二维离散小波变换 只能处理长宽一样的方形图像，灰度和彩色图像都可，要用其他图像只需把Lena.bmp改为其他图像，但图像要保存在m文件所在路径下。-Can only deal with the same length and width of the square image, grayscale and color images can be used to use other images only need to change Lena.bmp other images, but th