Morphological filters with multiple structuring elements

Many applications of mathematical morphology use only a single structuring element. In some cases, this may not produce the best result. Combination of morphological operators with other operations as well as the utilization of multiple structuring elements can improve the performance of morphological-based filters. This paper defines two new morphological operators with multiple structuring elements-multistage erosion (ME) and multistage dilation (MD). The properties of the ME and the MD are presented. Then a new morphological-based filter, which embodies the new morphological operators, called multistage morphological (MM) filter is proposed. The MM filter can remove noise effectively and preserve more geometrical features and details than a simple morphological filter, or other nonlinear filtering algorithms