对图像进行二维离散小波变换, 变换级数大于等于3级, 并进行重构, 最后计算重构图像的峰值信噪比(PSNR).-images of two-dimensional discrete wavelet transform, transform Series is greater than or equal to 3, and reconstruction, Image Reconstruction final calculation of the peak signal-to-noise ratio (PSNR).