Theoretical analysis of Winsorizing smoothers and their applications to image processing

The Winsorizing smoother (W smoother), which is a center weighted median (CWM) filter giving more weight only to the central value of each window, is studied. This filter can preserve image details while suppressing additive white and/or impulsive-type noise. The statistical properties of the W smoother are analyzed. It is shown that the W smoother can outperform the median filter, while its implementation is almost as simple as median filtering. Some relationships between W smoothers and other median-type filters, such as the weighted median filter and the multi-stage median filter, are derived