Advances in Reconstructing Archaeological Magnetic Signals; an Algorithm for Filtering Noise due to the Ploughing Effect

Archaeological remains are very often buried under uneven soil of agricultural fields crossed by rather parallel furrows and ridges. Consequently, ploughing in a magnetic survey might produce a repetitive, quite regular, linear noise in the data, which could impede optimal recovery of the archaeological magnetic anomalies; depending on the acquisition line orientation, this noise may show as an oblique, vertical or horizontal pattern in the magnetic maps. Several studies have tested and verified methods for oblique ploughing minimization, but, to our knowledge, no procedures regarding the vertical and horizontal types of noise have been published. The present research proposes a procedure to filter each type of ploughing effect through an algorithm working in the wavenumber domain. The procedure produces images with a considerable reduction of the noise in any direction, resulting in enhanced visibility and readability of the archaeological anomalies.