Wavelet design of time-varying filters

Linear time-varying filters can be efficiently implemented using a construction based on the wavelet transform. The method generates a vector of weights for the wavelet coefficients, known as the scale filter coefficients, using least-squares techniques. By sampling the wavelet filters and the desired transfer function of the time-varying filters using an exponential sampling comb, the least-squares inversion can be made stable and fast. Scale filters are used in aeromagnetic data processing to correct for survey altitude effects where they demonstrate a major improvement over conventional time-domain filters, especially in the low-frequency response