# Degradation Severity Estimation

Fading, stains and water marks on Dunhuang murals are semi-transparent damage that still leaves pigment and contours visible, yet a binary mask marks only where damage lies and cannot describe how severity varies inside that region. SC-PAD estimates a continuous terminal severity field from the degraded image and a coarse mask, reparameterizes a shared diffusion progress into pixel-wise local restoration progress, and drives image-space residual activation through a dynamic Alpha state with consistent endpoints and monotonic evolution. On a fixed 100-image test split, replacing the binary mask with predicted soft Alpha raised PSNR from 27.3421 dB to 30.6122 dB, while ground-truth Alpha added a further 3.2539 dB, marking severity estimation as the remaining bottleneck.

Fading, stains and water marks on Dunhuang murals are semi-transparent damage that still leaves pigment and contours visible, yet a binary mask marks only where damage lies and cannot describe how severity varies inside that region. SC-PAD estimates a continuous terminal severity field from the degraded image and a coarse mask, reparameterizes a shared diffusion progress into pixel-wise local restoration progress, and drives image-space residual activation through a dynamic Alpha state with consistent endpoints and monotonic evolution. On a fixed 100-image test split, replacing the binary mask with predicted soft Alpha raised PSNR from 27.3421 dB to 30.6122 dB, while ground-truth Alpha added a further 3.2539 dB, marking severity estimation as the remaining bottleneck.