Time-reassigned multisynchrosqueezing of the S-transform for seismic time-frequency analysis

To accurately capture the time-frequency spectral anomaly, a novel time-frequency analysis (TFA) method, termed as time-reassigned multisynchrosqueezing S-transform (TMSSST), is proposed. In this study, we derive a N-order group delay (GD) estimator designed for frequency-domain S-transform to cope with the signal with fast varying instantaneous frequency (IF). By introducing an iterative reassignment procedure, the proposed TMSSST not only can produce a highly energy-concentrated time-frequency representation (TFR) but also can reconstruct the original signal with a high accuracy. Three synthetic signals are employed to validate the effectiveness of the proposed method by comparing with some classical TFA techniques such as S-transform (ST), synchrosqueezing S-transform (SSST) and time-reassigned synchrosqueezing S-transform (TSSST). It is shown that the TMSSST does a better job in addressing strongly frequency-varying signal. Application on field data further indicates the potential of highlighting subsurface geological structures and thus, facilitating seismic interpretation.