P2D-6 Efficiency and Sensitivity Analysis of Chirplet Signal Decomposition for Ultrasonic NDE Applications

In this investigation, a chirplet signal decomposition algorithm has been studied by decomposing highly convoluted ultrasonic signals into a linear expansion of chirplets, and successively estimates all the echo parameters. The efficiency of the algorithm is essential for real-time NDE applications. Therefore, we have evaluated the estimation efficiency and the behavior of the chirplet parameters and their influence on the reconstruction error. The sensitivity analysis of chirplet parameters confirms the successive order for parameter estimation developed by the mathematical analysis of the algorithm. Moreover, a fast implementation of the chirplet signal decomposition algorithm is presented. The performance of the algorithm is evaluated in order to characterize the ultrasonic echoes backscattered from reverberant multilayered materials. Through extensive experimental studies, we have shown that the reverberation model of thin layers coupled with the chirplet signal decomposition allows for a very accurate estimation of transmission and reflection coefficients of each layer and also leads to an accurate estimation of the thickness of the layers by an order of magnitude beyond the resolution of the ultrasonic measuring system.