Datasets:

CVPR2024

/

CVPR2024-papers

like 1

RoMa: Robust Dense Feature Matching

Johan Edstedt, Qiyu Sun, Georg Bökman, Mårten Wadenbäck, Michael Felsberg

Feature matching is an important computer vision task that involves estimating correspondences between two images of a 3D scene and dense methods estimate all such correspondences. The aim is to learn a robust model i.e. a model able to match under challenging real-world changes. In this work we propose such a model leveraging frozen pretrained features from the foundation model DINOv2. Although these features are significantly more robust than local features trained from scratch they are inherently coarse. We therefore combine them with specialized ConvNet fine features creating a precisely localizable feature pyramid. To further improve robustness we propose a tailored transformer match decoder that predicts anchor probabilities which enables it to express multimodality. Finally we propose an improved loss formulation through regression-by-classification with subsequent robust regression. We conduct a comprehensive set of experiments that show that our method RoMa achieves significant gains setting a new state-of-the-art. In particular we achieve a 36% improvement on the extremely challenging WxBS benchmark. Code is provided at github.com/Parskatt/RoMa.

[]

[]

[]

[]

Omni-SMoLA: Boosting Generalist Multimodal Models with Soft Mixture of Low-rank Experts

Jialin Wu, Xia Hu, Yaqing Wang, Bo Pang, Radu Soricut

In this work we present Omni-SMoLA a multimodal architecture that mixes many multi-modal experts efficiently and achieves both high specialist and generalist performance. In contrast to previous models for which we see performance degradation on average when training the models on a wide range of tasks we show that the SMoLA low-rank experts are able to model different skills and task and overall improve the performance of a generalist model. This finding indicates that simple LMM fine-tuning is suboptimal for handling a wide range of tasks and that pairing the act of fine-tuning with specifically-designed architecture changes leads to better performing models.

[]

[]

[]

[]

SeMoLi: What Moves Together Belongs Together

http://arxiv.org/abs/2402.19463

Jenny Seidenschwarz, Aljosa Osep, Francesco Ferroni, Simon Lucey, Laura Leal-Taixe

We tackle semi-supervised object detection based on motion cues. Recent results suggest that heuristic-based clustering methods in conjunction with object trackers can be used to pseudo-label instances of moving objects and use these as supervisory signals to train 3D object detectors in Lidar data without manual supervision. We re-think this approach and suggest that both object detection as well as motion-inspired pseudo-labeling can be tackled in a data-driven manner. We leverage recent advances in scene flow estimation to obtain point trajectories from which we extract long-term class-agnostic motion patterns. Revisiting correlation clustering in the context of message passing networks we learn to group those motion patterns to cluster points to object instances. By estimating the full extent of the objects we obtain per-scan 3D bounding boxes that we use to supervise a Lidar object detection network. Our method not only outperforms prior heuristic-based approaches (57.5 AP +14 improvement over prior work) more importantly we show we can pseudo-label and train object detectors across datasets.

[]

[]

[]

[]

Insights from the Use of Previously Unseen Neural Architecture Search Datasets

http://arxiv.org/abs/2404.02189

Rob Geada, David Towers, Matthew Forshaw, Amir Atapour-Abarghouei, A. Stephen McGough

The boundless possibility of neural networks which can be used to solve a problem - each with different performance - leads to a situation where a Deep Learning expert is required to identify the best neural network. This goes against the hope of removing the need for experts. Neural Architecture Search (NAS) offers a solution to this by automatically identifying the best architecture. However to date NAS work has focused on a small set of datasets which we argue are not representative of real-world problems. We introduce eight new datasets created for a series of NAS Challenges: AddNIST Language MultNIST CIFARTile Gutenberg Isabella GeoClassing and Chesseract. These datasets and challenges are developed to direct attention to issues in NAS development and to encourage authors to consider how their models will perform on datasets unknown to them at development time. We present experimentation using standard Deep Learning methods as well as the best results from challenge participants

[]

[]

[]

[]

Adversarially Robust Few-shot Learning via Parameter Co-distillation of Similarity and Class Concept Learners

Junhao Dong, Piotr Koniusz, Junxi Chen, Xiaohua Xie, Yew-Soon Ong

Few-shot learning (FSL) facilitates a variety of computer vision tasks yet remains vulnerable to adversarial attacks. Existing adversarially robust FSL methods rely on either visual similarity learning or class concept learning. Our analysis reveals that these two learning paradigms are complementary exhibiting distinct robustness due to their unique decision boundary types (concepts clustering by the visual similarity label vs. classification by the class labels). To bridge this gap we propose a novel framework unifying adversarially robust similarity learning and class concept learning. Specifically we distill parameters from both network branches into a "unified embedding model" during robust optimization and redistribute them to individual network branches periodically. To capture generalizable robustness across diverse branches we initialize adversaries in each episode with cross-branch class-wise "global adversarial perturbations" instead of less informative random initialization. We also propose a branch robustness harmonization to modulate the optimization of similarity and class concept learners via their relative adversarial robustness. Extensive experiments demonstrate the state-of-the-art performance of our method in diverse few-shot scenarios.

[]

[]

[]

[]

Context-Guided Spatio-Temporal Video Grounding

http://arxiv.org/abs/2401.01578

Xin Gu, Heng Fan, Yan Huang, Tiejian Luo, Libo Zhang

Spatio-temporal video grounding (or STVG) task aims at locating a spatio-temporal tube for a specific instance given a text query. Despite advancements current methods easily suffer the distractors or heavy object appearance variations in videos due to insufficient object information from the text leading to degradation. Addressing this we propose a novel framework context-guided STVG (CG-STVG) which mines discriminative instance context for object in videos and applies it as a supplementary guidance for target localization. The key of CG-STVG lies in two specially designed modules including instance context generation (ICG) which focuses on discovering visual context information (in both appearance and motion) of the instance and instance context refinement (ICR) which aims to improve the instance context from ICG by eliminating irrelevant or even harmful information from the context. During grounding ICG together with ICR are deployed at each decoding stage of a Transformer architecture for instance context learning. Particularly instance context learned from one decoding stage is fed to the next stage and leveraged as a guidance containing rich and discriminative object feature to enhance the target-awareness in decoding feature which conversely benefits generating better new instance context for improving localization finally. Compared to existing methods CG-STVG enjoys object information in text query and guidance from mined instance visual context for more accurate target localization. In our experiments on three benchmarks including HCSTVG-v1/-v2 and VidSTG CG-STVG sets new state-of-the-arts in m_tIoU and m_vIoU on all of them showing efficacy. Code is released at https://github.com/HengLan/CGSTVG.

[]

[]

[]

[]

Explaining the Implicit Neural Canvas: Connecting Pixels to Neurons by Tracing their Contributions

http://arxiv.org/abs/2401.10217

Namitha Padmanabhan, Matthew Gwilliam, Pulkit Kumar, Shishira R Maiya, Max Ehrlich, Abhinav Shrivastava

The many variations of Implicit Neural Representations (INRs) where a neural network is trained as a continuous representation of a signal have tremendous practical utility for downstream tasks including novel view synthesis video compression and image super-resolution. Unfortunately the inner workings of these networks are seriously understudied. Our work eXplaining the Implicit Neural Canvas (XINC) is a unified framework for explaining properties of INRs by examining the strength of each neuron's contribution to each output pixel. We call the aggregate of these contribution maps the Implicit Neural Canvas and we use this concept to demonstrate that the INRs we study learn to "see" the frames they represent in surprising ways. For example INRs tend to have highly distributed representations. While lacking high-level object semantics they have a significant bias for color and edges and are almost entirely space-agnostic. We arrive at our conclusions by examining how objects are represented across time in video INRs using clustering to visualize similar neurons across layers and architectures and show that this is dominated by motion. These insights demonstrate the general usefulness of our analysis framework.

[]

[]

[]

[]

APISR: Anime Production Inspired Real-World Anime Super-Resolution

http://arxiv.org/abs/2403.01598

Boyang Wang, Fengyu Yang, Xihang Yu, Chao Zhang, Hanbin Zhao

While real-world anime super-resolution (SR) has gained increasing attention in the SR community existing methods still adopt techniques from the photorealistic domain. In this paper we analyze the anime production workflow and rethink how to use characteristics of it for the sake of the real-world anime SR. First we argue that video networks and datasets are not necessary for anime SR due to the repetition use of hand-drawing frames. Instead we propose an anime image collection pipeline by choosing the least compressed and the most informative frames from the video sources. Based on this pipeline we introduce the Anime Production-oriented Image (API) dataset. In addition we identify two anime-specific challenges of distorted and faint hand-drawn lines and unwanted color artifacts. We address the first issue by introducing a prediction-oriented compression module in the image degradation model and a pseudo-ground truth preparation with enhanced hand-drawn lines. In addition we introduce the balanced twin perceptual loss combining both anime and photorealistic high-level features to mitigate unwanted color artifacts and increase visual clarity. We evaluate our method through extensive experiments on the public benchmark showing our method outperforms state-of-the-art anime dataset-trained approaches.

[]

[]

[]

[]

MVCPS-NeuS: Multi-view Constrained Photometric Stereo for Neural Surface Reconstruction

Hiroaki Santo, Fumio Okura, Yasuyuki Matsushita

Multi-view photometric stereo (MVPS) recovers a high-fidelity 3D shape of a scene by benefiting from both multi-view stereo and photometric stereo. While photometric stereo boosts detailed shape reconstruction it necessitates recording images under various light conditions for each viewpoint. In particular calibrating the light directions for each view significantly increases the cost of acquiring images. To make MVPS more accessible we introduce a practical and easy-to-implement setup multi-view constrained photometric stereo (MVCPS) where the light directions are unknown but constrained to move together with the camera. Unlike conventional multi-view uncalibrated photometric stereo our constrained setting reduces the ambiguities of surface normal estimates from per-view linear ambiguities to a single and global linear one thereby simplifying the disambiguation process. The proposed method integrates the ambiguous surface normal into neural surface reconstruction (NeuS) to simultaneously resolve the global ambiguity and estimate the detailed 3D shape. Experiments demonstrate that our method estimates accurate shapes under sparse viewpoints using only a few multi-view constrained light sources.

[]

[]

[]

[]

ULIP-2: Towards Scalable Multimodal Pre-training for 3D Understanding

Le Xue, Ning Yu, Shu Zhang, Artemis Panagopoulou, Junnan Li, Roberto Martín-Martín, Jiajun Wu, Caiming Xiong, Ran Xu, Juan Carlos Niebles, Silvio Savarese

Recent advancements in multimodal pre-training have shown promising efficacy in 3D representation learning by aligning multimodal features across 3D shapes their 2D counterparts and language descriptions. However the methods used by existing frameworks to curate such multimodal data in particular language descriptions for 3D shapes are not scalable and the collected language descriptions are not diverse. To address this we introduce ULIP-2 a simple yet effective tri-modal pretraining framework that leverages large multimodal models to automatically generate holistic language descriptions for 3D shapes. It only needs 3D data as input eliminating the need for any manual 3D annotations and is therefore scalable to large datasets. ULIP-2 is also equipped with scaled-up backbones for better multi-modal representation learning. We conduct experiments on two large-scale 3D datasets Objaverse and ShapeNet and augment them with tri-modal datasets of 3D point clouds images and language for training ULIP-2. Experiments show that ULIP-2 demonstrates substantial benefits in three downstream tasks: zero-shot 3D classification standard 3D classification with fine-tuning and 3D captioning (3D-to-language generation). It achieves a new SOTA of 50.6% (top- 1) on Objaverse-LVIS and 84.7% (top-1) on ModelNet40 in zero-shot classification. In the ScanObjectNN benchmark for standard fine-tuning ULIP-2 reaches an overall accuracy of 91.5% with a compact model of only 1.4 million parameters. ULIP-2 sheds light on a new paradigm for scalable multimodal 3D representation learning without human annotations and shows significant improvements over existing baselines. The code and datasets are released at https://github.com/salesforce/ULIP.

[]

[]

[]

[]

Normalizing Flows on the Product Space of SO(3) Manifolds for Probabilistic Human Pose Modeling

Olaf Dünkel, Tim Salzmann, Florian Pfaff

Normalizing flows have proven their efficacy for density estimation in Euclidean space but their application to rotational representations crucial in various domains such as robotics or human pose modeling remains underexplored. Probabilistic models of the human pose can benefit from approaches that rigorously consider the rotational nature of human joints. For this purpose we introduce HuProSO3 a normalizing flow model that operates on a high-dimensional product space of SO(3) manifolds modeling the joint distribution for human joints with three degrees of freedom. HuProSO3's advantage over state-of-the-art approaches is demonstrated through its superior modeling accuracy in three different applications and its capability to evaluate the exact likelihood. This work not only addresses the technical challenge of learning densities on SO(3) manifolds but it also has broader implications for domains where the probabilistic regression of correlated 3D rotations is of importance. Code will be available at https://github.com/odunkel/HuProSO.

[]

[]

[]

[]

Adapting to Length Shift: FlexiLength Network for Trajectory Prediction

http://arxiv.org/abs/2404.00742

Yi Xu, Yun Fu

Trajectory prediction plays an important role in various applications including autonomous driving robotics and scene understanding. Existing approaches mainly focus on developing compact neural networks to increase prediction precision on public datasets typically employing a standardized input duration. However a notable issue arises when these models are evaluated with varying observation lengths leading to a significant performance drop a phenomenon we term the Observation Length Shift. To address this issue we introduce a general and effective framework the FlexiLength Network (FLN) to enhance the robustness of existing trajectory prediction techniques against varying observation periods. Specifically FLN integrates trajectory data with diverse observation lengths incorporates FlexiLength Calibration (FLC) to acquire temporal invariant representations and employs FlexiLength Adaptation (FLA) to further refine these representations for more accurate future trajectory predictions. Comprehensive experiments on multiple datasets i.e. ETH/UCY nuScenes and Argoverse 1 demonstrate the effectiveness and flexibility of our proposed FLN framework.

[]

[]

[]

[]

WorDepth: Variational Language Prior for Monocular Depth Estimation

http://arxiv.org/abs/2404.03635

Ziyao Zeng, Daniel Wang, Fengyu Yang, Hyoungseob Park, Stefano Soatto, Dong Lao, Alex Wong

Three-dimensional (3D) reconstruction from a single image is an ill-posed problem with inherent ambiguities i.e. scale. Predicting a 3D scene from text description(s) is similarly ill-posed i.e. spatial arrangements of objects described. We investigate the question of whether two inherently ambiguous modalities can be used in conjunction to produce metric-scaled reconstructions. To test this we focus on monocular depth estimation the problem of predicting a dense depth map from a single image but with an additional text caption describing the scene. To this end we begin by encoding the text caption as a mean and standard deviation; using a variational framework we learn the distribution of the plausible metric reconstructions of 3D scenes corresponding to the text captions as a prior. To "select" a specific reconstruction or depth map we encode the given image through a conditional sampler that samples from the latent space of the variational text encoder which is then decoded to the output depth map. Our approach is trained alternatingly between the text and image branches: in one optimization step we predict the mean and standard deviation from the text description and sample from a standard Gaussian and in the other we sample using a (image) conditional sampler. Once trained we directly predict depth from the encoded text using the conditional sampler. We demonstrate our approach on indoor (NYUv2) and outdoor (KITTI) scenarios where we show that language can consistently improve performance in both. Code: https://github.com/Adonis-galaxy/WorDepth.

[]

[]

[]

[]

WaveMo: Learning Wavefront Modulations to See Through Scattering

http://arxiv.org/abs/2404.07985

Mingyang Xie, Haiyun Guo, Brandon Y. Feng, Lingbo Jin, Ashok Veeraraghavan, Christopher A. Metzler

Imaging through scattering media is a fundamental and pervasive challenge in fields ranging from medical diagnostics to astronomy. A promising strategy to overcome this challenge is wavefront modulation which induces measurement diversity during image acquisition. Despite its importance designing optimal wavefront modulations to image through scattering remains under-explored. This paper introduces a novel learning-based framework to address the gap. Our approach jointly optimizes wavefront modulations and a computationally lightweight feedforward "proxy" reconstruction network. This network is trained to recover scenes obscured by scattering using measurements that are modified by these modulations. The learned modulations produced by our framework generalize effectively to unseen scattering scenarios and exhibit remarkable versatility. During deployment the learned modulations can be decoupled from the proxy network to augment other more computationally expensive restoration algorithms. Through extensive experiments we demonstrate our approach significantly advances the state of the art in imaging through scattering media. Our project webpage is at https://wavemo-2024.github.io/.

[]

[]

[]

[]

ReGenNet: Towards Human Action-Reaction Synthesis

http://arxiv.org/abs/2403.11882

Liang Xu, Yizhou Zhou, Yichao Yan, Xin Jin, Wenhan Zhu, Fengyun Rao, Xiaokang Yang, Wenjun Zeng

Humans constantly interact with their surrounding environments. Current human-centric generative models mainly focus on synthesizing humans plausibly interacting with static scenes and objects while the dynamic human action-reaction synthesis for ubiquitous causal human-human interactions is less explored. Human-human interactions can be regarded as asymmetric with actors and reactors in atomic interaction periods. In this paper we comprehensively analyze the asymmetric dynamic synchronous and detailed nature of human-human interactions and propose the first multi-setting human action-reaction synthesis benchmark to generate human reactions conditioned on given human actions. To begin with we propose to annotate the actor-reactor order of the interaction sequences for the NTU120 InterHuman and Chi3D datasets. Based on them a diffusion-based generative model with a Transformer decoder architecture called ReGenNet together with an explicit distance-based interaction loss is proposed to predict human reactions in an online manner where the future states of actors are unavailable to reactors. Quantitative and qualitative results show that our method can generate instant and plausible human reactions compared to the baselines and can generalize to unseen actor motions and viewpoint changes.

[]

[]

[]

[]

A Simple Baseline for Efficient Hand Mesh Reconstruction

http://arxiv.org/abs/2403.01813

Zhishan Zhou, Shihao Zhou, Zhi Lv, Minqiang Zou, Yao Tang, Jiajun Liang

Hand mesh reconstruction has attracted considerable attention in recent years with various approaches and techniques being proposed. Some of these methods incorporate complex components and designs which while effective may complicate the model and hinder efficiency. In this paper we decompose the mesh decoder into token generator and mesh regressor. Through extensive ablation experiments we found that the token generator should select discriminating and representative points while the mesh regressor needs to upsample sparse keypoints into dense meshes in multiple stages. Given these functionalities we can achieve high performance with minimal computational resources. Based on this observation we propose a simple yet effective baseline that outperforms state-of-the-art methods by a large margin while maintaining real-time efficiency. Our method outperforms existing solutions achieving state-of-the-art (SOTA) results across multiple datasets. On the FreiHAND dataset our approach produced a PA-MPJPE of 5.8mm and a PA-MPVPE of 6.1mm. Similarly on the DexYCB dataset we observed a PA-MPJPE of 5.5mm and a PA-MPVPE of 5.5mm. As for performance speed our method reached up to 33 frames per second (fps) when using HRNet and up to 70 fps when employing FastViT-MA36. Code will be made available.

[]

[]

[]

[]

Integrating Efficient Optimal Transport and Functional Maps For Unsupervised Shape Correspondence Learning

http://arxiv.org/abs/2403.01781

Tung Le, Khai Nguyen, Shanlin Sun, Nhat Ho, Xiaohui Xie

In the realm of computer vision and graphics accurately establishing correspondences between geometric 3D shapes is pivotal for applications like object tracking registration texture transfer and statistical shape analysis. Moving beyond traditional hand-crafted and data-driven feature learning methods we incorporate spectral methods with deep learning focusing on functional maps (FMs) and optimal transport (OT). Traditional OT-based approaches often reliant on entropy regularization OT in learning-based framework face computational challenges due to their quadratic cost. Our key contribution is to employ the sliced Wasserstein distance (SWD) for OT which is a valid fast optimal transport metric in an unsupervised shape matching framework. This unsupervised framework integrates functional map regularizers with a novel OT-based loss derived from SWD enhancing feature alignment between shapes treated as discrete probability measures. We also introduce an adaptive refinement process utilizing entropy regularized OT further refining feature alignments for accurate point-to-point correspondences. Our method demonstrates superior performance in non-rigid shape matching including near-isometric and non-isometric scenarios and excels in downstream tasks like segmentation transfer. The empirical results on diverse datasets highlight our framework's effectiveness and generalization capabilities setting new standards in non-rigid shape matching with efficient OT metrics and an adaptive refinement module.

[]

[]

[]

[]

PhotoMaker: Customizing Realistic Human Photos via Stacked ID Embedding

http://arxiv.org/abs/2312.04461

Zhen Li, Mingdeng Cao, Xintao Wang, Zhongang Qi, Ming-Ming Cheng, Ying Shan

Recent advances in text-to-image generation have made remarkable progress in synthesizing realistic human photos conditioned on given text prompts. However existing personalized generation methods cannot simultaneously satisfy the requirements of high efficiency promising identity (ID) fidelity and flexible text controllability. In this work we introduce PhotoMaker an efficient personalized text-to-image generation method which mainly encodes an arbitrary number of input ID images into a stack ID embedding for preserving ID information. Such an embedding also empowers our method to be applied in many interesting scenarios such as when replacing the corresponding class word and when combining the characteristics of different identities. Besides to better drive the training of our PhotoMaker we propose an ID-oriented data creation pipeline to assemble the training data. Under the nourishment of the dataset constructed through the proposed pipeline our PhotoMaker demonstrates comparable performance to test-time fine-tuning-based methods yet provides significant speed improvements strong generalization capabilities and a wide range of applications.

[]

[]

[]

[]

Score-Guided Diffusion for 3D Human Recovery

http://arxiv.org/abs/2403.09623

Anastasis Stathopoulos, Ligong Han, Dimitris Metaxas

We present Score-Guided Human Mesh Recovery (ScoreHMR) an approach for solving inverse problems for 3D human pose and shape reconstruction. These inverse problems involve fitting a human body model to image observations traditionally solved through optimization techniques. ScoreHMR mimics model fitting approaches but alignment with the image observation is achieved through score guidance in the latent space of a diffusion model. The diffusion model is trained to capture the conditional distribution of the human model parameters given an input image. By guiding its denoising process with a task-specific score ScoreHMR effectively solves inverse problems for various applications without the need for retraining the task-agnostic diffusion model. We evaluate our approach on three settings/applications. These are: (i) single-frame model fitting; (ii) reconstruction from multiple uncalibrated views; (iii) reconstructing humans in video sequences. ScoreHMR consistently outperforms all optimization baselines on popular benchmarks across all settings. We make our code and models available on the project website: https://statho.github.io/ScoreHMR.

[]

[]

[]

[]

Check Locate Rectify: A Training-Free Layout Calibration System for Text-to-Image Generation

http://arxiv.org/abs/2311.15773

Biao Gong, Siteng Huang, Yutong Feng, Shiwei Zhang, Yuyuan Li, Yu Liu

Diffusion models have recently achieved remarkable progress in generating realistic images. However challenges remain in accurately understanding and synthesizing the layout requirements in the textual prompts. To align the generated image with layout instructions we present a training-free layout calibration system SimM that intervenes in the generative process on the fly during inference time. Specifically following a "check-locate-rectify" pipeline the system first analyses the prompt to generate the target layout and compares it with the intermediate outputs to automatically detect errors. Then by moving the located activations and making intra- and inter-map adjustments the rectification process can be performed with negligible computational overhead. To evaluate SimM over a range of layout requirements we present a benchmark SimMBench that compensates for the lack of superlative spatial relations in existing datasets. And both quantitative and qualitative results demonstrate the effectiveness of the proposed SimM in calibrating the layout inconsistencies. Our project page is at https://simm-t2i.github.io/SimM.

[]

[]

[]

[]

ODCR: Orthogonal Decoupling Contrastive Regularization for Unpaired Image Dehazing

http://arxiv.org/abs/2404.17825

Zhongze Wang, Haitao Zhao, Jingchao Peng, Lujian Yao, Kaijie Zhao

Unpaired image dehazing (UID) holds significant research importance due to the challenges in acquiring haze/clear image pairs with identical backgrounds. This paper proposes a novel method for UID named Orthogonal Decoupling Contrastive Regularization (ODCR). Our method is grounded in the assumption that an image consists of both haze-related features which influence the degree of haze and haze-unrelated features such as texture and semantic information. ODCR aims to ensure that the haze-related features of the dehazing result closely resemble those of the clear image while the haze-unrelated features align with the input hazy image. To accomplish the motivation Orthogonal MLPs optimized geometrically on the Stiefel manifold are proposed which can project image features into an orthogonal space thereby reducing the relevance between different features. Furthermore a task-driven Depth-wise Feature Classifier (DWFC) is proposed which assigns weights to the orthogonal features based on the contribution of each channel's feature in predicting whether the feature source is hazy or clear in a self-supervised fashion. Finally a Weighted PatchNCE (WPNCE) loss is introduced to achieve the pulling of haze-related features in the output image toward those of clear images while bringing haze-unrelated features close to those of the hazy input. Extensive experiments demonstrate the superior performance of our ODCR method on UID.

[]

[]

[]

[]

Pose-Transformed Equivariant Network for 3D Point Trajectory Prediction

Ruixuan Yu, Jian Sun

Predicting 3D point trajectory is a fundamental learning task which commonly should be equivariant under Euclidean transformation e.g. SE(3). The existing equivariant models are commonly based on the group equivariant convolution equivariant message passing vector neuron frame averaging etc. In this paper we propose a novel pose-transformed equivariant network in which the points are firstly uniquely normalized and then transformed by the learned pose transformations upon which the points after motion are predicted and aggregated. Under each transformed pose we design the point position predictor consisting of multiple Pose-Transformed Points Prediction blocks in which the global and local motions are estimated and aggregated. This framework can be proven to be equivariant to SE(3) transformation over 3D points. We evaluate the pose-transformed equivariant network on extensive datasets including human motion capture molecular dynamics modeling and dynamics simulation. Extensive experimental comparisons demonstrated our SOTA performance compared with the existing equivariant networks for 3D point trajectory prediction.

[]

[]

[]

[]

OmniSeg3D: Omniversal 3D Segmentation via Hierarchical Contrastive Learning

http://arxiv.org/abs/2311.11666

Haiyang Ying, Yixuan Yin, Jinzhi Zhang, Fan Wang, Tao Yu, Ruqi Huang, Lu Fang

Towards holistic understanding of 3D scenes a general 3D segmentation method is needed that can segment diverse objects without restrictions on object quantity or categories while also reflecting the inherent hierarchical structure. To achieve this we propose OmniSeg3D an omniversal segmentation method aims for segmenting anything in 3D all at once. The key insight is to lift multi-view inconsistent 2D segmentations into a consistent 3D feature field through a hierarchical contrastive learning framework which is accomplished by two steps. Firstly we design a novel hierarchical representation based on category-agnostic 2D segmentations to model the multi-level relationship among pixels. Secondly image features rendered from the 3D feature field are clustered at different levels which can be further drawn closer or pushed apart according to the hierarchical relationship between different levels. In tackling the challenges posed by inconsistent 2D segmentations this framework yields a global consistent 3D feature field which further enables hierarchical segmentation multi-object selection and global discretization. Extensive experiments demonstrate the effectiveness of our method on high-quality 3D segmentation and accurate hierarchical structure understanding. A graphical user interface further facilitates flexible interaction for omniversal 3D segmentation.

[]

[]

[]

[]

Revisiting Sampson Approximations for Geometric Estimation Problems

http://arxiv.org/abs/2401.07114

Felix Rydell, Angélica Torres, Viktor Larsson

Many problems in computer vision can be formulated as geometric estimation problems i.e. given a collection of measurements (e.g. point correspondences) we wish to fit a model (e.g. an essential matrix) that agrees with our observations. This necessitates some measure of how much an observation "agrees" with a given model. A natural choice is to consider the smallest perturbation that makes the observation exactly satisfy the constraints. However for many problems this metric is expensive or otherwise intractable to compute. The so-called Sampson error approximates this geometric error through a linearization scheme. For epipolar geometry the Sampson error is a popular choice and in practice known to yield very tight approximations of the corresponding geometric residual (the reprojection error). In this paper we revisit the Sampson approximation and provide new theoretical insights as to why and when this approximation works as well as provide explicit bounds on the tightness under some mild assumptions. Our theoretical results are validated in several experiments on real data and in the context of different geometric estimation tasks.

[]

[]

[]

[]

Fixed Point Diffusion Models

http://arxiv.org/abs/2401.08741

Xingjian Bai, Luke Melas-Kyriazi

We introduce the Fixed Point Diffusion Model (FPDM) a novel approach to image generation that integrates the concept of fixed point solving into the framework of diffusion-based generative modeling. Our approach embeds an implicit fixed point solving layer into the denoising network of a diffusion model transforming the diffusion process into a sequence of closely-related fixed point problems. Combined with a new stochastic training method this approach significantly reduces model size reduces memory usage and accelerates training. Moreover it enables the development of two new techniques to improve sampling efficiency: reallocating computation across timesteps and reusing fixed point solutions between timesteps. We conduct extensive experiments with state-of-the-art models on ImageNet FFHQ CelebA-HQ and LSUN-Church demonstrating substantial improvements in performance and efficiency. Compared to the state-of-the-art DiT model FPDM contains 87% fewer parameters consumes 60% less memory during training and improves image generation quality in situations where sampling computation or time is limited.

[]

[]

[]

[]

Simple Semantic-Aided Few-Shot Learning

http://arxiv.org/abs/2311.18649

Hai Zhang, Junzhe Xu, Shanlin Jiang, Zhenan He

Learning from a limited amount of data namely Few-Shot Learning stands out as a challenging computer vision task. Several works exploit semantics and design complicated semantic fusion mechanisms to compensate for rare representative features within restricted data. However relying on naive semantics such as class names introduces biases due to their brevity while acquiring extensive semantics from external knowledge takes a huge time and effort. This limitation severely constrains the potential of semantics in Few-Shot Learning. In this paper we design an automatic way called Semantic Evolution to generate high-quality semantics. The incorporation of high-quality semantics alleviates the need for complex network structures and learning algorithms used in previous works. Hence we employ a simple two-layer network termed Semantic Alignment Network to transform semantics and visual features into robust class prototypes with rich discriminative features for few-shot classification. The experimental results show our framework outperforms all previous methods on six benchmarks demonstrating a simple network with high-quality semantics can beat intricate multi-modal modules on few-shot classification tasks. Code is available at https://github.com/zhangdoudou123/SemFew.

[]

[]

[]

[]

A Unified Framework for Microscopy Defocus Deblur with Multi-Pyramid Transformer and Contrastive Learning

http://arxiv.org/abs/2403.02611

Yuelin Zhang, Pengyu Zheng, Wanquan Yan, Chengyu Fang, Shing Shin Cheng

Defocus blur is a persistent problem in microscope imaging that poses harm to pathology interpretation and medical intervention in cell microscopy and microscope surgery. To address this problem a unified framework including the multi-pyramid transformer (MPT) and extended frequency contrastive regularization (EFCR) is proposed to tackle two outstanding challenges in microscopy deblur: longer attention span and data deficiency. The MPT employs an explicit pyramid structure at each network stage that integrates the cross-scale window attention (CSWA) the intra-scale channel attention (ISCA) and the feature-enhancing feed-forward network (FEFN) to capture long-range cross-scale spatial interaction and global channel context. The EFCR addresses the data deficiency problem by exploring latent deblur signals from different frequency bands. It also enables deblur knowledge transfer to learn cross-domain information from extra data improving deblur performance for labeled and unlabeled data. Extensive experiments and downstream task validation show the framework achieves state-of-the-art performance across multiple datasets. Project page: https://github.com/PieceZhang/MPT-CataBlur.

[]

[]

[]

[]

Frozen Feature Augmentation for Few-Shot Image Classification

Andreas Bär, Neil Houlsby, Mostafa Dehghani, Manoj Kumar

Training a linear classifier or lightweight model on top of pretrained vision model outputs so-called 'frozen features' leads to impressive performance on a number of downstream few-shot tasks. Currently frozen features are not modified during training. On the other hand when networks are trained directly on images data augmentation is a standard recipe that improves performance with no substantial overhead. In this paper we conduct an extensive pilot study on few-shot image classification that explores applying data augmentations in the frozen feature space dubbed 'frozen feature augmentation (FroFA)' covering twenty augmentations in total. Our study demonstrates that adopting a deceptively simple pointwise FroFA such as brightness can improve few-shot performance consistently across three network architectures three large pretraining datasets and eight transfer datasets.

[]

[]

[]

[]

Residual Learning in Diffusion Models

Junyu Zhang, Daochang Liu, Eunbyung Park, Shichao Zhang, Chang Xu

Diffusion models (DMs) have achieved remarkable generative performance particularly with the introduction of stochastic differential equations (SDEs). Nevertheless a gap emerges in the model sampling trajectory constructed by reverse-SDE due to the accumulation of score estimation and discretization errors. This gap results in a residual in the generated images adversely impacting the image quality. To remedy this we propose a novel residual learning framework built upon a correction function. The optimized function enables to improve image quality via rectifying the sampling trajectory effectively. Importantly our framework exhibits transferable residual correction ability i.e. a correction function optimized for one pre-trained DM can also enhance the sampling trajectory constructed by other different DMs on the same dataset. Experimental results on four widely-used datasets demonstrate the effectiveness and transferable capability of our framework.

[]

[]

[]

[]

Leveraging Cross-Modal Neighbor Representation for Improved CLIP Classification

http://arxiv.org/abs/2404.17753

Chao Yi, Lu Ren, De-Chuan Zhan, Han-Jia Ye

CLIP showcases exceptional cross-modal matching capabilities due to its training on image-text contrastive learning tasks. However without specific optimization for unimodal scenarios its performance in single-modality feature extraction might be suboptimal. Despite this some studies have directly used CLIP's image encoder for tasks like few-shot classification introducing a misalignment between its pre-training objectives and feature extraction methods. This inconsistency can diminish the quality of the image's feature representation adversely affecting CLIP's effectiveness in target tasks. In this paper we view text features as precise neighbors of image features in CLIP's space and present a novel CrOss-moDal nEighbor Representation (CODER) based on the distance structure between images and their neighbor texts. This feature extraction method aligns better with CLIP's pre-training objectives thereby fully leveraging CLIP's robust cross-modal capabilities. The key to construct a high-quality CODER lies in how to create a vast amount of high-quality and diverse texts to match with images. We introduce the Auto Text Generator (ATG) to automatically produce the required text in a data-free and training-free manner. We apply CODER to CLIP's zero-shot and few-shot image classification tasks. Experiment results across various datasets and models confirm CODER's effectiveness. Code is available at: https://github.com/YCaigogogo/CVPR24-CODER.

[]

[]

[]

[]

Beyond Textual Constraints: Learning Novel Diffusion Conditions with Fewer Examples

Yuyang Yu, Bangzhen Liu, Chenxi Zheng, Xuemiao Xu, Huaidong Zhang, Shengfeng He

In this paper we delve into a novel aspect of learning novel diffusion conditions with datasets an order of magnitude smaller. The rationale behind our approach is the elimination of textual constraints during the few-shot learning process. To that end we implement two optimization strategies. The first prompt-free conditional learning utilizes a prompt-free encoder derived from a pre-trained Stable Diffusion model. This strategy is designed to adapt new conditions to the diffusion process by minimizing the textual-visual correlation thereby ensuring a more precise alignment between the generated content and the specified conditions. The second strategy entails condition-specific negative rectification which addresses the inconsistencies typically brought about by Classifier-free guidance in few-shot training contexts. Our extensive experiments across a variety of condition modalities demonstrate the effectiveness and efficiency of our framework yielding results comparable to those obtained with datasets a thousand times larger. Our codes are available at https://github.com/Yuyan9Yu/BeyondTextConstraint.

[]

[]

[]

[]

Incorporating Geo-Diverse Knowledge into Prompting for Increased Geographical Robustness in Object Recognition

http://arxiv.org/abs/2401.01482

Kyle Buettner, Sina Malakouti, Xiang Lorraine Li, Adriana Kovashka

Existing object recognition models have been shown to lack robustness in diverse geographical scenarios due to domain shifts in design and context. Class representations need to be adapted to more accurately reflect an object concept under these shifts. In the absence of training data from target geographies we hypothesize that geographically diverse descriptive knowledge of categories can enhance robustness. For this purpose we explore the feasibility of probing a large language model for geography-based object knowledge and we examine the effects of integrating knowledge into zero-shot and learnable soft prompting with CLIP. Within this exploration we propose geography knowledge regularization to ensure that soft prompts trained on a source set of geographies generalize to an unseen target set. Accuracy gains over prompting baselines on DollarStreet while training only on Europe data are up to +2.8/1.2/1.6 on target data from Africa/Asia/Americas and +4.6 overall on the hardest classes. Competitive performance is shown vs. few-shot target training and analysis is provided to direct future study of geographical robustness.

[]

[]

[]

[]

Revisiting Adversarial Training Under Long-Tailed Distributions

http://arxiv.org/abs/2403.10073

Xinli Yue, Ningping Mou, Qian Wang, Lingchen Zhao

Deep neural networks are vulnerable to adversarial attacks leading to erroneous outputs. Adversarial training has been recognized as one of the most effective methods to counter such attacks. However existing adversarial training techniques have predominantly been evaluated on balanced datasets whereas real-world data often exhibit a long-tailed distribution casting doubt on the efficacy of these methods in practical scenarios. In this paper we delve into the performance of adversarial training under long-tailed distributions. Through an analysis of the prior method "RoBal" (Wu et al. CVPR'21) we discover that utilizing Balanced Softmax Loss (BSL) alone can obtain comparable performance to the complete RoBal approach while significantly reducing the training overhead. Then we reveal that adversarial training under long-tailed distributions also suffers from robust overfitting similar to uniform distributions. We explore utilizing data augmentation to mitigate this issue and unexpectedly discover that unlike results obtained with balanced data data augmentation not only effectively alleviates robust overfitting but also significantly improves robustness. We further identify that the improvement is attributed to the increased diversity of training data. Extensive experiments further corroborate that data augmentation alone can significantly improve robustness. Finally building on these findings we demonstrate that compared to RoBal the combination of BSL and data augmentation leads to a +6.66% improvement in model robustness under AutoAttack on CIFAR-10-LT. Our code is available at: https://github.com/NISPLab/AT-BSL.

[]

[]

[]

[]

Exploiting Style Latent Flows for Generalizing Deepfake Video Detection

http://arxiv.org/abs/2403.06592

Jongwook Choi, Taehoon Kim, Yonghyun Jeong, Seungryul Baek, Jongwon Choi

This paper presents a new approach for the detection of fake videos based on the analysis of style latent vectors and their abnormal behavior in temporal changes in the generated videos. We discovered that the generated facial videos suffer from the temporal distinctiveness in the temporal changes of style latent vectors which are inevitable during the generation of temporally stable videos with various facial expressions and geometric transformations. Our framework utilizes the StyleGRU module trained by contrastive learning to represent the dynamic properties of style latent vectors. Additionally we introduce a style attention module that integrates StyleGRU-generated features with content-based features enabling the detection of visual and temporal artifacts. We demonstrate our approach across various benchmark scenarios in deepfake detection showing its superiority in cross-dataset and cross-manipulation scenarios. Through further analysis we also validate the importance of using temporal changes of style latent vectors to improve the generality of deepfake video detection.

[]

[]

[]

[]

PIN: Positional Insert Unlocks Object Localisation Abilities in VLMs

http://arxiv.org/abs/2402.08657

Michael Dorkenwald, Nimrod Barazani, Cees G. M. Snoek, Yuki M. Asano

Vision-Language Models (VLMs) such as Flamingo and GPT-4V have shown immense potential by integrating large language models with vision systems. Nevertheless these models face challenges in the fundamental computer vision task of object localisation due to their training on multimodal data containing mostly captions without explicit spatial grounding. While it is possible to construct custom supervised training pipelines with bounding box annotations that integrate with VLMs these result in specialized and hard-to-scale models. In this paper we aim to explore the limits of caption-based VLMs and instead propose to tackle the challenge in a simpler manner by i) keeping the weights of a caption-based VLM frozen and ii) not using any supervised detection data. To this end we introduce an input-agnostic Positional Insert (PIN) a learnable spatial prompt containing a minimal set of parameters that are slid inside the frozen VLM unlocking object localisation capabilities. Our PIN module is trained with a simple next-token prediction task on synthetic data without requiring the introduction of new output heads. Our experiments demonstrate strong zero-shot localisation performances on a variety of images including Pascal VOC COCO LVIS and diverse images like paintings or cartoons.

[]

[]

[]

[]

UniGarmentManip: A Unified Framework for Category-Level Garment Manipulation via Dense Visual Correspondence

http://arxiv.org/abs/2405.06903

Ruihai Wu, Haoran Lu, Yiyan Wang, Yubo Wang, Hao Dong

Garment manipulation (e.g. unfolding folding and hanging clothes) is essential for future robots to accomplish home-assistant tasks while highly challenging due to the diversity of garment configurations geometries and deformations. Although able to manipulate similar shaped garments in a certain task previous works mostly have to design different policies for different tasks could not generalize to garments with diverse geometries and often rely heavily on human-annotated data. In this paper we leverage the property that garments in a certain category have similar structures and then learn the topological dense (point-level) visual correspondence among garments in the category level with different deformations in the self-supervised manner. The topological correspondence can be easily adapted to the functional correspondence to guide the manipulation policies for various downstream tasks within only one or few-shot demonstrations. Experiments over garments in 3 different categories on 3 representative tasks in diverse scenarios using one or two arms taking one or more steps inputting flat or messy garments demonstrate the effectiveness of our proposed method. Project page: https://warshallrho.github.io/unigarmentmanip.

[]

[]

[]

[]

Multi-Attribute Interactions Matter for 3D Visual Grounding

Can Xu, Yuehui Han, Rui Xu, Le Hui, Jin Xie, Jian Yang

3D visual grounding aims to localize 3D objects described by free-form language sentences. Following the detection-then-matching paradigm existing methods mainly focus on embedding object attributes in unimodal feature extraction and multimodal feature fusion to enhance the discriminability of the proposal feature for accurate grounding. However most of them ignore the explicit interaction of multiple attributes causing a bias in unimodal representation and misalignment in multimodal fusion. In this paper we propose a multi-attribute aware Transformer for 3D visual grounding learning the multi-attribute interactions to refine the intra-modal and inter-modal grounding cues. Specifically we first develop an attribute causal analysis module to quantify the causal effect of different attributes for the final prediction which provides powerful supervision to correct the misleading attributes and adaptively capture other discriminative features. Then we design an exchanging-based multimodal fusion module which dynamically replaces tokens with low attribute attention between modalities before directly integrating low-dimensional global features. This ensures an attribute-level multimodal information fusion and helps align the language and vision details more efficiently for fine-grained multimodal features. Extensive experiments show that our method can achieve state-of-the-art performance on ScanRefer and Sr3D/Nr3D datasets.

[]

[]

[]

[]

Video-P2P: Video Editing with Cross-attention Control

Shaoteng Liu, Yuechen Zhang, Wenbo Li, Zhe Lin, Jiaya Jia

Video-P2P is the first framework for real-world video editing with cross-attention control. While attention control has proven effective for image editing with pre-trained image generation models there are currently no large-scale video generation models publicly available. Video-P2P addresses this limitation by adapting an image generation diffusion model to complete various video editing tasks. Specifically we propose to first tune a Text-to-Set (T2S) model to complete an approximate inversion and then optimize a shared unconditional embedding to achieve accurate video inversion with a small memory cost. We further prove that it is crucial for consistent video editing. For attention control we introduce a novel decoupled-guidance strategy which uses different guidance strategies for the source and target prompts. The optimized unconditional embedding for the source prompt improves reconstruction ability while an initialized unconditional embedding for the target prompt enhances editability. Incorporating the attention maps of these two branches enables detailed editing. These technical designs enable various text-driven editing applications including word swap prompt refinement and attention re-weighting. Video-P2P works well on real-world videos for generating new characters while optimally preserving their original poses and scenes. It significantly outperforms previous approaches.

[]

[]

[]

[]

Hunting Attributes: Context Prototype-Aware Learning for Weakly Supervised Semantic Segmentation

http://arxiv.org/abs/2403.07630

Feilong Tang, Zhongxing Xu, Zhaojun Qu, Wei Feng, Xingjian Jiang, Zongyuan Ge

Recent weakly supervised semantic segmentation (WSSS) methods strive to incorporate contextual knowledge to improve the completeness of class activation maps (CAM). In this work we argue that the knowledge bias between instances and contexts affects the capability of the prototype to sufficiently understand instance semantics. Inspired by prototype learning theory we propose leveraging prototype awareness to capture diverse and fine-grained feature attributes of instances. The hypothesis is that contextual prototypes might erroneously activate similar and frequently co-occurring object categories due to this knowledge bias. Therefore we propose to enhance the prototype representation ability by mitigating the bias to better capture spatial coverage in semantic object regions. With this goal we present a Context Prototype-Aware Learning (CPAL) strategy which leverages semantic context to enrich instance comprehension. The core of this method is to accurately capture intra-class variations in object features through context-aware prototypes facilitating the adaptation to the semantic attributes of various instances. We design feature distribution alignment to optimize prototype awareness aligning instance feature distributions with dense features. In addition a unified training framework is proposed to combine label-guided classification supervision and prototypes-guided self-supervision. Experimental results on PASCAL VOC 2012 and MS COCO 2014 show that CPAL significantly improves off-the-shelf methods and achieves state-of-the-art performance. The project is available at \href https://github.com/Barrett-python/CPAL https://github.com/Barrett-python/CPAL.

[]

[]

[]

[]

SCINeRF: Neural Radiance Fields from a Snapshot Compressive Image

http://arxiv.org/abs/2403.20018

Yunhao Li, Xiaodong Wang, Ping Wang, Xin Yuan, Peidong Liu

In this paper we explore the potential of Snapshot Com- pressive Imaging (SCI) technique for recovering the under- lying 3D scene representation from a single temporal com- pressed image. SCI is a cost-effective method that enables the recording of high-dimensional data such as hyperspec- tral or temporal information into a single image using low- cost 2D imaging sensors. To achieve this a series of spe- cially designed 2D masks are usually employed which not only reduces storage requirements but also offers potential privacy protection. Inspired by this to take one step further our approach builds upon the powerful 3D scene represen- tation capabilities of neural radiance fields (NeRF). Specif- ically we formulate the physical imaging process of SCI as part of the training of NeRF allowing us to exploit its impressive performance in capturing complex scene struc- tures. To assess the effectiveness of our method we con- duct extensive evaluations using both synthetic data and real data captured by our SCI system. Extensive experi- mental results demonstrate that our proposed approach sur- passes the state-of-the-art methods in terms of image re- construction and novel view image synthesis. Moreover our method also exhibits the ability to restore high frame- rate multi-view consistent images by leveraging SCI and the rendering capabilities of NeRF. The code is available at https://github.com/WU-CVGL/SCINeRF.

[]

[]

[]

[]

PIE-NeRF: Physics-based Interactive Elastodynamics with NeRF

Yutao Feng, Yintong Shang, Xuan Li, Tianjia Shao, Chenfanfu Jiang, Yin Yang

We show that physics-based simulations can be seamlessly integrated with NeRF to generate high-quality elastodynamics of real-world objects. Unlike existing methods we discretize nonlinear hyperelasticity in a meshless way obviating the necessity for intermediate auxiliary shape proxies like a tetrahedral mesh or voxel grid. A quadratic generalized moving least square is employed to capture nonlinear dynamics and large deformation on the implicit model. Such meshless integration enables versatile simulations of complex and codimensional shapes. We adaptively place the least-square kernels according to the NeRF density field to significantly reduce the complexity of the nonlinear simulation. As a result physically realistic animations can be conveniently synthesized using our method for a wide range of hyperelastic materials at an interactive rate. For more information please visit https://fytalon.github.io/pienerf.

[]

[]

[]

[]

Improved Visual Grounding through Self-Consistent Explanations

http://arxiv.org/abs/2312.04554

Ruozhen He, Paola Cascante-Bonilla, Ziyan Yang, Alexander C. Berg, Vicente Ordonez

Vision-and-language models trained to match images with text can be combined with visual explanation methods to point to the locations of specific objects in an image. Our work shows that the localization --"grounding'"-- abilities of these models can be further improved by finetuning for self-consistent visual explanations. We propose a strategy for augmenting existing text-image datasets with paraphrases using a large language model and SelfEQ a weakly-supervised strategy on visual explanation maps for paraphrases that encourages self-consistency. Specifically for an input textual phrase we attempt to generate a paraphrase and finetune the model so that the phrase and paraphrase map to the same region in the image. We posit that this both expands the vocabulary that the model is able to handle and improves the quality of the object locations highlighted by gradient-based visual explanation methods (e.g. GradCAM). We demonstrate that SelfEQ improves performance on Flickr30k ReferIt and RefCOCO+ over a strong baseline method and several prior works. Particularly comparing to other methods that do not use any type of box annotations we obtain 84.07% on Flickr30k (an absolute improvement of 4.69%) 67.40% on ReferIt (an absolute improvement of 7.68%) and 75.10% 55.49% on RefCOCO+ test sets A and B respectively (an absolute improvement of 3.74% on average).

[]

[]

[]

[]

Monkey: Image Resolution and Text Label Are Important Things for Large Multi-modal Models

http://arxiv.org/abs/2311.06607

Zhang Li, Biao Yang, Qiang Liu, Zhiyin Ma, Shuo Zhang, Jingxu Yang, Yabo Sun, Yuliang Liu, Xiang Bai

Large Multimodal Models (LMMs) have shown promise in vision-language tasks but struggle with high-resolution input and detailed scene understanding. Addressing these challenges we introduce Monkey to enhance LMM capabilities. Firstly Monkey processes input images by dividing them into uniform patches each matching the size (e.g. 448x448) used in the original training of the well-trained vision encoder. Equipped with individual adapter for each patch Monkey can handle higher resolutions up to 1344x896 pixels enabling the detailed capture of complex visual information. Secondly it employs a multi-level description generation method enriching the context for scene-object associations. This two-part strategy ensures more effective learning from generated data: the higher resolution allows for a more detailed capture of visuals which in turn enhances the effectiveness of comprehensive descriptions. Extensive ablative results validate the effectiveness of our designs. Additionally experiments on 18 datasets further demonstrate that Monkey surpasses existing LMMs in many tasks like Image Captioning and various Visual Question Answering formats. Specially in qualitative tests focused on dense text question answering Monkey has exhibited encouraging results compared with GPT4V. Code is available at https://github.com/Yuliang-Liu/Monkey.

[]

[]

[]

[]

FlashAvatar: High-fidelity Head Avatar with Efficient Gaussian Embedding

http://arxiv.org/abs/2312.02214

Jun Xiang, Xuan Gao, Yudong Guo, Juyong Zhang

We propose FlashAvatar a novel and lightweight 3D animatable avatar representation that could reconstruct a digital avatar from a short monocular video sequence in minutes and render high-fidelity photo-realistic images at 300FPS on a consumer-grade GPU. To achieve this we maintain a uniform 3D Gaussian field embedded in the surface of a parametric face model and learn extra spatial offset to model non-surface regions and subtle facial details. While full use of geometric priors can capture high-frequency facial details and preserve exaggerated expressions proper initialization can help reduce the number of Gaussians thus enabling super-fast rendering speed. Extensive experimental results demonstrate that FlashAvatar outperforms existing works regarding visual quality and personalized details and is almost an order of magnitude faster in rendering speed. Project page: https://ustc3dv.github.io/FlashAvatar/

[]

[]

[]

[]

DifFlow3D: Toward Robust Uncertainty-Aware Scene Flow Estimation with Iterative Diffusion-Based Refinement

Jiuming Liu, Guangming Wang, Weicai Ye, Chaokang Jiang, Jinru Han, Zhe Liu, Guofeng Zhang, Dalong Du, Hesheng Wang

Scene flow estimation which aims to predict per-point 3D displacements of dynamic scenes is a fundamental task in the computer vision field. However previous works commonly suffer from unreliable correlation caused by locally constrained searching ranges and struggle with accumulated inaccuracy arising from the coarse-to-fine structure. To alleviate these problems we propose a novel uncertainty-aware scene flow estimation network (DifFlow3D) with the diffusion probabilistic model. Iterative diffusion-based refinement is designed to enhance the correlation robustness and resilience to challenging cases e.g. dynamics noisy inputs repetitive patterns etc. To restrain the generation diversity three key flow-related features are leveraged as conditions in our diffusion model. Furthermore we also develop an uncertainty estimation module within diffusion to evaluate the reliability of estimated scene flow. Our DifFlow3D achieves state-of-the-art performance with 24.0% and 29.1% EPE3D reduction respectively on FlyingThings3D and KITTI 2015 datasets. Notably our method achieves an unprecedented millimeter-level accuracy (0.0078m in EPE3D) on the KITTI dataset. Additionally our diffusion-based refinement paradigm can be readily integrated as a plug-and-play module into existing scene flow networks significantly increasing their estimation accuracy. Codes are released at https://github.com/IRMVLab/DifFlow3D.

[]

[]

[]

[]

Decompose-and-Compose: A Compositional Approach to Mitigating Spurious Correlation

Fahimeh Hosseini Noohdani, Parsa Hosseini, Aryan Yazdan Parast, Hamidreza Yaghoubi Araghi, Mahdieh Soleymani Baghshah

While standard Empirical Risk Minimization (ERM) training is proven effective for image classification on in-distribution data it fails to perform well on out-of-distribution samples. One of the main sources of distribution shift for image classification is the compositional nature of images. Specifically in addition to the main object or component(s) determining the label some other image components usually exist which may lead to the shift of input distribution between train and test environments. More importantly these components may have spurious correlations with the label. To address this issue we propose Decompose-and-Compose (DaC) which improves robustness to correlation shift by a compositional approach based on combining elements of images. Based on our observations models trained with ERM usually highly attend to either the causal components or the components having a high spurious correlation with the label (especially in datapoints on which models have a high confidence). In fact according to the amount of spurious correlation and the easiness of classification based on the causal or non-causal components the model usually attends to one of these more (on samples with high confidence). Following this we first try to identify the causal components of images using class activation maps of models trained with ERM. Afterward we intervene on images by combining them and retraining the model on the augmented data including the counterfactual ones. This work proposes a group-balancing method by intervening on images without requiring group labels or information regarding the spurious features during training. The method has an overall better worst group accuracy compared to previous methods with the same amount of supervision on the group labels in correlation shift. Our code is available at https://github.com/fhn98/DaC.

[]

[]

[]

[]

FlashEval: Towards Fast and Accurate Evaluation of Text-to-image Diffusion Generative Models

http://arxiv.org/abs/2403.16379

Lin Zhao, Tianchen Zhao, Zinan Lin, Xuefei Ning, Guohao Dai, Huazhong Yang, Yu Wang

In recent years there has been significant progress in the development of text-to-image generative models. Evaluating the quality of the generative models is one essential step in the development process. Unfortunately the evaluation process could consume a significant amount of computational resources making the required periodic evaluation of model performance (e.g. monitoring training progress) impractical. Therefore we seek to improve the evaluation efficiency by selecting the representative subset of the text-image dataset. We systematically investigate the design choices including the selection criteria (textural features or imagebased metrics) and the selection granularity (prompt-level or set-level). We find that the insights from prior work on subset selection for training data do not generalize to this problem and we propose FlashEval an iterative search algorithm tailored to evaluation data selection. We demonstrate the effectiveness of FlashEval on ranking diffusion models with various configurations including architectures quantization levels and sampler schedules on COCO and DiffusionDB datasets. Our searched 50-item subset could achieve comparable evaluation quality to the randomly sampled 500-item subset for COCO annotations on unseen models achieving a 10x evaluation speedup. We release the condensed subset of these commonly used datasets to help facilitate diffusion algorithm design and evaluation and open-source FlashEval as a tool for condensing future datasets accessible at https://github.com/thu-nics/FlashEval.

[]

[]

[]

[]

ZERO-IG: Zero-Shot Illumination-Guided Joint Denoising and Adaptive Enhancement for Low-Light Images

Yiqi Shi, Duo Liu, Liguo Zhang, Ye Tian, Xuezhi Xia, Xiaojing Fu

This paper presents a novel zero-shot method for jointly denoising and enhancing real-word low-light images. The proposed method is independent of training data and noise distribution. Guided by illumination we integrate denoising and enhancing processes seamlessly enabling end-to-end training. Pairs of downsampled images are extracted from a single original low-light image and processed to preliminarily reduce noise. Based on the smoothness of illumination near-authentic illumination can be estimated from the denoised low-light image. Specifically the illumination is constrained by the denoised image's brightness uniformly amplifying pixels to raise overall brightness to normal-light level. We simultaneously restrict the illumination by scaling each pixel of the denoised image based on its intensity controlling the enhancement amplitude for different pixels. Applying the illumination to the original low-light image yields an adaptively enhanced reflection. This prevents under-enhancement and localized overexposure. Notably we concatenate the reflection with the illumination preserving their computational relationship to ultimately remove noise from the original low-light image in the form of reflection. This provides sufficient image information for the denoising procedure without changing the noise characteristics. Extensive experiments demonstrate that our method outperforms other state-of-the-art methods. The source code is available at https://github.com/Doyle59217/ZeroIG.

[]

[]

[]

[]

View From Above: Orthogonal-View aware Cross-view Localization

Shan Wang, Chuong Nguyen, Jiawei Liu, Yanhao Zhang, Sundaram Muthu, Fahira Afzal Maken, Kaihao Zhang, Hongdong Li

This paper presents a novel aerial-to-ground feature aggregation strategy tailored for the task of cross-view image-based geo-localization. Conventional vision-based methods heavily rely on matching ground-view image features with a pre-recorded image database often through establishing planar homography correspondences via a planar ground assumption. As such they tend to ignore features that are off-ground and not suited for handling visual occlusions leading to unreliable localization in challenging scenarios. We propose a Top-to-Ground Aggregation module that capitalizes aerial orthographic views to aggregate features down to the ground level leveraging reliable off-ground information to improve feature alignment. Furthermore we introduce a Cycle Domain Adaptation loss that ensures feature extraction robustness across domain changes. Additionally an Equidistant Re-projection loss is introduced to equalize the impact of all keypoints on orientation error leading to a more extended distribution of keypoints which benefits orientation estimation. On both KITTI and Ford Multi-AV datasets our method consistently achieves the lowest mean longitudinal and lateral translations across different settings and obtains the smallest orientation error when the initial pose is less accurate a more challenging setting. Further it can complete an entire route through continual vehicle pose estimation with initial vehicle pose given only at the starting point.

[]

[]

[]

[]

FinePOSE: Fine-Grained Prompt-Driven 3D Human Pose Estimation via Diffusion Models

http://arxiv.org/abs/2405.05216

Jinglin Xu, Yijie Guo, Yuxin Peng

The 3D Human Pose Estimation (3D HPE) task uses 2D images or videos to predict human joint coordinates in 3D space. Despite recent advancements in deep learning-based methods they mostly ignore the capability of coupling accessible texts and naturally feasible knowledge of humans missing out on valuable implicit supervision to guide the 3D HPE task. Moreover previous efforts often study this task from the perspective of the whole human body neglecting fine-grained guidance hidden in different body parts. To this end we present a new Fine-Grained Prompt-Driven Denoiser based on a diffusion model for 3D HPE named FinePOSE. It consists of three core blocks enhancing the reverse process of the diffusion model: (1) Fine-grained Part-aware Prompt learning (FPP) block constructs fine-grained part-aware prompts via coupling accessible texts and naturally feasible knowledge of body parts with learnable prompts to model implicit guidance. (2) Fine-grained Prompt-pose Communication (FPC) block establishes fine-grained communications between learned part-aware prompts and poses to improve the denoising quality. (3) Prompt-driven Timestamp Stylization (PTS) block integrates learned prompt embedding and temporal information related to the noise level to enable adaptive adjustment at each denoising step. Extensive experiments on public single-human pose estimation datasets show that FinePOSE outperforms state-of-the-art methods. We further extend FinePOSE to multi-human pose estimation. Achieving 34.3mm average MPJPE on the EgoHumans dataset demonstrates the potential of FinePOSE to deal with complex multi-human scenarios. Code is available at https://github.com/PKU-ICST-MIPL/FinePOSE_CVPR2024.

[]

[]

[]

[]

BEM: Balanced and Entropy-based Mix for Long-Tailed Semi-Supervised Learning

http://arxiv.org/abs/2404.01179

Hongwei Zheng, Linyuan Zhou, Han Li, Jinming Su, Xiaoming Wei, Xiaoming Xu

Data mixing methods play a crucial role in semi-supervised learning (SSL) but their application is unexplored in long-tailed semi-supervised learning (LTSSL). The primary reason is that the in-batch mixing manner fails to address class imbalance. Furthermore existing LTSSL methods mainly focus on re-balancing data quantity but ignore class-wise uncertainty which is also vital for class balance. For instance some classes with sufficient samples might still exhibit high uncertainty due to indistinguishable features. To this end this paper introduces the Balanced and Entropy-based Mix (BEM) a pioneering mixing approach to re-balance the class distribution of both data quantity and uncertainty. Specifically we first propose a class balanced mix bank to store data of each class for mixing. This bank samples data based on the estimated quantity distribution thus re-balancing data quantity. Then we present an entropy-based learning approach to re-balance class-wise uncertainty including entropy-based sampling strategy entropy-based selection module and entropy-based class balanced loss. Our BEM first leverages data mixing for improving LTSSL and it can also serve as a complement to the existing re-balancing methods. Experimental results show that BEM significantly enhances various LTSSL frameworks and achieves state-of-the-art performances across multiple benchmarks.

[]

[]

[]

[]

HUGS: Holistic Urban 3D Scene Understanding via Gaussian Splatting

http://arxiv.org/abs/2403.12722

Hongyu Zhou, Jiahao Shao, Lu Xu, Dongfeng Bai, Weichao Qiu, Bingbing Liu, Yue Wang, Andreas Geiger, Yiyi Liao

Holistic understanding of urban scenes based on RGB images is a challenging yet important problem. It encompasses understanding both the geometry and appearance to enable novel view synthesis parsing semantic labels and tracking moving objects. Despite considerable progress existing approaches often focus on specific aspects of this task and require additional inputs such as LiDAR scans or manually annotated 3D bounding boxes. In this paper we introduce a novel pipeline that utilizes 3D Gaussian Splatting for holistic urban scene understanding. Our main idea involves the joint optimization of geometry appearance semantics and motion using a combination of static and dynamic 3D Gaussians where moving object poses are regularized via physical constraints. Our approach offers the ability to render new viewpoints in real-time yielding 2D and 3D semantic information with high accuracy and reconstruct dynamic scenes even in scenarios where 3D bounding box detection are highly noisy. Experimental results on KITTI KITTI-360 and Virtual KITTI 2 demonstrate the effectiveness of our approach. Our project page is at https://xdimlab.github.io/hugs_website.

[]

[]

[]

[]

DreamPropeller: Supercharge Text-to-3D Generation with Parallel Sampling

http://arxiv.org/abs/2311.17082

Linqi Zhou, Andy Shih, Chenlin Meng, Stefano Ermon

Recent methods such as Score Distillation Sampling (SDS) and Variational Score Distillation (VSD) using 2D diffusion models for text-to-3D generation have demonstrated impressive generation quality. However the long generation time of such algorithms significantly degrades the user experience. To tackle this problem we propose DreamPropeller a drop-in acceleration algorithm that can be wrapped around any existing text-to-3D generation pipeline based on score distillation. Our framework generalizes Picard iterations a classical algorithm for parallel sampling an ODE path and can account for non-ODE paths such as momentum-based gradient updates and changes in dimensions during the optimization process as in many cases of 3D generation. We show that our algorithm trades parallel compute for wallclock time and empirically achieves up to 4.7x speedup with a negligible drop in generation quality for all tested frameworks.

[]

[]

[]

[]

PeVL: Pose-Enhanced Vision-Language Model for Fine-Grained Human Action Recognition

Haosong Zhang, Mei Chee Leong, Liyuan Li, Weisi Lin

Recent progress in Vision-Language (VL) foundation models has revealed the great advantages of cross-modality learning. However due to a large gap between vision and text they might not be able to sufficiently utilize the benefits of cross-modality information. In the field of human action recognition the additional pose modality may bridge the gap between vision and text to improve the effectiveness of cross-modality learning. In this paper we propose a novel framework called the Pose-enhanced Vision-Language (PeVL) model to adapt the VL model with pose modality to learn effective knowledge of fine-grained human actions. Our PeVL model includes two novel components: an Unsymmetrical Cross-Modality Refinement (UCMR) block and a Semantic-Guided Multi-level Contrastive (SGMC) module. The UCMR block includes Pose-guided Visual Refinement (P2V-R) and Visual-enriched Pose Refinement (V2P-R) for effective cross-modality learning. The SGMC module includes Multi-level Contrastive Associations of vision-text and pose-text at both action and sub-action levels and a Semantic-Guided Loss enabling effective contrastive learning with text. Built upon a pre-trained VL foundation model our model integrates trainable adapters and can be trained end-to-end. Our novel PeVL design over VL foundation model yields remarkable performance gains on four fine- grained human action recognition datasets achieving a new SOTA with a significantly small number of FLOPs for low- cost re-training.

[]

[]

[]

[]

DeepCache: Accelerating Diffusion Models for Free

http://arxiv.org/abs/2312.00858

Xinyin Ma, Gongfan Fang, Xinchao Wang

Diffusion models have recently gained unprecedented attention in the field of image synthesis due to their remarkable generative capabilities. Notwithstanding their prowess these models often incur substantial computational costs primarily attributed to the sequential denoising process and cumbersome model size. Traditional methods for compressing diffusion models typically involve extensive retraining presenting cost and feasibility challenges. In this paper we introduce DeepCache a novel training-free paradigm that accelerates diffusion models from the perspective of model architecture. DeepCache capitalizes on the inherent temporal redundancy observed in the sequential denoising steps of diffusion models which caches and retrieves features across adjacent denoising stages thereby curtailing redundant computations. Utilizing the property of the U-Net we reuse the high-level features while updating the low-level features in a very cheap way. This innovative strategy in turn enables a speedup factor of 2.3xfor Stable Diffusion v1.5 with only a 0.05 decline in CLIP Score and 4.1xfor LDM-4-G with a slight decrease of 0.22 in FID on ImageNet. Our experiments also demonstrate DeepCache's superiority over existing pruning and distillation methods that necessitate retraining and its compatibility with current sampling techniques. Furthermore we find that under the same throughput DeepCache effectively achieves comparable or even marginally improved results with DDIM or PLMS.

[]

[]

[]

[]

GeoAuxNet: Towards Universal 3D Representation Learning for Multi-sensor Point Clouds

http://arxiv.org/abs/2403.19220

Shengjun Zhang, Xin Fei, Yueqi Duan

Point clouds captured by different sensors such as RGB-D cameras and LiDAR possess non-negligible domain gaps. Most existing methods design different network architectures and train separately on point clouds from various sensors. Typically point-based methods achieve outstanding performances on even-distributed dense point clouds from RGB-D cameras while voxel-based methods are more efficient for large-range sparse LiDAR point clouds. In this paper we propose geometry-to-voxel auxiliary learning to enable voxel representations to access point-level geometric information which supports better generalisation of the voxel-based backbone with additional interpretations of multi-sensor point clouds. Specifically we construct hierarchical geometry pools generated by a voxel-guided dynamic point network which efficiently provide auxiliary fine-grained geometric information adapted to different stages of voxel features. We conduct experiments on joint multi-sensor datasets to demonstrate the effectiveness of GeoAuxNet. Enjoying elaborate geometric information our method outperforms other models collectively trained on multi-sensor datasets and achieve competitive results with the-state-of-art experts on each single dataset.

[]

[]

[]

[]

Unveiling the Power of Audio-Visual Early Fusion Transformers with Dense Interactions through Masked Modeling

http://arxiv.org/abs/2312.01017

Shentong Mo, Pedro Morgado

Humans possess a remarkable ability to integrate auditory and visual information enabling a deeper understanding of the surrounding environment. This early fusion of audio and visual cues demonstrated through cognitive psychology and neuroscience research offers promising potential for developing multimodal perception models. However training early fusion architectures poses significant challenges as the increased model expressivity requires robust learning frameworks to harness their enhanced capabilities. In this paper we address this challenge by leveraging the masked reconstruction framework previously successful in unimodal settings to train audio-visual encoders with early fusion. Additionally we propose an attention-based fusion module that captures interactions between local audio and visual representations enhancing the model's ability to capture fine-grained interactions. While effective this procedure can become computationally intractable as the number of local representations increases. Thus to address the computational complexity we propose an alternative procedure that factorizes the local representations before representing audio-visual interactions. Extensive evaluations on a variety of datasets demonstrate the superiority of our approach in audio-event classification visual sound localization sound separation and audio-visual segmentation. These contributions enable the efficient training of deeply integrated audio-visual models and significantly advance the usefulness of early fusion architectures.

[]

[]

[]

[]

Learning Correlation Structures for Vision Transformers

http://arxiv.org/abs/2404.03924

Manjin Kim, Paul Hongsuck Seo, Cordelia Schmid, Minsu Cho

We introduce a new attention mechanism dubbed structural self-attention (StructSA) that leverages rich correlation patterns naturally emerging in key-query interactions of attention. StructSA generates attention maps by recognizing space-time structures of key-query correlations via convolution and uses them to dynamically aggregate local contexts of value features. This effectively leverages rich structural patterns in images and videos such as scene layouts object motion and inter-object relations.Using StructSA as a main building block we develop the structural vision transformer (StructViT) and evaluate its effectiveness on both image and video classification tasks achieving state-of-the-art results on ImageNet-1K Kinetics-400 Something-Something V1 & V2 Diving-48 and FineGym.

[]

[]

[]

[]

Dysen-VDM: Empowering Dynamics-aware Text-to-Video Diffusion with LLMs

Hao Fei, Shengqiong Wu, Wei Ji, Hanwang Zhang, Tat-Seng Chua

Text-to-video (T2V) synthesis has gained increasing attention in the community in which the recently emerged diffusion models (DMs) have promisingly shown stronger performance than the past approaches. While existing state-of-the-art DMs are competent to achieve high-resolution video generation they may largely suffer from key limitations (e.g. action occurrence disorders crude video motions) with respect to the intricate temporal dynamics modeling one of the crux of video synthesis. In this work we investigate strengthening the awareness of video dynamics for DMs for high-quality T2V generation. Inspired by human intuition we design an innovative dynamic scene manager (dubbed as Dysen) module which includes (step-1) extracting from input text the key actions with proper time-order arrangement (step-2) transforming the action schedules into the dynamic scene graph (DSG) representations and (step-3) enriching the scenes in the DSG with sufficient and reasonable details. Taking advantage of the existing powerful LLMs (e.g. ChatGPT) via in-context learning Dysen realizes (nearly) human-level temporal dynamics understanding. Finally the resulting video DSG with rich action scene details is encoded as fine-grained spatio-temporal features integrated into the backbone T2V DM for video generating. Experiments on popular T2V datasets suggest that our Dysen-VDM consistently outperforms prior arts with significant margins especially in scenarios with complex actions.

[]

[]

[]

[]

PrPSeg: Universal Proposition Learning for Panoramic Renal Pathology Segmentation

http://arxiv.org/abs/2402.19286

Ruining Deng, Quan Liu, Can Cui, Tianyuan Yao, Jialin Yue, Juming Xiong, Lining Yu, Yifei Wu, Mengmeng Yin, Yu Wang, Shilin Zhao, Yucheng Tang, Haichun Yang, Yuankai Huo

Understanding the anatomy of renal pathology is crucial for advancing disease diagnostics treatment evaluation and clinical research. The complex kidney system comprises various components across multiple levels including regions (cortex medulla) functional units (glomeruli tubules) and cells (podocytes mesangial cells in glomerulus). Prior studies have predominantly overlooked the intricate spatial interrelations among objects from clinical knowledge. In this research we introduce a novel universal proposition learning approach called panoramic renal pathology segmentation (PrPSeg) designed to segment comprehensively panoramic structures within kidney by integrating extensive knowledge of kidney anatomy. In this paper we propose (1) the design of a comprehensive universal proposition matrix for renal pathology facilitating the incorporation of classification and spatial relationships into the segmentation process; (2) a token-based dynamic head single network architecture with the improvement of the partial label image segmentation and capability for future data enlargement; and (3) an anatomy loss function quantifying the inter-object relationships across the kidney.

[]

[]

[]

[]

RepKPU: Point Cloud Upsampling with Kernel Point Representation and Deformation

Yi Rong, Haoran Zhou, Kang Xia, Cheng Mei, Jiahao Wang, Tong Lu

In this work we present RepKPU an efficient network for point cloud upsampling. We propose to promote upsampling performance by exploiting better shape representation and point generation strategy. Inspired by KPConv we propose a novel representation called RepKPoints to effectively characterize the local geometry whose advantages over prior representations are as follows: (1) density-sensitive; (2) large receptive fields; (3) position-adaptive which makes RepKPoints a generalized form of previous representations. Moreover we propose a novel paradigm namely Kernel-to-Displacement generation for point generation where point cloud upsampling is reformulated as the deformation of kernel points. Specifically we propose KP-Queries which is a set of kernel points with predefined positions and learned features to serve as the initial state of upsampling. Using cross-attention mechanisms we achieve interactions between RepKPoints and KP-Queries and subsequently KP-Queries are converted to displacement features followed by a MLP to predict the new positions of KP-Queries which serve as the generated points. Extensive experimental results demonstrate that RepKPU outperforms state-of-the-art methods on several widely-used benchmark datasets with high efficiency.

[]

[]

[]

[]

ConCon-Chi: Concept-Context Chimera Benchmark for Personalized Vision-Language Tasks

Andrea Rosasco, Stefano Berti, Giulia Pasquale, Damiano Malafronte, Shogo Sato, Hiroyuki Segawa, Tetsugo Inada, Lorenzo Natale

While recent Vision-Language (VL) models excel at open-vocabulary tasks it is unclear how to use them with specific or uncommon concepts. Personalized Text-to-Image Retrieval (TIR) or Generation (TIG) are recently introduced tasks that represent this challenge where the VL model has to learn a concept from few images and respectively discriminate or generate images of the target concept in arbitrary contexts. We identify the ability to learn new meanings and their compositionality with known ones as two key properties of a personalized system. We show that the available benchmarks offer a limited validation of personalized textual concept learning from images with respect to the above properties and introduce ConCon-Chi as a benchmark for both personalized TIR and TIG designed to fill this gap. We modelled the new-meaning concepts by crafting chimeric objects and formulating a large varied set of contexts where we photographed each object. To promote the compositionality assessment of the learned concepts with known contexts we combined different contexts with the same concept and vice-versa. We carry out a thorough evaluation of state-of-the-art methods on the resulting dataset. Our study suggests that future work on personalized TIR and TIG methods should focus on the above key properties and we propose principles and a dataset for their performance assessment. Dataset: https://doi.org/10.48557/QJ1166 and code: https://github.com/hsp-iit/concon-chi_benchmark.

[]

[]

[]

[]

Weakly-Supervised Audio-Visual Video Parsing with Prototype-based Pseudo-Labeling

Kranthi Kumar Rachavarapu, Kalyan Ramakrishnan, Rajagopalan A. N.

In this paper we address the weakly-supervised Audio-Visual Video Parsing (AVVP) problem which aims at labeling events in a video as audible visible or both and temporally localizing and classifying them into known categories. This is challenging since we only have access to video-level (weak) event labels when training but need to predict event labels at the segment (frame) level at test time. Recent methods employ multiple-instance learning (MIL) techniques that tend to focus solely on the most discriminative segments resulting in frequent misclassifications. Our idea is to first construct several prototype features for each event class by clustering key segments identified for the event in the training data. We then assign pseudo labels to all training segments based on their feature similarities with these prototypes and re-train the model under weak and strong supervision. We facilitate this by structuring the feature space with contrastive learning using pseudo labels. Experiments show that we outperform existing methods for weakly-supervised AVVP. We also show that learning with weak and iteratively re-estimated pseudo labels can be interpreted as an expectation-maximization (EM) algorithm providing further insight for our training procedure.

[]

[]

[]

[]

Intraoperative 2D/3D Image Registration via Differentiable X-ray Rendering

Vivek Gopalakrishnan, Neel Dey, Polina Golland

Surgical decisions are informed by aligning rapid portable 2D intraoperative images (e.g. X-rays) to a high-fidelity 3D preoperative reference scan (e.g. CT). However 2D/3D registration can often fail in practice: conventional optimization methods are prohibitively slow and susceptible to local minima while neural networks trained on small datasets fail on new patients or require impractical landmark supervision. We present DiffPose a self-supervised approach that leverages patient-specific simulation and differentiable physics-based rendering to achieve accurate 2D/3D registration without relying on manually labeled data. Preoperatively a CNN is trained to regress the pose of a randomly oriented synthetic X-ray rendered from the preoperative CT. The CNN then initializes rapid intraoperative test-time optimization that uses the differentiable X-ray renderer to refine the solution. Our work further proposes several geometrically principled methods for sampling camera poses from SE(3) for sparse differentiable rendering and for driving registration in the tangent space se(3) with geodesic and multiscale locality-sensitive losses. DiffPose achieves sub-millimeter accuracy across surgical datasets at intraoperative speeds improving upon existing unsupervised methods by an order of magnitude and even outperforming supervised baselines. Our implementation is at https://github.com/eigenvivek/DiffPose.

[]

[]

[]

[]

MICap: A Unified Model for Identity-Aware Movie Descriptions

http://arxiv.org/abs/2405.11483

Haran Raajesh, Naveen Reddy Desanur, Zeeshan Khan, Makarand Tapaswi

Characters are an important aspect of any storyline and identifying and including them in descriptions is necessary for story understanding. While previous work has largely ignored identity and generated captions with someone (anonymized names) recent work formulates id-aware captioning as a fill-in-the-blanks (FITB) task where given a caption with blanks the goal is to predict person id labels. However to predict captions with ids a two-stage approach is required: first predict captions with someone then fill in identities. In this work we present a new single stage approach that can seamlessly switch between id-aware caption generation or FITB when given a caption with blanks. Our model Movie-Identity Captioner (MICap) uses a shared auto-regressive decoder that benefits from training with FITB and full-caption generation objectives while the encoder can benefit from or disregard captions with blanks as input. Another challenge with id-aware captioning is the lack of a metric to capture subtle differences between person ids. To this end we introduce iSPICE a caption evaluation metric that focuses on identity tuples created through intermediate scene graphs. We evaluate MICap on Large-Scale Movie Description Challenge (LSMDC) where we show a 4.2% improvement in FITB accuracy and a 1-2% bump in classic captioning metrics.

[]

[]

[]

[]

MonoDiff: Monocular 3D Object Detection and Pose Estimation with Diffusion Models

Yasiru Ranasinghe, Deepti Hegde, Vishal M. Patel

3D object detection and pose estimation from a single-view image is challenging due to the high uncertainty caused by the absence of 3D perception. As a solution recent monocular 3D detection methods leverage additional modalities such as stereo image pairs and LiDAR point clouds to enhance image features at the expense of additional annotation costs. We propose using diffusion models to learn effective representations for monocular 3D detection without additional modalities or training data. We present MonoDiff a novel framework that employs the reverse diffusion process to estimate 3D bounding box and orientation. But considering the variability in bounding box sizes along different dimensions it is ineffective to sample noise from a standard Gaussian distribution. Hence we adopt a Gaussian mixture model to sample noise during the forward diffusion process and initialize the reverse diffusion process. Furthermore since the diffusion model generates the 3D parameters for a given object image we leverage 2D detection information to provide additional supervision by maintaining the correspondence between 3D/2D projection. Finally depending on the signal-to-noise ratio we incorporate a dynamic weighting scheme to account for the level of uncertainty in the supervision by projection at different timesteps. MonoDiff outperforms current state-of-the-art monocular 3D detection methods on the KITTI and Waymo benchmarks without additional depth priors. MonoDiff project is available at: https://dylran.github.io/monodiff.github.io.

[]

[]

[]

[]

General Object Foundation Model for Images and Videos at Scale

http://arxiv.org/abs/2312.09158

Junfeng Wu, Yi Jiang, Qihao Liu, Zehuan Yuan, Xiang Bai, Song Bai

We present GLEE in this work an object-level foundation model for locating and identifying objects in images and videos. Through a unified framework GLEEaccomplishes detection segmentation tracking grounding and identification of arbitrary objects in the open world scenario for various object perception tasks. Adopting a cohesive learning strategy GLEE acquires knowledge from diverse data sources with varying supervision levels to formulate general object representations excelling in zero-shot transfer to new data and tasks. Specifically we employ an image encoder text encoder and visual prompter to handle multi-modal inputs enabling to simultaneously solve various object-centric downstream tasks while maintaining state-of-the-art performance. Demonstrated through extensive training on over five million images from diverse benchmarks GLEE exhibits remarkable versatility and improved generalization performance efficiently tackling downstream tasks without the need for task-specific adaptation. By integrating large volumes of automatically labeled data we further enhance its zero-shot generalization capabilities. Additionally GLEE is capable of being integrated into Large Language Models serving as a foundational model to provide universal object-level information for multi-modal tasks. We hope that the versatility and universality of our method will mark a significant step in the development of efficient visual foundation models for AGI systems. The models and code are released at https://github.com/FoundationVision/GLEE.

[]

[]

[]

[]

An Upload-Efficient Scheme for Transferring Knowledge From a Server-Side Pre-trained Generator to Clients in Heterogeneous Federated Learning

http://arxiv.org/abs/2403.15760

Jianqing Zhang, Yang Liu, Yang Hua, Jian Cao

Heterogeneous Federated Learning (HtFL) enables collaborative learning on multiple clients with different model architectures while preserving privacy. Despite recent research progress knowledge sharing in HtFL is still difficult due to data and model heterogeneity. To tackle this issue we leverage the knowledge stored in pre-trained generators and propose a new upload-efficient knowledge transfer scheme called Federated Knowledge-Transfer Loop (FedKTL). Our FedKTL can produce client-task-related prototypical image-vector pairs via the generator's inference on the server. With these pairs each client can transfer pre-existing knowledge from the generator to its local model through an additional supervised local task. We conduct extensive experiments on four datasets under two types of data heterogeneity with 14 kinds of models including CNNs and ViTs. Results show that our upload-efficient FedKTL surpasses seven state-of-the-art methods by up to 7.31% in accuracy. Moreover our knowledge transfer scheme is applicable in scenarios with only one edge client. Code: https://github.com/TsingZ0/FedKTL

[]

[]

[]

[]

MeshGPT: Generating Triangle Meshes with Decoder-Only Transformers

http://arxiv.org/abs/2311.15475

Yawar Siddiqui, Antonio Alliegro, Alexey Artemov, Tatiana Tommasi, Daniele Sirigatti, Vladislav Rosov, Angela Dai, Matthias Nießner

We introduce MeshGPT a new approach for generating triangle meshes that reflects the compactness typical of artist-created meshes in contrast to dense triangle meshes extracted by iso-surfacing methods from neural fields. Inspired by recent advances in powerful large language models we adopt a sequence-based approach to autoregressively generate triangle meshes as sequences of triangles. We first learn a vocabulary of latent quantized embeddings using graph convolutions which inform these embeddings of the local mesh geometry and topology. These embeddings are sequenced and decoded into triangles by a decoder ensuring that they can effectively reconstruct the mesh. A transformer is then trained on this learned vocabulary to predict the index of the next embedding given previous embeddings. Once trained our model can be autoregressively sampled to generate new triangle meshes directly generating compact meshes with sharp edges more closely imitating the efficient triangulation patterns of human-crafted meshes. MeshGPT demonstrates a notable improvement over state of the art mesh generation methods with a 9% increase in shape coverage and a 30-point enhancement in FID scores across various categories.

[]

[]

[]

[]

Inlier Confidence Calibration for Point Cloud Registration

Yongzhe Yuan, Yue Wu, Xiaolong Fan, Maoguo Gong, Qiguang Miao, Wenping Ma

Inliers estimation constitutes a pivotal step in partially overlapping point cloud registration. Existing methods broadly obey coordinate-based scheme where inlier confidence is scored through simply capturing coordinate differences in the context. However this scheme results in massive inlier misinterpretation readily consequently affecting the registration performance. In this paper we explore to extend a new definition called inlier confidence calibration (ICC) to alleviate the above issues. Firstly we provide finely initial correspondences for ICC in order to generate high quality reference point cloud copy corresponding to the source point cloud. In particular we develop a soft assignment matrix optimization theorem that offers faster speed and greater precision compared to Sinkhorn. Benefiting from the high quality reference copy we argue the neighborhood patch formed by inlier and its neighborhood should have consistency between source point cloud and its reference copy. Based on this insight we construct transformation-invariant geometric constraints and capture geometric structure consistency to calibrate inlier confidence for estimated correspondences between source point cloud and its reference copy. Finally transformation is further calculated by the weighted SVD algorithm with the calibrated inlier confidence. Our model is trained in an unsupervised manner and extensive experiments on synthetic and real-world datasets illustrate the effectiveness of the proposed method.

[]

[]

[]

[]

Instance-aware Exploration-Verification-Exploitation for Instance ImageGoal Navigation

http://arxiv.org/abs/2402.17587

Xiaohan Lei, Min Wang, Wengang Zhou, Li Li, Houqiang Li

As a new embodied vision task Instance ImageGoal Navigation (IIN) aims to navigate to a specified object depicted by a goal image in an unexplored environment. The main challenge of this task lies in identifying the target object from different viewpoints while rejecting similar distractors. Existing ImageGoal Navigation methods usually adopt the simple Exploration-Exploitation framework and ignore the identification of specific instance during navigation. In this work we propose to imitate the human behaviour of "getting closer to confirm" when distinguishing objects from a distance. Specifically we design a new modular navigation framework named Instance-aware Exploration-Verification-Exploitation (IEVE) for instancelevel image goal navigation. Our method allows for active switching among the exploration verification and exploitation actions thereby facilitating the agent in making reasonable decisions under different situations. On the challenging HabitatMatterport 3D semantic (HM3DSEM) dataset our method surpasses previous state-of-theart work with a classical segmentation model (0.684 vs. 0.561 success) or a robust model (0.702 vs. 0.561 success). Our code will be made publicly available at https://github.com/XiaohanLei/IEVE.

[]

[]

[]

[]

One-2-3-45++: Fast Single Image to 3D Objects with Consistent Multi-View Generation and 3D Diffusion

Minghua Liu, Ruoxi Shi, Linghao Chen, Zhuoyang Zhang, Chao Xu, Xinyue Wei, Hansheng Chen, Chong Zeng, Jiayuan Gu, Hao Su

Recent advancements in open-world 3D object generation have been remarkable with image-to-3D methods offering superior fine-grained control over their text-to-3D counterparts. However most existing models fall short in simultaneously providing rapid generation speeds and high fidelity to input images - two features essential for practical applications. In this paper we present One-2-3-45++ an innovative method that transforms a single image into a detailed 3D textured mesh in approximately one minute. Our approach aims to fully harness the extensive knowledge embedded in 2D diffusion models and priors from valuable yet limited 3D data. This is achieved by initially finetuning a 2D diffusion model for consistent multi-view image generation followed by elevating these images to 3D with the aid of multi-view-conditioned 3D native diffusion models. Extensive experimental evaluations demonstrate that our method can produce high-quality diverse 3D assets that closely mirror the original input image.

[]

[]

[]

[]

Image Restoration by Denoising Diffusion Models with Iteratively Preconditioned Guidance

http://arxiv.org/abs/2312.16519

Tomer Garber, Tom Tirer

Training deep neural networks has become a common approach for addressing image restoration problems. An alternative for training a "task-specific" network for each observation model is to use pretrained deep denoisers for imposing only the signal's prior within iterative algorithms without additional training. Recently a sampling-based variant of this approach has become popular with the rise of diffusion/score-based generative models. Using denoisers for general purpose restoration requires guiding the iterations to ensure agreement of the signal with the observations. In low-noise settings guidance that is based on back-projection (BP) has been shown to be a promising strategy (used recently also under the names "pseudoinverse" or "range/-space" guidance). However the presence of noise in the observations hinders the gains from this approach. In this paper we propose a novel guidance technique based on preconditioning that allows traversing from BP-based guidance to least squares based guidance along the restoration scheme. The proposed approach is robust to noise while still having much simpler implementation than alternative methods (e.g. it does not require SVD or a large number of iterations). We use it within both an optimization scheme and a sampling-based scheme and demonstrate its advantages over existing methods for image deblurring and super-resolution.

[]

[]

[]

[]

Let's Think Outside the Box: Exploring Leap-of-Thought in Large Language Models with Creative Humor Generation

Shanshan Zhong, Zhongzhan Huang, Shanghua Gao, Wushao Wen, Liang Lin, Marinka Zitnik, Pan Zhou

Chain-of-Thought (CoT) guides large language models (LLMs) to reason step-by-step and can motivate their logical reasoning ability. While effective for logical tasks CoT is not conducive to creative problem-solving which often requires out-of-box thoughts and is crucial for innovation advancements. In this paper we explore the Leap-of-Thought (LoT) abilities within LLMs -- a non-sequential creative paradigm involving strong associations and knowledge leaps. To this end we study LLMs on the popular Oogiri game which needs participants to have good creativity and strong associative thinking for responding unexpectedly and humorously to the given image text or both and thus is suitable for LoT study. Then to investigate LLMs' LoT ability in the Oogiri game we first build a multimodal and multilingual Oogiri-GO dataset which contains over 130000 samples from the Oogiri game and observe the insufficient LoT ability or failures of most existing LLMs on the Oogiri game. Accordingly we introduce a creative Leap-of-Thought (CLoT) paradigm to improve LLM's LoT ability. CLoT first formulates the Oogiri-GO dataset into LoT-oriented instruction tuning data to train pretrained LLM for achieving certain LoT humor generation and discrimination abilities. Then CLoT designs an explorative self-refinement that encourages the LLM to generate more creative LoT data via exploring parallels between seemingly unrelated concepts and selects high-quality data to train itself for self-refinement. CLoT not only excels in humor generation in the Oogiri game as shown in Fig. 1 but also boosts creative abilities in various tasks like "cloud guessing game" and "divergent association task". These findings advance our understanding and offer a pathway to improve LLMs' creative capacities for innovative applications across domains. The dataset code and models have been released online: https://zhongshsh.github.io/CLoT.

[]

[]

[]

[]

SceneFun3D: Fine-Grained Functionality and Affordance Understanding in 3D Scenes

Alexandros Delitzas, Ayca Takmaz, Federico Tombari, Robert Sumner, Marc Pollefeys, Francis Engelmann

Existing 3D scene understanding methods are heavily focused on 3D semantic and instance segmentation. However identifying objects and their parts only constitutes an intermediate step towards a more fine-grained goal which is effectively interacting with the functional interactive elements (e.g. handles knobs buttons) in the scene to accomplish diverse tasks. To this end we introduce SceneFun3D a large-scale dataset with more than 14.8k highly accurate interaction annotations for 710 high-resolution real-world 3D indoor scenes. We accompany the annotations with motion parameter information describing how to interact with these elements and a diverse set of natural language descriptions of tasks that involve manipulating them in the scene context. To showcase the value of our dataset we introduce three novel tasks namely functionality segmentation task-driven affordance grounding and 3D motion estimation and adapt existing state-of-the-art methods to tackle them. Our experiments show that solving these tasks in real 3D scenes remains challenging despite recent progress in closed-set and open-set 3D scene understanding methods.

[]

[]

[]

[]

Readout Guidance: Learning Control from Diffusion Features

http://arxiv.org/abs/2312.02150

Grace Luo, Trevor Darrell, Oliver Wang, Dan B Goldman, Aleksander Holynski

We present Readout Guidance a method for controlling text-to-image diffusion models with learned signals. Readout Guidance uses readout heads lightweight networks trained to extract signals from the features of a pre-trained frozen diffusion model at every timestep. These readouts can encode single-image properties such as pose depth and edges; or higher-order properties that relate multiple images such as correspondence and appearance similarity. Furthermore by comparing the readout estimates to a user-defined target and back-propagating the gradient through the readout head these estimates can be used to guide the sampling process. Compared to prior methods for conditional generation Readout Guidance requires significantly fewer added parameters and training samples and offers a convenient and simple recipe for reproducing different forms of conditional control under a single framework with a single architecture and sampling procedure. We showcase these benefits in the applications of drag-based manipulation identity-consistent generation and spatially aligned control.

[]

[]

[]

[]

A Unified Approach for Text- and Image-guided 4D Scene Generation

Yufeng Zheng, Xueting Li, Koki Nagano, Sifei Liu, Otmar Hilliges, Shalini De Mello

Large-scale diffusion generative models are greatly simplifying image video and 3D asset creation from user provided text prompts and images. However the challenging problem of text-to-4D dynamic 3D scene generation with diffusion guidance remains largely unexplored. We propose Dream-in-4D which features a novel two-stage approach for text-to-4D synthesis leveraging (1) 3D and 2D diffusion guidance to effectively learn a high-quality static 3D asset in the first stage; (2) a deformable neural radiance field that explicitly disentangles the learned static asset from its deformation preserving quality during motion learning; and (3) a multi-resolution feature grid for the deformation field with a displacement total variation loss to effectively learn motion with video diffusion guidance in the second stage. Through a user preference study we demonstrate that our approach significantly advances image and motion quality 3D consistency and text fidelity for text-to-4D generation compared to baseline approaches. Thanks to its motion-disentangled representation Dream-in-4D can also be easily adapted for controllable generation where appearance is defined by one or multiple images without the need to modify the motion learning stage. Thus our method offers for the first time a unified approach for text-to-4D image-to-4D and personalized 4D generation tasks.

[]

[]

[]

[]

GaussianAvatar: Towards Realistic Human Avatar Modeling from a Single Video via Animatable 3D Gaussians

http://arxiv.org/abs/2312.02134

Liangxiao Hu, Hongwen Zhang, Yuxiang Zhang, Boyao Zhou, Boning Liu, Shengping Zhang, Liqiang Nie

We present GaussianAvatar an efficient approach to creating realistic human avatars with dynamic 3D appearances from a single video. We start by introducing animatable 3D Gaussians to explicitly represent humans in various poses and clothing styles. Such an explicit and animatable representation can fuse 3D appearances more efficiently and consistently from 2D observations. Our representation is further augmented with dynamic properties to support pose-dependent appearance modeling where a dynamic appearance network along with an optimizable feature tensor is designed to learn the motion-to-appearance mapping. Moreover by leveraging the differentiable motion condition our method enables a joint optimization of motions and appearances during avatar modeling which helps to tackle the long-standing issue of inaccurate motion estimation in monocular settings. The efficacy of GaussianAvatar is validated on both the public dataset and our collected dataset demonstrating its superior performances in terms of appearance quality and rendering efficiency.

[]

[]

[]

[]

MTMMC: A Large-Scale Real-World Multi-Modal Camera Tracking Benchmark

http://arxiv.org/abs/2403.20225

Sanghyun Woo, Kwanyong Park, Inkyu Shin, Myungchul Kim, In So Kweon

Multi-target multi-camera tracking is a crucial task that involves identifying and tracking individuals over time using video streams from multiple cameras. This task has practical applications in various fields such as visual surveillance crowd behavior analysis and anomaly detection. However due to the difficulty and cost of collecting and labeling data existing datasets for this task are either synthetically generated or artificially constructed within a controlled camera network setting which limits their ability to model real-world dynamics and generalize to diverse camera configurations. To address this issue we present MTMMC a real-world large-scale dataset that includes long video sequences captured by 16 multi-modal cameras in two different environments - campus and factory - across various time weather and season conditions. This dataset provides a challenging test bed for studying multi-camera tracking under diverse real-world complexities and includes an additional input modality of spatially aligned and temporally synchronized RGB and thermal cameras which enhances the accuracy of multi-camera tracking. MTMMC is a super-set of existing datasets benefiting independent fields such as person detection re-identification and multiple object tracking. We provide baselines and new learning setups on this dataset and set the reference scores for future studies. The datasets models and test server will be made publicly available.

[]

[]

[]

[]

Enhanced Motion-Text Alignment for Image-to-Video Transfer Learning

Wei Zhang, Chaoqun Wan, Tongliang Liu, Xinmei Tian, Xu Shen, Jieping Ye

Extending large image-text pre-trained models (e.g. CLIP) for video understanding has made significant advancements. To enable the capability of CLIP to perceive dynamic information in videos existing works are dedicated to equipping the visual encoder with various temporal modules. However these methods exhibit "asymmetry" between the visual and textual sides with neither temporal descriptions in input texts nor temporal modules in text encoder. This limitation hinders the potential of language supervision emphasized in CLIP and restricts the learning of temporal features as the text encoder has demonstrated limited proficiency in motion understanding. To address this issue we propose leveraging "MoTion-Enhanced Descriptions" (MoTED) to facilitate the extraction of distinctive temporal features in videos. Specifically we first generate discriminative motion-related descriptions via querying GPT-4 to compare easy-confusing action categories. Then we incorporate both the visual and textual encoders with additional perception modules to process the video frames and generated descriptions respectively. Finally we adopt a contrastive loss to align the visual and textual motion features. Extensive experiments on five benchmarks show that MoTED surpasses state-of-the-art methods with convincing gaps laying a solid foundation for empowering CLIP with strong temporal modeling.

[]

[]

[]

[]

DAP: A Dynamic Adversarial Patch for Evading Person Detectors

http://arxiv.org/abs/2305.11618

Amira Guesmi, Ruitian Ding, Muhammad Abdullah Hanif, Ihsen Alouani, Muhammad Shafique

Patch-based adversarial attacks were proven to compromise the robustness and reliability of computer vision systems. However their conspicuous and easily detectable nature challenge their practicality in real-world setting. To address this recent work has proposed using Generative Adversarial Networks (GANs) to generate naturalistic patches that may not attract human attention. However such approaches suffer from a limited latent space making it challenging to produce a patch that is efficient stealthy and robust to multiple real-world transformations. This paper introduces a novel approach that produces a Dynamic Adversarial Patch (DAP) designed to overcome these limitations. DAP maintains a naturalistic appearance while optimizing attack efficiency and robustness to real-world transformations. The approach involves redefining the optimization problem and introducing a novel objective function that incorporates a similarity metric to guide the patch's creation. Unlike GAN-based techniques the DAP directly modifies pixel values within the patch providing increased flexibility and adaptability to multiple transformations. Furthermore most clothing-based physical attacks assume static objects and ignore the possible transformations caused by non-rigid deformation due to changes in a person's pose. To address this limitation a `Creases Transformation' (CT) block is introduced enhancing the patch's resilience to a variety of real-world distortions. Experimental results demonstrate that the proposed approach outperforms state-of-the-art attacks achieving a success rate of up to 82.28% in the digital world when targeting the YOLOv7 detector and 65% in the physical world when targeting YOLOv3tiny detector deployed in edge-based smart cameras.

[]

[]

[]

[]

Learned Lossless Image Compression based on Bit Plane Slicing

Zhe Zhang, Huairui Wang, Zhenzhong Chen, Shan Liu

Autoregressive Initial Bits (ArIB) a framework that combines subimage autoregression and latent variable models has shown its advantages in lossless image compression. However in current methods the image splitting makes the information of latent variables being uniformly distributed in each subimage and causes inadequate use of latent variables in addition to posterior collapse. To tackle these issues we introduce Bit Plane Slicing (BPS) splitting images in the bit plane dimension with the considerations on different importance for latent variables. Thus BPS provides a more effective representation by arranging subimages with decreasing importance for latent variables. To solve the problem of the increased number of dimensions caused by BPS we further propose a dimension-tailored autoregressive model that tailors autoregression methods for each dimension based on their characteristics efficiently capturing the dependencies in plane space and color dimensions. As shown in the extensive experimental results our method demonstrates the superior compression performance with comparable inference speed when compared to the state-of-the-art normalizing-flow-based methods. The code is at https://github.com/ZZ022/ArIB-BPS.

[]

[]

[]

[]

UV-IDM: Identity-Conditioned Latent Diffusion Model for Face UV-Texture Generation

Hong Li, Yutang Feng, Song Xue, Xuhui Liu, Bohan Zeng, Shanglin Li, Boyu Liu, Jianzhuang Liu, Shumin Han, Baochang Zhang

3D face reconstruction aims at generating high-fidelity 3D face shapes and textures from single-view or multi-view images. However current prevailing facial texture generation methods generally suffer from low-quality texture identity information loss and inadequate handling of occlusions. To solve these problems we introduce an Identity-Conditioned Latent Diffusion Model for face UV-texture generation (UV-IDM) to generate photo-realistic textures based on the Basel Face Model (BFM). UV-IDM leverages the powerful texture generation capacity of a latent diffusion model (LDM) to obtain detailed facial textures. To preserve the identity during the reconstruction procedure we design an identity-conditioned module that can utilize any in-the-wild image as a robust condition for the LDM to guide texture generation. UV-IDM can be easily adapted to different BFM-based methods as a high-fidelity texture generator. Furthermore in light of the limited accessibility of most existing UV-texture datasets we build a large-scale and publicly available UV-texture dataset based on BFM termed BFM-UV. Extensive experiments show that our UV-IDM can generate high-fidelity textures in 3D face reconstruction within seconds while maintaining image consistency bringing new state-of-the-art performance in facial texture generation.

[]

[]

[]

[]

Mosaic-SDF for 3D Generative Models

http://arxiv.org/abs/2312.09222

Lior Yariv, Omri Puny, Oran Gafni, Yaron Lipman

Current diffusion or flow-based generative models for 3D shapes divide to two: distilling pre-trained 2D image diffusion models and training directly on 3D shapes. When training a diffusion or flow models on 3D shapes a crucial design choice is the shape representation. An effective shape representation needs to adhere three design principles: it should allow an efficient conversion of large 3D datasets to the representation form; it should provide a good tradeoff of approximation power versus number of parameters; and it should have a simple tensorial form that is compatible with existing powerful neural architectures. While standard 3D shape representations such as volumetric grids and point clouds do not adhere to all these principles simultaneously we advocate in this paper a new representation that does. We introduce Mosaic-SDF (M-SDF): a simple 3D shape representation that approximates the Signed Distance Function (SDF) of a given shape by using a set of local grids spread near the shape's boundary. The M-SDF representation is fast to compute for each shape individually making it readily parallelizable; it is parameter efficient as it only covers the space around the shape's boundary; and it has a simple matrix form compatible with Transformer-based architectures. We demonstrate the efficacy of the M-SDF representation by using it to train a 3D generative flow model including class-conditioned generation with the ShapeNetCore-V2 (3D Warehouse) dataset and text-to-3D generation using a dataset of about 600k caption-shape pairs.

[]

[]

[]

[]

Diffusion Handles Enabling 3D Edits for Diffusion Models by Lifting Activations to 3D

http://arxiv.org/abs/2312.02190

Karran Pandey, Paul Guerrero, Matheus Gadelha, Yannick Hold-Geoffroy, Karan Singh, Niloy J. Mitra

Diffusion handles is a novel approach to enable 3D object edits on diffusion images requiring only existing pre-trained diffusion models depth estimation without any fine-tuning or 3D object retrieval. The edited results remain plausible photo-real and preserve object identity. Diffusion handles address a critically missing facet of generative image-based creative design. Our key insight is to lift diffusion activations for a selected object to 3D using a proxy depth 3D-transform the depth and associated activations and project them back to image space. The diffusion process guided by the manipulated activations produces plausible edited images showing complex 3D occlusion and lighting effects. We evaluate diffusion handles: quantitatively on a large synthetic data benchmark; and qualitatively by a user study showing our output to be more plausible and better than prior art at both 3D editing and identity control.

[]

[]

[]

[]

A Pedestrian is Worth One Prompt: Towards Language Guidance Person Re-Identification

Zexian Yang, Dayan Wu, Chenming Wu, Zheng Lin, Jingzi Gu, Weiping Wang

Extensive advancements have been made in person ReID through the mining of semantic information. Nevertheless existing methods that utilize semantic-parts from a single image modality do not explicitly achieve this goal. Whiteness the impressive capabilities in multimodal understanding of Vision Language Foundation Model CLIP a recent two-stage CLIP-based method employs automated prompt engineering to obtain specific textual labels for classifying pedestrians. However we note that the predefined soft prompts may be inadequate in expressing the entire visual context and struggle to generalize to unseen classes. This paper presents an end-to-end Prompt-driven Semantic Guidance (PromptSG) framework that harnesses the rich semantics inherent in CLIP. Specifically we guide the model to attend to regions that are semantically faithful to the prompt. To provide personalized language descriptions for specific individuals we propose learning pseudo tokens that represent specific visual contexts. This design not only facilitates learning fine-grained attribute information but also can inherently leverage language prompts during inference. Without requiring additional labeling efforts our PromptSG achieves state-of-the-art by over 10% on MSMT17 and nearly 5% on the Market-1501 benchmark.

[]

[]

[]

[]

Friendly Sharpness-Aware Minimization

http://arxiv.org/abs/2403.12350

Tao Li, Pan Zhou, Zhengbao He, Xinwen Cheng, Xiaolin Huang

Sharpness-Aware Minimization (SAM) has been instrumental in improving deep neural network training by minimizing both training loss and loss sharpness. Despite the practical success the mechanisms behind SAM's generalization enhancements remain elusive limiting its progress in deep learning optimization. In this work we investigate SAM's core components for generalization improvement and introduce "Friendly-SAM" (F-SAM) to further enhance SAM's generalization. Our investigation reveals the key role of batch-specific stochastic gradient noise within the adversarial perturbation i.e. the current minibatch gradient which significantly influences SAM's generalization performance. By decomposing the adversarial perturbation in SAM into full gradient and stochastic gradient noise components we discover that relying solely on the full gradient component degrades generalization while excluding it leads to improved performance. The possible reason lies in the full gradient component's increase in sharpness loss for the entire dataset creating inconsistencies with the subsequent sharpness minimization step solely on the current minibatch data. Inspired by these insights F-SAM aims to mitigate the negative effects of the full gradient component. It removes the full gradient estimated by an exponentially moving average (EMA) of historical stochastic gradients and then leverages stochastic gradient noise for improved generalization. Moreover we provide theoretical validation for the EMA approximation and prove the convergence of F-SAM on non-convex problems. Extensive experiments demonstrate the superior generalization performance and robustness of F-SAM over vanilla SAM. Code is available at https://github.com/nblt/F-SAM.

[]

[]

[]

[]

BIVDiff: A Training-Free Framework for General-Purpose Video Synthesis via Bridging Image and Video Diffusion Models

http://arxiv.org/abs/2312.02813

Fengyuan Shi, Jiaxi Gu, Hang Xu, Songcen Xu, Wei Zhang, Limin Wang

Diffusion models have made tremendous progress in text-driven image and video generation. Now text-to-image foundation models are widely applied to various downstream image synthesis tasks such as controllable image generation and image editing while downstream video synthesis tasks are less explored for several reasons. First it requires huge memory and computation overhead to train a video generation foundation model. Even with video foundation models additional costly training is still required for downstream video synthesis tasks. Second although some works extend image diffusion models into videos in a training-free manner temporal consistency cannot be well preserved. Finally these adaption methods are specifically designed for one task and fail to generalize to different tasks. To mitigate these issues we propose a training-free general-purpose video synthesis framework coined as BIVDiff via bridging specific image diffusion models and general text-to-video foundation diffusion models. Specifically we first use a specific image diffusion model (e.g. ControlNet and Instruct Pix2Pix) for frame-wise video generation then perform Mixed Inversion on the generated video and finally input the inverted latents into the video diffusion models (e.g. VidRD and ZeroScope) for temporal smoothing. This decoupled framework enables flexible image model selection for different purposes with strong task generalization and high efficiency. To validate the effectiveness and general use of BIVDiff we perform a wide range of video synthesis tasks including controllable video generation video editing video inpainting and outpainting.

[]

[]

[]

[]

NC-TTT: A Noise Constrastive Approach for Test-Time Training

David Osowiechi, Gustavo A. Vargas Hakim, Mehrdad Noori, Milad Cheraghalikhani, Ali Bahri, Moslem Yazdanpanah, Ismail Ben Ayed, Christian Desrosiers

Despite their exceptional performance in vision tasks deep learning models often struggle when faced with domain shifts during testing. Test-Time Training (TTT) methods have recently gained popularity by their ability to enhance the robustness of models through the addition of an auxiliary objective that is jointly optimized with the main task. Being strictly unsupervised this auxiliary objective is used at test time to adapt the model without any access to labels. In this work we propose Noise-Contrastive Test-Time Training (NC-TTT) a novel unsupervised TTT technique based on the discrimination of noisy feature maps. By learning to classify noisy views of projected feature maps and then adapting the model accordingly on new domains classification performance can be recovered by an important margin. Experiments on several popular test-time adaptation baselines demonstrate the advantages of our method compared to recent approaches for this task. The code can be found at: https://github.com/GustavoVargasHakim/NCTTT.git

[]

[]

[]

[]

NetTrack: Tracking Highly Dynamic Objects with a Net

http://arxiv.org/abs/2403.11186

Guangze Zheng, Shijie Lin, Haobo Zuo, Changhong Fu, Jia Pan

The complex dynamicity of open-world objects presents non-negligible challenges for multi-object tracking (MOT) often manifested as severe deformations fast motion and occlusions. Most methods that solely depend on coarse-grained object cues such as boxes and the overall appearance of the object are susceptible to degradation due to distorted internal relationships of dynamic objects. To address this problem this work proposes NetTrack an efficient generic and affordable tracking framework to introduce fine-grained learning that is robust to dynamicity. Specifically NetTrack constructs a dynamicity-aware association with a fine-grained Net leveraging point-level visual cues. Correspondingly a fine-grained sampler and matching method have been incorporated. Furthermore NetTrack learns object-text correspondence for fine-grained localization. To evaluate MOT in extremely dynamic open-world scenarios a bird flock tracking (BFT) dataset is constructed which exhibits high dynamicity with diverse species and open-world scenarios. Comprehensive evaluation on BFT validates the effectiveness of fine-grained learning on object dynamicity and thorough transfer experiments on challenging open-world benchmarks i.e. TAO TAO-OW AnimalTrack and GMOT-40 validate the strong generalization ability of NetTrack even without finetuning.

[]

[]

[]

[]

Grounded Question-Answering in Long Egocentric Videos

http://arxiv.org/abs/2312.06505

Shangzhe Di, Weidi Xie

Existing approaches to video understanding mainly designed for short videos from a third-person perspective are limited in their applicability in certain fields such as robotics. In this paper we delve into open-ended question-answering (QA) in long egocentric videos which allows individuals or robots to inquire about their own past visual experiences. This task presents unique challenges including the complexity of temporally grounding queries within extensive video content the high resource demands for precise data annotation and the inherent difficulty of evaluating open-ended answers due to their ambiguous nature. Our proposed approach tackles these challenges by (i) integrating query grounding and answering within a unified model to reduce error propagation; (ii) employing large language models for efficient and scalable data synthesis; and (iii) introducing a close-ended QA task for evaluation to manage answer ambiguity. Extensive experiments demonstrate the effectiveness of our method which also achieves state-of-the-art performance on the QAEgo4D and Ego4D-NLQ benchmarks. Code data and models are open-sourced at https://github.com/Becomebright/GroundVQA.

[]

[]

[]

[]

HPNet: Dynamic Trajectory Forecasting with Historical Prediction Attention

http://arxiv.org/abs/2404.06351

Xiaolong Tang, Meina Kan, Shiguang Shan, Zhilong Ji, Jinfeng Bai, Xilin Chen

Predicting the trajectories of road agents is essential for autonomous driving systems. The recent mainstream methods follow a static paradigm which predicts the future trajectory by using a fixed duration of historical frames. These methods make the predictions independently even at adjacent time steps which leads to potential instability and temporal inconsistency. As successive time steps have largely overlapping historical frames their forecasting should have intrinsic correlation such as overlapping predicted trajectories should be consistent or be different but share the same motion goal depending on the road situation. Motivated by this in this work we introduce HPNet a novel dynamic trajectory forecasting method. Aiming for stable and accurate trajectory forecasting our method leverages not only historical frames including maps and agent states but also historical predictions. Specifically we newly design a Historical Prediction Attention module to automatically encode the dynamic relationship between successive predictions. Besides it also extends the attention range beyond the currently visible window benefitting from the use of historical predictions. The proposed Historical Prediction Attention together with the Agent Attention and Mode Attention is further formulated as the Triple Factorized Attention module serving as the core design of HPNet. Experiments on the Argoverse and INTERACTION datasets show that HPNet achieves state-of-the-art performance and generates accurate and stable future trajectories. Our code are available at https://github.com/XiaolongTang23/HPNet.

[]

[]

[]

[]

Flexible Depth Completion for Sparse and Varying Point Densities

Jinhyung Park, Yu-Jhe Li, Kris Kitani

While recent depth completion methods have achieved remarkable results filling in relatively dense depth maps (e.g. projected 64-line LiDAR on KITTI or 500 sampled points on NYUv2) with RGB guidance their performance on very sparse input (e.g. 4-line LiDAR or 32 depth point measurements) is unverified. These sparser regimes present new challenges as a 4-line LiDAR increases the distance between pixels without depth and their nearest depth point sixfold from 5 pixels to 30 pixels compared to 64 lines. Observing that existing methods struggle with sparse and variable distribution depth maps we propose an Affinity-Based Shift Correction (ASC) module that iteratively aligns depth predictions to input depth based on predicted affinities between image pixels and depth points. Our framework enables each depth point to adaptively influence and improve predictions across the image leading to largely improved results for fewer-line fewer-point and variable sparsity settings. Further we show improved performance in domain transfer from KITTI to nuScenes and from random sampling to irregular point distributions. Our correction module can easily be added to any depth completion or RGB-only depth estimation model notably allowing the latter to perform both completion and estimation with a single model.

[]

[]

[]

[]

Small Scale Data-Free Knowledge Distillation

He Liu, Yikai Wang, Huaping Liu, Fuchun Sun, Anbang Yao

Data-free knowledge distillation is able to utilize the knowledge learned by a large teacher network to augment the training of a smaller student network without accessing the original training data avoiding privacy security and proprietary risks in real applications. In this line of research existing methods typically follow an inversion-and-distillation paradigm in which a generative adversarial network on-the-fly trained with the guidance of the pre-trained teacher network is used to synthesize a large-scale sample set for knowledge distillation. In this paper we reexamine this common data-free knowledge distillation paradigm showing that there is considerable room to improve the overall training efficiency through a lens of "small-scale inverted data for knowledge distillation". In light of three empirical observations indicating the importance of how to balance class distributions in terms of synthetic sample diversity and difficulty during both data inversion and distillation processes we propose Small Scale Data-free Knowledge Distillation (SSD-KD). In formulation SSD-KD introduces a modulating function to balance synthetic samples and a priority sampling function to select proper samples facilitated by a dynamic replay buffer and a reinforcement learning strategy. As a result SSD-KD can perform distillation training conditioned on an extremely small scale of synthetic samples (e.g. 10x less than the original training data scale) making the overall training efficiency one or two orders of magnitude faster than many mainstream methods while retaining superior or competitive model performance as demonstrated on popular image classification and semantic segmentation benchmarks. The code is available at https://github.com/OSVAI/SSD-KD.

[]

[]

[]

[]

Shadows Don't Lie and Lines Can't Bend! Generative Models don't know Projective Geometry...for now

Ayush Sarkar, Hanlin Mai, Amitabh Mahapatra, Svetlana Lazebnik, D.A. Forsyth, Anand Bhattad

Generative models can produce impressively realistic images. This paper demonstrates that generated images have geometric features different from those of real images. We build a set of collections of generated images prequalified to fool simple signal-based classifiers into believing they are real. We then show that prequalified generated images can be identified reliably by classifiers that only look at geometric properties. We use three such classifiers. All three classifiers are denied access to image pixels and look only at derived geometric features. The first classifier looks at the perspective field of the image the second looks at lines detected in the image and the third looks at relations between detected objects and shadows. Our procedure detects generated images more reliably than SOTA local signal based detectors for images from a number of distinct generators. Saliency maps suggest that the classifiers can identify geometric problems reliably. We conclude that current generators cannot reliably reproduce geometric properties of real images.

[]

[]

[]

[]

CFPL-FAS: Class Free Prompt Learning for Generalizable Face Anti-spoofing

Ajian Liu, Shuai Xue, Jianwen Gan, Jun Wan, Yanyan Liang, Jiankang Deng, Sergio Escalera, Zhen Lei

Domain generalization (DG) based Face Anti-Spoofing (FAS) aims to improve the model's performance on unseen domains. Existing methods either rely on domain labels to align domain-invariant feature spaces or disentangle generalizable features from the whole sample which inevitably lead to the distortion of semantic feature structures and achieve limited generalization. In this work we make use of large-scale VLMs like CLIP and leverage the textual feature to dynamically adjust the classifier's weights for exploring generalizable visual features. Specifically we propose a novel Class Free Prompt Learning (CFPL) paradigm for DG FAS which utilizes two lightweight transformers namely Content Q-Former (CQF) and Style Q-Former (SQF) to learn the different semantic prompts conditioned on content and style features by using a set of learnable query vectors respectively. Thus the generalizable prompt can be learned by two improvements: (1) A Prompt-Text Matched (PTM) supervision is introduced to ensure CQF learns visual representation that is most informative of the content description. (2) A Diversified Style Prompt (DSP) technology is proposed to diversify the learning of style prompts by mixing feature statistics between instance-specific styles. Finally the learned text features modulate visual features to generalization through the designed Prompt Modulation (PM). Extensive experiments show that the CFPL is effective and outperforms the state-of-the-art methods on several cross-domain datasets.

[]

[]

[]

[]

SI-MIL: Taming Deep MIL for Self-Interpretability in Gigapixel Histopathology

Saarthak Kapse, Pushpak Pati, Srijan Das, Jingwei Zhang, Chao Chen, Maria Vakalopoulou, Joel Saltz, Dimitris Samaras, Rajarsi R. Gupta, Prateek Prasanna

Introducing interpretability and reasoning into Multiple Instance Learning (MIL) methods for Whole Slide Image (WSI) analysis is challenging given the complexity of gigapixel slides. Traditionally MIL interpretability is limited to identifying salient regions deemed pertinent for downstream tasks offering little insight to the end-user (pathologist) regarding the rationale behind these selections. To address this we propose Self-Interpretable MIL (SI-MIL) a method intrinsically designed for interpretability from the very outset. SI-MIL employs a deep MIL framework to guide an interpretable branch grounded on handcrafted pathological features facilitating linear predictions. Beyond identifying salient regions SI-MIL uniquely provides feature-level interpretations rooted in pathological insights for WSIs. Notably SI-MIL with its linear prediction constraints challenges the prevalent myth of an inevitable trade-off between model interpretability and performance demonstrating competitive results compared to state-of-the-art methods on WSI-level prediction tasks across three cancer types. In addition we thoroughly benchmark the local- and global-interpretability of SI-MIL in terms of statistical analysis a domain expert study and desiderata of interpretability namely user-friendliness and faithfulness.

[]

[]

[]

[]

GEARS: Local Geometry-aware Hand-object Interaction Synthesis

http://arxiv.org/abs/2404.01758

Keyang Zhou, Bharat Lal Bhatnagar, Jan Eric Lenssen, Gerard Pons-Moll

Generating realistic hand motion sequences in interaction with objects has gained increasing attention with the growing interest in digital humans. Prior work has illustrated the effectiveness of employing occupancy-based or distance-based virtual sensors to extract hand-object interaction features. Nonetheless these methods show limited generalizability across object categories shapes and sizes. We hypothesize that this is due to two reasons: 1) the limited expressiveness of employed virtual sensors and 2) scarcity of available training data. To tackle this challenge we introduce a novel joint-centered sensor designed to reason about local object geometry near potential interaction regions. The sensor queries for object surface points in the neighbourhood of each hand joint. As an important step towards mitigating the learning complexity we transform the points from global frame to hand template frame and use a shared module to process sensor features of each individual joint. This is followed by a spatio-temporal transformer network aimed at capturing correlation among the joints in different dimensions. Moreover we devise simple heuristic rules to augment the limited training sequences with vast static hand grasping samples. This leads to a broader spectrum of grasping types observed during training in turn enhancing our model's generalization capability. We evaluate on two public datasets GRAB and InterCap where our method shows superiority over baselines both quantitatively and perceptually.

[]

[]

[]

[]

Open Vocabulary Semantic Scene Sketch Understanding

http://arxiv.org/abs/2312.12463

Ahmed Bourouis, Judith E. Fan, Yulia Gryaditskaya

We study the underexplored but fundamental vision problem of machine understanding of abstract freehand scene sketches. We introduce a sketch encoder that results in semantically-aware feature space which we evaluate by testing its performance on a semantic sketch segmentation task. To train our model we rely only on the availability of bitmap sketches with their brief captions and do not require any pixel-level annotations. To obtain generalization to a large set of sketches and categories we build on a vision transformer encoder pretrained with the CLIP model. We freeze the text encoder and perform visual-prompt tuning of the visual encoder branch while introducing a set of critical modifications. Firstly we augment the classical key-query (k-q) self-attention blocks with value-value (v-v) self-attention blocks. Central to our model is a two-level hierarchical network design that enables efficient semantic disentanglement: The first level ensures holistic scene sketch encoding and the second level focuses on individual categories. We then in the second level of the hierarchy introduce a cross-attention between textual and visual branches. Our method outperforms zero-shot CLIP pixel accuracy of segmentation results by 37 points reaching an accuracy of 85.5% on the FS-COCO sketch dataset. Finally we conduct a user study that allows us to identify further improvements needed over our method to reconcile machine and human understanding of scene sketches.

[]

[]

[]

[]

IntrinsicAvatar: Physically Based Inverse Rendering of Dynamic Humans from Monocular Videos via Explicit Ray Tracing

http://arxiv.org/abs/2312.05210

Shaofei Wang, Bozidar Antic, Andreas Geiger, Siyu Tang

We present IntrinsicAvatar a novel approach to recovering the intrinsic properties of clothed human avatars including geometry albedo material and environment lighting from only monocular videos. Recent advancements in human-based neural rendering have enabled high-quality geometry and appearance reconstruction of clothed humans from just monocular videos. However these methods bake intrinsic properties such as albedo material and environment lighting into a single entangled neural representation. On the other hand only a handful of works tackle the problem of estimating geometry and disentangled appearance properties of clothed humans from monocular videos. They usually achieve limited quality and disentanglement due to approximations of secondary shading effects via learned MLPs. In this work we propose to model secondary shading effects explicitly via Monte-Carlo ray tracing. We model the rendering process of clothed humans as a volumetric scattering process and combine ray tracing with body articulation. Our approach can recover high-quality geometry albedo material and lighting properties of clothed humans from a single monocular video without requiring supervised pre-training using ground truth materials. Furthermore since we explicitly model the volumetric scattering process and ray tracing our model naturally generalizes to novel poses enabling animation of the reconstructed avatar in novel lighting conditions.

[]

[]

[]

[]