【作者】 常江；

【导师】 郭雷；

【作者基本信息】 西北工业大学 ， 模式识别与智能系统， 2007， 硕士

【摘要】 指纹识别技术作为最传统、最成熟的生物识别方式之一，已经在许多领域得以应用，但是指纹识别的核心技术仍存在许多尚未解决的问题。自动指纹识别技术现在是、未来几年仍将是一个重要且极具挑战性的数字图像处理、模式识别研究课题。本文对指纹图像增强、指纹图像二值化及二值图像增强等指纹预处理算法进行了大量的研究，主要研究与结果如下： (1) 研究了现有的主要滤波方式并根据指纹图像脊谷相间的特性提出了一种基于傅立叶变换的带阻滤波增强算法，很好的保留了图像中高频部分的有用信息，又能滤除图像中的噪声，同时使整个图像变得平滑，大大提高了指纹预处理的速度和效果。研究了基于指纹方向信息的指纹滤波方式，为下一步对指纹图像二值及二值图像增强做好了准备。 (2) 研究了目前常用二值化算法的优缺点，提出了基于带阻滤波的指纹图像二值化处理方法和指纹图像相位差分二值化处理方法，大大的提高了二值化对指纹特征的保持度，以及二值后处理方法——二值指纹图像方向图增强算法。针对现存指纹库的特点，存在着大量的带有边框线的指纹图像提出了一种对二值指纹图像边框滤除算法，很好的改善了这一问题。 最后总结了全文，分析了目前研究工作中需要进一步完善的地方，指出今后工作的研究方向。更多还原

【Abstract】 As one of most traditional and reliable biometric technology, Automatic fingerprint identification has been applied to many fields. But fingerprint identification technology still has some unfathomed problems. Automatic fingerprint identification technology is very important for digital image process and pattern identification research not only at present but also in the future. Some of key algorithms about fingerprint image buildup and binarization are provided. The detail is as follow,(1) After studying most of filters, an algorithm based on Fourier transform band-elimination filtering is presented according to fingerprint image’s characteristic. This filter can save high frequency in image and eliminate yawp in image, which greatly promoted fingerprint pretreatment efficiency. We researched fingerprint filter base on fingerprint direction.(2) Comparing some algorithms about binarization in common use, binarization based on band-elimination filter and potential difference binarization are provided, which greatly improved the retentivity of fingerprint characteristic and fingerprint binarization buildup algorithm. To meet the real needs of the database, this essay advocates a deleting arithmetic to eliminate the fringe line in fingerprint image, which effectively solved the problem and has been proven reliable in the test.Finally, according to summary of this thesis, the improvements need to be finished are analyzed, and the direction of future work is given.更多还原