用不确定性引导噪声,提升图像超分模型的细节还原能力。
Uncertainty-guided Perturbation for Image Super-Resolution Diffusion Model
- 根据低分辨率图块的不确定性动态调节噪声强度,区域自适应控制
- 在多个数据集上优于现有方法,且模型更小训练更快
- 适合追求高保真细节重建的图像超分应用
基于扩散模型的图像超分辨率方法在感知质量上显著优于生成对抗网络方法。得益于长马尔可夫链结构,扩散模型具备强大建模能力,可在真实场景中表现优异。与以往通过调整噪声调度或采样过程提升性能的方法不同,本文聚焦于更高效利用低分辨率(LR)信息。我们发现,LR图像的不同区域对应扩散过程中的不同时间步:平坦区域接近目标高分辨率分布,而边缘和纹理区域则较远。在平坦区域施加微弱噪声更有助于重建。我们将此特性与不确定性关联,提出不确定性引导的噪声加权机制。低不确定性区域(平坦区)接受更少噪声,以保留更多原始信息,从而提升性能。同时,改进了先前方法的网络结构,构建不确定性引导扰动超分模型(UPSR)。大量实验表明,尽管模型规模更小、训练开销更低,该方法在多个数据集上均超越当前最先进水平,定量与定性结果俱优。
原文摘要 · Abstract (English)
Diffusion-based image super-resolution methods have demonstrated significant advantages over GAN-based approaches, particularly in terms of perceptual quality. Building upon a lengthy Markov chain, diffusion-based methods possess remarkable modeling capacity, enabling them to achieve outstanding performance in real-world scenarios. Unlike previous methods that focus on modifying the noise schedule or sampling process to enhance performance, our approach emphasizes the improved utilization of LR information. We find that different regions of the LR image can be viewed as corresponding to different timesteps in a diffusion process, where flat areas are closer to the target HR distribution but edge and texture regions are farther away. In these flat areas, applying a slight noise is more advantageous for the reconstruction. We associate this characteristic with uncertainty and propose to apply uncertainty estimate to guide region-specific noise level control, a technique we refer to as Uncertainty-guided Noise Weighting. Pixels with lower uncertainty (i.e., flat regions) receive reduced noise to preserve more LR information, therefore improving performance. Furthermore, we modify the network architecture of previous methods to develop our Uncertainty-guided Perturbation Super-Resolution (UPSR) model. Extensive experimental results demonstrate that, despite reduced model size and training overhead, the proposed UWSR method outperforms current state-of-the-art methods across various datasets, both quantitatively and qualitatively.
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