Fingerprint Image Pre-processing Research

With rapid development of computer technology and Internet technology, the traditional identification method has been out of time. in many business, for example bank, insurance, network as well,the need of the security of information raise higher demand. Society is in urgent need of safety, effective and convenient identification method. Fingerprint with the advantage of uniqueness, invariance, and stability has become one of the reliable biometric identification technologies. So the research of the process of fingerprint image in fingerprint identification system has become an important research topic, and the significance is great.In this paper, the preprocessing of fingerprint image was studied, and the main work as follow:In terms of fingerprint binarization, for inaccurate Threshold results in leading to binary is not very ideal situation, the information entropy is used in binarization processing, and propose a simple entropy-based binary algorithm and one-dimensional entropy algorithm. For the problem of ridge fault, using the local feature of ridge and the block direction information of finger image, take a new approach to the restoration of the ridge. For the empty hollow in the ridge, use partial characteristics of fingerprint ridge and direction information on the fingerprint to fill the hole.The algorithms in this article, on the personal computer, using VC++ to have been done a lot of repeated experiments, reach the overall good results. The information entropy fingerprint binarization algorithm has good robustness, obtained more accurate segmentation threshold, and can be a good binarization algorithm to fingerprint image. Ridge restoration algorithm and fingerprint ridge hollow filling algorithm, for medium quality fingerprint images also made a good recovery effect.