当前，根据CNN处理的视频数据，主要执行动作识别。我们研究CNN的表示过程是否也可以通过将基于图像的动作音频表示为任务中的多模式动作识别。为此，我们提出了多模式的音频图像和视频动作识别器（MAIVAR），这是一个基于CNN的音频图像到视频融合模型，以视频和音频方式来实现卓越的动作识别性能。Maivar提取音频的有意义的图像表示，并将其与视频表示形式融合在一起，以获得更好的性能，与大规模动作识别数据集中的两种模式相比。

Deep convolutional networks have achieved great success for visual recognition in still images. However, for action recognition in videos, the advantage over traditional methods is not so evident. This paper aims to discover the principles to design effective ConvNet architectures for action recognition in videos and learn these models given limited training samples. Our first contribution is temporal segment network (TSN), a novel framework for video-based action recognition. which is based on the idea of long-range temporal structure modeling. It combines a sparse temporal sampling strategy and video-level supervision to enable efficient and effective learning using the whole action video. The other contribution is our study on a series of good practices in learning ConvNets on video data with the help of temporal segment network. Our approach obtains the state-the-of-art performance on the datasets of HMDB51 (69.4%) and UCF101 (94.2%). We also visualize the learned ConvNet models, which qualitatively demonstrates the effectiveness of temporal segment network and the proposed good practices. 1

The paucity of videos in current action classification datasets (UCF-101 and HMDB-51) has made it difficult to identify good video architectures, as most methods obtain similar performance on existing small-scale benchmarks. This paper re-evaluates state-of-the-art architectures in light of the new Kinetics Human Action Video dataset. Kinetics has two orders of magnitude more data, with 400 human action classes and over 400 clips per class, and is collected from realistic, challenging YouTube videos. We provide an analysis on how current architectures fare on the task of action classification on this dataset and how much performance improves on the smaller benchmark datasets after pre-training on Kinetics.We also introduce a new Two-Stream Inflated 3D Con-vNet (I3D) that is based on 2D ConvNet inflation: filters and pooling kernels of very deep image classification ConvNets are expanded into 3D, making it possible to learn seamless spatio-temporal feature extractors from video while leveraging successful ImageNet architecture designs and even their parameters. We show that, after pre-training on Kinetics, I3D models considerably improve upon the state-of-the-art in action classification, reaching 80.9% on HMDB-51 and 98.0% on UCF-101.

在本文中，我们提出了一种新的视频表示学习方法，名为时间挤压（TS）池，这可以从长期的视频帧中提取基本移动信息，并将其映射到一组名为挤压图像的几个图像中。通过将时间挤压池作为层嵌入到现成的卷积神经网络（CNN）中，我们设计了一个名为Temporal Squeeze网络（TESNet）的新视频分类模型。由此产生的挤压图像包含来自视频帧的基本移动信息，对应于视频分类任务的优化。我们在两个视频分类基准上评估我们的架构，并与最先进的结果进行了比较。

There is a natural correlation between the visual and auditive elements of a video. In this work we leverage this connection to learn general and effective models for both audio and video analysis from self-supervised temporal synchronization. We demonstrate that a calibrated curriculum learning scheme, a careful choice of negative examples, and the use of a contrastive loss are critical ingredients to obtain powerful multi-sensory representations from models optimized to discern temporal synchronization of audio-video pairs. Without further finetuning, the resulting audio features achieve performance superior or comparable to the state-of-the-art on established audio classification benchmarks (DCASE2014 and ESC-50). At the same time, our visual subnet provides a very effective initialization to improve the accuracy of video-based action recognition models: compared to learning from scratch, our self-supervised pretraining yields a remarkable gain of +19.9% in action recognition accuracy on UCF101 and a boost of +17.7% on HMDB51.

本文介绍了一种基于纯变压器的方法，称为视频动作识别的多模态视频变压器（MM-VIT）。与仅利用解码的RGB帧的其他方案不同，MM-VIT专门在压缩视频域中进行操作，并利用所有容易获得的模式，即I帧，运动向量，残差和音频波形。为了处理从多种方式提取的大量时空令牌，我们开发了几种可扩展的模型变体，它们将自我关注分解在空间，时间和模态尺寸上。此外，为了进一步探索丰富的模态互动及其效果，我们开发并比较了可以无缝集成到变压器构建块中的三种不同的交叉模态注意力机制。关于三个公共行动识别基准的广泛实验（UCF-101，某事-V2，Kinetics-600）证明了MM-VIT以效率和准确性的最先进的视频变压器，并且表现更好或同样地表现出对于具有计算重型光学流的最先进的CNN对应物。

Human activity recognition (HAR) using drone-mounted cameras has attracted considerable interest from the computer vision research community in recent years. A robust and efficient HAR system has a pivotal role in fields like video surveillance, crowd behavior analysis, sports analysis, and human-computer interaction. What makes it challenging are the complex poses, understanding different viewpoints, and the environmental scenarios where the action is taking place. To address such complexities, in this paper, we propose a novel Sparse Weighted Temporal Attention (SWTA) module to utilize sparsely sampled video frames for obtaining global weighted temporal attention. The proposed SWTA is comprised of two parts. First, temporal segment network that sparsely samples a given set of frames. Second, weighted temporal attention, which incorporates a fusion of attention maps derived from optical flow, with raw RGB images. This is followed by a basenet network, which comprises a convolutional neural network (CNN) module along with fully connected layers that provide us with activity recognition. The SWTA network can be used as a plug-in module to the existing deep CNN architectures, for optimizing them to learn temporal information by eliminating the need for a separate temporal stream. It has been evaluated on three publicly available benchmark datasets, namely Okutama, MOD20, and Drone-Action. The proposed model has received an accuracy of 72.76%, 92.56%, and 78.86% on the respective datasets thereby surpassing the previous state-of-the-art performances by a margin of 25.26%, 18.56%, and 2.94%, respectively.

Drone-camera based human activity recognition (HAR) has received significant attention from the computer vision research community in the past few years. A robust and efficient HAR system has a pivotal role in fields like video surveillance, crowd behavior analysis, sports analysis, and human-computer interaction. What makes it challenging are the complex poses, understanding different viewpoints, and the environmental scenarios where the action is taking place. To address such complexities, in this paper, we propose a novel Sparse Weighted Temporal Fusion (SWTF) module to utilize sparsely sampled video frames for obtaining global weighted temporal fusion outcome. The proposed SWTF is divided into two components. First, a temporal segment network that sparsely samples a given set of frames. Second, weighted temporal fusion, that incorporates a fusion of feature maps derived from optical flow, with raw RGB images. This is followed by base-network, which comprises a convolutional neural network module along with fully connected layers that provide us with activity recognition. The SWTF network can be used as a plug-in module to the existing deep CNN architectures, for optimizing them to learn temporal information by eliminating the need for a separate temporal stream. It has been evaluated on three publicly available benchmark datasets, namely Okutama, MOD20, and Drone-Action. The proposed model has received an accuracy of 72.76%, 92.56%, and 78.86% on the respective datasets thereby surpassing the previous state-of-the-art performances by a significant margin.

机器学习和非接触传感器的进步使您能够在医疗保健环境中理解复杂的人类行为。特别是，已经引入了几种深度学习系统，以实现对自闭症谱系障碍（ASD）等神经发展状况的全面分析。这种情况会影响儿童的早期发育阶段，并且诊断完全依赖于观察孩子的行为和检测行为提示。但是，诊断过程是耗时的，因为它需要长期的行为观察以及专家的稀缺性。我们展示了基于区域的计算机视觉系统的效果，以帮助临床医生和父母分析孩子的行为。为此，我们采用并增强了一个数据集，用于使用在不受控制的环境中捕获的儿童的视频来分析自闭症相关的动作（例如，在各种环境中使用消费级摄像机收集的视频）。通过检测视频中的目标儿童以减少背景噪声的影响，可以预处理数据。在时间卷积模型的有效性的推动下，我们提出了能够从视频帧中提取动作功能并通过分析视频中的框架之间的关系来从视频帧中提取动作功能并分类与自闭症相关的行为。通过对功能提取和学习策略的广泛评估，我们证明了通过膨胀的3D Convnet和多阶段的时间卷积网络实现最佳性能，达到了0.83加权的F1得分，以分类三种自闭症相关的动作，超越表现优于表现现有方法。我们还通过在同一系统中采用ESNET主链来提出一个轻重量解决方案，实现0.71加权F1得分的竞争结果，并在嵌入式系统上实现潜在的部署。

Convolutional Neural Networks (CNN) have been regarded as a powerful class of models for image recognition problems. Nevertheless, it is not trivial when utilizing a CNN for learning spatio-temporal video representation. A few studies have shown that performing 3D convolutions is a rewarding approach to capture both spatial and temporal dimensions in videos. However, the development of a very deep 3D CNN from scratch results in expensive computational cost and memory demand. A valid question is why not recycle off-the-shelf 2D networks for a 3D CNN. In this paper, we devise multiple variants of bottleneck building blocks in a residual learning framework by simulating 3 × 3 × 3 convolutions with 1 × 3 × 3 convolutional filters on spatial domain (equivalent to 2D CNN) plus 3 × 1 × 1 convolutions to construct temporal connections on adjacent feature maps in time. Furthermore, we propose a new architecture, named , that exploits all the variants of blocks but composes each in different placement of ResNet, following the philosophy that enhancing structural diversity with going deep could improve the power of neural networks. Our P3D ResNet achieves clear improvements on Sports-1M video classification dataset against 3D CNN and frame-based 2D CNN by 5.3% and 1.8%, respectively. We further examine the generalization performance of video representation produced by our pre-trained P3D ResNet on five different benchmarks and three different tasks, demonstrating superior performances over several state-of-the-art techniques.

事件摄像机是新型生物启发传感器，其异步捕获“事件”形式的像素级强度变化。由于它们的传感机制，事件相机几乎没有运动模糊，这是一个非常高的时间分辨率，并且需要比传统的基于帧的相机更小的电力和存储器。这些特性使它们成为一个完美的拟合若干现实世界应用，如在可穿戴设备上的专门动作识别，其中快速相机运动和有限的电力挑战传统视觉传感器。然而，迄今为止，基于事件的愿景的不断增长的愿景领域已经忽略了在此类应用中的活动摄像机的潜力。在本文中，我们表明事件数据是自我监测行动识别的非常有价值的模态。为此，我们介绍了N-EPIC-Kitchens，这是大型史诗厨房数据集的第一个基于事件的相机扩展。在此背景下，我们提出了两种策略：（i）使用传统的视频处理架构（E $ ^ 2 $（GO））和（ii）使用事件数据直接处理事件相机数据（E $ ^ 2 $（GO））和蒸馏光流信息（E $ ^ 2 $（go）mo）。在我们提出的基准测试中，我们表明事件数据为RGB和光流提供了可比性的性能，但在部署时没有任何额外的流量计算，以及相对于RGB的信息高达4％的性能。

Spatiotemporal and motion features are two complementary and crucial information for video action recognition. Recent state-of-the-art methods adopt a 3D CNN stream to learn spatiotemporal features and another flow stream to learn motion features. In this work, we aim to efficiently encode these two features in a unified 2D framework. To this end, we first propose an STM block, which contains a Channel-wise SpatioTemporal Module (CSTM) to present the spatiotemporal features and a Channel-wise Motion Module (CMM) to efficiently encode motion features. We then replace original residual blocks in the ResNet architecture with STM blcoks to form a simple yet effective STM network by introducing very limited extra computation cost. Extensive experiments demonstrate that the proposed STM network outperforms the state-of-the-art methods on both temporal-related datasets (i.e., Something-Something v1 & v2 and Jester) and scene-related datasets (i.e., Kinetics-400, UCF-101, and HMDB-51) with the help of encoding spatiotemporal and motion features together. * The work was done during an internship at SenseTime.

未来的活动预期是在Egocentric视觉中具有挑战性问题。作为标准的未来活动预期范式，递归序列预测遭受错误的累积。为了解决这个问题，我们提出了一个简单有效的自我监管的学习框架，旨在使中间表现为连续调节中间代表性，以产生表示（a）与先前观察到的对比的当前时间戳框架中的新颖信息内容和（b）反映其与先前观察到的帧的相关性。前者通过最小化对比损失来实现，并且后者可以通过动态重量机制来实现在观察到的内容中的信息帧中，具有当前帧的特征与观察到的帧之间的相似性比较。通过多任务学习可以进一步增强学习的最终视频表示，该多任务学习在目标活动标签上执行联合特征学习和自动检测到的动作和对象类令牌。在大多数自我传统视频数据集和两个第三人称视频数据集中，SRL在大多数情况下急剧表现出现有的现有最先进。通过实验性事实，还可以准确识别支持活动语义的行动和对象概念的实验性。

纯视觉变压器体系结构对于简短的视频分类和动作识别任务非常有效。但是，由于自我注意力的二次复杂性和缺乏归纳偏见，变压器是资源密集的，并且遭受了数据效率低下的困扰。长期的视频理解任务扩大了变压器的数据和内存效率问题，使当前方法无法在数据或内存限制域上实施。本文介绍了有效的时空注意网络（Stan），该网络使用两流变压器体系结构来模拟静态图像特征和时间上下文特征之间的依赖性。我们提出的方法可以在单个GPU上进行长达两分钟的视频，这是数据效率的，并且可以在几个长的视频理解任务上实现SOTA性能。

该报告描述了我们对2022 Epic-Kitchens Action识别挑战的获胜解决方案背后的方法。我们的方法基于我们最近的工作，视频识别的多视图变压器（MTV），并将其适应多模式输入。我们的最终提交由多模式MTV（M＆M）模型的合奏组成，它改变了主链尺寸和输入方式。我们的方法在动作类中的测试集上达到了52.8％的TOP-1准确性，比去年的获胜参赛作品高4.1％。

In this paper, we develop an efficient multi-scale network to predict action classes in partial videos in an end-to-end manner. Unlike most existing methods with offline feature generation, our method directly takes frames as input and further models motion evolution on two different temporal scales.Therefore, we solve the complexity problems of the two stages of modeling and the problem of insufficient temporal and spatial information of a single scale. Our proposed End-to-End MultiScale Network (E2EMSNet) is composed of two scales which are named segment scale and observed global scale. The segment scale leverages temporal difference over consecutive frames for finer motion patterns by supplying 2D convolutions. For observed global scale, a Long Short-Term Memory (LSTM) is incorporated to capture motion features of observed frames. Our model provides a simple and efficient modeling framework with a small computational cost. Our E2EMSNet is evaluated on three challenging datasets: BIT, HMDB51, and UCF101. The extensive experiments demonstrate the effectiveness of our method for action prediction in videos.

We investigate architectures of discriminatively trained deep Convolutional Networks (ConvNets) for action recognition in video. The challenge is to capture the complementary information on appearance from still frames and motion between frames. We also aim to generalise the best performing hand-crafted features within a data-driven learning framework. Our contribution is three-fold. First, we propose a two-stream ConvNet architecture which incorporates spatial and temporal networks. Second, we demonstrate that a ConvNet trained on multi-frame dense optical flow is able to achieve very good performance in spite of limited training data. Finally, we show that multitask learning, applied to two different action classification datasets, can be used to increase the amount of training data and improve the performance on both. Our architecture is trained and evaluated on the standard video actions benchmarks of UCF-101 and HMDB-51, where it is competitive with the state of the art. It also exceeds by a large margin previous attempts to use deep nets for video classification.

利用在大规模图像文本对中预先训练的视觉和语言模型（VLM）成为开放式视觉识别的有希望的范式。在这项工作中，我们通过利用视频中自然存在的运动和音频来扩展这种范式。我们提出\ textbf {mov}，这是\ textbf {m} ult-imodal \ textbf {o} pen- \ textbf {v} ocabulary视频分类的简单而有效的方法。在MOV中，我们直接使用具有最小修改的预训练VLM的视觉编码器来编码视频，光流和音频频谱图。我们设计一种跨模式融合机制来汇总免费的多模式信息。 Kinetics-700和VGGSOUND的实验表明，引入流量或音频模态会带来预先训练的VLM和现有方法的大量性能增长。具体而言，MOV极大地提高了基础类别的准确性，而在新颖的课程上则更好地概括了。 MOV在UCF和HMDB零摄像视频分类基准上实现了最新结果，从而极大地超过了基于VLMS的传统零摄像方法和最新方法。代码和模型将发布。

Humans perceive the world by concurrently processing and fusing high-dimensional inputs from multiple modalities such as vision and audio. Machine perception models, in stark contrast, are typically modality-specific and optimised for unimodal benchmarks, and hence late-stage fusion of final representations or predictions from each modality (`late-fusion') is still a dominant paradigm for multimodal video classification. Instead, we introduce a novel transformer based architecture that uses `fusion bottlenecks' for modality fusion at multiple layers. Compared to traditional pairwise self-attention, our model forces information between different modalities to pass through a small number of bottleneck latents, requiring the model to collate and condense the most relevant information in each modality and only share what is necessary. We find that such a strategy improves fusion performance, at the same time reducing computational cost. We conduct thorough ablation studies, and achieve state-of-the-art results on multiple audio-visual classification benchmarks including Audioset, Epic-Kitchens and VGGSound. All code and models will be released.

由于其低成本和快速移动性，无人驾驶汽车（UAV）现在已广泛应用于数据获取。随着航空视频量的增加，对这些视频自动解析的需求正在激增。为了实现这一目标，当前的研究主要集中于在空间和时间维度沿着卷积的整体特征提取整体特征。但是，这些方法受到小时接收场的限制，无法充分捕获长期的时间依赖性，这对于描述复杂动力学很重要。在本文中，我们提出了一个新颖的深神经网络，称为futh-net，不仅为整体特征建模，而且还模拟了空中视频分类的时间关系。此外，在新型融合模块中，多尺度的时间关系可以完善整体特征，以产生更具歧视性的视频表示。更特别地，FUTH-NET采用了两条道路架构：（1）学习框架外观和短期时间变化的一般特征的整体代表途径，以及（2）捕获跨任意跨越任意时间关系的时间关系途径框架，提供长期的时间依赖性。之后，提出了一个新型的融合模块，以时空整合从这两种途径中学到的两个特征。我们的模型对两个航空视频分类数据集进行了评估，即ERA和无人机操作，并实现了最新结果。这表明了其在不同识别任务（事件分类和人类行动识别）之间的有效性和良好的概括能力。为了促进进一步的研究，我们在https://gitlab.lrz.de/ai4eo/reasoning/futh-net上发布该代码。