The Design And Implementation Of Sound Source Localization System Based On Small Size Microphone Array

Sound source localization(SSL) based on microphone array is an important branch of audio processing, and has been widely used in video conferencing systems, car phones and guns localization systems, etc. There has been two kinds of microphone arrays: large-scale array and small-scale array. The thesis aimed at designing and realizing an indoor and real-time SSL system using small microphone array.Time delay estimation(TDE) technology is a mainstream SSL technology, and has been widely used because of its simple principle and easy realization. In SSL systems based on TDE, SSL is divided into two phases: TDE and localization, SSL result is closely realted to these two: TDE error would be magnified during localization because of the geometric characteristic of hyperboloid, which wound result in lower localization success rate and larger localization error.During the stage of TDE, the issue reserched some common TDE methods, some optimal methods was proposed, including TDE interpolation, TDE filtering and TDE compensation, and AED algorithm, which is one of the TDE methods, was improved to raise TDE success rate and precision. In the stage of localization, localization algorithm based on TDE redundancy was proposed, according to the shortcomings of traditional geometric positioning algorithm in near field. Besides, the hardware platform of SSL system was built using data acquisition card(DAQ) and microphone module, which is designed in the issue; the preprocess technology of captured acoustic signal was researched and implemented; a new effective frame detection strategy for the sound of clapping was also proposed. At last SRP-PHAT was reserched and realized on simulated platform, and its feasibility was verified.The thesis adopted 4-element cross microphone array, whose radius is 25 cm, taking full advantage of the 40 k Hz sample rate of DAQ, combined with improved and optimal methods proposed above, finally realized an indoor real-time SSL system. Several comparison experiments were performed, and the results proved the advantages of those proposed methods. Experiment results showed that the SSL system could acquire high azimuth estimation precision, distance estimation was also proved effective except some special areas, and the SSL system was able to meet the requirement of instantaneity in most cases.