Michigan State University
Manual fingerprint classification proceeds by carefully inspecting the geometric characteristics of major ridge curves in a fingerprint image. The authors propose an automatic approach of identifying the geometric characteristics of ridges based on curves generated by the orientation field called Orientation Field Flow Curves (OFFCs). The geometric characteristics of OFFCs are analyzed by studying the isometric maps of tangent planes as a point traverses along the curve from one end to the other. The path traced by the isometric map consists of several important features such as sign change points and locations as well as values of local extremes that uniquely identify the inherent geometric characteristics of each OFFC.