超声检测涂层厚度中小波变换模极大值法的研究

详细信息

Application of Wavelet Transform Modulus Maxima Method in Ultrasonic Thickness Measurement of Coating

摘要: 超声测量涂层厚度时，由于涂层上、下界面超声信号会产生干涉，在时域内难以识别出涂层界面回波。采用Mexh小波进行连续小波变换来分析超声A扫描信号，求其模极大值，并以此作为识别涂层界面反射回波信号的标准。进而可由超声波在其中的传播速率及其两界面反射回波的时间差计算涂层厚度。对铝涂层的金相测量验证了上述超声测厚方法的可行性。
- 薄涂层 /
- 超声检测 /
- 小波变换 /
- 小波变换模极大值
Abstract: In the measurement of coating thickness with UT technique, it is different to identify the reflected interface echoes in the time domain due to the interference of the UT signals from the surface and interface of the coatings. Continuous wavelet transform with Mexh Hat was applied in UT A-signal analysis, the modulus maxima was calculated and adopted as the criteria in the identification of the reflected signal from interface of the coating. The coating thickness was then determined by the UT velocity in the coatings and the time of interface reflected echo. The above measured Al coating thickness was checked with optical microscope analysis of the same coating, satisfying results were achieved.
- Coated thin layer /
- Ultrasonic testing /
- Wavelet transform /
- Wavelet transform modulus maxima

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