Directional filtering for linear feature enhancement in geophysical maps

Geophysical maps of data acquired in ground and airborne surveys are extensively used for mineral, groundwater, and petroleum exploration. Lineaments in these maps are often indicative of contacts, basement faulting, and other tectonic features of interest. To aid the interpretation of these maps, a versatile processing technique of directional filtering, based on the 2-D “normal” Radon transform, is used to enhance or suppress specific lineaments. Synthetic data and field examples using electromagnetic and radiometric data are used to demonstrate the superiority of the Radon transform method over conventional Fourier transform filtering. The Radon transform technique is shown to be more versatile and less susceptible to processing artefacts than the Fourier transform methods.