Sparse Reconstruction Based Time-frequency Representation for Time-of-flight Extraction of Undersampled Lamb Wave Signal

Lamb wave has received considerable attention for inspecting defects. However, the undersampling might occur and lead to the incomplete signal samples. This paper proposes the sparse reconstruction based method to extract the time-of-flight (TOF) in undersampled Lamb wave signal. The sparsity of time-frequency representation (TFR) is utilized to build the sparse reconstruction model and the orthogonal matching pursuit is applied to solve this model. The TOF is calculated according to the time-frequency information in the TFR. The method is implemented on simulated Lamb wave signal and the relative error of TOF is 1.48 %. The results demonstrate that the accurate TOF is obtained in undersampled situation.