管道缺陷超声导波监测信号匹配追踪去噪

Pipeline Defect Detection Signal De-noising Based on Matching Pursuit Method

采用超声导波进行管道缺陷监测过程中混入干扰噪声严重影响缺陷反射回波的提取和识别,提出了一种新的管道缺陷超声导波监测信号匹配追踪去噪方法。将Hanning窗调制的正弦波激励信号经过时间平移和幅值调制作为基本原子形成自定义过完备波形字典,对管道缺陷超声导波监测信号进行匹配追踪稀疏分解,提取其中有效成分进行信号重构,经多次迭代实现信号去噪。对有限元数值模拟和实际管道缺陷监测信号分别采用传统小波阈值和提出的匹配追踪法进行去噪处理,结果表明,当信噪比较低时匹配追踪法明显优于小波阈值法,即使在干扰噪声完全淹没缺陷反射回波的场合,仍然可以提取出清晰干净的缺陷反射回波信号,为正确分析和评估现役管道安全运行状况提供了一条新的途径。

In the process of pipeline defect detection using ultrasonic guided wave,interference noise is mixed in,which seriously affects the extraction and identification of defect reflection signal.A new de-noising method for pipeline defect detection signal based on matching pursuit was proposed.The Hanning windowed sinusoidal excitation signal was used as the basic atom to form a self-defined over complete waveform dictionary after time translation and amplitude modulation.On this basis,the effective components were extracted by matching pursuit sparse decomposition from the pipeline defect detection signal,and the remaining noise were discarded,so as to realize signal de-noising.The finite element numerical simulation and the experimental pipeline defect detection signals were de-noised by traditional wavelet threshold and the matching pursuit method proposed respectively.The results show that the matching pursuit method is obviously better than the wavelet threshold method when the signal-to-noise ratio is low,even though the interference noise completely submerges the defect reflection echo,the matching pursuit method can still extract the clear reflection echo of defects.It provides a new way to correctly analyze and evaluate the pipeline safety operation.