Table 1 Quantitative comparison of image enhancement results in Fig. 4. PSNR (Peak Signal-to-Noise Ratio) and SSIM (Structural similarity index Measure) are full-reference metrics where higher values indicate better quality. PSNR measures the ratio between the maximum possible signal power and noise power, while SSIM assesses structural similarity between images.niqe (Natural image quality Evaluator) and BRISQUE (Blind/Reference-free image Spatial quality Evaluator) are no-reference metrics where lower values indicate better quality. These metrics evaluate perceptual image quality without requiring reference images, which is particularly useful for real-world enhancement tasks.

From: A hybrid zero-reference and dehazing network for joint low-light underground image enhancement