摘要：超声检测是在疾病的治疗、交通运输、工业等方面被广泛使用。论文研究了电磁超声检测技术原理，通过Ansoft maxwell仿真软件对金属导体下的涡流场进行了仿真。针对电磁超声检测信号幅值小、信噪比低的缺点，用小波变换对信号进行消噪处理，然后用希尔伯特变换提取信号包络并对处理后的数据进行超声成像,该方法通过Matlab仿真验证。

 

 

关键词:电磁超声检测，涡流场，小波变换，希尔伯特变换

目   录

 

1 前言·······················································5

1.1 课题研究的背景及意义·····································5

1.2 国内外研究现状···········································5

1.3 本节研究内容·············································6

2 电磁超声检测基本工作原理···································6

2.1 电磁超声换能原理·········································6

2.2 电磁场和超声波场分析·····································7

2.3 电磁超声有限元仿真·······································9

3 信号处理··················································13

3.1 小波变换理论············································13

3.2 小波分解信号和去噪原理的分析····························14

3.3 小波变换在matlab中的仿真·······························15

3.4 希尔伯特变换求包络原理··································19

3.5 希尔伯特变换求包络仿真··································20

结论························································25

参考文献····················································26

致谢························································28