Median-type filters with adaptive substructures

In this paper, adaptive filter structures suitable for filtering signals with rapidly varying characteristics are presented. In the proposed Adaptive Median Hybrid (AMH) filters, adaptive filter substructures are used to estimate the current signal value from future signal values and from past input or output signal values. The output of the overall filter is the median of the adaptive filter outputs and the input signal value. Using computer simulations, the convergence properties of the filters in stationary and nonstationary signals have been analyzed. Due to the median operation, the AMH filters adapt and preserve abrupt changes in signal statistics substantially better than conventional adaptive filters.