人类视频运动转移(HVMT)的目的是鉴于源头的形象,生成了模仿驾驶人员运动的视频。 HVMT的现有方法主要利用生成对抗网络(GAN),以根据根据源人员图像和每个驾驶视频框架估计的流量来执行翘曲操作。但是,由于源头,量表和驾驶人员之间的巨大差异,这些方法始终会产生明显的人工制品。为了克服这些挑战,本文提出了基于gan的新型人类运动转移(远程移动)框架。为了产生逼真的动作,远遥采用了渐进的一代范式:它首先在没有基于流动的翘曲的情况下生成每个身体的零件,然后将所有零件变成驾驶运动的完整人。此外,为了保留自然的全球外观,我们设计了一个全球对齐模块,以根据其布局与驾驶员的规模和位置保持一致。此外,我们提出了一个纹理对准模块,以使人的每个部分都根据纹理的相似性对齐。最后,通过广泛的定量和定性实验,我们的远及以两个公共基准取得了最先进的结果。
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现有的步态识别研究以实验室场景为主。由于人们生活在现实世界中,因此野外的步态识别是一个更实用的问题,最近引起了多媒体和计算机视觉社区的关注。在现有基准上获得最先进性能的当前方法在最近提出的野外数据集上的准确性差得多,因为这些方法几乎无法模拟不受约束场景中步态序列的各种时间动力学。因此,本文提出了一种新型的多跳时间开关方法,以实现实际场景中步态模式的有效时间建模。具体来说,我们设计了一个新型的步态识别网络,称为多跳临时交换机网络(MTSGait),以同时学习空间特征和多尺度的时间功能。与现有的3D卷积进行时间建模的方法不同,我们的MTSGAIT通过2D卷积对步态序列的时间动力学进行建模。通过这种方式,与基于3D卷积的模型相比,它以较少的模型参数来达到高效率,并减少了优化的难度。基于2D卷积内核的特定设计,我们的方法可以消除相邻帧之间特征的不对准。此外,提出了一种新的采样策略,即非环保连续采样,以使模型学习更强大的时间特征。最后,与最新方法相比,提出的方法在两个公共步态数据集(即增长和步态3D)上取得了出色的性能。
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人类运动转移是指合成的照片现实和时间连贯的视频,使一个人能够模仿他人的运动。但是,当前的合成视频遭受了序列帧的时间不一致,这些框架显着降低了视频质量,但远未通过像素域中的现有方法来解决。最近,由于图像合成方法的频率不足,一些有关DeepFake检测的作品试图区分频域中的自然图像和合成图像。尽管如此,从自然和合成视频之间的频域间隙方面的各个方面研究合成视频的时间不一致。在本文中,我们建议深入研究频率空间,以进行时间一致的人类运动转移。首先,我们对频域中的自然和合成视频进行了首次综合分析,以揭示单个帧的空间维度和视频的时间维度的频率差距。为了弥补自然视频和合成视频之间的频率差距,我们提出了一个新型的基于频率的人类运动转移框架,名为Fremotr,该框架可以有效地减轻空间伪像以及合成视频的时间不一致。 Fremotr探索了两个基于频率的新型正则化模块:1)频域外观正则化(FAR),以改善个人在单个帧中的外观和2)时间频率正则化(TFR),以确保相邻框架之间的时间一致性。最后,全面的实验表明,FremoTR不仅在时间一致性指标中产生卓越的性能,而且还提高了合成视频的框架级视觉质量。特别是,时间一致性指标比最新模型提高了近30%。
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Large training data and expensive model tweaking are standard features of deep learning for images. As a result, data owners often utilize cloud resources to develop large-scale complex models, which raises privacy concerns. Existing solutions are either too expensive to be practical or do not sufficiently protect the confidentiality of data and models. In this paper, we study and compare novel \emph{image disguising} mechanisms, DisguisedNets and InstaHide, aiming to achieve a better trade-off among the level of protection for outsourced DNN model training, the expenses, and the utility of data. DisguisedNets are novel combinations of image blocktization, block-level random permutation, and two block-level secure transformations: random multidimensional projection (RMT) and AES pixel-level encryption (AES). InstaHide is an image mixup and random pixel flipping technique \cite{huang20}. We have analyzed and evaluated them under a multi-level threat model. RMT provides a better security guarantee than InstaHide, under the Level-1 adversarial knowledge with well-preserved model quality. In contrast, AES provides a security guarantee under the Level-2 adversarial knowledge, but it may affect model quality more. The unique features of image disguising also help us to protect models from model-targeted attacks. We have done an extensive experimental evaluation to understand how these methods work in different settings for different datasets.
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A storyboard is a roadmap for video creation which consists of shot-by-shot images to visualize key plots in a text synopsis. Creating video storyboards however remains challenging which not only requires association between high-level texts and images, but also demands for long-term reasoning to make transitions smooth across shots. In this paper, we propose a new task called Text synopsis to Video Storyboard (TeViS) which aims to retrieve an ordered sequence of images to visualize the text synopsis. We construct a MovieNet-TeViS benchmark based on the public MovieNet dataset. It contains 10K text synopses each paired with keyframes that are manually selected from corresponding movies by considering both relevance and cinematic coherence. We also present an encoder-decoder baseline for the task. The model uses a pretrained vision-and-language model to improve high-level text-image matching. To improve coherence in long-term shots, we further propose to pre-train the decoder on large-scale movie frames without text. Experimental results demonstrate that our proposed model significantly outperforms other models to create text-relevant and coherent storyboards. Nevertheless, there is still a large gap compared to human performance suggesting room for promising future work.
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Solving real-world optimal control problems are challenging tasks, as the system dynamics can be highly non-linear or including nonconvex objectives and constraints, while in some cases the dynamics are unknown, making it hard to numerically solve the optimal control actions. To deal with such modeling and computation challenges, in this paper, we integrate Neural Networks with the Pontryagin's Minimum Principle (PMP), and propose a computationally efficient framework NN-PMP. The resulting controller can be implemented for systems with unknown and complex dynamics. It can not only utilize the accurate surrogate models parameterized by neural networks, but also efficiently recover the optimality conditions along with the optimal action sequences via PMP conditions. A toy example on a nonlinear Martian Base operation along with a real-world lossy energy storage arbitrage example demonstrates our proposed NN-PMP is a general and versatile computation tool for finding optimal solutions. Compared with solutions provided by the numerical optimization solver with approximated linear dynamics, NN-PMP achieves more efficient system modeling and higher performance in terms of control objectives.
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The task of reconstructing 3D human motion has wideranging applications. The gold standard Motion capture (MoCap) systems are accurate but inaccessible to the general public due to their cost, hardware and space constraints. In contrast, monocular human mesh recovery (HMR) methods are much more accessible than MoCap as they take single-view videos as inputs. Replacing the multi-view Mo- Cap systems with a monocular HMR method would break the current barriers to collecting accurate 3D motion thus making exciting applications like motion analysis and motiondriven animation accessible to the general public. However, performance of existing HMR methods degrade when the video contains challenging and dynamic motion that is not in existing MoCap datasets used for training. This reduces its appeal as dynamic motion is frequently the target in 3D motion recovery in the aforementioned applications. Our study aims to bridge the gap between monocular HMR and multi-view MoCap systems by leveraging information shared across multiple video instances of the same action. We introduce the Neural Motion (NeMo) field. It is optimized to represent the underlying 3D motions across a set of videos of the same action. Empirically, we show that NeMo can recover 3D motion in sports using videos from the Penn Action dataset, where NeMo outperforms existing HMR methods in terms of 2D keypoint detection. To further validate NeMo using 3D metrics, we collected a small MoCap dataset mimicking actions in Penn Action,and show that NeMo achieves better 3D reconstruction compared to various baselines.
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A major goal of multimodal research is to improve machine understanding of images and text. Tasks include image captioning, text-to-image generation, and vision-language representation learning. So far, research has focused on the relationships between images and text. For example, captioning models attempt to understand the semantics of images which are then transformed into text. An important question is: which annotation reflects best a deep understanding of image content? Similarly, given a text, what is the best image that can present the semantics of the text? In this work, we argue that the best text or caption for a given image is the text which would generate the image which is the most similar to that image. Likewise, the best image for a given text is the image that results in the caption which is best aligned with the original text. To this end, we propose a unified framework that includes both a text-to-image generative model and an image-to-text generative model. Extensive experiments validate our approach.
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Model-based attacks can infer training data information from deep neural network models. These attacks heavily depend on the attacker's knowledge of the application domain, e.g., using it to determine the auxiliary data for model-inversion attacks. However, attackers may not know what the model is used for in practice. We propose a generative adversarial network (GAN) based method to explore likely or similar domains of a target model -- the model domain inference (MDI) attack. For a given target (classification) model, we assume that the attacker knows nothing but the input and output formats and can use the model to derive the prediction for any input in the desired form. Our basic idea is to use the target model to affect a GAN training process for a candidate domain's dataset that is easy to obtain. We find that the target model may distract the training procedure less if the domain is more similar to the target domain. We then measure the distraction level with the distance between GAN-generated datasets, which can be used to rank candidate domains for the target model. Our experiments show that the auxiliary dataset from an MDI top-ranked domain can effectively boost the result of model-inversion attacks.
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To reproduce the success of text-to-image (T2I) generation, recent works in text-to-video (T2V) generation employ large-scale text-video dataset for fine-tuning. However, such paradigm is computationally expensive. Humans have the amazing ability to learn new visual concepts from just one single exemplar. We hereby study a new T2V generation problem$\unicode{x2014}$One-Shot Video Generation, where only a single text-video pair is presented for training an open-domain T2V generator. Intuitively, we propose to adapt the T2I diffusion model pretrained on massive image data for T2V generation. We make two key observations: 1) T2I models are able to generate images that align well with the verb terms; 2) extending T2I models to generate multiple images concurrently exhibits surprisingly good content consistency. To further learn continuous motion, we propose Tune-A-Video with a tailored Sparse-Causal Attention, which generates videos from text prompts via an efficient one-shot tuning of pretrained T2I diffusion models. Tune-A-Video is capable of producing temporally-coherent videos over various applications such as change of subject or background, attribute editing, style transfer, demonstrating the versatility and effectiveness of our method.
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