Department of Computer Science and Engineering, Michigan State University, East Lansing, MI 48824, USA.
IEEE Trans Pattern Anal Mach Intell. 2012 Mar;34(3):451-64. doi: 10.1109/TPAMI.2011.161.
The widespread deployment of Automated Fingerprint Identification Systems (AFIS) in law enforcement and border control applications has heightened the need for ensuring that these systems are not compromised. While several issues related to fingerprint system security have been investigated, including the use of fake fingerprints for masquerading identity, the problem of fingerprint alteration or obfuscation has received very little attention. Fingerprint obfuscation refers to the deliberate alteration of the fingerprint pattern by an individual for the purpose of masking his identity. Several cases of fingerprint obfuscation have been reported in the press. Fingerprint image quality assessment software (e.g., NFIQ) cannot always detect altered fingerprints since the implicit image quality due to alteration may not change significantly. The main contributions of this paper are: 1) compiling case studies of incidents where individuals were found to have altered their fingerprints for circumventing AFIS, 2) investigating the impact of fingerprint alteration on the accuracy of a commercial fingerprint matcher, 3) classifying the alterations into three major categories and suggesting possible countermeasures, 4) developing a technique to automatically detect altered fingerprints based on analyzing orientation field and minutiae distribution, and 5) evaluating the proposed technique and the NFIQ algorithm on a large database of altered fingerprints provided by a law enforcement agency. Experimental results show the feasibility of the proposed approach in detecting altered fingerprints and highlight the need to further pursue this problem.
自动指纹识别系统（AFIS）在执法和边境控制应用中的广泛部署，提高了确保这些系统不受损害的需求。尽管已经研究了与指纹系统安全性相关的几个问题，包括使用假指纹进行身份伪装，但指纹改变或模糊化的问题几乎没有得到关注。指纹模糊化是指个人为了掩盖身份而故意改变指纹模式。新闻中已经报道了几起指纹模糊化的案例。由于由于改变而导致的隐含图像质量可能不会发生显著变化，因此指纹图像质量评估软件（例如 NFIQ）并不总能检测到改变的指纹。本文的主要贡献有：1）编译案例研究，其中发现个人为了绕过 AFIS 而改变了他们的指纹，2）研究指纹改变对商业指纹匹配器准确性的影响，3）将改变分为三大类，并提出可能的对策，4）开发一种基于分析方向场和细节点分布自动检测改变指纹的技术，5）在执法机构提供的大量改变指纹数据库上评估提出的技术和 NFIQ 算法。实验结果表明了所提出的方法在检测改变指纹方面的可行性，并强调需要进一步研究这个问题。
