GenAI4ELab/papercli-papers huggingface dataset:
Hyperspherical Classification with Dynamic Label-to-Prototype Assignment
Authors: Mohammad Saeed Ebrahimi Saadabadi; Ali Dabouei; Sahar Rahimi Malakshan; Nasser M. Nasrabadi
Venue: CVPR 2024 (main)

Abstract: Aiming to enhance the utilization of metric space by the parametric softmax classifier recent studies suggest replacing it with a non-parametric alternative. Although a non-parametric classifier may provide better metric space utilization it introduces the challenge of capturing inter-class relationships. A shared characteristic among prior non-parametric classifiers is the static assignment of labels to prototypes during the training i.e. each prototype consistently represents a class throughout the training course. Orthogonal to previous works we present a simple yet effective method to optimize the category assigned to each prototype (label-to-prototype assignment) during the training. To this aim we formalize the problem as a two-step optimization objective over network parameters and label-to-prototype assignment mapping. We solve this optimization using a sequential combination of gradient descent and Bipartide matching. We demonstrate the benefits of the proposed approach by conducting experiments on balanced and long-tail classification problems using different backbone network architectures. In particular our method outperforms its competitors by 1.22% accuracy on CIFAR-100 and 2.15% on ImageNet-200 using a metric space dimension half of the size of its competitors. \href https://github.com/msed-Ebrahimi/DL2PA_CVPR24  Code
VTimeLLM: Empower LLM to Grasp Video Moments
Authors: Bin Huang; Xin Wang; Hong Chen; Zihan Song; Wenwu Zhu
Venue: CVPR 2024 (main)

Abstract: Large language models (LLMs) have shown remarkable text understanding capabilities which have been extended as Video LLMs to handle video data for comprehending visual details. However existing Video LLMs can only provide a coarse description of the entire video failing to capture the precise start and end time boundary of specific events. In this paper we solve this issue via proposing VTimeLLM a novel Video LLM designed for fine-grained video moment understanding and reasoning with respect to time boundary. Specifically our VTimeLLM adopts a boundary-aware three-stage training strategy which respectively utilizes image-text pairs for feature alignment multiple-event videos to increase temporal-boundary awareness and high-quality video-instruction tuning to further improve temporal understanding ability as well as align with human intents. Extensive experiments demonstrate that in fine-grained time-related comprehension tasks for videos such as Temporal Video Grounding and Dense Video Captioning VTimeLLM significantly outperforms existing Video LLMs. Besides benefits from the fine-grained temporal understanding of the videos further enable VTimeLLM to beat existing Video LLMs in video dialogue benchmark showing its superior cross-modal understanding and reasoning abilities.
FLHetBench: Benchmarking Device and State Heterogeneity in Federated Learning
Authors: Junyuan Zhang; Shuang Zeng; Miao Zhang; Runxi Wang; Feifei Wang; Yuyin Zhou; Paul Pu Liang; Liangqiong Qu
Venue: CVPR 2024 (main)

Abstract: Federated learning (FL) is a powerful technology that enables collaborative training of machine learning models without sharing private data among clients. The fundamental challenge in FL lies in learning over extremely heterogeneous data distributions device capacities and device state availabilities all of which adversely impact performance and communication efficiency. While data heterogeneity has been well-studied in the literature this paper introduces FLHetBench the first FL benchmark targeted toward understanding device and state heterogeneity. FLHetBench comprises two new sampling methods to generate real-world device and state databases with varying heterogeneity and new metrics for quantifying the success of FL methods under these real-world constraints. Using FLHetBench we conduct a comprehensive evaluation of existing methods and find that they struggle under these settings which inspires us to propose BiasPrompt+ a new method employing staleness-aware aggregation and fast weights to tackle these new heterogeneity challenges. Experiments on various FL tasks and datasets validate the effectiveness of our BiasPrompt+ method and highlight the value of FLHetBench in fostering the development of more efficient and robust FL solutions under real-world device and state constraints.
Flattening the Parent Bias: Hierarchical Semantic Segmentation in the Poincare Ball
Authors: Simon Weber; Bar?? Zöngür; Nikita Araslanov; Daniel Cremers
Venue: CVPR 2024 (main)

Abstract: Hierarchy is a natural representation of semantic taxonomies including the ones routinely used in image segmentation. Indeed recent work on semantic segmentation reports improved accuracy from supervised training leveraging hierarchical label structures. Encouraged by these results we revisit the fundamental assumptions behind that work. We postulate and then empirically verify that the reasons for the observed improvement in segmentation accuracy may be entirely unrelated to the use of the semantic hierarchy. To demonstrate this we design a range of cross-domain experiments with a representative hierarchical approach. We find that on the new testing domains a flat (non-hierarchical) segmentation network in which the parents are inferred from the children has superior segmentation accuracy to the hierarchical approach across the board. Complementing these findings and inspired by the intrinsic properties of hyperbolic spaces we study a more principled approach to hierarchical segmentation using the Poincare ball model. The hyperbolic representation largely outperforms the previous (Euclidean) hierarchical approach as well and is on par with our flat Euclidean baseline in terms of segmentation accuracy. However it additionally exhibits surprisingly strong calibration quality of the parent nodes in the semantic hierarchy especially on the more challenging domains. Our combined analysis suggests that the established practice of hierarchical segmentation may be limited to in-domain settings whereas flat classifiers generalize substantially better especially if they are modeled in the hyperbolic space.
Privacy-Preserving Optics for Enhancing Protection in Face De-Identification
Authors: Jhon Lopez; Carlos Hinojosa; Henry Arguello; Bernard Ghanem
Venue: CVPR 2024 (main)

Abstract: The modern surge in camera usage alongside widespread computer vision technology applications poses significant privacy and security concerns. Current artificial intelligence (AI) technologies aid in recognizing relevant events and assisting in daily tasks in homes offices hospitals etc. The need to access or process personal information for these purposes raises privacy concerns. While software-level solutions like face de-identification provide a good privacy/utility trade-off they present vulnerabilities to sniffing attacks. In this paper we propose a hardware-level face de-identification method to solve this vulnerability. Specifically our approach first learns an optical encoder along with a regression model to obtain a face heatmap while hiding the face identity from the source image. We also propose an anonymization framework that generates a new face using the privacy-preserving image face heatmap and a reference face image from a public dataset as input. We validate our approach with extensive simulations and hardware experiments.
SmartRefine: A Scenario-Adaptive Refinement Framework for Efficient Motion Prediction
Authors: Yang Zhou; Hao Shao; Letian Wang; Steven L. Waslander; Hongsheng Li; Yu Liu
Venue: CVPR 2024 (main)

Abstract: Predicting the future motion of surrounding agents is essential for autonomous vehicles (AVs) to operate safely in dynamic human-robot-mixed environments. Context information such as road maps and surrounding agents' states provides crucial geometric and semantic information for motion behavior prediction. To this end recent works explore two-stage prediction frameworks where coarse trajectories are first proposed and then used to select critical context information for trajectory refinement. However they either incur a large amount of computation or bring limited improvement if not both. In this paper we introduce a novel scenario-adaptive refinement strategy named SmartRefine to refine prediction with minimal additional computation. Specifically SmartRefine can comprehensively adapt refinement configurations based on each scenario's properties and smartly chooses the number of refinement iterations by introducing a quality score to measure the prediction quality and remaining refinement potential of each scenario. SmartRefine is designed as a generic and flexible approach that can be seamlessly integrated into most state-of-the-art motion prediction models. Experiments on Argoverse (1 & 2) show that our method consistently improves the prediction accuracy of multiple state-of-the-art prediction models. Specifically by adding SmartRefine to QCNet we outperform all published ensemble-free works on the Argoverse 2 leaderboard (single agent track) at submission. Comprehensive studies are also conducted to ablate design choices and explore the mechanism behind multi-iteration refinement. Codes are available at https://github.com/opendilab/SmartRefine/.
MVBench: A Comprehensive Multi-modal Video Understanding Benchmark
Authors: Kunchang Li; Yali Wang; Yinan He; Yizhuo Li; Yi Wang; Yi Liu; Zun Wang; Jilan Xu; Guo Chen; Ping Luo; Limin Wang; Yu Qiao
Venue: CVPR 2024 (main)

Abstract: With the rapid development of Multi-modal Large Language Models (MLLMs) a number of diagnostic benchmarks have recently emerged to evaluate the comprehension capabilities of these models. However most benchmarks predominantly assess spatial understanding in the static image tasks while overlooking temporal understanding in the dynamic video tasks. To alleviate this issue we introduce a comprehensive Multi-modal Video understanding Benchmark namely MVBench which covers 20 challenging video tasks that cannot be effectively solved with a single frame. Specifically we first introduce a novel static-to-dynamic method to define these temporal-related tasks. By transforming various static tasks into dynamic ones we enable the systematic generation of video tasks that require a broad spectrum of temporal skills ranging from perception to cognition. Then guided by the task definition we automatically convert public video annotations into multiple-choice QA to evaluate each task. On one hand such a distinct paradigm allows us to build MVBench efficiently without much manual intervention. On the other hand it guarantees evaluation fairness with ground-truth video annotations avoiding the biased scoring of LLMs. Moreover we further develop a robust video MLLM baseline i.e. VideoChat2 by progressive multi-modal training with diverse instruction-tuning data. The extensive results on our MVBench reveal that the existing MLLMs are far from satisfactory in temporal understanding while our VideoChat2 largely surpasses these leading models by over 15% on MVBench.
Multi-Scale Video Anomaly Detection by Multi-Grained Spatio-Temporal Representation Learning
Authors: Menghao Zhang; Jingyu Wang; Qi Qi; Haifeng Sun; Zirui Zhuang; Pengfei Ren; Ruilong Ma; Jianxin Liao
Venue: CVPR 2024 (main)

Abstract: ecent progress in video anomaly detection suggests that the features of appearance and motion play crucial roles in distinguishing abnormal patterns from normal ones. However we note that the effect of spatial scales of anomalies is ignored. The fact that many abnormal events occur in limited localized regions and severe background noise interferes with the learning of anomalous changes. Meanwhile most existing methods are limited by coarse-grained modeling approaches which are inadequate for learning highly discriminative features to discriminate subtle differences between small-scale anomalies and normal patterns. To this end this paper address multi-scale video anomaly detection by multi-grained spatio-temporal representation learning. We utilize video continuity to design three proxy tasks to perform feature learning at both coarse-grained and fine-grained levels i.e. continuity judgment discontinuity localization and missing frame estimation. In particular we formulate missing frame estimation as a contrastive learning task in feature space instead of a reconstruction task in RGB space to learn highly discriminative features. Experiments show that our proposed method outperforms state-of-the-art methods on four datasets especially in scenes with small-scale anomalies.
An Aggregation-Free Federated Learning for Tackling Data Heterogeneity
Authors: Yuan Wang; Huazhu Fu; Renuga Kanagavelu; Qingsong Wei; Yong Liu; Rick Siow Mong Goh
Venue: CVPR 2024 (main)

Abstract: The performance of Federated Learning (FL) hinges on the effectiveness of utilizing knowledge from distributed datasets. Traditional FL methods adopt an aggregate-then-adapt framework where clients update local models based on a global model aggregated by the server from the previous training round. This process can cause client drift especially with significant cross-client data heterogeneity impacting model performance and convergence of the FL algorithm. To address these challenges we introduce FedAF a novel aggregation-free FL algorithm. In this framework clients collaboratively learn condensed data by leveraging peer knowledge the server subsequently trains the global model using the condensed data and soft labels received from the clients. FedAF inherently avoids the issue of client drift enhances the quality of condensed data amid notable data heterogeneity and improves the global model performance. Extensive numerical studies on several popular benchmark datasets show FedAF surpasses various state-of-the-art FL algorithms in handling label-skew and feature-skew data heterogeneity leading to superior global model accuracy and faster convergence.
Generative Multimodal Models are In-Context Learners
Authors: Quan Sun; Yufeng Cui; Xiaosong Zhang; Fan Zhang; Qiying Yu; Yueze Wang; Yongming Rao; Jingjing Liu; Tiejun Huang; Xinlong Wang
Venue: CVPR 2024 (main)

Abstract: Humans can easily solve multimodal tasks in context with only a few demonstrations or simple instructions which current multimodal systems largely struggle to imitate. In this work we demonstrate that by effectively scaling up generative multimodal models their task-agnostic in-context learning capabilities can be significantly enhanced. We introduce Emu2 a generative multimodal model with 37 billion parameters which serves as a base model and general-purpose interface for a variety of multimodal tasks. Emu2 not only achieves strong performance in few-shot setting but can also be instruct-tuned to follow specific instructions such as visual question answering and object-grounded image generation. Emu2 even emerges to solve tasks that require on-the-fly reasoning such as visual prompting which existing models are unlikely to handle. We identify additional tasks where Emu2's in-context learning can further improve and discuss its broader societal impact. Our code and models will be made publicly available to facilitate future research.
Synergistic Global-space Camera and Human Reconstruction from Videos
Authors: Yizhou Zhao; Tuanfeng Yang Wang; Bhiksha Raj; Min Xu; Jimei Yang; Chun-Hao Paul Huang
Venue: CVPR 2024 (main)

Abstract: Remarkable strides have been made in reconstructing static scenes or human bodies from monocular videos. Yet the two problems have largely been approached independently without much synergy. Most visual SLAM methods can only reconstruct camera trajectories and scene structures up to scale while most HMR methods reconstruct human meshes in metric scale but fall short in reasoning with cameras and scenes. This work introduces Synergistic Camera and Human Reconstruction (SynCHMR) to marry the best of both worlds. Specifically we design Human-aware Metric SLAM to reconstruct metric-scale camera poses and scene point clouds using camera-frame HMR as a strong prior addressing depth scale and dynamic ambiguities. Conditioning on the dense scene recovered we further learn a Scene-aware SMPL Denoiser to enhance world-frame HMR by incorporating spatiotemporal coherency and dynamic scene constraints. Together they lead to consistent reconstructions of camera trajectories human meshes and dense scene point clouds in a common world frame.
Hierarchical Intra-modal Correlation Learning for Label-free 3D Semantic Segmentation
Authors: Xin Kang; Lei Chu; Jiahao Li; Xuejin Chen; Yan Lu
Venue: CVPR 2024 (main)

Abstract: Recent methods for label-free 3D semantic segmentation aim to assist 3D model training by leveraging the open-world recognition ability of pre-trained vision language models. However these methods usually suffer from inconsistent and noisy pseudo-labels provided by the vision language models. To address this issue we present a hierarchical intra-modal correlation learning framework that captures visual and geometric correlations in 3D scenes at three levels: intra-set intra-scene and inter-scene to help learn more compact 3D representations. We refine pseudo-labels using intra-set correlations within each geometric consistency set and align features of visually and geometrically similar points using intra-scene and inter-scene correlation learning. We also introduce a feedback mechanism to distill the correlation learning capability into the 3D model. Experiments on both indoor and outdoor datasets show the superiority of our method. We achieve a state-of-the-art 36.6% mIoU on the ScanNet dataset and a 23.0% mIoU on the nuScenes dataset with improvements of 7.8% mIoU and 2.2% mIoU compared with previous SOTA. We also provide theoretical analysis and qualitative visualization results to discuss the mechanism and conduct thorough ablation studies to support the effectiveness of our framework.
Feature Re-Embedding: Towards Foundation Model-Level Performance in Computational Pathology
Authors: Wenhao Tang; Fengtao Zhou; Sheng Huang; Xiang Zhu; Yi Zhang; Bo Liu
Venue: CVPR 2024 (main)

Abstract: Multiple instance learning (MIL) is the most widely used framework in computational pathology encompassing sub-typing diagnosis prognosis and more. However the existing MIL paradigm typically requires an offline instance feature extractor such as a pre-trained ResNet or a foundation model. This approach lacks the capability for feature fine-tuning within the specific downstream tasks limiting its adaptability and performance. To address this issue we propose a Re-embedded Regional Transformer (RRT) for re-embedding the instance features online which captures fine-grained local features and establishes connections across different regions. Unlike existing works that focus on pre-training powerful feature extractor or designing sophisticated instance aggregator RRT is tailored to re-embed instance features online. It serves as a portable module that can seamlessly integrate into mainstream MIL models. Extensive experimental results on common computational pathology tasks validate that: 1) feature re-embedding improves the performance of MIL models based on ResNet-50 features to the level of foundation model features and further enhances the performance of foundation model features; 2) the RRT can introduce more significant performance improvements to various MIL models; 3) RRT-MIL as an RRT-enhanced AB-MIL outperforms other latest methods by a large margin. The code is available at: https://github.com/DearCaat/RRT-MIL.
DiffSal: Joint Audio and Video Learning for Diffusion Saliency Prediction
Authors: Junwen Xiong; Peng Zhang; Tao You; Chuanyue Li; Wei Huang; Yufei Zha
Venue: CVPR 2024 (main)

Abstract: Audio-visual saliency prediction can draw support from diverse modality complements but further performance enhancement is still challenged by customized architectures as well as task-specific loss functions. In recent studies denoising diffusion models have shown more promising in unifying task frameworks owing to their inherent ability of generalization. Following this motivation a novel Diffusion architecture for generalized audio-visual Saliency prediction (DiffSal) is proposed in this work which formulates the prediction problem as a conditional generative task of the saliency map by utilizing input audio and video as the conditions. Based on the spatio-temporal audio-visual features an extra network Saliency-UNet is designed to perform multi-modal attention modulation for progressive refinement of the ground-truth saliency map from the noisy map. Extensive experiments demonstrate that the proposed DiffSal can achieve excellent performance across six challenging audio-visual benchmarks with an average relative improvement of 6.3% over the previous state-of-the-art results by six metrics.
Revisiting Single Image Reflection Removal In the Wild
Authors: Yurui Zhu; Xueyang Fu; Peng-Tao Jiang; Hao Zhang; Qibin Sun; Jinwei Chen; Zheng-Jun Zha; Bo Li
Venue: CVPR 2024 (main)

Abstract: This research focuses on the issue of single-image reflection removal (SIRR) in real-world conditions examining it from two angles: the collection pipeline of real reflection pairs and the perception of real reflection locations. We devise an advanced reflection collection pipeline that is highly adaptable to a wide range of real-world reflection scenarios and incurs reduced costs in collecting large-scale aligned reflection pairs. In the process we develop a large-scale high-quality reflection dataset named Reflection Removal in the Wild (RRW). RRW contains over 14950 high-resolution real-world reflection pairs a dataset forty-five times larger than its predecessors. Regarding perception of reflection locations we identify that numerous virtual reflection objects visible in reflection images are not present in the corresponding ground-truth images. This observation drawn from the aligned pairs leads us to conceive the Maximum Reflection Filter (MaxRF). The MaxRF could accurately and explicitly characterize reflection locations from pairs of images. Building upon this we design a reflection location-aware cascaded framework specifically tailored for SIRR. Powered by these innovative techniques our solution achieves superior performance than current leading methods across multiple real-world benchmarks. Codes and datasets are available at \href https://github.com/zhuyr97/Reflection_RemoVal_CVPR2024  \color blue  here .
3D Face Reconstruction with the Geometric Guidance of Facial Part Segmentation
Authors: Zidu Wang; Xiangyu Zhu; Tianshuo Zhang; Baiqin Wang; Zhen Lei
Venue: CVPR 2024 (main)

Abstract: 3D Morphable Models (3DMMs) provide promising 3D face reconstructions in various applications. However existing methods struggle to reconstruct faces with extreme expressions due to deficiencies in supervisory signals such as sparse or inaccurate landmarks. Segmentation information contains effective geometric contexts for face reconstruction. Certain attempts intuitively depend on differentiable renderers to compare the rendered silhouettes of reconstruction with segmentation which is prone to issues like local optima and gradient instability. In this paper we fully utilize the facial part segmentation geometry by introducing Part Re-projection Distance Loss (PRDL). Specifically PRDL transforms facial part segmentation into 2D points and re-projects the reconstruction onto the image plane. Subsequently by introducing grid anchors and computing different statistical distances from these anchors to the point sets PRDL establishes geometry descriptors to optimize the distribution of the point sets for face reconstruction. PRDL exhibits a clear gradient compared to the renderer-based methods and presents state-of-the-art reconstruction performance in extensive quantitative and qualitative experiments. Our project is available at https://github.com/wang-zidu/3DDFA-V3.