Application of P4 Polyphase codes pulse compression method to air-coupled ultrasonic testing systems

Area of Science:

• Materials Science
• Acoustics
• Signal Processing

Background:

• Air-coupled ultrasonic testing systems often suffer from low signal-to-noise ratios (SNR).
• Existing pulse compression techniques have limitations in optimizing ultrasound signal quality.

Purpose of the Study:

• To investigate the application of P4 Polyphase sequences for coding ultrasound signals.
• To enhance the signal-to-noise ratio (SNR) and time-domain resolution in air-coupled ultrasonic non-destructive testing (NDT).

Main Methods:

• Implementation of P4 Polyphase sequences for ultrasound signal coding in an air-coupled piezoelectric transducer NDT system.
• Study of parameter selection for P4 Polyphase sequences to achieve optimal pulse compression.
• Application of a hybrid signal processing method.

Main Results:

• Achieved an improvement in SNR up to 12.11dB.
• Enhanced time-domain resolution by approximately 35% compared to conventional methods.
• Demonstrated successful results in molded composite materials.

Conclusions:

• P4 Polyphase sequences effectively improve SNR and resolution in air-coupled ultrasonic testing.
• The proposed hybrid signal processing method offers significant advantages over conventional techniques.
• This approach shows promise for advanced NDT applications, particularly with composite materials.