Efficient Analytical Modeling Method for Pulse Eddy Current Testing Based on Morlet Wavelet Transform

Abstract

Pulsed eddy current (PEC) testing is a key non-destructive evaluation technique, but conventional FFT-based analytical modeling is computationally expensive due to full-spectrum impedance change evaluations up to the Nyquist limit. This paper proposes a novel modeling method using the Morlet wavelet transform. The method establishes a direct mapping between the wavelet scale factor and angular frequency, enabling time-domain reconstruction from discrete scale-dependent frequencies without global FFT sampling. An adaptive scale-truncation strategy further reduces computational cost by omitting negligible high-frequency components. Numerical results demonstrate that, with the optimal parameters (wavenumber 25 and discretization parameter 0.1), the proposed method requires only 96 frequency points, as opposed to 1000 at a sampling frequency of 1 MHz. This translates to a computational saving of over 90%, while maintaining relative errors below 1% at signal peaks. The method's accuracy and robustness are validated across wide parameter ranges and against experimental data. This work offers an efficient, theoretically sound alternative to FFT-based modeling, with potential for real-time inverse applications.