最大类间方差法原理：最大类间方差法是由日本学者大津于1979年提出的,是一种自适应的阈值确定的方法,又叫大津法,简称OTSU。它是按图像的灰度特性,将图像分成背景和目标2 部分。-Otsu method works: Otsu method by Otsu, Japan scholars put forward in 1979, is an adaptive method of determining the threshold, also known as Otsu method, refer