Recursive median filtering with partial replaces.
A. Burian, Pauli Kuosmanen · 1999
The median filter is a special case of nonlinear filter used for smoothing signals. Since the output of the median filter is always one of the input samples, it is conceivable that certain signals could pass through the median filter unaltered. These signals, invariant to further passes of the median filter, define the signature of a filter and are referred to as root signals. This represents the convergence property of median filters. The convergence behavior of different schemes of recursive median filters, and algorithms for image processing