Calibration Method And Device For Sound Source Location System Based On Beamforming

Sound source location system based on beamforming method calculates sound field and sound source through signal amplitude and phase difference.It shows acoustic phase image to users,which has been widely used in varies areas,such as manufacturing industry,research institutions,etc.Now all parameters of sound source location system are provide by manufacture factory,which means that there still lacks of unified calibration procedure to measure its technical index and precision.So research on the calibration of sound source location system is an important point that needed to be addressed.Firstly,after studied the beamforming method,working principle of sound source location system product and parameters offered by manufacturers,microphone array characteristics is deeply researched to calibrate sound source location system.Lateral spatial resolution,main side lobe suppression ratio and positioning error are selected as key calibration parameters.Through analyzing pure tone signal correlation,slip frequency and dynamic range,this paper developed a calibration method of sound source location system.To make sure the method is suitable for the system,LabVIEW is used for simulating sound source location system.Then,according to the calibration method and steps,this paper establishes standard calibration system device,including the standard sound source system,signal acquisition and analysis system and control system.Standard sound source system comprises abrupt cross section waveguide and tapered waveguide.The waveguide makes sound source system as a approximate point sound source.Abrupt cross section waveguide is mainly for low frequency signal,whose size is calculated on the principle of sound diffusion in standing wave tube;tapered waveguide is mainly for high frequency signal,whose size is calculated on the hypothesis approximate 1-D plane wave.Acquisition and analysis system uses the Danish B&K PULSE system and microphone.Data processing system is used to realize the real-time analysis results of Visual Studio programming control,read PULSE call.The transmission system is composed of stepping motor,programmable logical controller(PLC)and driver component.Motor controls the standard sound source to realize the calibration through computer,which is mainly for lateral spatial resolution.At last,GFAI and B&K products use the standard equipment to check the calibration method and evaluate uncertainty analysis.The results show that the calibration method and device in this paper can realize the calibration of sound source localization system based on beamforming method.The results also prove that the calibration method is reasonable and correct,also meets the requirements of calibrating and tracing.