PSNR ≥ 45

SSIM ≥ 0.99

5

Excellent

33 ≤ PSNR < 45

0.95 ≤ SSIM < 0.99

4

Good

27.4 ≤ PSNR < 33

0.88 ≤ SSIM < 0.95

3

Reasonable

18.7 ≤ PSNR < 27.4

0.5 ≤ SSIM < 0.88

2

Poor

18.7 < PSNR

0.5 < SSIM

1

Bad