【作者】 贾哲；

【导师】 李临生； 田启川；

【作者基本信息】 太原科技大学 ， 控制理论与控制工程， 2008， 硕士

【摘要】 随着计算机和网络的迅速发展,人们对身份认证的准确性、安全性与实用性提出了更高的要求。基于生物特征识别的智能身份认证技术也逐渐受到广泛的关注。在众多的生物识别技术中,指纹识别技术是发展最早、应用最广泛的一种。指纹识别技术充分利用了指纹的普遍性、唯一性和永久性的生物特征,已逐步取代了传统的基于标志和数字的识别方式,目前在网络、银行、金融、医疗和安检等行业均得到了广泛应用。本文对指纹识别系统的原理和基本过程进行了分析研究,重点研究了指纹图像预处理算法,并且进行了验证。首先,针对传统模板滤波后指纹脊线粘连及各个方向过渡不均的情况,提出了一种对称滤波模版算法,该算法采用以圆形直径旋转的滤波模版,在指纹图像不同方向上滤波效果均等,并有效的矫正了脊线的方向,去除了图像模糊引起的脊线边缘粘连,得到脊线和谷线了分离且平滑过渡滤波图像。再次,详细研究了改进OPTA算法,针对该算法引起的毛刺较多及分叉点处细化不全问题进行了详细的研究,改进了消除模板,有效地去除水平方向的毛刺,提出了一种可变的消除模版和矫正消除模版,用可变的消除模版消除了垂直方向的毛刺,用矫正消除模版,使分叉点处细化更彻底,最终得到了比较光滑的细化图像。最后,研究了指纹识别过程中伪特征的滤除方法,针对细节点提取过程中,图像边缘点作为特征点提取出来的这一问题,提出了一种边缘信息去伪法,有效的消除了边缘特征点。测试图像的直观显示证明了这些研究方法的有效性。更多还原

【Abstract】 With the rapid Progress of computer science and network technique,An accurate,secure and practical techno1ogy of Personal identification becomes more and more important. Technology of Personal identification based on Biometrics has received extensive attention. Technology of Fingerprint recognition is the earliest one and is app1ied widely in the all techniques of biometrics recognition, Then is taking full advantage of the universality, uniqueness and permanency of the fingerprint, and gradually has taken place of traditional identification method that is based on symbol and number. Nowadays the technology of fingerprint identification is fully used in network, bank, finance, insurance and security.This paper research the basic principles and process of the fingerprint identification system,and focus on the pre-processing algorithms of fingerprint image and finally verify.Firstly, aiming at conglutination of ridge line and inhomogeneous transition in all directions in the traditional filter template, then proposed symmetrical filter template algorithm ,the method used rotate the filter template of circular diameter to equal filtering effect in different directions, corrected the orientation of ridge line, removed conglutination of ridge line, and separated the ridge from the valley clearly.Secondly, this paper study deeply improved opta algorithm,aiming at incomplete thinning and many burrs, used improved elimination of templates, removed burrs of the horizontal direction effectively; proposed changeable template and correcting template, the changeable template eliminate the vertical direction of the burr, correcting template made the bifurcation point thoroughly and eventually figured out smooth fingerprint image .Finally, this paper study elimination of false minutiae in process of the fingerprint identification, aiming at extracting border points as the feature points in the process of extracting minutiae, this paper proposed judge of border information and eliminated effectively border minutiae.The test images prove the validity of the methods.更多还原