中文说明：matlab 下经典的利用wavedec2，appcoef2，detcoef2对图像进行分解提取高低频系数完成图像压缩和重构的源程序.
English Description：
Matlab classic use wavedec2, appcoef2, detcoef2 to decompose the image, extract high and low frequency coefficients, complete the source program of image compression and reconstruction