盲图修复（IR）是计算机视觉中常见但充满挑战的问题。基于经典模型的方法和最新的深度学习（DL）方法代表了有关此问题的两种不同方法，每种方法都有自己的优点和缺点。在本文中，我们提出了一种新颖的盲图恢复方法，旨在整合它们的两种优势。具体而言，我们为盲IR构建了一个普通的贝叶斯生成模型，该模型明确描绘了降解过程。在此提出的模型中，PICEL的非I.I.D。高斯分布用于适合图像噪声。它的灵活性比简单的I.I.D。在大多数常规方法中采用的高斯或拉普拉斯分布，以处理图像降解中包含的更复杂的噪声类型。为了解决该模型，我们设计了一个变异推理算法，其中所有预期的后验分布都被参数化为深神经网络，以提高其模型能力。值得注意的是，这种推论算法诱导统一的框架共同处理退化估计和图像恢复的任务。此外，利用了前一种任务中估计的降解信息来指导后一种红外过程。对两项典型的盲型IR任务进行实验，即图像降解和超分辨率，表明所提出的方法比当前最新的方法实现了卓越的性能。

虽然最近基于模型的盲目单图像超分辨率（SISR）的研究已经取得了巨大的成功，但大多数人都不认为图像劣化。首先，它们总是假设图像噪声obeys独立和相同分布的（i.i.d.）高斯或拉普拉斯分布，这在很大程度上低估了真实噪音的复杂性。其次，以前的常用核前沿（例如，归一化，稀疏性）不足以保证理性内核解决方案，从而退化后续SISR任务的性能。为了解决上述问题，本文提出了一种基于模型的盲人SISR方法，该方法在概率框架下，从噪声和模糊内核的角度精心模仿图像劣化。具体而言，而不是传统的i.i.d.噪声假设，基于补丁的非i.i.d。提出噪声模型来解决复杂的真实噪声，期望增加噪声表示模型的自由度。至于模糊内核，我们新建构建一个简洁但有效的内核生成器，并将其插入所提出的盲人SISR方法作为明确的内核（EKP）。为了解决所提出的模型，专门设计了理论上接地的蒙特卡罗EM算法。综合实验证明了我们对综合性和实时数据集的最新技术的方法的优越性。

本文提出了图像恢复的新变异推理框架和一个卷积神经网络（CNN）结构，该结构可以解决所提出的框架所描述的恢复问题。较早的基于CNN的图像恢复方法主要集中在网络体系结构设计或培训策略上，具有非盲方案，其中已知或假定降解模型。为了更接近现实世界的应用程序，CNN还接受了整个数据集的盲目培训，包括各种降解。然而，给定有多样化的图像的高质量图像的条件分布太复杂了，无法通过单个CNN学习。因此，也有一些方法可以提供其他先验信息来培训CNN。与以前的方法不同，我们更多地专注于基于贝叶斯观点以及如何重新重新重构目标的恢复目标。具体而言，我们的方法放松了原始的后推理问题，以更好地管理子问题，因此表现得像分裂和互动方案。结果，与以前的框架相比，提出的框架提高了几个恢复问题的性能。具体而言，我们的方法在高斯denoising，现实世界中的降噪，盲图超级分辨率和JPEG压缩伪像减少方面提供了最先进的性能。

Recent years have witnessed the unprecedented success of deep convolutional neural networks (CNNs) in single image super-resolution (SISR). However, existing CNN-based SISR methods mostly assume that a low-resolution (LR) image is bicubicly downsampled from a high-resolution (HR) image, thus inevitably giving rise to poor performance when the true degradation does not follow this assumption. Moreover, they lack scalability in learning a single model to nonblindly deal with multiple degradations. To address these issues, we propose a general framework with dimensionality stretching strategy that enables a single convolutional super-resolution network to take two key factors of the SISR degradation process, i.e., blur kernel and noise level, as input. Consequently, the super-resolver can handle multiple and even spatially variant degradations, which significantly improves the practicability. Extensive experimental results on synthetic and real LR images show that the proposed convolutional super-resolution network not only can produce favorable results on multiple degradations but also is computationally efficient, providing a highly effective and scalable solution to practical SISR applications.

尽管目前基于深度学习的方法在盲目的单图像超分辨率（SISR）任务中已获得了有希望的表现，但其中大多数主要集中在启发式上构建多样化的网络体系结构，并更少强调对Blur之间的物理发电机制的明确嵌入内核和高分辨率（HR）图像。为了减轻这个问题，我们提出了一个模型驱动的深神经网络，称为blind SISR。具体而言，为了解决经典的SISR模型，我们提出了一种简单的效果迭代算法。然后，通过将所涉及的迭代步骤展开到相应的网络模块中，我们自然构建了KXNET。所提出的KXNET的主要特异性是整个学习过程与此SISR任务的固有物理机制完全合理地集成在一起。因此，学习的模糊内核具有清晰的物理模式，并且模糊内核和HR图像之间的相互迭代过程可以很好地指导KXNET沿正确的方向发展。关于合成和真实数据的广泛实验很好地证明了我们方法的卓越准确性和一般性超出了当前代表性的最先进的盲目SISR方法。代码可在：\ url {https://github.com/jiahong-fu/kxnet}中获得。

While deep learning-based methods for blind face restoration have achieved unprecedented success, they still suffer from two major limitations. First, most of them deteriorate when facing complex degradations out of their training data. Second, these methods require multiple constraints, e.g., fidelity, perceptual, and adversarial losses, which require laborious hyper-parameter tuning to stabilize and balance their influences. In this work, we propose a novel method named DifFace that is capable of coping with unseen and complex degradations more gracefully without complicated loss designs. The key of our method is to establish a posterior distribution from the observed low-quality (LQ) image to its high-quality (HQ) counterpart. In particular, we design a transition distribution from the LQ image to the intermediate state of a pre-trained diffusion model and then gradually transmit from this intermediate state to the HQ target by recursively applying a pre-trained diffusion model. The transition distribution only relies on a restoration backbone that is trained with $L_2$ loss on some synthetic data, which favorably avoids the cumbersome training process in existing methods. Moreover, the transition distribution can contract the error of the restoration backbone and thus makes our method more robust to unknown degradations. Comprehensive experiments show that DifFace is superior to current state-of-the-art methods, especially in cases with severe degradations. Our code and model are available at https://github.com/zsyOAOA/DifFace.

As a common weather, rain streaks adversely degrade the image quality. Hence, removing rains from an image has become an important issue in the field. To handle such an ill-posed single image deraining task, in this paper, we specifically build a novel deep architecture, called rain convolutional dictionary network (RCDNet), which embeds the intrinsic priors of rain streaks and has clear interpretability. In specific, we first establish a RCD model for representing rain streaks and utilize the proximal gradient descent technique to design an iterative algorithm only containing simple operators for solving the model. By unfolding it, we then build the RCDNet in which every network module has clear physical meanings and corresponds to each operation involved in the algorithm. This good interpretability greatly facilitates an easy visualization and analysis on what happens inside the network and why it works well in inference process. Moreover, taking into account the domain gap issue in real scenarios, we further design a novel dynamic RCDNet, where the rain kernels can be dynamically inferred corresponding to input rainy images and then help shrink the space for rain layer estimation with few rain maps so as to ensure a fine generalization performance in the inconsistent scenarios of rain types between training and testing data. By end-to-end training such an interpretable network, all involved rain kernels and proximal operators can be automatically extracted, faithfully characterizing the features of both rain and clean background layers, and thus naturally lead to better deraining performance. Comprehensive experiments substantiate the superiority of our method, especially on its well generality to diverse testing scenarios and good interpretability for all its modules. Code is available in \emph{\url{https://github.com/hongwang01/DRCDNet}}.

在实践中，很难收集配对的培训数据，但是不合格的样本广泛存在。当前的方法旨在通过探索损坏的数据和清洁数据之间的关系来从未配对样本中生成合成的培训数据。这项工作提出了Lud-Vae，这是一种从边际分布中采样的数据中学习关节概率密度函数的深层生成方法。我们的方法基于一个经过精心设计的概率图形模型，在该模型中，干净和损坏的数据域在条件上是独立的。使用变异推断，我们最大化证据下限（ELBO）以估计关节概率密度函数。此外，我们表明在推理不变假设下没有配对样品的情况下，ELBO是可以计算的。该属性在未配对的环境中提供了我们方法的数学原理。最后，我们将我们的方法应用于现实世界图像denoising，超分辨率和低光图像增强任务，并使用Lud-vae生成的合成数据训练模型。实验结果验证了我们方法比其他方法的优势。

最近，基于深度学习的图像降级方法在测试数据上具有与训练集相同的测试数据的有希望的性能，在该数据中，已经学习了基于合成或收集的现实世界训练数据的各种denoising模型。但是，在处理真实世界的嘈杂图像时，Denoising的性能仍然受到限制。在本文中，我们提出了一种简单而有效的贝叶斯深集合（BDE）方法，用于真实世界图像denoising，其中可以融合使用各种训练数据设置进行预训练的几位代表性的深层Denoiser，以提高稳健性。 BDE的基础是，现实世界的图像噪声高度取决于信号依赖性，并且在现实世界中的嘈杂图像中的异质噪声可以由不同的Deoisiser分别处理。特别是，我们将受过良好训练的CBDNET，NBNET，HINET，UFORFORMER和GMSNET进入Denoiser池，并采用U-NET来预测Pixel的加权图以融合这些DeOisiser。引入了贝叶斯深度学习策略，而不是仅仅学习像素的加权地图，而是为了预测加权不确定性和加权图，可以通过该策略来建模预测差异，以改善现实世界中的嘈杂图像的鲁棒性。广泛的实验表明，可以通过融合现有的DINOISER而不是训练一个以昂贵的成本来训练一个大的Denoiser来更好地消除现实世界的噪音。在DND数据集上，我们的BDE实现了 +0.28〜dB PSNR的增益，而不是最先进的denoising方法。此外，我们注意到，在应用于现实世界嘈杂的图像时，基于不同高斯噪声水平的BDE Denoiser优于最先进的CBDNET。此外，我们的BDE可以扩展到其他图像恢复任务，并在基准数据集上获得 +0.30dB， +0.18dB和 +0.12dB PSNR的收益，以分别用于图像去除图像，图像降低和单个图像超级分辨率。

基于深度学习的高光谱图像（HSI）恢复方法因其出色的性能而广受欢迎，但每当任务更改的细节时，通常都需要昂贵的网络再培训。在本文中，我们建议使用有效的插入方法以统一的方法恢复HSI，该方法可以共同保留基于优化方法的灵活性，并利用深神经网络的强大表示能力。具体而言，我们首先开发了一个新的深HSI DeNoiser，利用了门控复发单元，短期和长期的跳过连接以及增强的噪声水平图，以更好地利用HSIS内丰富的空间光谱信息。因此，这导致在高斯和复杂的噪声设置下，在HSI DeNosing上的最新性能。然后，在处理各种HSI恢复任务之前，将提议的DeNoiser插入即插即用的框架中。通过对HSI超分辨率，压缩感测和内部进行的广泛实验，我们证明了我们的方法经常实现卓越的性能，这与每个任务上的最先进的竞争性或甚至更好任何特定任务的培训。

Face Restoration (FR) aims to restore High-Quality (HQ) faces from Low-Quality (LQ) input images, which is a domain-specific image restoration problem in the low-level computer vision area. The early face restoration methods mainly use statistic priors and degradation models, which are difficult to meet the requirements of real-world applications in practice. In recent years, face restoration has witnessed great progress after stepping into the deep learning era. However, there are few works to study deep learning-based face restoration methods systematically. Thus, this paper comprehensively surveys recent advances in deep learning techniques for face restoration. Specifically, we first summarize different problem formulations and analyze the characteristic of the face image. Second, we discuss the challenges of face restoration. Concerning these challenges, we present a comprehensive review of existing FR methods, including prior based methods and deep learning-based methods. Then, we explore developed techniques in the task of FR covering network architectures, loss functions, and benchmark datasets. We also conduct a systematic benchmark evaluation on representative methods. Finally, we discuss future directions, including network designs, metrics, benchmark datasets, applications,etc. We also provide an open-source repository for all the discussed methods, which is available at https://github.com/TaoWangzj/Awesome-Face-Restoration.

盲级超分辨率（SR）旨在从低分辨率（LR）图像中恢复高质量的视觉纹理，通常通过下采样模糊内核和添加剂噪声来降解。由于现实世界中复杂的图像降解的挑战，此任务非常困难。现有的SR方法要么假定预定义的模糊内核或固定噪声，这限制了这些方法在具有挑战性的情况下。在本文中，我们提出了一个用于盲目超级分辨率（DMSR）的降解引导的元修复网络，该网络促进了真实病例的图像恢复。 DMSR由降解提取器和元修复模块组成。萃取器估计LR输入中的降解，并指导元恢复模块以预测恢复参数的恢复参数。 DMSR通过新颖的降解一致性损失和重建损失共同优化。通过这样的优化，DMSR在三个广泛使用的基准上以很大的边距优于SOTA。一项包括16个受试者的用户研究进一步验证了现实世界中的盲目SR任务中DMSR的优势。

Model-based optimization methods and discriminative learning methods have been the two dominant strategies for solving various inverse problems in low-level vision. Typically, those two kinds of methods have their respective merits and drawbacks, e.g., model-based optimization methods are flexible for handling different inverse problems but are usually time-consuming with sophisticated priors for the purpose of good performance; in the meanwhile, discriminative learning methods have fast testing speed but their application range is greatly restricted by the specialized task. Recent works have revealed that, with the aid of variable splitting techniques, denoiser prior can be plugged in as a modular part of model-based optimization methods to solve other inverse problems (e.g., deblurring). Such an integration induces considerable advantage when the denoiser is obtained via discriminative learning. However, the study of integration with fast discriminative denoiser prior is still lacking. To this end, this paper aims to train a set of fast and effective CNN (convolutional neural network) denoisers and integrate them into model-based optimization method to solve other inverse problems. Experimental results demonstrate that the learned set of denoisers not only achieve promising Gaussian denoising results but also can be used as prior to deliver good performance for various low-level vision applications.

极度依赖于从划痕的模型的降级或优化的降解或优化的迭代估计，现有的盲超分辨率（SR）方法通常是耗时和效率较低，因为退化的估计从盲初始化进行并且缺乏可解释降解前沿。为了解决它，本文提出了一种使用端到端网络的盲SR的过渡学习方法，没有任何额外的推断中的额外迭代，并探讨了未知降级的有效表示。首先，我们分析并证明降解的过渡性作为可解释的先前信息，以间接推断出未知的降解模型，包括广泛使用的添加剂和卷曲降解。然后，我们提出了一种新颖的过渡性学习方法，用于盲目超分辨率（TLSR），通过自适应地推断过渡转换功能来解决未知的降级而没有推断的任何迭代操作。具体地，端到端TLSR网络包括一定程度的过渡性（点）估计网络，同一性特征提取网络和过渡学习模块。对盲人SR任务的定量和定性评估表明，拟议的TLSR实现了优异的性能，并且对最先进的盲人SR方法的复杂性较少。该代码可在github.com/yuanfeihuang/tlsr获得。

Discriminative model learning for image denoising has been recently attracting considerable attentions due to its favorable denoising performance. In this paper, we take one step forward by investigating the construction of feed-forward denoising convolutional neural networks (DnCNNs) to embrace the progress in very deep architecture, learning algorithm, and regularization method into image denoising. Specifically, residual learning and batch normalization are utilized to speed up the training process as well as boost the denoising performance. Different from the existing discriminative denoising models which usually train a specific model for additive white Gaussian noise (AWGN) at a certain noise level, our DnCNN model is able to handle Gaussian denoising with unknown noise level (i.e., blind Gaussian denoising). With the residual learning strategy, DnCNN implicitly removes the latent clean image in the hidden layers. This property motivates us to train a single DnCNN model to tackle with several general image denoising tasks such as Gaussian denoising, single image super-resolution and JPEG image deblocking. Our extensive experiments demonstrate that our DnCNN model can not only exhibit high effectiveness in several general image denoising tasks, but also be efficiently implemented by benefiting from GPU computing.

现有的视频denoising方法通常假设嘈杂的视频通过添加高斯噪声从干净的视频中降低。但是，经过这种降解假设训练的深层模型将不可避免地导致由于退化不匹配而导致的真实视频的性能差。尽管一些研究试图在摄像机捕获的嘈杂和无噪声视频对上训练深层模型，但此类模型只能对特定的相机很好地工作，并且对其他视频的推广不佳。在本文中，我们建议提高此限制，并专注于一般真实视频的问题，目的是在看不见的现实世界视频上概括。我们首先调查视频噪音的共同行为来解决这个问题，并观察两个重要特征：1）缩减有助于降低空间空间中的噪声水平； 2）来自相邻框架的信息有助于消除时间上的当前框架的噪声空间。在这两个观察结果的推动下，我们通过充分利用上述两个特征提出了多尺度的复发架构。其次，我们通过随机调整不同的噪声类型来训练Denoising模型来提出合成真实的噪声降解模型。借助合成和丰富的降解空间，我们的退化模型可以帮助弥合训练数据和现实世界数据之间的分布差距。广泛的实验表明，与现有方法相比，我们所提出的方法实现了最先进的性能和更好的概括能力，而在合成高斯denoising和实用的真实视频denoisising方面都具有现有方法。

在弱光环境下，手持式摄影在长时间的曝光设置下遭受了严重的相机震动。尽管现有的Deblurry算法在暴露良好的模糊图像上表现出了令人鼓舞的性能，但它们仍然无法应对低光快照。在实用的低光脱毛中，复杂的噪声和饱和区是两个主导挑战。在这项工作中，我们提出了一种称为图像的新型非盲脱毛方法，并具有特征空间Wiener Deonervolution网络（Infwide），以系统地解决这些问题。在算法设计方面，Infwide提出了一个两分支的架构，该体系结构明确消除了噪声并幻觉，使图像空间中的饱和区域抑制了特征空间中的响起文物，并将两个互补输出与一个微妙的多尺度融合网络集成在一起高质量的夜间照片浮雕。为了进行有效的网络培训，我们设计了一组损失功能，集成了前向成像模型和向后重建，以形成近环的正则化，以确保深神经网络的良好收敛性。此外，为了优化Infwide在实际弱光条件下的适用性，采用基于物理过程的低光噪声模型来合成现实的嘈杂夜间照片进行模型训练。利用传统的Wiener Deonervolution算法的身体驱动的特征并引起了深层神经网络的表示能力，Infwide可以恢复细节，同时抑制在脱毛期间的不愉快的人工制品。关于合成数据和实际数据的广泛实验证明了所提出的方法的出色性能。

Convolutional Neural Network (CNN)-based image super-resolution (SR) has exhibited impressive success on known degraded low-resolution (LR) images. However, this type of approach is hard to hold its performance in practical scenarios when the degradation process is unknown. Despite existing blind SR methods proposed to solve this problem using blur kernel estimation, the perceptual quality and reconstruction accuracy are still unsatisfactory. In this paper, we analyze the degradation of a high-resolution (HR) image from image intrinsic components according to a degradation-based formulation model. We propose a components decomposition and co-optimization network (CDCN) for blind SR. Firstly, CDCN decomposes the input LR image into structure and detail components in feature space. Then, the mutual collaboration block (MCB) is presented to exploit the relationship between both two components. In this way, the detail component can provide informative features to enrich the structural context and the structure component can carry structural context for better detail revealing via a mutual complementary manner. After that, we present a degradation-driven learning strategy to jointly supervise the HR image detail and structure restoration process. Finally, a multi-scale fusion module followed by an upsampling layer is designed to fuse the structure and detail features and perform SR reconstruction. Empowered by such degradation-based components decomposition, collaboration, and mutual optimization, we can bridge the correlation between component learning and degradation modelling for blind SR, thereby producing SR results with more accurate textures. Extensive experiments on both synthetic SR datasets and real-world images show that the proposed method achieves the state-of-the-art performance compared to existing methods.

在本文中，我们考虑了基于参考的超分辨率（REFSR）中的两个具有挑战性的问题，（i）如何选择适当的参考图像，以及（ii）如何以一种自我监督的方式学习真实世界RefSR。特别是，我们从双摄像头Zooms（SelfDZSR）观察到现实世界图像SR的新颖的自我监督学习方法。考虑到多台相机在现代智能手机中的普及，可以自然利用越来越多的缩放（远摄）图像作为指导较小的变焦（短对焦）图像的SR。此外，SelfDZSR学习了一个深层网络，以获得短对焦图像的SR结果，以具有与远摄图像相同的分辨率。为此，我们将远摄图像而不是其他高分辨率图像作为监督信息，然后从中选择中心贴片作为对相应的短对焦图像补丁的引用。为了减轻短对焦低分辨率（LR）图像和远摄地面真相（GT）图像之间未对准的影响，我们设计了辅助LR发电机，并将GT映射到辅助LR，同时保持空间位置不变。 。然后，可以利用辅助-LR通过建议的自适应空间变压器网络（ADASTN）将LR特征变形，并将REF特征与GT匹配。在测试过程中，可以直接部署SelfDZSR，以使用远摄映像的引用来超级解决整个短对焦图像。实验表明，我们的方法可以针对最先进的方法实现更好的定量和定性性能。代码可在https://github.com/cszhilu1998/selfdzsr上找到。

突发超级分辨率（SR）提供了从低质量图像恢复丰富细节的可能性。然而，由于实际应用中的低分辨率（LR）图像具有多种复杂和未知的降级，所以现有的非盲（例如，双臂）设计的网络通常导致恢复高分辨率（HR）图像的严重性能下降。此外，处理多重未对准的嘈杂的原始输入也是具有挑战性的。在本文中，我们解决了从现代手持设备获取的原始突发序列重建HR图像的问题。中央观点是一个内核引导策略，可以用两个步骤解决突发SR：内核建模和HR恢复。前者估计来自原始输入的突发内核，而后者基于估计的内核预测超分辨图像。此外，我们引入了内核感知可变形对准模块，其可以通过考虑模糊的前沿而有效地对准原始图像。对综合和现实世界数据集的广泛实验表明，所提出的方法可以在爆发SR问题中对最先进的性能进行。