Objective Evaluation Method Of Sound Source Localization Ability Of Hearing Aids

The hearing aid is a kind of medical equipment can be effective in the treatment of ear hearing loss,on hearing compensation can solve the human ear play a significant role.With the constantly develop of innovation for hearing technology,hearing aids become miniaturized,digital,intelligent and with sound source localization.The sound source localization performance directly affects the recognition of voice range of users,and even affects the user’s physical and mental health;therefore,people have been study the human auditory system and hope to help people with hearing disabilities.Sound source localization is one of the key technologies.In order to help the deaf people select the appropriate of hearing aid;we need a complete objective evaluation program of sound source localization performance for hearing aids.In this paper,an objective evaluation method of sound source localization is improved,and a method for evaluating the performance of sound source localization of hearing aids is proposed.The scheme consists of an audio acquisition module,an algorithm improvement module and an calculation module.The method can effectively evaluate the sound source positioning function of the hearing aid.The main work includes the four aspects:(1)The thesis studies the principle of binaural source localization in details,and discusses the localization cue and Head Related Transfer Function(HRTF),Localization cue includes Interaural Time Difference(ITD)and Interaural Level Difference(ILD),the paper utilizes ITD to locate source,and use the ILD to detect the trend of sound source location.Last we calculate the localization results by the HRTF database from MIT lab.(2)We build the experimental system;and use standard pure tone and Chinese speech,according to the 1/3 octave,we use the 16 frequency bands from 200 Hz to 6300 Hz and each audio is 10s;The Chinese speech is 60s;We build the circular source array,speakers from different angles to simulate the actual sound source environment;implement the current index calculation based on MATLAB.(3)In the field of hearing aids,the existing algorithm have shortcomings and we need to detect the small phase difference of binaural signal,So we improved the existing algorithm.Finally,experiment show that the method is accurate.(4)We use the existing algorithm and the improved algorithms for pure tone and speech to experiment;we can get the ITD and ILD.(4)Select hearing aids of high,medium and low grades under the same brand as test samples,according to the proposed method in the paper,a set of objective comparative experiment are done,by analysis,the trend of indicators calculated is consistent with the prices of hearing aids,so the proposed scheme is effective and feasible.