Cylinder Near-field Acoustical Holography In Half-space And Its Visualization

Since the early-1980s birth, near field acoustical holography (NAH) has become a powerful tool of the reconstruction of three-dimensional space sound field and noise source separation and identification. It has the widespread prospects for development in the engineering application.This paper has mainly researched on cylinder acoustical holography that is based on the theory of Spatial Transformation of Sound Field. It has made the theory validation to the cylinder acoustical holography's algorithm, and discussed the relationship between the parameter and sound field reconstructed result of cylinder acoustical holography application, given the rationalization of how to set the parameter consequently. In view of the actual condition, this paper paid more attention to the cylinder acoustical holography algorithm in half-free space that is more applied. Regarding half-free space situation, in order to adapt to different situations this article proposed that two kinds of solution ways: the image method and the sound field separating method, and discussed how to select suitable parameter for this two methods when they are used in different conditions. Based on theoretical analysis, this paper has also done the research on simulation and experimentationIn order to show the result of acoustical holography more vividly, this paper developed visualization software of sound field that can be used in analysis of near field acoustical holography. This software can draw many kinds of graphics just like 3D and 2D mesh graphics, vector graphics, contour graphics and so on. It can also realize interactive control to the graph like rotation, zoom, pan, inserting slice by simple operation.