Reconnecting broken ridges in fingerprint images

In this paper, we present a new method for reconnecting broken ridges in fingerprint images. The method is based on the use of a discrete directional mask and on the standard deviation of the gray-levels to determine ridge direction. The obtained direction map is smoothed by counting the occurrences of the directions in a sufficiently large window. The fingerprint image is, then, binarized and thinned. Linking paths to connect broken ridges are generated by using a morphological transformation to guide the process.