焊接缺陷超声检测回波信号的双谱分析

Bispectrum Analysis on UltrasonicTesting for Echo Signal of Welding Flaw

针对焊接缺陷超声检测中信号处理的特征提取问题 ,应用高阶谱方法对三类压力容器焊接缺陷的超声回波信号进行了分析。在焊接缺陷超声检测中 ,回波信号的相位携带有被检对象重要的结构特征信息。高阶谱方法与常规的功率谱分析方法不同 ,它不仅有振幅而且包含有相位 ,能揭示常规功率谱分析所不能表现的重要信息。本文应用高阶累积量技术对缺陷回波信号进行双谱分析 ,提取出缺陷回波基于双谱的平均相位信息作为特征参量 ,取得了较好的识别结果。

The ultrasonic echoes of welding flaws for three types of pressure vessel are analyzed for feature extraction of signal processing using higher-order spectrum method. The phase of signal spectrum carries the important structure feature information of real welding flaw in ultrasonic testing. The higher-order spectrum analysis, having both of the amplitude and the phase information is different from the conventional power spectrum analysis, it can reveal some new information about the flaw echoes, which are not obtained by the conventional power spectrum analysis. The higher-order statistics method is used to estimate the bispectrum of flaw echo. The feature vector of the average phase information based on the bispectrum is extracted. Experiment results of classification show that the method is feasible and effective.