Denoising Diffusion Probabilistic Models for Robust Image Super-Resolution in the Wild

TL;DR

This paper introduces SR3+, a diffusion-based model that significantly improves blind image super-resolution, especially on out-of-distribution images, by employing self-supervised training and noise-conditioning techniques.

Contribution

The paper proposes SR3+ with novel self-supervised training and noise-conditioning augmentation, establishing a new state-of-the-art in blind super-resolution.

Findings

SR3+ outperforms SR3 and Real-ESRGAN on benchmark datasets.

Larger models and datasets further improve SR3+'s performance.

SR3+ achieves a DRealSR FID score of 32.37 with larger models.

Abstract

Diffusion models have shown promising results on single-image super-resolution and other image- to-image translation tasks. Despite this success, they have not outperformed state-of-the-art GAN models on the more challenging blind super-resolution task, where the input images are out of distribution, with unknown degradations. This paper introduces SR3+, a diffusion-based model for blind super-resolution, establishing a new state-of-the-art. To this end, we advocate self-supervised training with a combination of composite, parameterized degradations for self-supervised training, and noise-conditioing augmentation during training and testing. With these innovations, a large-scale convolutional architecture, and large-scale datasets, SR3+ greatly outperforms SR3. It outperforms Real-ESRGAN when trained on the same data, with a DRealSR FID score of 36.82 vs. 37.22, which further improves to FID of 32.37 with larger models, and further still with larger training sets.