Video Super-Resolution (VSR) aims to restore high-resolution (HR) videos from low-resolution (LR) videos. Existing VSR techniques usually recover HR frames by extracting pertinent textures from nearby frames with known degradation processes. Despite significant progress, grand challenges are remained to effectively extract and transmit high-quality textures from high-degraded low-quality sequences, such as blur, additive noises, and compression artifacts. In this work, a novel Frequency-Transformer (FTVSR) is proposed for handling low-quality videos that carry out self-attention in a combined space-time-frequency domain. First, video frames are split into patches and each patch is transformed into spectral maps in which each channel represents a frequency band. It permits a fine-grained self-attention on each frequency band, so that real visual texture can be distinguished from artifacts. Second, a novel dual frequency attention (DFA) mechanism is proposed to capture the global frequency relations and local frequency relations, which can handle different complicated degradation processes in real-world scenarios. Third, we explore different self-attention schemes for video processing in the frequency domain and discover that a ``divided attention'' which conducts a joint space-frequency attention before applying temporal-frequency attention, leads to the best video enhancement quality. Extensive experiments on three widely-used VSR datasets show that FTVSR outperforms state-of-the-art methods on different low-quality videos with clear visual margins. Code and pre-trained models are available at https://github.com/researchmm/FTVSR.
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视频3D人类姿势估计旨在将视频中人类关节的3D坐标定位。最近的基于变压器的方法着重于从顺序2D姿势捕获时空信息,由于在2D姿势估计的步骤中丢失了视觉深度特征,因此无法有效地对上下文深度特征进行建模。在本文中,我们将范式简化为端到端框架,实例引导的视频变压器(IVT),该范式可以有效地从视觉特征中学习时空的上下文深度信息,并直接从视频框架中预测3D姿势。特别是,我们首先将视频框架作为一系列实例引导令牌,每个令牌都可以预测人类实例的3D姿势。这些令牌包含身体结构信息,因为它们是由关节偏移从人体中心到相应身体关节的指导提取的。然后,这些令牌被发送到IVT中,以学习时空的上下文深度。此外,我们提出了一种跨尺度实例引导的注意机制,以处理多个人之间的变异量表。最后,每个人的3D姿势都是通过坐标回归从实例引导的代币中解码的。在三个广泛使用的3D姿势估计基准上进行的实验表明,拟议的IVT实现了最先进的性能。
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压缩视频超分辨率(VSR)旨在从压缩的低分辨率对应物中恢复高分辨率帧。最近的VSR方法通常通过借用相邻视频帧的相关纹理来增强输入框架。尽管已经取得了一些进展,但是从压缩视频中有效提取和转移高质量纹理的巨大挑战,这些视频通常会高度退化。在本文中,我们提出了一种用于压缩视频超分辨率(FTVSR)的新型频率转换器,该频率在联合时空频域中进行自我注意。首先,我们将视频框架分为斑块,然后将每个贴片转换为DCT光谱图,每个通道代表频带。这样的设计使每个频带都可以进行细粒度的自我注意力,因此可以将真实的视觉纹理与伪影区分开,并进一步用于视频框架修复。其次,我们研究了不同的自我发场方案,并发现在对每个频带上应用暂时关注之前,会引起关节空间的注意力,从而带来最佳的视频增强质量。两个广泛使用的视频超分辨率基准的实验结果表明,FTVSR在未压缩和压缩视频的最先进的方法中都具有清晰的视觉边距。代码可在https://github.com/researchmm/ftvsr上找到。
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多人3D姿势估计是一项具有挑战性的任务,因为遮挡和深度歧义,尤其是在人群场景的情况下。为了解决这些问题,大多数现有方法通过使用图神经网络增强特征表示或添加结构约束来探索建模身体上下文提示。但是,这些方法对于它们的单根公式并不强大,该公式将3D从根节点带有预定义的图形。在本文中,我们提出了GR-M3D,该GR-M3D模拟了\ textbf {m} ulti-person \ textbf {3d}构成构成构成效果估计,并使用动态\ textbf {g} raph \ textbf {r textbf {r} eSounting。预测GR-M3D中的解码图而不是预定。特别是,它首先生成几个数据图,并通过刻度和深度意识到的细化模块(SDAR)增强它们。然后从这些数据图估算每个人的多个根关键点和密集的解码路径。基于它们,动态解码图是通过将路径权重分配给解码路径来构建的,而路径权重是从这些增强的数据图推断出来的。此过程被命名为动态图推理(DGR)。最后,根据每个检测到的人的动态解码图对3D姿势进行解码。 GR-M3D可以根据输入数据采用软路径权重,通过采用软路径权重来调整解码图的结构,这使得解码图最能适应不同的输入人员,并且比以前的方法更有能力处理闭塞和深度歧义。我们从经验上表明,提出的自下而上方法甚至超过自上而下的方法,并在三个3D姿势数据集上实现最先进的方法。
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Accurate determination of a small molecule candidate (ligand) binding pose in its target protein pocket is important for computer-aided drug discovery. Typical rigid-body docking methods ignore the pocket flexibility of protein, while the more accurate pose generation using molecular dynamics is hindered by slow protein dynamics. We develop a tiered tensor transform (3T) algorithm to rapidly generate diverse protein-ligand complex conformations for both pose and affinity estimation in drug screening, requiring neither machine learning training nor lengthy dynamics computation, while maintaining both coarse-grain-like coordinated protein dynamics and atomistic-level details of the complex pocket. The 3T conformation structures we generate are closer to experimental co-crystal structures than those generated by docking software, and more importantly achieve significantly higher accuracy in active ligand classification than traditional ensemble docking using hundreds of experimental protein conformations. 3T structure transformation is decoupled from the system physics, making future usage in other computational scientific domains possible.
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Feature selection helps reduce data acquisition costs in ML, but the standard approach is to train models with static feature subsets. Here, we consider the dynamic feature selection (DFS) problem where a model sequentially queries features based on the presently available information. DFS is often addressed with reinforcement learning (RL), but we explore a simpler approach of greedily selecting features based on their conditional mutual information. This method is theoretically appealing but requires oracle access to the data distribution, so we develop a learning approach based on amortized optimization. The proposed method is shown to recover the greedy policy when trained to optimality and outperforms numerous existing feature selection methods in our experiments, thus validating it as a simple but powerful approach for this problem.
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Deep neural networks are vulnerable to adversarial attacks. In this paper, we take the role of investigators who want to trace the attack and identify the source, that is, the particular model which the adversarial examples are generated from. Techniques derived would aid forensic investigation of attack incidents and serve as deterrence to potential attacks. We consider the buyers-seller setting where a machine learning model is to be distributed to various buyers and each buyer receives a slightly different copy with same functionality. A malicious buyer generates adversarial examples from a particular copy $\mathcal{M}_i$ and uses them to attack other copies. From these adversarial examples, the investigator wants to identify the source $\mathcal{M}_i$. To address this problem, we propose a two-stage separate-and-trace framework. The model separation stage generates multiple copies of a model for a same classification task. This process injects unique characteristics into each copy so that adversarial examples generated have distinct and traceable features. We give a parallel structure which embeds a ``tracer'' in each copy, and a noise-sensitive training loss to achieve this goal. The tracing stage takes in adversarial examples and a few candidate models, and identifies the likely source. Based on the unique features induced by the noise-sensitive loss function, we could effectively trace the potential adversarial copy by considering the output logits from each tracer. Empirical results show that it is possible to trace the origin of the adversarial example and the mechanism can be applied to a wide range of architectures and datasets.
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Due to the issue that existing wireless sensor network (WSN)-based anomaly detection methods only consider and analyze temporal features, in this paper, a self-supervised learning-based anomaly node detection method based on an autoencoder is designed. This method integrates temporal WSN data flow feature extraction, spatial position feature extraction and intermodal WSN correlation feature extraction into the design of the autoencoder to make full use of the spatial and temporal information of the WSN for anomaly detection. First, a fully connected network is used to extract the temporal features of nodes by considering a single mode from a local spatial perspective. Second, a graph neural network (GNN) is used to introduce the WSN topology from a global spatial perspective for anomaly detection and extract the spatial and temporal features of the data flows of nodes and their neighbors by considering a single mode. Then, the adaptive fusion method involving weighted summation is used to extract the relevant features between different models. In addition, this paper introduces a gated recurrent unit (GRU) to solve the long-term dependence problem of the time dimension. Eventually, the reconstructed output of the decoder and the hidden layer representation of the autoencoder are fed into a fully connected network to calculate the anomaly probability of the current system. Since the spatial feature extraction operation is advanced, the designed method can be applied to the task of large-scale network anomaly detection by adding a clustering operation. Experiments show that the designed method outperforms the baselines, and the F1 score reaches 90.6%, which is 5.2% higher than those of the existing anomaly detection methods based on unsupervised reconstruction and prediction. Code and model are available at https://github.com/GuetYe/anomaly_detection/GLSL
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With the increase in health consciousness, noninvasive body monitoring has aroused interest among researchers. As one of the most important pieces of physiological information, researchers have remotely estimated the heart rate (HR) from facial videos in recent years. Although progress has been made over the past few years, there are still some limitations, like the processing time increasing with accuracy and the lack of comprehensive and challenging datasets for use and comparison. Recently, it was shown that HR information can be extracted from facial videos by spatial decomposition and temporal filtering. Inspired by this, a new framework is introduced in this paper to remotely estimate the HR under realistic conditions by combining spatial and temporal filtering and a convolutional neural network. Our proposed approach shows better performance compared with the benchmark on the MMSE-HR dataset in terms of both the average HR estimation and short-time HR estimation. High consistency in short-time HR estimation is observed between our method and the ground truth.
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Currently, most deep learning methods cannot solve the problem of scarcity of industrial product defect samples and significant differences in characteristics. This paper proposes an unsupervised defect detection algorithm based on a reconstruction network, which is realized using only a large number of easily obtained defect-free sample data. The network includes two parts: image reconstruction and surface defect area detection. The reconstruction network is designed through a fully convolutional autoencoder with a lightweight structure. Only a small number of normal samples are used for training so that the reconstruction network can be A defect-free reconstructed image is generated. A function combining structural loss and $\mathit{L}1$ loss is proposed as the loss function of the reconstruction network to solve the problem of poor detection of irregular texture surface defects. Further, the residual of the reconstructed image and the image to be tested is used as the possible region of the defect, and conventional image operations can realize the location of the fault. The unsupervised defect detection algorithm of the proposed reconstruction network is used on multiple defect image sample sets. Compared with other similar algorithms, the results show that the unsupervised defect detection algorithm of the reconstructed network has strong robustness and accuracy.
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