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Denoising Ultrasonic Echo Signals with S-Transform and Non-negative matrix factorization

Ultrasonic Non-Destructive Evaluation (NDE) has been proven to be an effective means to assure the measurement of material properties. However, accurate detection of defect echoes buried in strong noise is challenging. A novel de-noising method based on S-transform and Non-negative matrix factorization is proposed in this paper. In the first stage, the S-transform was performed on the original signal to obtain the time-frequency distribution. Subsequently, the feature separation of echo signal and noise is realized by non-negative matrix decomposition. Finally, clear denoising defect waveforms are acquired by the inverse S-transform. Both simulation analysis and experimental results show the effectiveness and superiority of the proposed method in noise suppression of ultrasonic NDE.