New Directional Morphological Approaches for the Characterization of Fingerprints

Abstract

The present paper proposes two methods to characterize finger prints. The first method estimates the main orientations of the structures of ridges and valleys. This proposed approach detects the preferential directions that characterize the fingerprint as orientation fields using directional granulometries. This approach allows to have a better characterization by means of two parameters; the sizes and the orientations of the structures contained in the fingerprint. In order to achieve the characterization of the fingerprint orientations, the directional morphology is applied to detect the regions of same orientation. Then, the morphological transformations with line segments as structuring elements are applied using a quadtree structure to go from global approach to a local one. The second method uses directional erosions to build two images that contain the sizes and orientations of the fingerprint. Then the rank-max connected opening is applied to filter the image containing the sizes of the ridges in order to select the main structures. Here it is illustrated that the obtained information enables us to reconstruct the directional behavior of the fingerprint. The proposed methods are applied to characterize the four typical classes of finger prints with excellent results.