Comparison of edge enhancement methods for potential field data: applications to a synthetic model and the Laxmi Basin, Arabian Sea

Edge detection plays a critical role in delineating subsurface source boundaries from gravity and magnetic data. This study presents a systematic comparison of the common used edge-enhancement techniques, including the total horizontal derivative (THDR), tilt angle (TDR), analytical signal amplitude (ASA), theta map (THETA), THDR_NTilt, Gompertz function (GF), improved logistic (IL), and wavelet space entropy (WSE), using both synthetic magnetic model and free air gravity data from the Laxmi Basin, Arabian Sea. A 3D synthetic nine prism magnetic model is used to evaluate boundary localization accuracy and robustness of each technique. Quantitative evaluation using RMS error analysis under Gaussian noise shows that WSE provides the lowest error and superior noise robustness compared to conventional derivative-based filters. Application to free air gravity data shows that, among all the methods considered, the WSE method reliably delineates the geological boundaries of the Laxmi Ridge, as well as the Raman and Panikkar seamounts and the Wadia Guyot, showing close agreement with the bathymetry map. These results highlight the ability of WSE to preserve structural continuity, making it a robust and effective tool for potential field data interpretation in complex geological settings.