说明：  一种二维Otsu快速算法的Matlab实现，该算法的原文参见《二维直方图区域斜分阈值分割及快速递推算法》，该文已附在内。
(A two-dimensional Otsu fast algorithm Matlab realize that the original algorithm see " Two-dimensional histogram oblique segmentation area and fast recursive algorithm" , the paper has been attached into account.)