mtybilly/Instruct2DS huggingface dataset:
Segment Every Out-of-Distribution Object
Authors: Wenjie Zhao, Jia Li, Xin Dong, Yu Xiang, Yunhui Guo
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Semantic segmentation models while effective for in-distribution categories face challenges in real-world deployment due to encountering out-of-distribution (OoD) objects. Detecting these OoD objects is crucial for safety-critical applications. Existing methods rely on anomaly scores but choosing a suitable threshold for generating masks presents difficulties and can lead to fragmentation and inaccuracy. This paper introduces a method to convert anomaly Score To segmentation Mask called S2M a simple and effective framework for OoD detection in semantic segmentation. Unlike assigning anomaly scores to pixels S2M directly segments the entire OoD object. By transforming anomaly scores into prompts for a promptable segmentation model S2M eliminates the need for threshold selection. Extensive experiments demonstrate that S2M outperforms the state-of-the-art by approximately 20% in IoU and 40% in mean F1 score on average across various benchmarks including Fishyscapes Segment-Me-If-You-Can and RoadAnomaly datasets.
Building Vision-Language Models on Solid Foundations with Masked Distillation
Authors: Sepehr Sameni, Kushal Kafle, Hao Tan, Simon Jenni
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Recent advancements in Vision-Language Models (VLMs) have marked a significant leap in bridging the gap between computer vision and natural language processing. However traditional VLMs trained through contrastive learning on limited and noisy image-text pairs often lack the spatial and linguistic understanding to generalize well to dense vision tasks or less common languages. Our approach Solid Foundation CLIP (SF-CLIP) circumvents this issue by implicitly building on the solid visual and language understanding of foundational models trained on vast amounts of unimodal data. SF-CLIP integrates contrastive image-text pretraining with a masked knowledge distillation from large foundational text and vision models. This methodology guides our VLM in developing robust text and image representations. As a result SF-CLIP shows exceptional zero-shot classification accuracy and enhanced image and text retrieval capabilities setting a new state of the art for ViT-B/16 trained on YFCC15M and CC12M. Moreover the dense per-patch supervision enhances our zero-shot and linear probe performance in semantic segmentation tasks. A remarkable aspect of our model is its multilingual proficiency evidenced by strong retrieval results in multiple languages despite being trained predominantly on English data. We achieve all of these improvements without sacrificing the training efficiency through our selective application of masked distillation and the inheritance of teacher word embeddings.
Wavelet-based Fourier Information Interaction with Frequency Diffusion Adjustment for Underwater Image Restoration
Authors: Chen Zhao, Weiling Cai, Chenyu Dong, Chengwei Hu
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Underwater images are subject to intricate and diverse degradation inevitably affecting the effectiveness of underwater visual tasks. However most approaches primarily operate in the raw pixel space of images which limits the exploration of the frequency characteristics of underwater images leading to an inadequate utilization of deep models' representational capabilities in producing high-quality images. In this paper we introduce a novel Underwater Image Enhancement (UIE) framework named WF-Diff designed to fully leverage the characteristics of frequency domain information and diffusion models. WF-Diff consists of two detachable networks: Wavelet-based Fourier information interaction network (WFI2-net) and Frequency Residual Diffusion Adjustment Module (FRDAM). With our full exploration of the frequency domain information WFI2-net aims to achieve preliminary enhancement of frequency information in the wavelet space. Our proposed FRDAM can further refine the high- and low-frequency information of the initial enhanced images which can be viewed as a plug-and-play universal module to adjust the detail of the underwater images. With the above techniques our algorithm can show SOTA performance on real-world underwater image datasets and achieves competitive performance in visual quality.
CroSel: Cross Selection of Confident Pseudo Labels for Partial-Label Learning
Authors: Shiyu Tian, Hongxin Wei, Yiqun Wang, Lei Feng
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Partial-label learning (PLL) is an important weakly supervised learning problem which allows each training example to have a candidate label set instead of a single ground-truth label. Identification-based methods have been widely explored to tackle label ambiguity issues in PLL which regard the true label as a latent variable to be identified. However identifying the true labels accurately and completely remains challenging causing noise in pseudo labels during model training. In this paper we propose a new method called CroSel which leverages historical predictions from the model to identify true labels for most training examples. First we introduce a cross selection strategy which enables two deep models to select true labels of partially labeled data for each other. Besides we propose a novel consistency regularization term called co-mix to avoid sample waste and tiny noise caused by false selection. In this way CroSel can pick out the true labels of most examples with high precision. Extensive experiments demonstrate the superiority of CroSel which consistently outperforms previous state-of-the-art methods on benchmark datasets. Additionally our method achieves over 90% accuracy and quantity for selecting true labels on CIFAR-type datasets under various settings.
PoNQ: a Neural QEM-based Mesh Representation
Authors: Nissim Maruani, Maks Ovsjanikov, Pierre Alliez, Mathieu Desbrun
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Although polygon meshes have been a standard representation in geometry processing their irregular and combinatorial nature hinders their suitability for learning-based applications. In this work we introduce a novel learnable mesh representation through a set of local 3D sample Points and their associated Normals and Quadric error metrics (QEM) w.r.t. the underlying shape which we denote PoNQ. A global mesh is directly derived from PoNQ by efficiently leveraging the knowledge of the local quadric errors. Besides marking the first use of QEM within a neural shape representation our contribution guarantees both topological and geometrical properties by ensuring that a PoNQ mesh does not self-intersect and is always the boundary of a volume. Notably our representation does not rely on a regular grid is supervised directly by the target surface alone and also handles open surfaces with boundaries and/or sharp features. We demonstrate the efficacy of PoNQ through a learning-based mesh prediction from SDF grids and show that our method surpasses recent state-of-the-art techniques in terms of both surface and edge-based metrics.
ModaVerse: Efficiently Transforming Modalities with LLMs
Authors: Xinyu Wang, Bohan Zhuang, Qi Wu
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Humans possess the capability to comprehend diverse modalities and seamlessly transfer information between them. In this work we introduce ModaVerse a Multi-modal Large Language Model (MLLM) capable of comprehending and transforming content across various modalities including images videos and audio. Predominant MLLM frameworks have largely relied on aligning latent spaces of textual and non-textual features. This alignment process which synchronizes a language model trained on textual data with encoders and decoders trained on multi-modal data often necessitates extensive training of several projection layers in multiple stages. Inspired by LLM-as-agent methodologies we propose a novel Input/Output (I/O) alignment mechanism that operates directly at the level of natural language. It aligns the LLM's output with the input of generative models avoiding the complexities associated with latent feature alignments and simplifying the multiple training stages of existing MLLMs into a single efficient process. By conducting experiments on several benchmarks we demonstrate that our approach attains comparable performance with the state of the art while achieving considerable efficiencies in data usage.
TransLoc4D: Transformer-based 4D Radar Place Recognition
Authors: Guohao Peng, Heshan Li, Yangyang Zhao, Jun Zhang, Zhenyu Wu, Pengyu Zheng, Danwei Wang
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Place Recognition is crucial for unmanned vehicles in terms of localization and mapping. Recent years have witnessed numerous explorations in the field where 2D cameras and 3D LiDARs are mostly employed. Despite their admirable performance they may encounter challenges in adverse weather such as rain and fog. Hopefully 4D millimeter-wave Radar emerges as a promising alternative as its longer wavelength makes it virtually immune to interference from tiny particles of fog and rain. Therefore in this work we propose a novel 4D Radar place recognition model TransLoc4D based on sparse convolution and Transformer structures. Specifically a Minkloc4D backbone is first proposed to leverage the geometric intensity and velocity information from 4D Radar scans. While mainstream 3D LiDAR solutions merely capture geometric structures of point clouds Minkloc4D explores the intensity and velocity properties of 4D Radar scans and demonstrates their effectiveness. After feature extraction a Transformer layer is introduced to enhance local features where linear self-attention captures the long-range dependency of point cloud alleviating its sparsity and noise. To validate TransLoc4D we construct two datasets and set up benchmarks for 4D radar place recognition. Experiments show TransLoc4D is feasible and can robustly deal with dynamic and adverse environments.
Frequency-aware Event-based Video Deblurring for Real-World Motion Blur
Authors: Taewoo Kim, Hoonhee Cho, Kuk-Jin Yoon
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Video deblurring aims to restore sharp frames from blurred video clips. Despite notable progress in video deblurring works it is still a challenging problem because of the loss of motion information during the duration of the exposure time. Since event cameras can capture clear motion information asynchronously with high temporal resolution several works exploit the event camera for deblurring as they can provide abundant motion information. However despite these approaches there were few cases of actively exploiting the long-range temporal dependency of videos. To tackle these deficiencies we present an event-based video deblurring framework by actively utilizing temporal information from videos. To be specific we first introduce a frequency-based cross-modal feature enhancement module. Second we propose event-guided video alignment modules by considering the valuable characteristics of the event and videos. In addition we designed a hybrid camera system to collect the first real-world event-based video deblurring dataset. For the first time we build a dataset containing synchronized high-resolution real-world blurred videos and corresponding sharp videos and event streams. Experimental results validate that our frameworks significantly outperform the state-of-the-art frame-based and event-based deblurring works in the various datasets. In addition we designed a hybrid camera system to collect the first real-world event-based video deblurring dataset. For the first time we build a dataset containing synchronized high-resolution real-world blurred videos and corresponding sharp videos and event streams. Experimental results validate that our frameworks significantly outperform the state-of-the-art frame-based and event-based deblurring works in the various datasets. The project pages are available at https://sites.google.com/view/fevd-cvpr2024.
Multiscale Vision Transformers Meet Bipartite Matching for Efficient Single-stage Action Localization
Authors: Ioanna Ntinou, Enrique Sanchez, Georgios Tzimiropoulos
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Action Localization is a challenging problem that combines detection and recognition tasks which are often addressed separately. State-of-the-art methods rely on off-the-shelf bounding box detections pre-computed at high resolution and propose transformer models that focus on the classification task alone. Such two-stage solutions are prohibitive for real-time deployment. On the other hand single-stage methods target both tasks by devoting part of the network (generally the backbone) to sharing the majority of the workload compromising performance for speed. These methods build on adding a DETR head with learnable queries that after cross- and self-attention can be sent to corresponding MLPs for detecting a person's bounding box and action. However DETR-like architectures are challenging to train and can incur in big complexity. In this paper we observe that a straight bipartite matching loss can be applied to the output tokens of a vision transformer. This results in a backbone + MLP architecture that can do both tasks without the need of an extra encoder-decoder head and learnable queries. We show that a single MViTv2-S architecture trained with bipartite matching to perform both tasks surpasses the same MViTv2-S when trained with RoI align on pre-computed bounding boxes. With a careful design of token pooling and the proposed training pipeline our Bipartite-Matching Vision Transformer model BMViT achieves +3 mAP on AVA2.2. w.r.t. the two-stage MViTv2-S counterpart. Code is available at https://github.com/IoannaNti/BMViT
Boosting Order-Preserving and Transferability for Neural Architecture Search: a Joint Architecture Refined Search and Fine-tuning Approach
Authors: Beichen Zhang, Xiaoxing Wang, Xiaohan Qin, Junchi Yan
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Supernet is a core component in many recent Neural Architecture Search (NAS) methods. It not only helps embody the search space but also provides a (relative) estimation of the final performance of candidate architectures. Thus it is critical that the top architectures ranked by a supernet should be consistent with those ranked by true performance which is known as the order-preserving ability. In this work we analyze the order-preserving ability on the whole search space (global) and a sub-space of top architectures (local) and empirically show that the local order-preserving for current two-stage NAS methods still need to be improved. To rectify this we propose a novel concept of Supernet Shifting a refined search strategy combining architecture searching with supernet fine-tuning. Specifically apart from evaluating the training loss is also accumulated in searching and the supernet is updated every iteration. Since superior architectures are sampled more frequently in evolutionary searching the supernet is encouraged to focus on top architectures thus improving local order-preserving. Besides a pre-trained supernet is often un-reusable for one-shot methods. We show that Supernet Shifting can fulfill transferring supernet to a new dataset. Specifically the last classifier layer will be unset and trained through evolutionary searching. Comprehensive experiments show that our method has better order-preserving ability and can find a dominating architecture. Moreover the pre-trained supernet can be easily transferred into a new dataset with no loss of performance.
Dr. Bokeh: DiffeRentiable Occlusion-aware Bokeh Rendering
Authors: Yichen Sheng, Zixun Yu, Lu Ling, Zhiwen Cao, Xuaner Zhang, Xin Lu, Ke Xian, Haiting Lin, Bedrich Benes
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Bokeh is widely used in photography to draw attention to the subject while effectively isolating distractions in the background. Computational methods can simulate bokeh effects without relying on a physical camera lens but the inaccurate lens modeling in existing filtering-based methods leads to artifacts that need post-processing or learning-based methods to fix. We propose Dr.Bokeh a novel rendering method that addresses the issue by directly correcting the defect that violates the physics in the current filtering-based bokeh rendering equation. Dr.Bokeh first preprocesses the input RGBD to obtain a layered scene representation. Dr.Bokeh then takes the layered representation and user-defined lens parameters to render photo-realistic lens blur based on the novel occlusion-aware bokeh rendering method. Experiments show that the non-learning based renderer Dr.Bokeh outperforms state-of-the-art bokeh rendering algorithms in terms of photo-realism. In addition extensive quantitative and qualitative evaluations show the more accurate lens model further pushes the limit of a closely related field depth-from-defocus.
Unsegment Anything by Simulating Deformation
Authors: Jiahao Lu, Xingyi Yang, Xinchao Wang
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Foundation segmentation models while powerful pose a significant risk: they enable users to effortlessly extract any objects from any digital content with a single click potentially leading to copyright infringement or malicious misuse. To mitigate this risk we introduce a new task "Anything Unsegmentable" to grant any image "the right to be unsegmented". The ambitious pursuit of the task is to achieve highly transferable adversarial attack against all prompt-based segmentation models regardless of model parameterizations and prompts. We highlight the non-transferable and heterogeneous nature of prompt-specific adversarial noises. Our approach focuses on disrupting image encoder features to achieve prompt-agnostic attacks. Intriguingly targeted feature attacks exhibit better transferability compared to untargeted ones suggesting the optimal update direction aligns with the image manifold. Based on the observations we design a novel attack named Unsegment Anything by Simulating Deformation (UAD). Our attack optimizes a differentiable deformation function to create a target deformed image which alters structural information while preserving achievable feature distance by adversarial example. Extensive experiments verify the effectiveness of our approach compromising a variety of promptable segmentation models with different architectures and prompt interfaces.
Transductive Zero-Shot and Few-Shot CLIP
Authors: Ségolène Martin, Yunshi Huang, Fereshteh Shakeri, Jean-Christophe Pesquet, Ismail Ben Ayed
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Transductive inference has been widely investigated in few-shot image classification but completely overlooked in the recent fast growing literature on adapting vision-langage models like CLIP. This paper addresses the transductive zero-shot and few-shot CLIP classification challenge in which inference is performed jointly across a mini-batch of unlabeled query samples rather than treating each instance independently. This paper addresses the transductive zero-shot and few-shot CLIP classification challenge in which inference is performed jointly across a mini-batch of unlabeled query samples rather than treating each instance independently. We initially construct informative vision-text probability features leading to a classification problem on the unit simplex set. Inspired by Expectation-Maximization (EM) our optimization-based classifying objective models the data probability distribution for each class using a Dirichlet law. The minimization problem is then tackled with a novel block Majorization-Minimization algorithm which simultaneously estimates the distribution parameters and class assignments. Extensivenumerical experiments on 11 datasets underscore the benefits and efficacy of our batch inference approach. On zero-shot tasks with test batches of 75 samples our approach yields near 20% improvement in ImageNet accuracy over CLIP's zero-shot performance. Additionally we outperform state-of-the-art methods in the few-shot setting. Code is available at https://github.com/SegoleneMartin/transductive-CLIP.
Deep Single Image Camera Calibration by Heatmap Regression to Recover Fisheye Images Under Manhattan World Assumption
Authors: Nobuhiko Wakai, Satoshi Sato, Yasunori Ishii, Takayoshi Yamashita
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: A Manhattan world lying along cuboid buildings is useful for camera angle estimation. However accurate and robust angle estimation from fisheye images in the Manhattan world has remained an open challenge because general scene images tend to lack constraints such as lines arcs and vanishing points. To achieve higher accuracy and robustness we propose a learning-based calibration method that uses heatmap regression which is similar to pose estimation using keypoints to detect the directions of labeled image coordinates. Simultaneously our two estimators recover the rotation and remove fisheye distortion by remapping from a general scene image. Without considering vanishing-point constraints we find that additional points for learning-based methods can be defined. To compensate for the lack of vanishing points in images we introduce auxiliary diagonal points that have the optimal 3D arrangement of spatial uniformity. Extensive experiments demonstrated that our method outperforms conventional methods on large-scale datasets and with off-the-shelf cameras.
ID-Blau: Image Deblurring by Implicit Diffusion-based reBLurring AUgmentation
Authors: Jia-Hao Wu, Fu-Jen Tsai, Yan-Tsung Peng, Chung-Chi Tsai, Chia-Wen Lin, Yen-Yu Lin
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Image deblurring aims to remove undesired blurs from an image captured in a dynamic scene. Much research has been dedicated to improving deblurring performance through model architectural designs. However there is little work on data augmentation for image deblurring. Since continuous motion causes blurred artifacts during image exposure we aspire to develop a groundbreaking blur augmentation method to generate diverse blurred images by simulating motion trajectories in a continuous space. This paper proposes Implicit Diffusion-based reBLurring AUgmentation (ID-Blau) utilizing a sharp image paired with a controllable blur condition map to produce a corresponding blurred image. We parameterize the blur patterns of a blurred image with their orientations and magnitudes as a pixel-wise blur condition map to simulate motion trajectories and implicitly represent them in a continuous space. By sampling diverse blur conditions ID-Blau can generate various blurred images unseen in the training set. Experimental results demonstrate that ID-Blau can produce realistic blurred images for training and thus significantly improve performance for state-of-the-art deblurring models. The source code is available at https://github.com/plusgood-steven/ID-Blau.
LAENeRF: Local Appearance Editing for Neural Radiance Fields
Authors: Lukas Radl, Michael Steiner, Andreas Kurz, Markus Steinberger
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Due to the omnipresence of Neural Radiance Fields (NeRFs) the interest towards editable implicit 3D representations has surged over the last years. However editing implicit or hybrid representations as used for NeRFs is difficult due to the entanglement of appearance and geometry encoded in the model parameters. Despite these challenges recent research has shown first promising steps towards photorealistic and non-photorealistic appearance edits. The main open issues of related work include limited interactivity a lack of support for local edits and large memory requirements rendering them less useful in practice. We address these limitations with LAENeRF a unified framework for photorealistic and non-photorealistic appearance editing of NeRFs. To tackle local editing we leverage a voxel grid as starting point for region selection. We learn a mapping from expected ray terminations to final output color which can optionally be supervised by a style loss resulting in a framework which can perform photorealistic and non-photorealistic appearance editing of selected regions. Relying on a single point per ray for our mapping we limit memory requirements and enable fast optimization. To guarantee interactivity we compose the output color using a set of learned modifiable base colors composed with additive layer mixing. Compared to concurrent work LAENeRF enables recoloring and stylization while keeping processing time low. Furthermore we demonstrate that our approach surpasses baseline methods both quantitatively and qualitatively.
CSTA: CNN-based Spatiotemporal Attention for Video Summarization
Authors: Jaewon Son, Jaehun Park, Kwangsu Kim
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Video summarization aims to generate a concise representation of a video capturing its essential content and key moments while reducing its overall length. Although several methods employ attention mechanisms to handle long-term dependencies they often fail to capture the visual significance inherent in frames. To address this limitation we propose a CNN-based SpatioTemporal Attention (CSTA) method that stacks each feature of frames from a single video to form image-like frame representations and applies 2D CNN to these frame features. Our methodology relies on CNN to comprehend the inter and intra-frame relations and to find crucial attributes in videos by exploiting its ability to learn absolute positions within images. In contrast to previous work compromising efficiency by designing additional modules to focus on spatial importance CSTA requires minimal computational overhead as it uses CNN as a sliding window. Extensive experiments on two benchmark datasets (SumMe and TVSum) demonstrate that our proposed approach achieves state-of-the-art performance with fewer MACs compared to previous methods. Codes are available at https://github.com/thswodnjs3/CSTA.
Adversarial Score Distillation: When score distillation meets GAN
Authors: Min Wei, Jingkai Zhou, Junyao Sun, Xuesong Zhang
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Existing score distillation methods are sensitive to classifier-free guidance (CFG) scale manifested as over-smoothness or instability at small CFG scales while over-saturation at large ones. To explain and analyze these issues we revisit the derivation of Score Distillation Sampling (SDS) and decipher existing score distillation with the Wasserstein Generative Adversarial Network (WGAN) paradigm. With the WGAN paradigm we find that existing score distillation either employs a fixed sub-optimal discriminator or conducts incomplete discriminator optimization resulting in the scale-sensitive issue. We propose the Adversarial Score Distillation (ASD) which maintains an optimizable discriminator and updates it using the complete optimization objective. Experiments show that the proposed ASD performs favorably in 2D distillation and text-to-3D tasks against existing methods. Furthermore to explore the generalization ability of our paradigm we extend ASD to the image editing task which achieves competitive results. The project page and code are at https://github.com/2y7c3/ASD
Decentralized Directed Collaboration for Personalized Federated Learning
Authors: Yingqi Liu, Yifan Shi, Qinglun Li, Baoyuan Wu, Xueqian Wang, Li Shen
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Personalized Federated Learning (PFL) is proposed to find the greatest personalized models for each client. To avoid the central failure and communication bottleneck in the server-based FL we concentrate on the Decentralized Personalized Federated Learning (DPFL) that performs distributed model training in a Peer-to-Peer (P2P) manner. Most personalized works in DPFL are based on undirected and symmetric topologies however the data computation and communication resources heterogeneity result in large variances in the personalized models which lead the undirected aggregation to suboptimal personalized performance and unguaranteed convergence. To address these issues we propose a directed collaboration DPFL framework by incorporating stochastic gradient push and partial model personalized called Decentralized Federated Partial Gradient Push (DFedPGP). It personalizes the linear classifier in the modern deep model to customize the local solution and learns a consensus representation in a fully decentralized manner. Clients only share gradients with a subset of neighbors based on the directed and asymmetric topologies which guarantees flexible choices for resource efficiency and better convergence. Theoretically we show that the proposed DFedPGP achieves a superior convergence rate of O(1/?T) in the general non-convex setting and tighter connectivity among clients will speed up the convergence. The proposed method achieves state-of-the-art (SOTA) accuracy in both data and computation heterogeneity scenarios demonstrating the efficiency of the directed collaboration and partial gradient push.
Vector Graphics Generation via Mutually Impulsed Dual-domain Diffusion
Authors: Zhongyin Zhao, Ye Chen, Zhangli Hu, Xuanhong Chen, Bingbing Ni
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Intelligent generation of vector graphics has very promising applications in the fields of advertising and logo design artistic painting animation production etc. However current mainstream vector image generation methods lack the encoding of image appearance information that is associated with the original vector representation and therefore lose valid supervision signal from the strong correlation between the discrete vector parameter (drawing instruction) sequence and the target shape/structure of the corresponding pixel image. On the one hand the generation process based on pure vector domain completely ignores the similarity measurement between shape parameter (and their combination) and the paired pixel image appearance pattern; on the other hand two-stage methods (i.e. generation-and-vectorization) based on pixel diffusion followed by differentiable image-to-vector translation suffer from wrong error-correction signal caused by approximate gradients. To address the above issues we propose a novel generation framework based on dual-domain (vector-pixel) diffusion with cross-modality impulse signals from each other. First in each diffusion step the current representation extracted from the other domain is used as a condition variable to constrain the subsequent sampling operation yielding shape-aware new parameterizations; second independent supervision signals from both domains avoid the gradient error accumulation problem caused by cross-domain representation conversion. Extensive experimental results on popular benchmarks including font and icon datasets demonstrate the great advantages of our proposed framework in terms of generated shape quality.
PEM: Prototype-based Efficient MaskFormer for Image Segmentation
Authors: Niccolò Cavagnero, Gabriele Rosi, Claudia Cuttano, Francesca Pistilli, Marco Ciccone, Giuseppe Averta, Fabio Cermelli
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Recent transformer-based architectures have shown impressive results in the field of image segmentation. Thanks to their flexibility they obtain outstanding performance in multiple segmentation tasks such as semantic and panoptic under a single unified framework. To achieve such impressive performance these architectures employ intensive operations and require substantial computational resources which are often not available especially on edge devices. To fill this gap we propose Prototype-based Efficient MaskFormer (PEM) an efficient transformer-based architecture that can operate in multiple segmentation tasks. PEM proposes a novel prototype-based cross-attention which leverages the redundancy of visual features to restrict the computation and improve the efficiency without harming the performance. In addition PEM introduces an efficient multi-scale feature pyramid network capable of extracting features that have high semantic content in an efficient way thanks to the combination of deformable convolutions and context-based self-modulation. We benchmark the proposed PEM architecture on two tasks semantic and panoptic segmentation evaluated on two different datasets Cityscapes and ADE20K. PEM demonstrates outstanding performance on every task and dataset outperforming task-specific architectures while being comparable and even better than computationally expensive baselines. Code is available at https://github.com/NiccoloCavagnero/PEM.
Referring Expression Counting
Authors: Siyang Dai, Jun Liu, Ngai-Man Cheung
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Existing counting tasks are limited to the class level which don't account for fine-grained details within the class. In real applications it often requires in-context or referring human input for counting target objects. Take urban analysis as an example fine-grained information such as traffic flow in different directions pedestrians and vehicles waiting or moving at different sides of the junction is more beneficial. Current settings of both class-specific and class-agnostic counting treat objects of the same class indifferently which pose limitations in real use cases. To this end we propose a new task named Referring Expression Counting (REC) which aims to count objects with different attributes within the same class. To evaluate the REC task we create a novel dataset named REC-8K which contains 8011 images and 17122 referring expressions. Experiments on REC-8K show that our proposed method achieves state-of-the-art performance compared with several text-based counting methods and an open-set object detection model. We also outperform prior models on the class agnostic counting (CAC) benchmark [36] for the zero-shot setting and perform on par with the few-shot methods. Code and dataset is available at https://github.com/sydai/referring-expression-counting.
ScoreHypo: Probabilistic Human Mesh Estimation with Hypothesis Scoring
Authors: Yuan Xu, Xiaoxuan Ma, Jiajun Su, Wentao Zhu, Yu Qiao, Yizhou Wang
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Monocular 3D human mesh estimation is an ill-posed problem characterized by inherent ambiguity and occlusion. While recent probabilistic methods propose generating multiple solutions little attention is paid to obtaining high-quality estimates from them. To address this limitation we introduce ScoreHypo a versatile framework by first leverages our novel HypoNet to generate multiple hypotheses followed by employing a meticulously designed scorer ScoreNet to evaluate and select high-quality estimates. ScoreHypo formulates the estimation process as a reverse denoising process where HypoNet produces a diverse set of plausible estimates that effectively align with the image cues. Subsequently ScoreNet is employed to rigorously evaluate and rank these estimates based on their quality and finally identify superior ones. Experimental results demonstrate that HypoNet outperforms existing state-of-the-art probabilistic methods as a multi-hypothesis mesh estimator. Moreover the estimates selected by ScoreNet significantly outperform random generation or simple averaging. Notably the trained ScoreNet exhibits generalizability as it can effectively score existing methods and significantly reduce their errors by more than 15%. Code and models are available at https://xy02-05.github.io/ScoreHypo.
GES : Generalized Exponential Splatting for Efficient Radiance Field Rendering
Authors: Abdullah Hamdi, Luke Melas-Kyriazi, Jinjie Mai, Guocheng Qian, Ruoshi Liu, Carl Vondrick, Bernard Ghanem, Andrea Vedaldi
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Advancements in 3D Gaussian Splatting have significantly accelerated 3D reconstruction and generation. However it may require a large number of Gaussians which creates a substantial memory footprint. This paper introduces GES (Generalized Exponential Splatting) a novel representation that employs Generalized Exponential Function (GEF) to model 3D scenes requiring far fewer particles to represent a scene and thus significantly outperforming Gaussian Splatting methods in efficiency with a plug-and-play replacement ability for Gaussian-based utilities. GES is validated theoretically and empirically in both principled 1D setup and realistic 3D scenes. It is shown to represent signals with sharp edges more accurately which are typically challenging for Gaussians due to their inherent low-pass characteristics. Our empirical analysis demonstrates that GEF outperforms Gaussians in fitting natural-occurring signals (E.g. squares triangles parabolic signals) thereby reducing the need for extensive splitting operations that increase the memory footprint of Gaussian Splatting. With the aid of a frequency-modulated loss GES achieves competitive performance in novel-view synthesis benchmarks while requiring less than half the memory storage of Gaussian Splatting and increasing the rendering speed by up to 39%. The code is available on the project website https://abdullahamdi.com/ges .
Learning to Predict Activity Progress by Self-Supervised Video Alignment
Authors: Gerard Donahue, Ehsan Elhamifar
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: In this paper we tackle the problem of self-supervised video alignment and activity progress prediction using in-the-wild videos. Our proposed self-supervised representation learning method carefully addresses different action orderings redundant actions and background frames to generate improved video representations compared to previous methods. Our model generalizes temporal cycle-consistency learning to allow for more flexibility in determining cycle-consistent neighbors. More specifically to handle repeated actions we propose a multi-neighbor cycle consistency and a multi-cycle-back regression loss by finding multiple soft nearest neighbors using a Gaussian Mixture Model. To handle background and redundant frames we introduce a context-dependent drop function in our framework discouraging the alignment of droppable frames. On the other hand to learn from videos of multiple activities jointly we propose a multi-head crosstask network allowing us to embed a video and estimate progress without knowing its activity label. Experiments on multiple datasets show that our method outperforms the state-of-the-art for video alignment and progress prediction.
VicTR: Video-conditioned Text Representations for Activity Recognition
Authors: Kumara Kahatapitiya, Anurag Arnab, Arsha Nagrani, Michael S. Ryoo
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Vision-Language models (VLMs) have excelled in the image-domain--- especially in zero-shot settings--- thanks to the availability of vast pretraining data (i.e. paired image-text samples). However for videos such paired data is not as abundant. Therefore video-VLMs are usually designed by adapting pretrained image-VLMs to the video-domain instead of training from scratch. All such recipes rely on augmenting visual embeddings with temporal information (i.e. image --> video) often keeping text embeddings unchanged or even being discarded. In this paper we argue the contrary that better video-VLMs can be designed by focusing more on augmenting text rather than visual information. More specifically we introduce Video-conditioned Text Representations (VicTR): a form of text embeddings optimized w.r.t. visual embeddings creating a more-flexible contrastive latent space. Our model can further make use of freely-available semantic information in the form of visually-grounded auxiliary text (e.g. object or scene information). We evaluate our model on few-shot zero-shot (HMDB-51 UCF-101) short-form (Kinetics-400) and long-form (Charades) activity recognition benchmarks showing strong performance among video-VLMs.
Label-Efficient Group Robustness via Out-of-Distribution Concept Curation
Authors: Yiwei Yang, Anthony Z. Liu, Robert Wolfe, Aylin Caliskan, Bill Howe
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Deep neural networks are prone to capture correlations between spurious attributes and class labels leading to low accuracy on some combinations of class labels and spurious attribute values. When a spurious attribute represents a protected class these low-accuracy groups can manifest discriminatory bias. Existing methods attempting to improve worst-group accuracy assume the training data validation data or both are reliably labeled by the spurious attribute. But a model may be perceived to be biased towards a concept that is not represented by pre-existing labels on the training data. In these situations the spurious attribute must be defined with external information. We propose Concept Correction a framework that represents a concept as a curated set of images from any source then labels each training sample by its similarity to the concept set to control spurious correlations. For example concept sets representing gender can be used to measure and control gender bias even without explicit labels. We demonstrate and evaluate an instance of the framework as Concept DRO which uses concept sets to estimate group labels then uses these labels to train with a state of the art distributively robust optimization objective. We show that Concept DRO outperforms existing methods that do not require labels of spurious attributes by up to 33.1% on three image classification datasets and is competitive with the best methods that assume access to labels. We consider how the size and quality of the concept set influences performance and find that even smaller manually curated sets of noisy AI-generated images are effective at controlling spurious correlations suggesting that high-quality reusable concept sets are easy to create and effective in reducing bias.
MMCert: Provable Defense against Adversarial Attacks to Multi-modal Models
Authors: Yanting Wang, Hongye Fu, Wei Zou, Jinyuan Jia
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Different from a unimodal model whose input is from a single modality the input (called multi-modal input) of a multi-modal model is from multiple modalities such as image 3D points audio text etc. Similar to unimodal models many existing studies show that a multi-modal model is also vulnerable to adversarial perturbation where an attacker could add small perturbation to all modalities of a multi-modal input such that the multi-modal model makes incorrect predictions for it. Existing certified defenses are mostly designed for unimodal models which achieve sub-optimal certified robustness guarantees when extended to multi-modal models as shown in our experimental results. In our work we propose MMCert the first certified defense against adversarial attacks to a multi-modal model. We derive a lower bound on the performance of our MMCert under arbitrary adversarial attacks with bounded perturbations to both modalities (e.g. in the context of auto-driving we bound the number of changed pixels in both RGB image and depth image). We evaluate our MMCert using two benchmark datasets: one for the multi-modal road segmentation task and the other for the multi-modal emotion recognition task. Moreover we compare our MMCert with a state-of-the-art certified defense extended from unimodal models. Our experimental results show that our MMCert outperforms the baseline.
3DToonify: Creating Your High-Fidelity 3D Stylized Avatar Easily from 2D Portrait Images
Authors: Yifang Men, Hanxi Liu, Yuan Yao, Miaomiao Cui, Xuansong Xie, Zhouhui Lian
Published in: IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), 2024 (Main Conference Track), 2024

Abstract: Visual content creation has aroused a surge of interest given its applications in mobile photography and AR/VR. Portrait style transfer and 3D recovery from monocular images as two representative tasks have so far evolved independently. In this paper we make a connection between the two and tackle the challenging task of 3D portrait stylization - modeling high-fidelity 3D stylized avatars from captured 2D portrait images. However naively combining the techniques from the two isolated areas may suffer from either inadequate stylization or absence of 3D assets. To this end we propose 3DToonify a new framework that introduces a progressive training scheme to achieve 3D style adaption on spatial neural representation (SNR). SNR is constructed with implicit fields and they are dynamically optimized by the progressive training scheme which consists of three stages: guided prior learning deformable geometry adaption and explicit texture adaption. In this way stylized geometry and texture are learned in SNR in an explicit and structured way with only a single stylized exemplar needed. Moreover our method obtains style-adaptive underlying structures (i.e. deformable geometry and exaggerated texture) and view-consistent stylized avatar rendering from arbitrary novel viewpoints. Both qualitative and quantitative experiments have been conducted to demonstrate the effectiveness and superiority of our method for automatically generating exemplar-guided 3D stylized avatars.