Research On A New Method Of Sound Source Localization Based On Microphone Array

Target localization has been widely used in military,industrial and civilian fields.Sound source localization technique,which is an important branch of passive target target localization,has been widely studied.With the development of digital signal processing and array signal processing techniques,the sound source localization system based on microphone array has shown full potential in civilian fields,especially in the audio and video conference,security monitoring and intelligent robot positioning with indoor environment.However,there are mainly two problems in the application of sound source localization.One problem is that the existing method has large computational complexity.The other problem is that the sound propagation speed is easily affected by the environment temperature,which affects the real-time performance and positioning accuracy of the sound source localization.In order to solve the problem of the computation complexity,most sound source localization methods adopt numerical methods to calculate the solution.These methods increase the amount of calculation,which is not conducive to the real-time positioning,and cannot avoid manual intervention.In order to solve the problem that the sound propagation speed is easily affected by the environment temperature,some research work has considered the influence of environmental temperature and achieved some progress by using additional temperature sensor,additional sound speed calibration process or complex numerical solution to overcome this influence.These approaches also increase the complexity of the system and is unfavorable for real-time positioning.Therefore,this dissertation studies a new sound source localization method based on microphone array,aiming at solving the metioned two problems of current sound source localization methods.The main works and contributions of this dissertation are as follows:1.A new sound source localization method with microphone array based on the time difference of arrival(TDOA)is proposed.A five-element microphone array is used to establish the sound source localization model by taking the sound velocity as a variable,which avoids the influence of ambient temperature change.The analytical solution approach is proposed to solve the localization problem,which avoids the possible artificial interventions in conventional numerical solution approach.2.To overcome the problem that the analytical solution of the new method is difficult to obtain and simplify the calculation process,the three-dimensional cross structure is proposed by referring to the common microphone array topologys.Three basic configurations are summarized from the three-dimensional cross structure and three corresponding positioning models are established.Based on the models,the analytical solutions of each configuration are derived.Considering the effectiveness of the signal propagation and the complexity of the array installation,two configurations are selected and the rotation rules are provided to be applicable to different array angles.3.A microphone sound source localization system for indoor positioning is developed.The hardware of the system is developed by reasonable microphone selection,array topology design and data acquisition unit design.The software of the system consists of the sound source signal preprocessing module,the delay estimation module and the position calculation module.Performance evaluation experiment is carried out to verify the effectiveness of the system.4.With the two selected configurations,simulation is carried out to obtain the applicable scope and the positioning performance.Practical positioning experiment is then designed accordingly to evaluate the proposed method.Experimental results show that the new proposed method is effective.The practical positioning results are consistent with the simulation results.Compare the two selected configurations,configuration two has better positioning performance,which shows better or comparable positioning accuracy than those under the same positioning scenario in literature.By changing the ambient temperature,positioning experiment is further carried out based on the configuration two to investigate the robustness of the new method to the ambient temperature change.Experimental results show that the new method can effetively overcome the influence of the temperature change.Compared with the method of using default sound velocity,the proposed method has higher source localization accuracy.Compared with the method of using temperature compensation,the new method can achieve the same positioning accuracy,but has the advantage of not requiring additional temperature sensors.