Full-reference image quality evaluation is an objective measurement method in image processing that determines the perceptual quality and fidelity of a processed, degraded, or enhanced image by directly comparing it against a complete, pristine reference image considered to be the ground truth. This approach quantifies deviations such as noise, blur, compression artifacts, and structural distortions by evaluating pixel-level and perceptual discrepancies between the test image and the original benchmark. Unlike no-reference or reduced-reference methods that evaluate images without full prior knowledge, full-reference evaluation relies entirely on the availability of an ideal target, utilizing standardized mathematical and perceptual metrics such as peak signal-to-noise ratio and structural similarity index to gauge how closely an output matches the reference.