双尺度小波变换的在线手写签名认证的研究与实现

发布时间：2018-05-30 14:51

本文选题：手写签名认证 + 小波变换　；参考：《沈阳建筑大学》2014年硕士论文

【摘要】：随着互联网络的飞速发展,人们的生活和工作都产生了巨大的变化,人们在适应这—过程的同时,也在利用其优势为工作生活带来便捷。电子商务随即出现,但同时令信息安全成为人们日益关注的热点问题。传统的身份认证是基于用户本人所持有的用于鉴别身份的物品的,但是却存在着被盗用或丢失的危险,所以安全性并不高,用户在使用时感到了不安和麻烦。这时基于生物特征的身份认证走入了人们的视线。在线手写签名认证是基于生物特征的身份认证技术的一种比较常用的方法,它有别于其他的身份认证方法,具有实用性强、操作简单的特点,且其唯一性和稳定性也使得这种方法在生物特征的身份认证领域上占有很重要的地位。对于当今全球电子商务的迅猛发展,在线手写签名认证也具有巨大的推动作用,其研究结果也同样有很高的使用价值和实际意义。本文提出了一种双尺度小波变换的在线手写签名认证技术。首先将手写板与计算机连接,对签名样本进行数据获取,并以文本文档的格式存储于计算机中,将采集的数据进行预处理,去掉干扰和噪声,也就是降噪的过程,为以后的特征提取过程减少工作量,其主要工作包括：起抬笔的处理、平滑、归一化等工作。其次利用双尺度小波变换对经过预处理后的数据信息进行特征值的提取,通过对双尺度小波变换的不同尺度不同频域所构造的信号图像进行研究和分析,确定一个有利于识别出真伪签名的尺度和频域,从中选取出有效的特征值重构成新的特征值。最后利用动态时问规整算法对小波变换进行特征提取处理后的信号求出相异度,根据数学统计法设定动态阈值来设计分类器,达到对真伪签名认证的效果。根据大量的实验验证,可以达到4%的误拒率,2%的低错误率。从实验结果上可以看出本文所研究的内容能比较有效的认证出真伪签名。本文引入了可撤销签名的概念于在线手写签名的认证中,主要思想是对签名图像利用某种方法进行变形,使得用户所看到的都是变形后的图像,真正的签名图像是不被外界所接触的,若数据库对外泄露或者有人恶意对数据库的模块进行攻击,系统的可撤销性也会将事后对用户的危害降低到最小,起到了对用户个人信息防伪的作用,保护了用户的个人隐私,同时通过实验证明了可撤销签名的在线手写签名认证能达到8%的误拒率,5%的错误率。虽然错误率相比于未进行可撤销签名的在线手写签名认证的错误率有小范围的提升,但是却能在有效认证签名身份的同时,也加强了信息的安全性。
[Abstract]:With the rapid development of the Internet, people's life and work have changed greatly, people adapt to this process, but also take advantage of its advantages to bring convenience to work and life. E-commerce appeared immediately, but at the same time, information security has become a hot issue that people pay more and more attention to. The traditional authentication is based on the objects held by the user for identifying identity, but there is the risk of embezzlement or loss, so the security is not high, and the user feels uneasy and troublesome when using. At this time, biometric identity authentication into the eyes of people. Online handwritten signature authentication is a common method of biometric authentication technology. It is different from other authentication methods and has the characteristics of practicability and simple operation. And its uniqueness and stability also make this method play an important role in the field of biometric identity authentication. With the rapid development of electronic commerce in the world, online handwritten signature authentication also plays an important role, and the research results are also of high value and practical significance. In this paper, a two-scale wavelet transform (DWT)-based on-line handwritten signature authentication technique is proposed. First of all, the handwritten board is connected with the computer to obtain the data of the signature sample, and the data is stored in the computer in the format of the text document. The collected data is preprocessed to remove the interference and noise, that is, the process of noise reduction. In order to reduce the workload of the later feature extraction process, the main work includes: lifting pen processing, smoothing, normalization and so on. Secondly, using the two-scale wavelet transform to extract the characteristic value of the pre-processed data, the signal images constructed in different scale and different frequency domain of the two-scale wavelet transform are studied and analyzed. A scale and frequency domain for identifying genuine and false signatures are determined and valid eigenvalues are selected for reconstruction to new eigenvalues. At last, the dynamic time warping algorithm is used to extract the feature of wavelet transform to get the difference degree, and the dynamic threshold is set according to the mathematical statistics method to design the classifier, which can be used to authenticate the true and false signatures. According to a large number of experiments, the error rejection rate of 4% is less than 2%. From the experimental results, we can see that the content of this paper can effectively verify the true signature. In this paper, the concept of revocable signature is introduced into the authentication of online handwritten signature. The main idea is to deform the signature image by some method, so that the user can see the distorted image. The real signature image is not exposed to the outside world. If the database is leaked or someone maliciously attacks the module of the database, the revocability of the system will also minimize the harm to the user after the event. It plays an important role in preventing user's personal information and protecting user's privacy. At the same time, it is proved by experiments that the online handwritten signature authentication with cancelable signature can achieve 8% false rejection rate and 5% error rate. Although the error rate of online handwritten signature authentication without cancellable signature is improved in a small range, it can effectively authenticate the signature identity and enhance the security of the information at the same time.
【学位授予单位】：沈阳建筑大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN918.91

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