自动指纹识别中的图像预处理算法研究

提出了一种有效的指纹图像预处理方法.实验结果表明,这种算法能有效地去除指纹传感器录入指纹时,由传感器表面残留纹印引入的噪声,有效地分割出有效指纹区域与无效指纹区域,进一步增强指纹的脊线与谷线,使指纹纹线变得清晰、连续、光滑,具有较好的对比度,同时具有较快的响应速度,大大缩短了指纹图像预处理时间。     

Score normalization in multimodal biometric systems

Multimodal biometric systems consolidate the evidence presented by multiple biometric sources and typically provide better recognition performance compared to systems based on a single biometric modality. Although information fusion in a multimodal system can be performed at various levels, integration at the matching score level is the most common approach due to the ease in accessing and combining the scores generated by different matchers. Since the matching scores output by the various modalities are heterogeneous, score normalization is needed to transform these scores into a common domain, prior to combining them. In this paper, we have studied the performance of different normalization techniques and fusion rules in the context of a multimodal biometric system based on the face, fingerprint and hand-geometry traits of a user. Experiments conducted on a database of 100 users indicate that the application of min–max, z-score, and tanh normalization schemes followed by a simple sum of scores fusion method results in better recognition performance compared to other methods. However, experiments also reveal that the min–max and z-score normalization techniques are sensitive to outliers in the data, highlighting the need for a robust and efficient normalization procedure like the tanh normalization. It was also observed that multimodal systems utilizing user-specific weights perform better compared to systems that assign the same set of weights to the multiple biometric traits of all users.     

Fingerprint classification using fast Fourier transform and nonlinear discriminant analysis

In this paper, we present a new approach for fingerprint classification based on discrete Fourier transform (DFT) and nonlinear discriminant analysis. Utilizing the DFT and directional filters, a reliable and efficient directional image is constructed from each fingerprint image, and then nonlinear discriminant analysis is applied to the constructed directional images, reducing the dimension dramatically and extracting the discriminant features. The proposed method explores the capability of DFT and directional filtering in dealing with low-quality images and the effectiveness of nonlinear feature extraction method in fingerprint classification. Experimental results demonstrates competitive performance compared with other published results.     

An asymmetric fingerprint matching algorithm for Java Card TM

We propose a light-weight fingerprint matching algorithm that can be executed inside the devices with a limited computational power. The algorithm is based on the minutiae local structures (the “neighborhoods”), that are invariant with respect to global transformations like translation and rotation. The match algorithm has been implemented inside a smartcard over the Java Card^TM platform, meeting the individual’s need for information privacy and overall authentication procedure security. The main characteristic of the algorithm is to have an asymmetric behavior, in respect to the execution time, between correct positive and negative matches. The performances in terms of authentication reliability and speed were tested on some databases from the Fingerprint Verification Competition 2002 and 2004 editions (FVC2002 and FVC2004). Moreover, our procedure showed better reliability when compared with a related algorithm on the same database. We can achieve a false acceptance rate (FAR) of 0.1%, a false rejection rate of about 6%, and from 0.3 to 8 s to match most of the finger pairs during the FAR tests.     

指纹取象与指纹识别

信息化社会的到来,使指纹自动识别系统在身份认证方面有着广阔的前景。文章主要介绍了现有提取指纹图象的几种设备和方法,并提出了一套完整的指纹识别算法。该算法包括预处理、特征抽取、样本数据库建立和指纹比对,经实验证明,该算法具有很强的可靠性和安全性。     

指纹识别中的一种局部矢量匹配算法

指纹匹配技术分为两种：基于细节点的匹配和基于纹线相关性的匹配。文章属于基于细节点的匹配，采用细节点及其临近的5个点形成局部矢量，每枚指纹分解成若干个这样的局部矢量。于是，两枚指纹的匹配就转变为矢量数组的匹配。     

基于指纹识别的学生宿舍安全管理系统

本文介绍了指纹识别技术,论述了指纹识别在学生宿舍安全管理系统中的应用及特点,提出了指纹识别技术在学生宿舍安全管理系统的解决方案.     

Measuring Fingerprint Image Quality Using the Fourier Spectrum

The fingerprint image quality has a significant effect on the performance of automatic fingerprint identification system. A method for measure of fingerprint image quality based on Fourier spectrum is proposed. First the band frequency which corresponds to the global average period of ridge is searched. Then the quality score of the fingerprint image is computed by measuring relative magnitude of the band frequency components. The method is verified to have good performance by experiments.     

Fingerprint classification by a hierarchical classifier

Fingerprint classification is still a challenging problem due to large intra-class variability, small inter-class variability and the presence of noise. To deal with these difficulties, we propose a regularized orientation diffusion model for fingerprint orientation extraction and a hierarchical classifier for fingerprint classification in this paper. The proposed classification algorithm is composed of five cascading stages. The first stage rapidly distinguishes a majority of Arch by using complex filter responses. The second stage distinguishes a majority of Whorl by using core points and ridge line flow classifier. In the third stage, K-NN classifier finds the top two categories by using orientation field and complex filter responses. In the fourth stage, ridge line flow classifier is used to distinguish Loop from other classes except Whorl. SVM is adopted to make the final classification in the last stage. The regularized orientation diffusion model has been evaluated on a web-based automated evaluation system FVC-onGoing, and a promising result is obtained. The classification method has been evaluated on the NIST SD 4. It achieved a classification accuracy of 95.9% for five-class classification and 97.2% for four-class classification without rejection.     

基于指纹识别的图书借阅管理系统设计与实现

介绍目前图书管理系统中身份认证存在的缺陷和指纹识别技术的原理．提出一种基于指纹识别技术的图书借阅管理系统解决方案。对系统功能模块进行设计、数据流进行分析．按系统开发方法,采用．NET技术和SQLServer进行系统开发,实现基于指纹识别的图书借阅管理系统。