基于Hilbert-Huang变换的管道超声检测信号处理

Pipeline Ultrasonic Testing Signal Processing Based on Hilbert-Huang Transform

针对利用快速傅里叶变换法处理管道超声检测信号的转换精度不高、容易误判等问题,提出了基于Hilbert-Huang变换的非线性、非平稳信号处理方法.对原始管道超声回波信号进行经验模态分解,将复杂信号分解为有限的几个固有模态函数,对其进行Hilbert变换得到HilbertHuang幅值谱,再对时间进行积分得到Hilbert-Huang边际谱,从而获取管道壁厚对应的频率信息.结果表明,所提出的方法相较于快速傅里叶变换法的精度更高,并满足管道壁厚的检测要求.

Aimed at the problem that the conversion accuracy of fast fourier transform method used in the pipeline ultrasonic inspection signal processing is not high and it is easy to misjudge, a nonlinear and nonstationary signal processing method based on Hilbert-Huang transform was proposed. By empirical mode decomposition, the complex original ultrasonic echo signal was decomposed into a limited number of intrinsic mode functions and Hilhert-Huang amplitude spectrum was obtained by using Hilbert transform. In order to obtain the frequency information of the wall thickness, the Hilbert-Huang marginal spectrum was obtained by means of the integral of Hilbert-Huang amplitude spectrum in time. The results show that the proposed method is more accurate than the fast Fourier transform method, which can meet the requirement of wall thickness measurement.