Abstract: Segmentation is an important part of fingerprint image preprocessing.Based on the segmentation of variance method，which the artificial choice of threshold is difficult and inaccurate，as well as the incorrect segmentation caused by random noise，this paper proposes a local threshold segmentation on the combination of the variance and gradient.Compared with some typical fingerprint segmentation algorithm in the experiment，the local threshold segmentation is efficient and fast，which is suitable for low-quality fingerprint images，especially have better results to the images which is difficult to the global threshold segmentation algorithm.

摘要： 指纹图像分割是指纹识别预处理中重要的一步。在灰度方差法的基础上，针对人为选择阈值的困难和不准确性，以及因噪声带来的误分割，提出了一种灰度方差和灰度梯度结合的局部阈值分割方法。在实验中，通过和其他典型指纹分割方法的比较，该方法可以高效快速的对指纹图像进行分割，对噪声比较大的低质量指纹图像分割较好，特别对一些用全局阈值不易分割的指纹图像有较好的效果。