中文说明：利用最大熵方法求图像二值化的阈值输入的图像名称，读取名称是M的图像文件统计各个灰度级出现的概率
English Description：
The maximum entropy method is used to calculate the threshold value of image binarization, input the image name, read the image file whose name is m, and count the probability of each gray level