Core Point Detection Using Orthogonal Gradient Magnitudes of Fingerprint Orientation Field

ingerprints are the oldest and most widely recognized biometric trait. All human being posses fingerprint and these fingerprints are result of unique ridge and valley structure formed by skin over the fingers. Ridges and valleys are often run in parallel; these structures have bifurcation and ridge endings called as termination. The ridge structure as a whole takes different shapes, characterized by high curvature, terminations, bifurcations, crossover etc. These regions are called singular regions or singularities. These singularities may be classified into three topologies; loop, delta and whorl. What makes fingerprint unique is the distribution of such structures at local level. These are called as minutiae [1]. At a global level the fingerprint pattern exhibits the area that ridge lines assume distinctive shapes. Such an area or region with unique pattern of curvature, bifurcation, termination is known as a singular region and is classified into core point and delta point. The singular points can be viewed as the points where the orientation field is discontinuous. Core points are the points where the innermost ridge loops are at their steepest. Delta points are the points from which three patterns i.e. loop, delta and whorl deviate. Definitions may vary across papers, but this definition of singular point is the most popular one [2]. F