Thin-plate Spline Modelling of Elastic Deformations in Fingerprints

This paper presents a novel minutiae matching method that describes elastic distortions by means of a thin-plate spline model and uses that model to normalize the shape of the test fingerprint with respect to the template. The method first determines possible matching minutiae pairs by means of comparing local neighborhoods of the minutiae. Next, a thin-plate spline model is used to describe the non-linear distortions between the two sets of possible pairs. One of the fingerprints is deformed and registered according to the estimated model, and then the number of matching minutiae is counted. This method is able to model all possible non-linear distortions and therefore to use very tight bounding boxes. Experiments show considerable improvement with respect to minutiae matching based on translation, rotation and scaling only. Furthermore, it turns out that the nature of elastic distortion in practice is quite different from the theoretical models proposed in literature.