Research On Indoor High-precision Sound Source Localization Based On Time-reversal Method

Indoor sound source localization refers to the technology of determining the sound source position through the acoustic signal received by microphones,which is widely used in the video conference,remote monitoring,and indoor robot design.The traditional indoor sound source localization methods only consider the direct sound,and are greatly affected by the background noise.At the same time,the array and algorithm are also complicated,which cause many difficulties to the application.Based on the characteristics of time-reversal method to compensate the multipath effect and adaptive focus,this paper introduces it to indoor sound source localization.Based on the time-reversal method,MUSIC algorithm,and sparse reconstruction algorithm,several indoor sound source localization methods and improvement methods are proposed.First,the establishment of the room impulse response database is introduced,and then simulation and experimental research on different factors are conducted.The main work of this article includes:1)An indoor sound source localization method based on dual-channel spatial impulse response matching is proposedAccording to the focusing principle of time-reversal method,a dual-channel spatial impulse response matching method is proposed.By matching the data received by dualmicrophone with the database to complete the target sound source localization.Firstly,localization precision of experiment in the anechoic chamber is 100%;then factors affecting the localization performance in actual room are studied,including size of sound source,SNR,microphone adapterization range,reverberation time,obstructions,height of sound source,the sound source directivity,different environment,and so on.The results indicate that the method can get good localization accuracy under low SNR and high reverberation environment;when environment changes,it is also robust.For sound source movement,an efficient search algorithm is proposed to ensure good localization precision and accuracy,and reduce the test time;2)Study on the application of meshless Galerkin method in indoor sound field calculationThe meshless Galerkin method is used to simulate the room impulse response.Then sound source signals received by dual-microphone are matched with the database.The localization accuracy is 89%.It shows that it is also feasible to obtain impulse response based on numerical calculation and use dual-channel spatial impulse response matching method to implement sound source localization;in the time-reversal array and time-reversal and l1-norm indoor sound source localization methods,the meshless Galerkin method is used to simulate the impulse response of the room.3)An indoor sound source localization method based on time-reversal microphone arrayTraditional indoor sound source localization methods are greatly affected by noise and reverberation.Time-reversal array method and DORT-MUSIC method based on time-reversal microphone array are proposed.The simulations and experiments on microphone spacing,number of array elements,signal-to-noise ratios,and sound source frequencies are carried out.The results show that the DORT-MUSIC algorithm has higher focusing resolution than the time-reversal method for mid-low frequency sound source.4)An indoor sound source localization method based on time-reversal and l1-norm is proposedSince the sparse signal reconstruction algorithm can obtain better localization performance under low SNR and a small amount of data,and the sparse array can obtain larger aperture compared with the conventional array,it is introduced to localization field.The indoor sound source localization method based on time-reversal and l1-norm is proposed,and the method is simulated and experimentally studied.The simulations are carried out in a normal room,the experiments are carried out in a reverberation room.The localization performance of the method is studied by simulation under signal-to-noise ratios,sound absorption coefficients,and sound source frequencies.The influence of sound sources under different frequencies on the localization performance of the method is studied in the reverberation room.The results show that,compared with the time-reversal array method,this method can obtain better localization performance in the environment of low signal-to-noise ratio and high reverberation for mid-low frequency sound source.