A Comparative Analysis of Edge Detection Methods in Magnetic Data Jeon, Taehwan; Rim, Hyoungrea; Park, Yeong-Sue;
Many edge detection methods, based on horizontal and vertical derivatives, have been introduced to provide us with intuitive information about the horizontal distribution of a subsurface anomalous body. Understanding the characteristics of each edge detection method is important for selecting an optimized method. In order to compare the characteristics of the individual methods, this study applied each method to synthetic magnetic data created using homogeneous prisms with different sizes, the numbers of bodies, and spacings between them. Seven edge detection methods were comprehensively and quantitatively analyzed: the total horizontal derivative (HD), the vertical derivative (VD), the 3D analytic signal (AS), the title derivative (TD), the theta map (TM), the horizontal derivative of tilt angle (HTD), and the normalized total horizontal derivative (NHD). HD and VD showed average good performance for a single-body model, but failed to detect multiple bodies. AS traced the edge for a single-body model comparatively well, but it was unable to detect an angulated corner and multiple bodies at the same time. TD and TM performed well in delineating the edges of shallower and larger bodies, but they showed relatively poor performance for deeper and smaller bodies. In contrast, they had a significant advantage in detecting the edges of multiple bodies. HTD showed poor performance in tracing close bodies since it was sensitive to an interference effect. NHD showed great performance under an appropriate window.
Cordell, L., 1979, Gravimetric expression of Graben faulting in Santa Fe Country and the Espanola basin, New Mexico: New Mexico Geological Society Guidebook, 30th Field Conference, 59-64.
Evjen, H.M., 1936, The place of the vertical gradient in gravitational interpretations: Geophysics, 1, 127-136.
Gunn, P.J., 1975, Linear transformations of gravity and magnetic fields: Geophysical Prospecting, 23, 300-312.
Li, X. and Chouteau, M., 1998, Three-dimensional gravity modeling in all space: Surveys in Geophysics, 19, 339-368.
Ma, G. and Li, L., 2012, Edge detection in potential fields with the normalized total horizontal derivative: Computers and Geosciences, 41, 83-87.
Miller, H.G. and Singh, V., 1994, Potential field tilt-a new concept for location of potential field sources: Journal of Applied Geophysics, 32, 213-217.
Nabighian, M.N., 1972, The analytic signal of two dimensional magnetic bodies with polygonal cross section: its properties and use for automated anomaly interpretation: Geophysics, 37, 507-517.
Roest, W.R., Verhoef, J., and Pilkington, M., 1992, Magnetic interpretation using the 3-D analytic signal:Geophysics, 57, 116-125.
Verduzco, B., Fairhead, J.D., and Green, C.M., 2004, New insights into magnetic derivatives for structural mapping:The Leading Edge, 23, 116-119.
Wijns, C., Perez, C., and Kowalczyk, P., 2005, Theta map:edge detection in magnetic data: Geophysics, 70, 39-43.