Split-spectrum processing technique for SNR enhancement of ultrasonic guided wave

Area of Science:

• Materials Science
• Non-Destructive Testing
• Signal Processing

Background:

• Ultrasonic guided wave (UGW) systems are crucial for industrial structural integrity monitoring.
• UGW signal interpretation is challenging due to multi-modal and dispersive propagation, degrading signal-to-noise ratio (SNR) and spatial resolution.
• Existing UGW inspection methods face limitations in signal clarity and defect detection accuracy.

Purpose of the Study:

• To enhance the SNR and spatial resolution of UGW signals for pipe inspection using the split-spectrum processing (SSP) technique.
• To investigate the sensitivity of SSP performance to filter bank parameters for UGW applications.
• To optimize SSP filter bank parameters for real-time UGW inspection scenarios.

Main Methods:

• Application of the split-spectrum processing (SSP) technique to UGW signals.
• Optimization of SSP filter bank parameters, including processing bandwidth, filter bandwidth, filter separation, and number of filters.
• Synthetic and experimental comparison of the proposed SSP method with conventional approaches using different recombination algorithms (Polarity Thresholding - PT, and PT with Minimization - PTM).

Main Results:

• Optimum filter bank parameters were identified to significantly improve UGW SNR and spatial resolution.
• The Polarity Thresholding (PT) and PT with Minimization (PTM) recombination algorithms demonstrated superior performance.
• Substantial SNR improvements of up to 36.9dB (PT) and 38.9dB (PTM) were achieved.

Conclusions:

• The optimized SSP technique effectively enhances UGW signal quality for pipe inspection.
• The proposed method, particularly with PT and PTM algorithms, offers a significant advancement in UGW inspection reliability.
• This research provides a pathway for more dependable structural integrity assessments in industrial applications.