The matching pursuit approach based on the modulated Gaussian pulse for efficient guided-wave damage inspection

Abstract

The success of the guided-wave damage inspection technology depends not only on the generation and measurement of desired waveforms but also on the signal processing of the measured waves, but less attention has been paid to the latter. This research aims to develop an efficient signal processing technique especially suitable for the current guided-wave technology. To achieve this objective, the use of a two-stage matching pursuit approach based on the Gabor dictionary is proposed. Instead of truncated sine pulses commonly used in waveguide inspection, Gabor pulses, the modulated Gaussian pulses, are chosen as the elastic energy carrier to facilitate the matching pursuit algorithm. To extract meaningful waves out of noisy signals, a two-stage matching pursuit strategy is developed, which consists of the following: rough approximations with a set of predetermined parameters characterizing the Gabor pulse, and fine adjustments of the parameters by optimization. The parameters estimated from measured longitudinal elastic waves can be then directly used to assess not only the location but also the size of a crack in a rod. For the estimation of the crack size, in particular, Love's theory is incorporated in the matching pursuit analysis. Several experiments were conducted to verify the validity of the proposed approach in damage assessment.

Review of magnetostrictive patch transducers and applications in ultrasonic nondestructive testing of waveguides

“…For the experiment, a modulated Gaussian pulse or Gabor function f Gp (t) was employed (e.g., [113] for NDT applications): …”

Guided Waves Mode Discrimination in Pipes NDT Based on the Matching Pursuit Method

“…Equation (5) shows that the frequency of a Gabor atom keeps unchangeable as time changes, and it is not suitable for guided waves signal processing because guided wave's propagation speed is changeable with different frequency. In this work, Chirplet functions [16] is selected as the matching atoms, and which can be expressed as…”

“…In which, the time-frequency localization is excellent and different chirp-rates result in different slopes of the time-frequency distributions. Once the guided wave signal is decomposed into Chirplet atoms, the chirp-rate parameter will reflect the time-frequency character, so that the guided wave mode information is manifested [16]. in Figure 4.…”

“…Peng Xu proposed a kind of two dictionaries matching pursuit (TDMP) to decompose and reconstruct signals which can reduce the computation load [15]. Jin-Chul Hong proposed a chirp dictionarybased matching pursuit approach to estimate the location and size of a crack from longitudinal wave signals measured in cracked rod, which shows that this approach is very useful [16]. In addition, MP can be applied to guided waves modes extraction and identification.…”

Analysis of internal wave reflection within a magnetostrictive patch transducer for high-frequency guided torsional waves

“…As an excitation pulse for the transmitter, the Gabor pulse is adopted to concentrate the energy at a specific frequency [25],…”