中文说明：k-均值聚类算法实现灰度图像分割，输入图像矩阵和聚类中心个数，返回为最终的聚类中心和图像中每个像素所属类的编号（对应于图像矩阵）
English Description：
The K-means clustering algorithm realizes gray image segmentation, inputs the image matrix and the number of clustering centers, and returns the final clustering center and the class number of each pixel in the image (corresponding to the image matrix)