Comparison of time frequency analysis techniques for ultrasonic NDE signal

In ultrasonic NDE applications, it is challenging to analyze ultrasonic backscattered signal in presence of high scattering noise. The ultrasound trace embodies the shape, size and orientation of reflectors and reveals the physical property of propagation path. The signal loss due to the effect of attenuation and scattering makes ultrasonic backscattered signal nonstationary. Therefore, a proper signal analysis technique is needed. As an effective tool of nonstationary signal analysis, time-frequency (TF) signal representations have been used in many applications, including ultrasound NDE. In this paper, other time-frequency analysis techniques have been reviewed. Especially, a model-based TF analysis and parameter estimation technique is discussed. Simulation and experimental results have shown its effectiveness in signal decomposition. Additionally two different models, i.e., chirplet model and Gabor model are compared in terms of energy compact in time-frequency representation of ultrasonic NDE signals.