Study On Filter-and-sum Beamforming Sound Source Identification Algorithm For Spherical Microphone Array

The sound source identification based on microphone array beamforming technology is simple and fast to fulfill,as well as its resolution in high frequency is good.Among the array,solid spherical microphone array has the advantages of good rotation symmetry,steady numerical stability and diffraction ability.Furthermore,it can not only records the whole sound field information and images the 3-D acoustic environment,but also provides isotropic directionality.Therefore,it has been widely applied in many interior sound source identification fields such as automobile and high-speed rail.This paper studied on the filter and sum beamforming algorithm for sound source identification by spherical microphone array.Firstly,the paper gave out the sound pressure function expression for plane wave and spherical wave respectively,and spherical harmonics angularly resolved pressure algorithm based on single monopole point source was studied.Secondly,a second order cone programming optimum filter model was constructed,taking the minimum of the maximum sidelobe as the objective and the mainlobe peak of sound pressure contribution without distortion as the constraint.The CVX convex optimization solver was used to obtain the filter parameters then,and spherical microphone array beamforming filter-and-sum algorithm which outputs pressure contribution was proposed.Thirdly,performance simulations of sound source identification were carried out by the software MATLAB for the rigid spherical microphone array with 36 channels.Lastly,the test in acoustic room was implemented to verify the correction of the algorithm.Both of simulation analysis and experiment showed that the algorithm can quantify the acoustic contribution by pressure contribution from source to target,and the accuracy was almost independent of the focusing distance.Furthermore,it had excellent sidelobe suppression performance and good spatial resolution.