The Research On Sound Localization And Loudness Compensation Of Digital Hearing Aids

Hearing compensation is the main role of digital hearing aids for hearing-impaired patients.Sound source localization and loudness compensation are the key technologies which affect theperformance of digital hearing aids. After studied the traditional algorithms of sound sourcelocalization and loudness compensation, in this paper some further research and improve thealgorithms are carried out. The main work is as follows:Firstly, with preliminary study of the traditional sound source localization technology, the paperfocuses on time delay estimation algorithm and puts forward a new method. In a condition withnoise, the method uses wavelet threshold for denoising to eliminate the impact of noise throughspectral subtraction.The simulation results show that the method combines the advantages of twomethods, greatly enhances the noise immunity of the system and improves the accuracy of timedelay estimation.Secondly, loudness compensation method is studied in wavelet domain. The noise is amplifiedduring the loudness compensation, which exists in digital hearing aids. In order to reduce theinfluence, the preprocessing is usually taken to eliminate noise before loudness compensation. Inthis paper, deep research on loudness compensation based on wavelet thresholding denoisingmethod is conducted, without adding any pretreatment, which amplifies the coefficients whichrepresent the signal by setting the appropriate threshold and reduces the impact of noise at the sametime of loudness compensation.Thirdly, loudness compensation of digital hearing aids is further researched. Most of thealgorithm ignore the fact that high frequency part of the speech is often serious compressed andamplified. This method leads to reduce hearing comfort, even makes negative influence. In order toincrease voice recognition rate, freqence shift will be applied to loudness compensation. Themothod not only achieves the goal of compensation but also effectively reduces the negativeinfluence of loudness compensation, thereby increasing the speech recognition of hearing-impairedpatients.