Learning Diffusion Texture Priors for Image Restoration

Diffusion Models have shown remarkable performance in image generation tasks, which are capable of generating diverse and realistic image content. When adopting diffusion models for image restoration, the crucial challenge lies in how to preserve high-level image fidelity in the randomness diffusion process and generate accurate background structures and realistic texture details. In this paper, we propose a general framework and develop a Diffusion Texture Prior Model (DTPM) for image restoration tasks. DTPM explicitly models high-quality texture details through the diffusion process, rather than global contextual content. In phase one of the training stage, we pre-train DTPM on approximately 55K high-quality image samples, after which we freeze most of its parameters. In phase two, we insert conditional guidance adapters into DTPM and equip it with an initial predictor, thereby facilitating its rapid adaptation to downstream image restoration tasks. Our DTPM could mitigate the randomness of traditional diffusion models by utilizing encapsulated rich and diverse texture knowledge and background structural information provided by the initial predictor during the sampling process. Our comprehensive evaluations of five image restoration tasks demonstrate DTPM's superiority over existing regression and diffusion-based image restoration methods in perceptual quality and its exceptional generalization capabilities. The code will be publicly available.