Magnetic resonance sounding signal extraction using the shaping-regularized Prony method

SUMMARY Magnetic resonance sounding (MRS) can be used to implement groundwater detection non-invasively because of the direct relationship between the signal parameters and aquifer properties. Most current approaches to extracting MRS parameters need to use prior knowledge of the precise Larmor frequency to detect the signal envelope, and are vulnerable to the residual noise after de-noising. In this paper, we use a shaping-regularized Prony method to extract MRS signals from high-frequency oscillating data instead of from envelopes of data. Only an approximate Larmor frequency is required in advance. Besides, irrelevant noise components can be dropped during the extraction process. We investigate the selection of an appropriate decomposition quantity for the SRP method and present an intuitive regularization method to control the shape of the estimated coefficients. Impact of different types and magnitudes of noise on the proposed method are analysed. The extraction results obtained from numerical simulations and field surveys reveal that the SRP method yields accurate and reliable parameters estimation and preserves complete signal information. The tolerance to the interference in signal extraction of the proposed method is obviously better than that of the SD method.