Human mesh reconstruction (HMR) from monocular video is the key step to many mixed reality and robotic applications. Although existing methods show promising results by capturing frames' temporal information, these methods predict human mesh with the design of implicit temporal learning modules in a sequence to frame manner. To mine more temporal information from the video, we present a bi-level clip inference network for HMR, which leverages both local motion and global context explicitly for dense 3D reconstruction. Specifically, we propose a novel bi-level temporal fusion strategy that takes both neighboring and long-range relations into consideration. In addition, different from traditional frame-wise operation, we investigate an alternative perspective by treating video-based HMR as clip-wise inference. We evaluate the proposed method on multiple datasets (3DPW, Human3.6M, and MPI-INF-3DHP) quantitatively and qualitatively, demonstrating a significant improvement over existing methods (in terms of PA-MPJPE, ACC-Error etc). Furthermore, we extend the proposed method on more challenging Multiple Shots HMR task to demonstrate its generalizability. Some visual demos can be seen https://github.com/bicf0/bicf_demo.
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Online continual learning aims to continuously train neural networks from a continuous data stream with a single pass-through data. As the most effective approach, the rehearsal-based methods replay part of previous data. Commonly used predictors in existing methods tend to generate biased dot-product logits that prefer to the classes of current data, which is known as a bias issue and a phenomenon of forgetting. Many approaches have been proposed to overcome the forgetting problem by correcting the bias; however, they still need to be improved in online fashion. In this paper, we try to address the bias issue by a more straightforward and more efficient method. By decomposing the dot-product logits into an angle factor and a norm factor, we empirically find that the bias problem mainly occurs in the angle factor, which can be used to learn novel knowledge as cosine logits. On the contrary, the norm factor abandoned by existing methods helps remember historical knowledge. Based on this observation, we intuitively propose to leverage the norm factor to balance the new and old knowledge for addressing the bias. To this end, we develop a heuristic approach called unbias experience replay (UER). UER learns current samples only by the angle factor and further replays previous samples by both the norm and angle factors. Extensive experiments on three datasets show that UER achieves superior performance over various state-of-the-art methods. The code is in https://github.com/FelixHuiweiLin/UER.
Advertisement videos (ads) play an integral part in the domain of Internet e-commerce, as they amplify the reach of particular products to a broad audience or can serve as a medium to raise awareness about specific issues through concise narrative structures. The narrative structures of advertisements involve several elements like reasoning about the broad content (topic and the underlying message) and examining fine-grained details involving the transition of perceived tone due to the sequence of events and interaction among characters. In this work, to facilitate the understanding of advertisements along the three dimensions of topic categorization, perceived tone transition, and social message detection, we introduce a multimodal multilingual benchmark called MM-AU comprised of 8.4 K videos (147hrs) curated from multiple web-based sources. We explore multiple zero-shot reasoning baselines through the application of large language models on the ads transcripts. Further, we demonstrate that leveraging signals from multiple modalities, including audio, video, and text, in multimodal transformer-based supervised models leads to improved performance compared to unimodal approaches.
Gait recognition aims at identifying individuals by unique walking patterns at a long distance. However, prevailing methods suffer from a large degradation when applied to large-scale surveillance systems. We find a significant cause of this issue is that previous methods heavily rely on full-view person annotations to reduce view differences by pulling closer the anchor to positive samples from different viewpoints. But, subjects under in-the-wild scenarios usually have only a limited number of sequences from different viewpoints. As a result, the available viewpoints of each subject are sparse compared to the whole dataset, and simply minimizing intra-identity differences cannot well reducing the view differences in the whole dataset. In this work, we formulate this overlooked problem as Sparse-View Gait Recognition and provide a comprehensive analysis of it by a Structural Causal Model for causalities among latent features, view distribution, and labels. Based on our analysis, we propose a simple yet effective method that enables networks to learn a more robust representation among different views. Specifically, our method consists of two parts: 1) an effective metric learning algorithmic implementation based on the backdoor adjustment, which improves the consistency of representations among different views; 2) an unsupervised view cluster algorithm to discover and identify the most influential view contexts. We evaluate the effectiveness of our method on popular GREW, Gait3D, CASIA-B, and OU-MVLP, showing that our method consistently outperforms baselines and achieves state-of-the-art performance. The code will be available at https://github.com/wj1tr0y/GaitCSV.
Social Relation Recognition is an important part of Video Understanding, providing insights into the information that videos convey. Most previous works mainly focused on graph generation for characters, instead of edges which are more suitable for relation modelling. Furthermore, previous methods tend to recognize social relations for single frames or short video clips within their receptive fields, neglecting the importance of continuous reasoning throughout the entire video. To tackle these challenges, we propose a novel Shifted GCN-GAT and Cumulative-Transformer framework, named SGCAT-CT. The overall architecture consists of an SGCAT module for shifted graph operations on novel relation graphs and a CT module for temporal processing with memory. SGCAT-CT conducts continuous recognition of social relations and memorizes information from as early as the beginning of a long video. Experiments conducted on several video datasets demonstrate encouraging performance on long videos. Our code will be released at https://github.com/HarryWgCN/SGCAT-CT.
PetalView: Fine-grained Location and Orientation Extraction of Street-view Images via Cross-view Local Search
PDF ↗Satellite-based street-view information extraction by cross-view matching refers to a task that extracts the location and orientation information of a given street-view image query by using one or multiple geo-referenced satellite images. Recent work has initiated a new research direction to find accurate information within a local area covered by one satellite image centered at a location prior (e.g., from GPS). It can be used as a standalone solution or complementary step following a large-scale search with multiple satellite candidates. However, these existing works require an accurate initial orientation (angle) prior (e.g., from IMU) and/or do not efficiently search through all possible poses. To allow efficient search and to give accurate prediction regardless of the existence or the accuracy of the angle prior, we present PetalView extractors with multi-scale search. The PetalView extractors give semantically meaningful features that are equivalent across two drastically different views, and the multi-scale search strategy efficiently inspects the satellite image from coarse to fine granularity to provide sub-meter and sub-degree precision extraction. Moreover, when an angle prior is given, we propose a learnable prior angle mixer to utilize this information. Our method obtains the best performance on the VIGOR dataset and successfully improves the performance on KITTI dataset test~1 set with the recall within 1 meter (r@1m) for location estimation to 68.88% and recall within 1 degree (r@1d) 21.10% when no angle prior is available, and with angle prior achieves stable estimations at r@1m and r@1d above 70% and 21%, up to a 40-degree noise level.
Video-based visible-infrared person re-identification (VVI-ReID) aims to retrieve video sequences of the same pedestrian from different modalities. The key of VVI-ReID is to learn discriminative sequence-level representations that are invariant to both intra- and inter-modal discrepancies. However, most works only focus on the elimination of modality-gap while ignore the distractors within the modality. Moreover, existing sequence-level representation learning approaches are limited to a single video, failing to mine the correlations among multiple videos of the same pedestrian. In this paper, we propose a Style Augmentation, Attack and Defense network with Graph-based dual interaction (SAADG) to guarantee the semantic consistency against both intra-modal discrepancies and inter-modal gap. Specifically, we first generate diverse styles for video frames by random style variation in image spaces. Followed by the style attack and defense, the intra- and inter-modal discrepancies are modeled as different types of style disturbance (attack), and our model achieves to keep the id-related content invariant under such attack. Besides, a graph-based dual interaction module is further introduced to fully explore the cross-view and cross-modal correlations among various videos of the same identity, which are then transferred to the sequence-level representations. Extensive experiments on the public SYSU-MM01 and HITSZ-VCM datasets show that our approach achieves the remarkable performance compared with state-of-the-arts. The code is available at https://github.com/ChuhaoZhou99/SAADG_VVIReID.
Blind face restoration aims to recover high-quality face images from low-quality ones with complex and unknown degradation. Existing approaches have achieved promising performance by leveraging pre-trained dictionaries or generative priors. However, these methods may fail to exploit the full potential of degraded inputs and facial identity features due to complex degradation. To address this issue, we propose a novel method that explores the correlation of degraded spatial identity features by learning a general representation using memory network. Specifically, our approach enhances degraded features with more identity by leveraging similar facial features retrieved from memory network. We also propose a fusion approach that fuses memorized spatial features with GAN prior features via affine transformation and blending fusion to improve fidelity and realism. Additionally, the memory network is updated online in an unsupervised manner along with other modules, which obviates the requirement for pre-training. Experimental results on synthetic and popular real-world datasets demonstrate the effectiveness of our proposed method, which achieves at least comparable and often better performance than other state-of-the-art approaches.
Using a Graph convolution network (GCN) for constructing and aggregating node features has been helpful for skeleton-based action recognition. The strength of the nodes' relation of an action sequence distinguishes it from other actions. This work proposes a novel spatial module called Multi-scale self-relational graph convolution (MS-SRGC) for dynamically modeling joint relations of action instances. Modeling the joints' relations is crucial in determining the spatial distinctiveness between skeleton sequences; hence MS-SRGC shows effectiveness for activity recognition. We also propose a Hybrid multi-scale temporal convolution network (HMS-TCN) that captures different ranges of time steps along the temporal dimension of the skeleton sequence. In addition, we propose a Spatio-temporal blackout (STB) module that randomly zeroes some continue frames for selected strategic joint groups. We sequentially stack our spatial (MS-SRGC) and temporal (HMS-TCN) modules to form a Self-relational graph convolution network (SR-GCN) block, which we use to construct our SR-GCN model. We append our STB on the SR-GCN model top for the randomized operation. With the effectiveness of ensemble networks, we perform extensive experiments on single and multiple ensembles. Our results beat the state-of-the-art methods on the NTU RGB-D, NTU RGB-D 120, and Northwestern-UCLA datasets.
Recently, one-stage visual grounders attract high attention due to their comparable accuracy but significantly higher efficiency than two-stage grounders. However, inter-object relation modeling has not been well studied for one-stage grounders. Inter-object relationship modeling, though important, is not necessarily performed among all objects, as only part of them are related to the text query and may confuse the model. We call these objects "suspected objects". However, exploring their relationships in the one-stage paradigm is non-trivial because: (1) no object proposals are available as the basis on which to select suspected objects and perform relationship modeling; (2) suspected objects are more confusing than others, as they may share similar semantics, be entangled with certain relationships, etc, and thereby more easily mislead the model's prediction. Toward this end, we propose a Suspected Object Transformation mechanism (SOT), which can be seamlessly integrated into existing CNN and Transformer-based one-stage visual grounders to encourage the target object selection among the suspected ones. Suspected objects are dynamically discovered from a learned activation map adapted to the model's current discrimination ability during training. Afterward, on top of suspected objects, a Keyword-Aware Discrimination module (KAD) and an Exploration by Random Connection strategy (ERC) are concurrently proposed to help the model rethink its initial prediction. On the one hand, KAD leverages keywords contributing high to suspected object discrimination. On the other hand, ERC allows the model to seek the correct object instead of being trapped in a situation that always exploits the current false prediction. Extensive experiments demonstrate the effectiveness of our proposed method.
Multi-stage architectures have exhibited efficacy in image dehazing, which usually decomposes a challenging task into multiple more tractable sub-tasks and progressively estimates latent hazy-free images. Despite the remarkable progress, existing methods still suffer from the following shortcomings: (1) limited exploration of frequency domain information; (2) insufficient information interaction; (3) severe feature redundancy. To remedy these issues, we propose a novel Mutual Information-driven Triple interaction Network (MITNet) based on spatial-frequency dual domain information and two-stage architecture. To be specific, the first stage, named amplitude-guided haze removal, aims to recover the amplitude spectrum of the hazy images for haze removal. And the second stage, named phase-guided structure refined, devotes to learning the transformation and refinement of the phase spectrum. To facilitate the information exchange between two stages, an Adaptive Triple Interaction Module (ATIM) is developed to simultaneously aggregate cross-domain, cross-scale, and cross-stage features, where the fused features are further used to generate content-adaptive dynamic filters so that applying them to enhance global context representation. In addition, we impose the mutual information minimization constraint on paired scale encoder and decoder features from both stages. Such an operation can effectively reduce information redundancy and enhance cross-stage feature complementarity. Extensive experiments on multiple public datasets exhibit that our MITNet performs superior performance with lower model complexity. The code and models are available at https://github.com/it-hao/MITNet.
Let us define transition as the "exchange" between two mechanisms with comparable functionality, but with different algorithms and implementation concepts, which are optimal depending on the respective conditions of the respective context. It is much more that adaptability; it does not cover just the smooth automatic control of e.g., a MAPE loop or a control loop which is in charge to maximize the quality of service of streamed media data while errors occur. Resilience describes the ability of a system to either absorb large changes (and crises) and recover from them in the short term or to overcome them by acquiring comparable or new basic functionality through overall system adjustments. In doing so, the system's readiness increases continuously and sustainably by learning from past changes of the context (and crises). Just one extreme example: In the situation of a severe danger due to a nature disaster, a person -located in the affected area of the disaster- transmits to the rescue team an on-the-fly generated 360-degree panoramic point cloud of the situation. He still has sufficient energy supply and for whatever reason the communication facilities are still available. Due to energy shortage, a lot of other traffic and some damages of the infrastructure, multimedia communication must be adjusted continuously to the environment and requirements. In an extreme situation data is send over high latency low bandwidth satellite channels. Media might become a short textual description of the actual surrounding. Assume it happens without any manual interaction of the person sending this data. Multimedia and Communications Mechanisms must be exchanged; media must be "customized". Transitions happen to support the user in e.g., such an extreme stress situation. In the collaborative research project MAKI as well as our center researching resilient infrastructures of digital cities that can withstand crises and disasters emergenCITY, we address some of these issues. However, in the next years beyond multimedia networks, many multimedia systems, interfaces, applications, etc. will be affected.
When an emergency event, or an incident relevant for peacekeeping first occurs, getting the right information as quickly as possible is critical in saving lives. When an event is ongoing, information on what is happening can be critical in making decisions to keep people safe and take control of the particular situation unfolding. In both cases, first responders and peacekeepers have to quickly make decisions that include what resources to deploy and where. Fortunately, in most emergencies, people use social media to publicly share information. At the same time, sensor data is increasingly becoming available. But a platform to detect emergency situations and deliver the right information has to deal with ingesting thousands of noisy data points per second: sifting through and identifying relevant information, from different sources, in different formats, with varying levels of detail, in real time, so that relevant individuals and teams can be alerted at the right level and at the right time. In this talk I will describe the technical challenges in processing vast amounts of heterogeneous, noisy data in real time, highlighting the importance of interdisciplinary research and a human-centered approach to address problems in peacekeeping and emergency response. I will give specific examples specifically discussing how LLMs can be deployed at scale, including relevant future research directions in Multimedia.
The worldwide flourishing of the Internet of Things (IoT) in the past decade has enabled numerous new applications through the internetworking of a wide variety of devices and sensors. In recent years, visual sensors have seen a considerable boom in IoT systems because they are capable of providing richer and more versatile information. Internetworking of large-scale visual sensors has been named the Internet of Video Things (IoVT). IoVT has a new array of unique characteristics in terms of sensing, transmission, storage, and analysis, all are fundamentally different from the conventional IoT. These new characteristics of IoVT are expected to impose significant challenges on existing technical infrastructures. In this keynote talk, an overview of recent advances in various fronts of IoVT will be introduced and a broad range of technological and systematic challenges will be addressed. Several emerging IoVT applications will be discussed to illustrate the great potential of IoVT in a broad range of practical scenarios.