Path-based morphological openings

A well-known problem in image analysis is the extraction of thin and elongated features such as edges, fractures, fibres, vessels, etc. In many cases, such features are not linear but curved rather than straight. A well-known morphological tool for the extraction of linear features is the opening by straight line segments of a certain length. In this paper we extend this class of morphological filters with openings with narrow structuring elements which are not necessarily straight line segments, but which can be connected paths defined by an adjacency relation.