Ultrasonic imaging through reverberation media.

Area of Science:

• Materials Science
• Non-Destructive Testing (NDT)
• Ultrasonic Imaging

Background:

• Thin layered media, such as thermal barrier and corrosion-resistant coatings, are crucial for protecting base materials.
• Non-destructive testing (NDT) of base materials beneath these thin layers presents significant challenges.
• Surface and reverberation waves in thin layers create structural noise, obscuring defect signals in ultrasonic imaging.

Purpose of the Study:

• To develop an effective pre-processing method for ultrasonic total focusing method (TFM).
• To suppress structural noises that interfere with the NDT of base materials under thin layered media.
• To enhance the clarity and reliability of ultrasonic imaging for defect detection.

Main Methods:

• A pre-processing technique for ultrasonic total focusing method (TFM) was developed.
• Principal Component Analysis (PCA) was employed to differentiate and suppress structural noises.
• The method leverages dissimilar similarity characteristics between structural noises and defect signals in diagonal matrices.

Main Results:

• The proposed pre-processing method effectively removed structural noises.
• Signal-to-Noise Ratio (SNR) was improved by approximately 5-8 dB.
• Array performance indicators were reduced by about 30-40%, indicating enhanced imaging quality.

Conclusions:

• The developed pre-processing method significantly improves ultrasonic NDT of base materials under thin layered media.
• PCA-based noise suppression offers a viable solution for overcoming challenges posed by structural noises.
• This advancement enhances the capability of NDT for critical material inspection.