C-stack filters

The author introduces the combination stack filter, or C-stack filter, as a generalization of stack filters. This class of filters was developed in order to incorporate multilevel information into threshold level Boolean-function based filters (stack filters). C-stack filters generalize stack filters by performing a one-to-one transformation on the input sequence prior to Boolean filtering. The transformed sequence contains both the rank and spatial information not lost in the thresholding process. The knowledge of the rank information at the threshold level increases the number of filters possible and their performance. A brief review of stack and generalized stack filters is presented as well as several simulation results comparing stack, generalized stack, and C-stack filters