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Alternative TitleLow Quality Image Preprocessing in Fingerprint Recognition System
Thesis Advisor王阳生
Degree Grantor中国科学院研究生院
Place of Conferral中国科学院自动化研究所
Degree Discipline模式识别与智能系统
Keyword低质量 预处理 指纹识别 感兴趣区域分割 Low Quality Preprocessing Fingerprint Recognition Segmentation Of Region Of Interst
Abstract指纹识别作为生物特征识别中较早发展起来的一个重要分支,其应用空间 变得越来越广阔。随着当今社会对身份识别与认证的需求同益增长,人们对指 纹自动识别系统性能的要求也逐步提高。这种情况下,输入指纹图像的质量就 成为影响系统性能的一个重要的因素。尽管目前指纹识别算法已经逐步走向成 熟,但是低质量指纹图像的处理技术的研究相对较少,本文j下是以低质量指纹 图像作为研究对象,在指纹分割、狄度信息恢复、增强、二值化以及算法流程 等环节进行了研究,并取得一定的研究成果。本文的主要工作及贡献概括如下: (1)提出了一种改进的基于感兴趣区域的分割方法。该方法对指纹图像分 块区域的灰度特征进行统计,并引入评价机制,对重新计算过的统计特征进行 分割。该方法对于汗渍、伪迹,以及前景被污染的噪声起到了良好的抑制作用。 (2)改进了目前的增强流程以及算法实现。结合低质量指纹图像纹理信息 微弱、滤波器参数无法与之适应等特点,结合了归一化和直方图规定化的方法 增加了灰度信息恢复环节;选用基于Gabor滤波器的增强方式,并自适应调整 Gabor滤波参数。 (3)提出了用于处理低质量指纹增强图的二值化方法。本文借鉴了前人在 直接处理指纹灰度图像的思想,利用契比雪夫逼近法逼近指纹图像局部灰度, 然后利用地形法判决脊线、谷线的位置,该方法对于指纹的纹理恢复特别是细 节特征提取有着很明显的优势。 (4)针对低质量指纹图像预处理的特性,提出了更加适合的应用系统预处 理流程。 本文最后给出了系统测试结果,事实证明本文在低质量指纹图像预处理方 面进行了有益的探索。
Other AbstractAs a well-developed branch of biometrics recognition, fingerprint recognition has a more and more extensive application field because of its great importance. Social activities have such an increasingly demand on the identification and verification that they put forward a more and more restrict requirement on the performance of fingerprint recognition system. Thus the quality of the input fingerprint image becomes a critical factor. There are by far few research on low quality fingerprint image preprocessing, which is the main object in this paper. We focus on several aspects such as fingerprint segmentation, gray level restoration, image enhancement and binarization, and receive some valuable result. The main contribution of this thesis include following issues: (1) We propose a new segmentation method based on region of interest. This method inducts gray level evaluating into the blockwise statistics and apply segmentation to the statistical features. It is proved to have good effect on reducing the influence by sweat spot, false trace and other noise. (2) We improve the flow of enhancement and the algorithm implement. We combine normalization and histogram equalization to restore the gray level information and the weak texture. And we also adopt the Gabor filter in enhancement with the parameter adaptively selected. (3) In order to deal with the low quality enhancement result, we propose a method of binarization with the fingerprint texture approximated by Chebyshev polynomial and deciding whether ridge or valley by means of topographic method. It give the good result especially on the weak texture. (4) We propose a more flexible and reliable flow in low quality fingerprint image preprocessing. According the experiment result of the whole database, our research work are proved to be helpful.
Other Identifier780
Document Type学位论文
Recommended Citation
GB/T 7714
许可. 指纹识别系统中低质量图像预处理技术研究[D]. 中国科学院自动化研究所. 中国科学院研究生院,2004.
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