Research On Microphone Array Sound Source Localization Algorithms In Digital Hearing Aids

The auditory sense of the patients with hearing impairment can be improved by digital hearing aids,at the same time,it can improve the ability of language communication.Sound source localization is one of the core algorithms in hearing AIDS.This thesis studies the common localization algorithm and puts forwards some improvements.The main work of the thesis includes:Firstly,the principle and key technology of hearing aid are described,including sound source localization,speech enhancement and echo cancellation are described.By analyzing the popular algorithms,ultimately,the paper choose the auditory localization which based on the time delay estimation(TDE)because it is easy to implement.Afterwards,it briefly introduces the basic knowledge of voice signal,reverberation,the model of room impulse response as well as the digital model of speech signal,and the signal model of microphone array is established.Secondly,the generalized cross correlation(GCC)and minimum mean square(LMS)adaptive delay estimation algorithms are studied in depth.In response to the shortcomings of GCC,combined with the second correlation,fine interpolation of correlation peak(FICP),and Hilbert difference method,an improved algorithm is proposed.Simulation results show that the improved algorithm can improve the performance.As the performance of LMS adaptive algorithm decreases rapidly in reverberation environment,the improved algorithm turns the approximation of one-path reverb into the approximation of the two-path reverberation.The simulation results show that the stability and accuracy of the improved algorithm are improved in the case of high noise and reverberation.Finally,the paper briefly introduced geometric model of microphone and sound source,the topological structure of microphones and the model of far and near field.The sound source localization based on time delay estimation is studied in detail.This paper briefly discusses the method of source localization algorithm,and designs the positioning system based on the planar four-element cross array.The time delay estimation in the positioning system is based on the improved generalized cross correlation method,and then the plane four-element cross array is used to realize the positioning.Experimental results show that the system can realize the sound source localization,and the realization is easy.