Figure2. TheoverallpipelineoftheproposedFinPercep-RMandCo-evolutionaryCurriculumLearning(CCL)framework. FinPercep-RM producesaFine-grainedPerceptualDegradationMapthatcapturesspatiallylocalizeddefectlikelihoodandintensity, andtherewardmodel is progressively expanded from small-variance, coarse-grained rewards to large-variance, fine-grained signals. During training, under the CCL mechanism, the Generator first learns with the coarse global reward from RM for a stable and easy initialization, and is then co- 0 evolutionarily guided by increasingly strict RM versions to enhance local fidelity and suppress reward hacking. k