Multiple Acoustic Source Positioning Systerm Design And Implementation Based On Near Field Acoustic Holography

Noise pullution get great concen because it is one of three major environmental problems. The major method of noise control is reduction of source noise. Sound field visualization has important research value as the tool of noise source identification. This paper will introduce main method of sound field visualization which consisit of sound intensity method, beamforming and near field holography. The conclution about methods help researchs choose suitable agloritm for their application. That can save some time for your program.Based on background of the project and research value, I choose near field holograohy as object of study and do the futher research. The theory and realization of near field holography will be present in this paper. Then I give the flow diagram of planar near field holography and make simulation. Research on Green formula which is the most important part of sound field reconst rution shows that it is closely related with reconstrution frequence and distance between holography planar and reconstrution planar. Then I discuss the influence of distabce and frequence on performance of reconstrution by control various methods and give the suitble value range of distance and frenquence. This study has directive function for the systerm building.The systerm adopt Lab VIEW as platform of software considing of thoery of planar near field holography and image processing technology. After hardware selection, this paper give the basic process of sound field visualization. Then the sound field systerm based on near field holography and Lab VIEW is builded. After that I do experiment of sound field visualization in conditions of single and multiple sound source then analyze the result. Comparing it with simulation, the paper give the influence of distance and frequence on construction result and show the appropriate range of values. As a result, the near field holography is introduced into the systerm of sound field visualization. And the practical application value of near field holography is proved by the process above.In conclution, this paper make a summary of sound field visualization methods and give the appropraite range of distance and frequence value. Finally, a sound field visualization systerm is conducted by Lab VIEW which can improve the efficiency and save the cost. This reseach make a certain contribution for application of near field visualization.