Fingerprint Image Enhancement System

A fingerprint image enhancement system is described in this paper.Fingerprint is unique identifiers of individuals and has been used for a long time. Government agencies (such as the police) and many kinds of departments needing high security have to collect increasing amount of fingerprints for transmission, storage, and automated analysis. We need some preprocessing and some enhancement technique to improve the recognition of fingerprint image.Get ride of the background and unrecoverable region can not only reduce the time of subsequent processing, but also improve the reliability of feature extraction considerably. A fingerprint image segmentation method based on 2D maximum between-cluster variance is suggested in this paper. First, we use coherence of orientation to turn fingerprint image into image with greater even gray areas. Then we successfully achieve the fingerprint region with image segmentation method based on 2D maximum between-cluster variance. Last, we use Graham convex hull algorithm to smooth the contour of fingerprint region.Based on character of fingerprint, Gabor filters with frequency-selective and orientation-selective properties are used to enhance fingerprint image. We estimate the orient field by a least mean square algorithm and estimate local ridge frequency by projection method. According with estimated orient field and ridge frequency, we use Gabor filters to enhance fingerprint image. In the region of singular point, we adopt a different filter to enhance.In the last part of this dissertation, summarize the work of this dissertation, analyze the improvements need to be done and give the directions of future work.