Linear filter for upward- down ward continuation by using wavelet transform and its application in magnetic data processing

Linear filters are used for a wide range of magnetic science including noise attenuation, spatial derivatives, upward and downward continuation and reduction to the pole. The majority of these filters are spatially-invariant, meaning that the filter has a constant wave number response over the whole signal. In contrast, many signals which encountered real problems such as magnetic signals, typically exhibit a spatially-varying wave number content which motivates us to design filters with spatially-varying wave number responses. This leads to better preservation of anomaly gradients in the calculated derivatives than is possible using conventional Fourier or space domain smoothing techniques.