基于连续方向图的指纹图像预处理算法

在研究和分析了现有的预处理算法的基础上，提出了一种基于连续方向图的指纹图像预处理算法。主要包括指纹图像规格化、连续方向图计算、方向自适应滤波、二值化和细化等算法，这种连续方向图过渡平滑、自然，且有很好的连续性、渐变性和抗噪性，同时又具有极高的精确度，能更精确地反映指纹脊线的结构特征。从而使得滤波效果更佳；实验结果表明，该算法处理效果好、运算速度快，有效的满足了预处理的要求，为指纹的特征提取和识别奠定了坚实的基础。

Algorithm for Fingerprint Image Preprocessing Based on Continuous Directional Image

After investigation and analyzing the existemt prerocessing algorithm, all algorithm based on the continuous directional images is proposed for the preprocessing of fingerprint images. This algorithm is composed of normalization, continuous directional image computation directional adaptive filtering, binarization and thinning. This continuous directional image transits smoothly and exhibits not only good continuity, gradualness, and excellent robusiness to the noises, but also very high precision. It can represent the basic structural features of the fingerprint more precisely and makes the filtering well. The experiment shows that this suggestedalgorithm has the advantages of good processing effect and fast operating speed. It can effectively meet the needs of the preprocessing, which establishes the solid foundation to the feature extraction and fingerprint idemification.