It is known that the decomposition in low-rank and sparse matrices (\textbf{L+S} for short) can be achieved by several Robust PCA techniques. Besides the low rankness, the local smoothness (\textbf{LSS}) is a vitally essential prior for many real-world matrix data such as hyperspectral images and surveillance videos, which makes such matrices have low-rankness and local smoothness properties at the same time. This poses an interesting question: Can we make a matrix decomposition in terms of \textbf{L\&LSS +S } form exactly? To address this issue, we propose in this paper a new RPCA model based on three-dimensional correlated total variation regularization (3DCTV-RPCA for short) by fully exploiting and encoding the prior expression underlying such joint low-rank and local smoothness matrices. Specifically, using a modification of Golfing scheme, we prove that under some mild assumptions, the proposed 3DCTV-RPCA model can decompose both components exactly, which should be the first theoretical guarantee among all such related methods combining low rankness and local smoothness. In addition, by utilizing Fast Fourier Transform (FFT), we propose an efficient ADMM algorithm with a solid convergence guarantee for solving the resulting optimization problem. Finally, a series of experiments on both simulations and real applications are carried out to demonstrate the general validity of the proposed 3DCTV-RPCA model.
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在计算断层摄影(CT)成像过程中,患者内的金属植入物总是造成有害伪影,这对重建的CT图像的视觉质量产生了负面影响,并且对随后的临床诊断产生负面影响。对于金属伪影减少(MAR)任务,基于深度学习的方法取得了有希望的表现。然而,大多数主要共享两个主要常见限制:1)CT物理成像几何约束是完全融入深网络结构中的; 2)整个框架对特定MAR任务具有薄弱的可解释性;因此,难以评估每个网络模块的作用。为了减轻这些问题,在本文中,我们构建了一种新的可解释的双域网络,称为Indudonet +,CT成像过程被精细地嵌入到其中。具体地说,我们推出了一个联合空间和氡域重建模型,并提出了一种仅具有简单操作员的优化算法来解决它。通过将所提出的算法中涉及的迭代步骤展开到相应的网络模块中,我们可以轻松地构建Indudonet +,以明确的解释性。此外,我们分析了不同组织之间的CT值,并将现有的观察合并到Endudonet +的现有网络中,这显着提高了其泛化性能。综合数据和临床数据的综合实验证实了所提出的方法的优越性以及超出当前最先进(SOTA)MAR方法的卓越概括性性能。代码可用于\ url {https://github.com/hongwang01/indududonet_plus}。
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联邦元学习(FML)已成为应对当今边缘学习竞技场中的数据限制和异质性挑战的承诺范式。然而,其性能通常受到缓慢的收敛性和相应的低通信效率的限制。此外,由于可用的无线电频谱和物联网设备的能量容量通常不足,因此在在实际无线网络中部署FML时,控制资源分配和能量消耗是至关重要的。为了克服挑战,在本文中,我们严格地分析了每个设备对每轮全球损失减少的贡献,并使用非统一的设备选择方案开发FML算法(称为Nufm)以加速收敛。之后,我们制定了集成NuFM在多通道无线系统中的资源分配问题,共同提高收敛速率并最小化壁钟时间以及能量成本。通过逐步解构原始问题,我们设计了一个联合设备选择和资源分配策略,以解决理论保证问题。此外,我们表明Nufm的计算复杂性可以通过$ O(d ^ 2)$至$ o(d)$(使用模型维度$ d $)通过组合两个一阶近似技术来降低。广泛的仿真结果表明,与现有基线相比,所提出的方法的有效性和优越性。
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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。
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尽管在机器人抓住方面取得了令人印象深刻的进展,但机器人在复杂的任务中不熟练(例如,在杂乱中搜索并掌握指定的目标)。这些任务不仅涉及抓住,而是对世界的全面感知(例如,对象关系)。最近,令人鼓舞的结果表明,可以通过学习来理解高级概念。然而,这种算法通常是数据密集型的,并且缺乏数据严重限制了它们的性能。在本文中,我们提出了一个名为Reactad的新数据集,用于学习物体和掌握之间的关系。我们收集对象姿势,分段,掌握和目标驱动的关系掌握任务的关系。我们的数据集以2D图像和3D点云的两种形式收集。此外,由于所有数据都会自动生成,因此可以自由地导入数据生成的新对象。我们还发布了一个真实的验证数据集,以评估模型的SIM-to-Real性能,这些模型正在接受重新研磨的模型。最后,我们进行了一系列的实验,表明,根据关系和掌握检测,培训的模型可以概括到现实场景。我们的数据集和代码可以在:https://github.com/poisonwine/gerad
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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。
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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.
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Deploying reliable deep learning techniques in interdisciplinary applications needs learned models to output accurate and ({even more importantly}) explainable predictions. Existing approaches typically explicate network outputs in a post-hoc fashion, under an implicit assumption that faithful explanations come from accurate predictions/classifications. We have an opposite claim that explanations boost (or even determine) classification. That is, end-to-end learning of explanation factors to augment discriminative representation extraction could be a more intuitive strategy to inversely assure fine-grained explainability, e.g., in those neuroimaging and neuroscience studies with high-dimensional data containing noisy, redundant, and task-irrelevant information. In this paper, we propose such an explainable geometric deep network dubbed as NeuroExplainer, with applications to uncover altered infant cortical development patterns associated with preterm birth. Given fundamental cortical attributes as network input, our NeuroExplainer adopts a hierarchical attention-decoding framework to learn fine-grained attentions and respective discriminative representations to accurately recognize preterm infants from term-born infants at term-equivalent age. NeuroExplainer learns the hierarchical attention-decoding modules under subject-level weak supervision coupled with targeted regularizers deduced from domain knowledge regarding brain development. These prior-guided constraints implicitly maximizes the explainability metrics (i.e., fidelity, sparsity, and stability) in network training, driving the learned network to output detailed explanations and accurate classifications. Experimental results on the public dHCP benchmark suggest that NeuroExplainer led to quantitatively reliable explanation results that are qualitatively consistent with representative neuroimaging studies.
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Seismic data often undergoes severe noise due to environmental factors, which seriously affects subsequent applications. Traditional hand-crafted denoisers such as filters and regularizations utilize interpretable domain knowledge to design generalizable denoising techniques, while their representation capacities may be inferior to deep learning denoisers, which can learn complex and representative denoising mappings from abundant training pairs. However, due to the scarcity of high-quality training pairs, deep learning denoisers may sustain some generalization issues over various scenarios. In this work, we propose a self-supervised method that combines the capacities of deep denoiser and the generalization abilities of hand-crafted regularization for seismic data random noise attenuation. Specifically, we leverage the Self2Self (S2S) learning framework with a trace-wise masking strategy for seismic data denoising by solely using the observed noisy data. Parallelly, we suggest the weighted total variation (WTV) to further capture the horizontal local smooth structure of seismic data. Our method, dubbed as S2S-WTV, enjoys both high representation abilities brought from the self-supervised deep network and good generalization abilities of the hand-crafted WTV regularizer and the self-supervised nature. Therefore, our method can more effectively and stably remove the random noise and preserve the details and edges of the clean signal. To tackle the S2S-WTV optimization model, we introduce an alternating direction multiplier method (ADMM)-based algorithm. Extensive experiments on synthetic and field noisy seismic data demonstrate the effectiveness of our method as compared with state-of-the-art traditional and deep learning-based seismic data denoising methods.
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During X-ray computed tomography (CT) scanning, metallic implants carrying with patients often lead to adverse artifacts in the captured CT images and then impair the clinical treatment. Against this metal artifact reduction (MAR) task, the existing deep-learning-based methods have gained promising reconstruction performance. Nevertheless, there is still some room for further improvement of MAR performance and generalization ability, since some important prior knowledge underlying this specific task has not been fully exploited. Hereby, in this paper, we carefully analyze the characteristics of metal artifacts and propose an orientation-shared convolution representation strategy to adapt the physical prior structures of artifacts, i.e., rotationally symmetrical streaking patterns. The proposed method rationally adopts Fourier-series-expansion-based filter parametrization in artifact modeling, which can better separate artifacts from anatomical tissues and boost the model generalizability. Comprehensive experiments executed on synthesized and clinical datasets show the superiority of our method in detail preservation beyond the current representative MAR methods. Code will be available at \url{https://github.com/hongwang01/OSCNet}
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