欠采样条件下金属构件近表面缺陷深度高精度测量方法  

High-precision measurement method for near-surface defect depth of metal components under sub-Nyquist sampling conditions

作　　者：吕丽 姚贞建 杨梦冉 赵宇星 Lyu Li;Yao Zhenjian;Yang Mengran;Zhao Yuxing(School of Electrical and Information Engineering,Wuhan Institute of Technology,Wuhan 430205,China)

机构地区：[1]武汉工程大学电气信息学院,武汉430205

出　　处：《电子测量与仪器学报》2024年第8期68-78,共11页Journal of Electronic Measurement and Instrumentation

摘　　要：针对欠采样条件下金属构件近表面缺陷深度测量时,缺陷回波与表面回波重叠,导致缺陷深度测量不准确的问题,提出一种基于超声回波信号重采样和时频变换的金属构件近表面缺陷深度高精度测量方法。采用变分模态分解将超声回波信号分解为一系列窄带模态分量,根据相关系数实现有用模态分量聚类,得到预处理信号;对预处理信号进行三次样条插值处理,实现欠采样回波信号数据扩充,得到重构信号;基于同步提取变换得到重构信号的时频谱及其幅值分布曲线,并根据超声单收发原理,实现金属构件近表面缺陷深度高精度测量。实验结果表明,本文方法可实现欠采样条件下金属构件近表面缺陷深度的准确测量,测量相对误差为2.161%,明显优于包络法和时频变换法,其测量相对误差分别为3.570%和13.182%。此外,分析了欠采样率、信号噪声和缺陷位置对近表面缺陷深度测量精度的影响,结果一致表明本文方法在不同采样率、不同噪声和不同缺陷深度情况下对近表面缺陷深度测量,比传统方法均具有更好的准确性和鲁棒性。In order to solve the problem that the defect echo overlaps with the surface echo when measuring the defect depth near the surface of metal components under sub-Nyquist sampling condition which leads to inaccurate depth measurement,a high-precision measurement method for the near-surface defect depth of metal components based on ultrasonic echo resampling and time-frequency transformation is proposed.The ultrasonic echo signal is decomposed into a series of narrowband mode components by variational mode decomposition,and the useful mode components are clustered based on the correlation coefficient to obtain the preprocessed signal.The preprocessed signal is then processed by cubic spline interpolation to realize the data expansion of the sub-Nyquist sampling echo signal and obtain the reconstructed signal.Based on the synchro extracting transform,the time-frequency spectrum and amplitude distribution curve of the reconstructed signal are obtained.According to the principle of ultrasonic single transceiver,the high-precision depth measurement of the near-surface defect of metal components is finally realized.The experimental results show that the proposed method can accurately measure the near-surface defect depth of the metal component under the condition of sub-Nyquist sampling condition,and the measurement relative error is 2.161%,which is obviously less than that of the envelope method and the time-frequency transform method,whose relative error are 3.570%and 13.182%,respectively.Furthermore,the effects of the sub-Nyquist sampling rate,the signal noise and the defect location on the measurement accuracy of the near-surface defect depth are investigated.The results consistently demonstrate that the proposed method has better accuracy and robustness than the traditional methods for the near-surface defect depth measurement under different sampling rates,different noise and different defect depths.

关 键 词：超声检测 近表面缺陷 欠采样 时频变换 信号处理 

分 类 号：TN06[电子电信—物理电子学]