最近在给搞图像去雾的师兄打杂，整理几个评价图像的指标：PSNR,MSE,SSIM,WSNR
PSNR,MSE,SSIM: http://www.voidcn.com/blog/xiaohaijiejie/article/p-3086738.html
PSNR,MSE： http://www.cnblogs.com/tiandsp/archive/2012/11/14/2770462.html
