe input speech signal in each frequency band and then selects the relevant noise reduction procedure. Results showed thatthe Wiener filter based algorithm is capable of enhancing speech even when the input acoustic signal has a very low Signal toNoise Ratio (SNR). Performance of the algorithm was compared with other similar algorithms on the basis of improvement inintelligibility and SNR of the output, at different SNR levels of the input speech. Wiener filter based algorithm providedsignificant improvement in SNR and intelligibility compared to other techniques