Sensitivity of time-frequency representations in the presence of noise in guided waves NDE

Time frequency representation (TFR) of ultrasonic signals plays an important role in describing the propagation and dispersive effects in thin walled structures. In this paper, Generalized time-frequency representations viz. the Wigner-Ville distribution, Choi-William distribution and Short-Time Fourier Transform are discussed in the context of mode analysis. A comparison on the estimation of various modes and the obscuring interference terms, due to bilinear structure of TFRs, is presented for lamb waves in aluminum plates. Studies on the performance of TFRs in the presence of strong colored noise are presented. © 2006 American Institute of Physics.