title: Typical PSNR values
body: <p>In <a href="http://en.wikipedia.org/wiki/Image_restoration" rel="nofollow">Image Restoration</a> problem, (still image not video image), why <a href="http://en.wikipedia.org/wiki/Peak_signal-to-noise_ratio" rel="nofollow">Peak Signal-to-Noise Ratio</a> (PSNR) should not be more than 50 or 55 dB? I got 63 dB and they say it is wrong. why and How it is wrong?</p>