利用二维Mallat小波分解原理，对一幅标准图像进行3级分解，获取小波高/低频系数，并分别用低频分量LL1、LL2、LL3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地PSNR-2D Mallat wavelet decomposition principle, a standard image 3 decomposition, to obtain of Wavelet high/low frequency coefficients, and the low-frequency component LL1, LL2, LL3 wavelet coefficients of image reconstruction, these three cases were calculated and the original image.Compare PSNR