How metrics are calculated?

[zhebawomenjiuyaochangshenle]

Hello, I would like to know how the indicators in Table 1 and Table 2 of your paper are calculated (NIQE,UNIQUE,PSNR,SSIM)? The index obtained by the method I used when calculating the input image is too far from the index in your paper. Besides, I have inquired the index in other low-illumination enhancement papers and found that your index is more referable. Can you give the calculation code of the indicator? I would appreciate it.