Localized Cultural Denoising of High-Resolution Aeromagnetic Data

We show how a denoising technique based on the wavelet transform can be used to deal with localized noise related to DC electrified railway lines. This method, which performs localized and sharp filtering of cultural noise, was applied to high-resolution aeromagnetic data acquired in the Phlegrean volcanic area, southern Italy, in 1999 and 2001. The helicopter-borne survey was aimed at giving new detailed insights into the distribution of the magnetization of the area and, therefore, into the volcanological characteristics of the region. The surveyed area is characterized by the presence of towns, buildings and DC electrified railway lines whose magnetic effects influenced the measurements and were responsible for some of the measured anomalies. This cultural noise has, therefore, to be minimized as much as possible in order to allow the data to be interpreted accurately. Due to the excellent space-scale localization properties of the discrete wavelet transform, the cultural disturbance was removed very precisely, leaving the field in the adjacent areas unchanged.