Research On Sound Field Reconstruction Based On Parallel Beam And Sector Beam Scanning

The traditional acoustic field reconstruction method is microphone array method,however,the volume of microphone limits the resolution of acoustic field reconstruction,and the microphone belongs to contact measurement,which will affect its characteristics when immersed in sound field.The optical method can overcome this problem,the laser beam can be very narrow,the resolution of the optical reconstruction image is better than the traditional method,and it is a non-invasive measurement method,it will not change the characteristics of the sound field.In some extreme environments,such as high temperature and high pressure,the measurement of microphone will be distorted,but the laser itself will not be disturbed by these factors.Therefore,it has many advantages in the field of sound field measurement and reconstruction,and many researchers have explored its physical effect,reconstruction algorithm and practical application expansion.On the basis of previous studies,this paper mainly carried out the following work:(1)A sound pressure measurement system based on single beam laser is built.The measurement results of optical method and microphone method are compared,the frequency band range of optical method is determined.The influence factors such as the vibration of reflector in the experiment are analyzed and the uncertainty of measurement is evaluated.(2)A sound field scanning method based on Radon inverse transform is presented,and then the air sound field is reconstructed by parallel beam scanning.In the experiment,the sound field reconstruction of conical loudspeaker,square sound source and dipolar sound source are carried out respectively.The effects of sound source frequency and reconstruction resolution on sound field reconstruction image artifact are analyzed.(3)A sound field reconstruction system based on scanning laser vibrometer is established,and the fan beam scanning method is used to reconstruct the air sound field.In the experiment,the sound field reconstruction of conical loudspeaker is completed by the data rearrangement algorithm of sector reconstruction and the reconstruction results are analyzed.The noise reduction algorithm is used to optimize the reconstructed image.