Research On A Dome-style Microphone Array For Sound Source Localization

Sound source localization is achieved by using a microphone array to measurethe sound field. With specific localization algorithm, the microphone array could beused to focus the position of sound source by showing acoustic image. This paper isstarted from basic theory of microphone array system for sound source localization.And the main work is as follows:(1) Research of source model is made by designing the mathematical modelabout near-field and far-field sound source. The sound source localization based ontime-delay estimation is studied. Steering beamforming method is also studiedincluding conventional beamforming, MVDR, MUSIC, etc.(2) Research of the array’s parameters in this system is studied, including beampattern, main lobe width and so on. Several beamforming algorithms for some kindsof array were compared in simulation model, and the most optimized formation isachieved. Also, different effect among these algorithms in computational speed andcoherent sound source detection has been compared.(3) A new dome microphone array system has been developed. The hardware isdesigned in a tight complex style with a central box and88front devices, such ashousing structure, fixing structure and internal linking structure. The64-channel dataacquisition is based on a multi-card acquisition system, which worked synchronouslyto achieve a sampling rate of30kS/s. One switching circuit was designed to controlcameras’ power supply and switch the signal, which contains a stable power supplymodule. Software was developed on the LabVIEW environment to perform acousticimaging. The software’s function was enhanced upon an old acoustic imaging systemand optimized for the dome-style microphone array. In this program, there are threemain function modules, which are element coordinate addition program, cameraswitching program and image calibration program.(4) Properties of the dome-style microphone array were tested in hardware andsoftware. Coordinates of each element is measured with correlation detection by pulsesound source and wideband noise. Acoustic imaging frequency range, angularresolution and localization accuracy of the dome-style microphone array have beenmeasured by use of point source, linear source and plate source, which are fantastic.