Image denoising is the process of removing noise from noisy images, which is an image domain transferring task, i.e., from a single or several noise level domains to a photo-realistic domain. In this paper, we propose an effective image denoising method by learning two image priors from the perspective of domain alignment. We tackle the domain alignment on two levels. 1) the feature-level prior is to learn domain-invariant features for corrupted images with different level noise; 2) the pixel-level prior is used to push the denoised images to the natural image manifold. The two image priors are based on $\mathcal{H}$-divergence theory and implemented by learning classifiers in adversarial training manners. We evaluate our approach on multiple datasets. The results demonstrate the effectiveness of our approach for robust image denoising on both synthetic and real-world noisy images. Furthermore, we show that the feature-level prior is capable of alleviating the discrepancy between different level noise. It can be used to improve the blind denoising performance in terms of distortion measures (PSNR and SSIM), while pixel-level prior can effectively improve the perceptual quality to ensure the realistic outputs, which is further validated by subjective evaluation.

本文提出了一种基于领域对齐的有效图像去噪方法，该方法学习了两个图像先验知识，其中特征级先验用于学习对抗训练中的不同噪声水平下对抗特征，像素级先验则用于推动去噪图像到自然图像流形。结果表明，该方法有效地提高了合成和真实噪声图像的去噪能力，并可以用于盲去噪任务以及提高感知质量。

盲图像去噪的深度图像先验学习