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

Abstract

The success of the guided-wave damage inspection technology depends not only on thegeneration and measurement of desired waveforms but also on the signal processing of themeasured waves, but less attention has been paid to the latter. This research aims todevelop an efficient signal processing technique especially suitable for the currentguided-wave technology. To achieve this objective, the use of a two-stage matching pursuitapproach based on the Gabor dictionary is proposed. Instead of truncated sine pulsescommonly used in waveguide inspection, Gabor pulses, the modulated Gaussian pulses, arechosen as the elastic energy carrier to facilitate the matching pursuit algorithm. To extractmeaningful waves out of noisy signals, a two-stage matching pursuit strategy is developed,which consists of the following: rough approximations with a set of predeterminedparameters characterizing the Gabor pulse, and fine adjustments of the parametersby optimization. The parameters estimated from measured longitudinal elasticwaves can be then directly used to assess not only the location but also the sizeof a crack in a rod. For the estimation of the crack size, in particular, Love’stheory is incorporated in the matching pursuit analysis. Several experiments wereconducted to verify the validity of the proposed approach in damage assessment.