The Research Of Fingerprint Image Preprocessing And Thinning Algorithm

There is no two fingerprints are exactly the same, this point has been accepted by most people, and due to their uniqueness and persistence, fingerprints are used as main basis of personal identity. Fingerprint identification has been applied for a long time. At present, it has been adopted by the government and becomes an effective identity recognition approach in law. Fingerprint identification is of convenience, high efficiency, security and reliability. It has also been applied in many fields such as financial security, data encryption, and electronically business and will play a more and more important role in our future life necessarily.Fingerprint identification is usually made up of several sections: preprocessing, thinning, post-processing, minutiae extraction, minutiae matching. This paper introduces the current status and correlative techniques about fingerprint identification according to above-mentioned processes at first, analyses its working principle and each process of preprocessing also. Basing on these a set of preprocessing algorithms is redesigned. Segmentation, Enhancement, and minutiae extraction algorithm are the emphases among them.Firstly, a few important parts of fingerprint image pre-processing are analyzed and a fingerprint quality evaluation method is improved based on previous tasks, which can judge the fingerprints too dry or too wet even those located reflectively. It can avoid inputting those images with low quality or non-standard and reduce workload and identification time in the future work. The image of direction is determined by fingerprint images'orientation. we also application of filter shows good ridge separation and continuity, and background noise reduction. A fuzzy based algorithm for contrast enhancement of fingerprint image and edge detection is improved. Experimental results demonstrate that this method is effective in performing detail sharpening and removing noise without destroying the useful information contained in a fingerprint image. On the basis of the OPTA algorithm,the thinning templates age redesigned,and a new improved thinning algorithm is presented.Through experiments,the new algorithm has been proved to have many advantages such as complete thinning,quick speed,smooth skeleton,center location of ridges。maintenance of minutiae,and so on.The system of the preprocessing on fingerprint image is realized by visual C# on windows platform. Experiments have been done and the results show that the algorithm dealing with fingerprint images is robust, it can make the images get enhancement effective.