Performance of Several Types of Median Filters in Spectral Domain

Median filter is well known for removing impulsive noise and preserving edges. Repeatedly filtering of any one-dimensional signal with a median filter will produce a root signal. Any impulses in the input signal will be removed by sufficient number of passes of median filter, where any root like features in the input signal will be preserved. A signal of finite length will be filtered to a root signal after a finite number of passes of a median filter of a fixed window, results in the convergence of the signal. In this paper, root signal and its properties are analyzed for One-dimensional signal. Adaptive length median filter, weighted median filter, FIR hybrid median filter and Linear combination of weighted median filter have been taken and their root signals are obtained. Their performances are analyzed by determining Power spectrum density, Mean square error and Signal to noise ratio.