为解决薄板焊缝超声TOFD检测中信号易出现混叠的问题, 提出了一种基于小波匹配追踪的超声TOFD稀疏化成像方法。针对传统匹配追踪算法存在的原子库原子数量巨大, 算法计算效率低等问题, 首先利用小波变换对超声TOFD检测原始信号在频域内进行分解, 然后根据单个子带的特性建立原子库, 利用匹配追踪算法将子带信号与原子库中的原子进行优化匹配, 实现了信号的稀疏化处理, 解决了超声TOFD检测技术在薄板焊缝应用中的关键技术难点。

In order to overcome the problem existing in the procedure of ultrasonic TOFD imaging inspection for weld of thin material such as the signals are prone to be superimposed, a sparse ultrasonic TOFD imaging technique based on wavelet-matching pursuit was proposed. Because the traditional matching pursuit method has the problem that the number of the atoms in the dictionary is large and the computing efficiency is low, firstly, an original ultrasonic TOFD detection signal was decomposed into subband signal using wavelet transform, and the atoms dictionary was established according to the characteristics of subband, after that, matching pursuit was used to derive a sparse representation of the subband signal. So the difficulty in applying ultrasonic TOFD inspection technology to weld of thin material can be solved.