Directional composite morphological filter in image processing

In this paper, two pairs of dual morphological filters, the composite morphological filters (CMFs) are introduced. They have distinctive properties comparing with other similar morphological operations. CMFs are used to construct a directional morphological filter in impulsive noise removal procedures. It is proven that it has better noise-removal and detail-preserving abilities than classical morphological filters and other non-linear filters such as median or centre weighted median based filters. A threshold scheme is added to improve the final filtering performances.