OTSU方法计算图像二值化的自适应阈值,算法对输入的灰度图像的直方图进行分析，将直方图分成两个部分，使得两部分之间的距离最大。划分点就是求得的阈值。

-OTSU method of adaptive image binarization threshold, the algorithm of the input histogram analysis of gray image, the histogram is divided into two parts, making the maximum distance between the two parts. Point is obtained by the threshold.