本程序目的是对某一标准图像进行二维Mallat小波的3级分解，获得小波高/低频系数，分别用低频分量LL1、LL2、LL3的小波系数进行图像重建，分别计算这三种情况和原始图像比较的PSNR。-The purpose of this program is of a standard two-dimensional images of three Mallat wavelet decomposition, wavelet get high/low frequency coefficients, respectively, with the low-frequency component of LL1, LL2, LL3 wavelet coefficients for image reconstruction, three cases were calculated, and the original compared images PSNR.