What is the difference between MSE and PSNR of images? I have some doubts.


What is the difference between quality parameters MSE and PSNR?
Which is used when?
Is there any advantage of PSNR over MSE or vice versa?


Also I have heard people saying that MSE and PSNR should never be used to check image quality. Instead one should use UQI and SSIM. I read about UQI and SSIM and came to know they are close to human visual system but I read a technical report which says that SSIM is sometimes better than MSE and sometimes MSE is better. Here is the link
http://www.cs.uregina.ca/Research/Techreports/2008-02.pdf

Now I am confused which one to use(among MSE and SSIM) and why? 

Also it is said that SSIM is upgraded version of UQI. Then what's the difference between these two?
Why do people still use UQI irrespective of the fact that SSIM is there?
These metrics are used to compute certain signal properties. They are roughly divided into 2 categories as 1-objective, 2-subjective. Objective criteria are too mechanical and do not take any human perception weighting. Subjective criteria are either model based computations or directly opinion based measurements. Which is to use when is a matter of application.