中文说明： 灰色图像在matlab中以矩阵形式存在，灰度级为k的话，矩阵元素大小为0——2的k次方-1，为了减小视觉的分辨不清图像的缺陷，想到对灰色图像进行彩色处理，这就叫做灰度图像的伪彩色处理，而伪彩色处理经常用的三种方法是灰度级分割、灰度级——彩色变换、频域变换法
English Description：
Gray image exists in the form of matrix in MATLAB. If the gray level is k, the size of matrix element is 0-2 to the k-th power-1. In order to reduce the defect of blurred image, we think of color processing of gray image, which is called pseudo color processing of gray image. The three methods of pseudo color processing are gray level segmentation, gray level color transformation and frequency conversion Domain transformation method