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Top1. Introduction
Fingerprint based biometrics is perhaps the most deeply investigated research problem in the literature and still a very active research area for personal identification. The fingerprint properties like, collectivity, acceptability, uniqueness, universality etc. make it practical and popular to be implemented in our networked society. Fingerprint images are represented by the pattern of ridges and furrows on human fingertips, which are considered as oldest and highest reliable biometrics (Maio and Jain, 2009; Berry and Stoney, 2009). If one looks at the finer details of these ridge and furrows, local and global characteristics point are observed on these ridges. These local characteristics points are ridge bifurcation and ridge termination and are also known as minutiae points. Minutiae features like coordinates, direction with respect to x-axis, and type (bifurcation or termination) are represented by a tupple shown as {x, y; θ; t}. The global features normally provide the information about singularities or Singular Points (SP) such as core and delta points. Most important point is the core point, which is the point of highest curvature lies on innermost ridge and is used as a reference for fingerprint registration. Global features are used for fingerprint classification, fingerprint matching, and alignment (Hong and Jain, 1999; Kawagoe and Tojo, 1984; Jain et al., 2000).
Automatic Fingerprint Matching System (AFMS) is a computer based techniques for human recognition and operates in two modes, Verification mode (1: 1 matching) or Identification Mode (1: N matching). The fingerprint matching algorithms are mainly classified into three categories: (i) minutiae-based, (ii) Pattern or image-based matching, and (iii) correlation based matching. Most of the algorithms proposed in the literature belong to the first category (i.e. minutiae-based). Minutiae based algorithms search the best alignment of minutiae points between input and query image to find the match or non-match (Jiang and Yau, 2000; Liu et al., 2000). A well–known algorithm, proposed by Tico and Kuosmanen (2003) utilizes minutiae points and directional information around the minutiae for matching. An image-based algorithm extracts the features vector from gray scale fingerprint images and performs matching by means of distance based matcher or statistical classifier (Jain et al., 2000; Yang et al., 2006). In correlation based matching algorithms input and query images are compared to maximize the correlation at different alignments to find the match (Maio and Jain, 2009; Bazen et al., 2000; Karna et al., 2008).
Due to the poor image quality and diverse input conditions, minutiae based algorithms results in low matching accuracy. In additions to this, a minutia based algorithms also does not fully utilizes the rich discriminatory information of fingerprints.