A fractional fourier transform(FrFT) based chirplet signal decomposition (FrFT-CSD) algorithm is proposed to analyze ultrasonic\r\nsignals for NDE applications. Particularly, this method is utilized to isolate dominant chirplet echoes for successive steps in\r\nsignal decomposition and parameter estimation. FrFT rotates the signal with an optimal transform order. The search of optimal\r\ntransform order is conducted by determining the highest kurtosis value of the signal in the transformed domain. A simulation\r\nstudy reveals the relationship among the kurtosis, the transform order of FrFT, and the chirp rate parameter in the simulated\r\nultrasonic echoes. Benchmark and ultrasonic experimental data are used to evaluate the FrFT-CSD algorithm. Signal processing\r\nresults show that FrFT-CSD not only reconstructs signal successfully, but also characterizes echoes and estimates echo parameters\r\naccurately. This study has a broad range of applications of importance in signal detection, estimation, and pattern recognition.
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