Researches Of Fingerprint Identification Preprocessing Algorithm And Application Of Fingerprint Feature In Digital Signature

With the development of the Internet and the information society to accelerate the pace, to the people, the information security is highly required. Traditional security system is based on token or password, this system is becoming more fragile. To cope with this challenge, we look to biometrics and hope to enhance identity verification by using our body's physical character and behavior. As biometric technology can not be copied, transplanted and modeled, biometric technology more widely applied in the field of information security. In a variety of biometric technology, fingerprint recognition technology is the most mature and most promising biometric technology. Although research and development of automatic fingerprint recognition, the application of the technology does not prevail at present. The reason is that the accuracy and speed of recognition is far from satisfactory to many practical circumstances. To improve the performance of automatic fingerprint recognition is meaningful both in theory aspect and promoting its application.Fingerprint identification is usually made up of several sections: preprocessing, minutiae extraction, minutiae matching. Based on the achievements of Fingerprint Identification algorithm selected and analyzed at home and abroad in recent years, this paper aims to make studies on several algorithms of Fingerprint Identification preprocessing, putting forward the optimized algorithm of Fingerprint Identification preprocessing and we designed a Fingerprint feature identity based digital signature scheme. The main points we research can be described as follows:(1) Researching fingerprint image segmentation algorithms, based on analysis of the advantages and disadvantages of the fingerprint image segmentation algorithm, Aiming at the advantages and disadvantages of the fingerprint image segmentation algorithm based on the gray variance, this paper presents an improved segmentation algorithm. Experimental results show that the modified algorithm has higher segmentation performance than the original fingerprint image segmentation algorithm based on the gray variance, and the algorithm is robust.(2) Researching algorithms for smoothing fingerprint orientation fields. The traditional algorithm for smoothing fingerprint orientation field based on the low-pass filter was improved. Based on the base of the fingerprint orientation consistency, a variable window adaptive smoothing algorithm of the fingerprint orientation field was proposed. The algorithm uses the correctness of Fingerprint Orientation Field to compute the weighted average of the orientation field. Experiments show that this algorithm can effectively deal with the orientation field images which have noises and really describe the topological structure of the fingerprint ridge.(3) Proposing a fingerprint image enhancement algorithm. By a stepwise decomposition of the two-dimension Gabor function, the Gabor functions are broken down into the combination of the Gaussian functions and the trigonometric functions, and then the Gaussian filter is implemented in the recursive method. By this method, the fingerprint images can be fast enhanced. Experimental results show that the effect of this method on image enhancement is the same as that of Gabor enhancement, and it was superior to the traditional methods in algorithm speed. In addition, two enhancement results in different directions can be obtained by one time filtering.(4) Researching an application of Fingerprint Identification algorithm in cryptology, that is in digital signature. A Fingerprint feature identity based digital signature scheme is proposed and the security of this scheme has been analyzed.