全局阈值分割对于小目标物效果不理想，动态阈值容易产生阴影等干扰，但综合考虑全局阈值和动态阈值可以达到比较理想的结果。模糊C均值算法用于灰度图像分割是一种非监督模糊聚类后再标定的过程，该文在不明显增加运算量的前提下，利用模糊C均值自动聚类的功能分别得到全局阈值和动态阈值，完成对阈值矩阵的构造和图像的分割。The global threshold may not work well for image segmentation with small objects. The image segmented by single dynamic threshold usually contains interference like shadow. The gray image segmentation is a process that the image is labeled after an unsupervised clustering by Fuzzy C-Means(FCM). In consideration without increase of computation complexity, we propose an algorithm for gray image segmentation by creating a threshold matrix obtained by global threshold and dynamic threshold that are the FCM clustering results.