A Sparse Ultrasonic TOFD Imaging Method for the Weld of Thin Plate Based on Wavelet-Matching Pursuit

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.