基于柱面近场声全息的植物病害胁迫分析

Plant Disease Stress Analysis Based on Cylindrical Near-field Acoustic Holography

为了解植物受病害胁迫时产生声发射信号的分布规律,探寻植物病害程度与声发射位置的关系,利用近场声全息技术,建立了基于空间声场变换的重建模型,给出了重建算法,并利用Matlab软件进行模拟仿真。通过不断调整全息柱面尺寸、测量点间距、重建半径等参数,获取最佳参数配置,并利用窗函数去除混入的高斯噪声。仿真结果显示,可用于指导实际全息检测和定位,实现对植物病害的声发射信号的准确识别与定位。

When plant suffered from disease, the acoustic emission signal released. In order to understand the acoustic emission signal distribution regularities, the relationship between the degree of plant disease and acoustic emission signal＇ s position was analyzed. The near-field acoustic holography based on spatial transformation of sound fields was used for the purpose of reconstruction model. The reconstruction algorithm was given out in order to realize the simulation through Matlab software. The parameters, such as the size of holographic cylindrical, the spacing of measurement points, the holographic radius, the reconstruction radius and so on should be adjusted constantly to obtain the optimal parameters. In view of the impact of environmental noise and acoustic emission signal characteristics, the window function was introduced into ultrasonic frequency signal to obtain the optimum simulation results. It was showed that cylindrical near-field acoustic holography based on spatial transformation of sound fields can be applied for recognition and positioning of acoustic emission signal accurately.