An edge gradient enhancing adaptive order statistic filter

We consider an adaptive order statistic (OS) filter that can enhance gradients of edges while suppressing impulsive and some nonimpulsive noise components. In particular, comparison and selection (CS) filters are introduced, in which the output is determined by comparing the sample mean and median values inside each window. It is shown theoretically that CS filters can enhance gradients of a variety of edges including noisy blurred ones. Some root properties of CS filters are also shown. Finally, experimental results are presented to illustrate the performance characteristics of these filters.