Estimating the parameters of ultrasonic echo signal in the Gabor transform domain and its resolution analysis

The accurate estimation of parameters of an ultrasonic signal is essential in ultrasonic non-destructive testing (NDT). In this paper, a novel method for parameter estimation based on the Gabor transform (GT) is proposed. Firstly, the GT is used in ultrasonic signal processing in order to estimate time of flight (TOF) and center frequency (CF) by calculating where maximum modulus of Gabor transform function of the signal is attained. The quasi-Newton method is employed to improve the estimation accuracy and reduce computational complexity. The Gabor transform function of the signal has an analytic expression which contributes to derive other estimators relating to TOF and CF such as bandwidth factor, phase and amplitude. The parameters of multi-component echo signal are estimated by estimating the parameters of each component successively. Numerical simulation has been carried out to show the performances of the proposed method in estimating parameters of ultrasonic signal.