一种改进的基于方向滤波的指纹图像增强算法

An improved orientation filter-based algorithm for fingerprint enhancement

在指纹滤波增强方法的基础上,提出一种基于方向滤波器的指纹图像增强算法.对指纹图像进行标准化处理,使用扩展的各相同性索贝尔算子计算梯度,并计算出指纹的方向图;根据指纹图像的特点提出了一组方向滤波器,根据纹线的局部方向对指纹图像进行滤波,起到了消除噪声、增强有效纹线信息的作用,为提取特征点提供了良好的图像质量,实验结果证明各相同性索贝尔算子在纹线方向提取上有良好的应用效果.

On the basis of traditional fingerprint enhancement methods, an improved algorithm for fingerprint enhancement is proposed. The fingerprints were standardized, the grads of every pixel in the images were calculated by using the extended isotropic Sobel operator and the direction field of the fingerprints was worked out. According to the characteristics of fingerprints, the proposed algorithm also designs a group of oriented filters, and then manipulates them to filter the image depending on the orientation of the local ridge. The algorithm decreases the noise and boosts up the efficient information carried by the ridges and it provides a better image for the minutia extraction process. The result reveals the better efficiency of using isotropic Sobel operator in getting direction of ridges in a fingerprint image.