CVPR 2024 Papers

We address the challenging task of identifying segmenting and tracking hand-held objects which is crucial for applications such as human action segmentation and performance evaluation. This task is particularly challenging due to heavy occlusion rapid motion and the transitory nature of objects being hand-held where an object may be held released and subsequently picked up again. To tackle these challenges we have developed a novel transformer-based architecture called HOIST-Former. HOIST-Former is adept at spatially and temporally segmenting hands and objects by iteratively pooling features from each other ensuring that the processes of identification segmentation and tracking of hand-held objects depend on the hands' positions and their contextual appearance. We further refine HOIST-Former with a contact loss that focuses on areas where hands are in contact with objects. Moreover we also contribute an in-the-wild video dataset called HOIST which comprises 4125 videos complete with bounding boxes segmentation masks and tracking IDs for hand-held objects. Through experiments on the HOIST dataset and two additional public datasets we demonstrate the efficacy of HOIST-Former in segmenting and tracking hand-held objects.

Human hands are highly articulated and versatile at handling objects. Jointly estimating the 3D poses of a hand and the object it manipulates from a monocular camera is challenging due to frequent occlusions. Thus existing methods often rely on intermediate 3D shape representations to increase performance. These representations are typically explicit such as 3D point clouds or meshes and thus provide information in the direct surroundings of the intermediate hand pose estimate. To address this we introduce HOISDF a Signed Distance Field (SDF) guided hand-object pose estimation network which jointly exploits hand and object SDFs to provide a global implicit representation over the complete reconstruction volume. Specifically the role of the SDFs is threefold: equip the visual encoder with implicit shape information help to encode hand-object interactions and guide the hand and object pose regression via SDF-based sampling and by augmenting the feature representations. We show that HOISDF achieves state-of-the-art results on hand-object pose estimation benchmarks (DexYCB and HO3Dv2). Code is available https://github.com/amathislab/HOISDF.

Humans naturally interact with both others and the surrounding multiple objects engaging in various social activities. However recent advances in modeling human-object interactions mostly focus on perceiving isolated individuals and objects due to fundamental data scarcity. In this paper we introduce HOI-M^3 a novel large-scale dataset for modeling the interactions of Multiple huMans and Multiple objects. Notably it provides accurate 3D tracking for both humans and objects from dense RGB and object-mounted IMU inputs covering 199 sequences and 181M frames of diverse humans and objects under rich activities. With the unique HOI-M^3 dataset we introduce two novel data-driven tasks with companion strong baselines: monocular capture and unstructured generation of multiple human-object interactions. Extensive experiments demonstrate that our dataset is challenging and worthy of further research about multiple human-object interactions and behavior analysis. Our HOI-M^3 dataset corresponding codes and pre-trained models will be disseminated to the community for future research.

Class-Incremental Learning (CIL) trains a model to continually recognize new classes from non-stationary data while retaining learned knowledge. A major challenge of CIL arises when applying to real-world data characterized by non-uniform distribution which introduces a dual imbalance problem involving (i) disparities between stored exemplars of old tasks and new class data (inter-phase imbalance) and (ii) severe class imbalances within each individual task (intra-phase imbalance). We show that this dual imbalance issue causes skewed gradient updates with biased weights in FC layers thus inducing over/under-fitting and catastrophic forgetting in CIL. Our method addresses it by reweighting the gradients towards balanced optimization and unbiased classifier learning. Additionally we observe imbalanced forgetting where paradoxically the instance-rich classes suffer higher performance degradation during CIL due to a larger amount of training data becoming unavailable in subsequent learning phases. To tackle this we further introduce a distribution-aware knowledge distillation loss to mitigate forgetting by aligning output logits proportionally with the distribution of lost training data. We validate our method on CIFAR-100 ImageNetSubset and Food101 across various evaluation protocols and demonstrate consistent improvements compared to existing works showing great potential to apply CIL in real-world scenarios with enhanced robustness and effectiveness.

Interactive Segmentation (IS) segments specific objects or parts in the image according to user input. Current IS pipelines fall into two categories: single-granularity output and multi-granularity output. The latter aims to alleviate the spatial ambiguity present in the former. However the multi-granularity output pipeline suffers from limited interaction flexibility and produces redundant results. In this work we introduce Granularity-Controllable Interactive Segmentation (GraCo) a novel approach that allows precise control of prediction granularity by introducing additional parameters to input. This enhances the customization of the interactive system and eliminates redundancy while resolving ambiguity. Nevertheless the exorbitant cost of annotating multi-granularity masks and the lack of available datasets with granularity annotations make it difficult for models to acquire the necessary guidance to control output granularity. To address this problem we design an any-granularity mask generator that exploits the semantic property of the pre-trained IS model to automatically generate abundant mask-granularity pairs without requiring additional manual annotation. Based on these pairs we propose a granularity-controllable learning strategy that efficiently imparts the granularity controllability to the IS model. Extensive experiments on intricate scenarios at object and part levels demonstrate that our GraCo has significant advantages over previous methods. This highlights the potential of GraCo to be a flexible annotation tool capable of adapting to diverse segmentation scenarios. The project page: https://zhao-yian.github.io/GraCo.

Prompt learning in pretrained visual-language models has shown remarkable flexibility across various downstream tasks. Leveraging its inherent lightweight nature recent research attempted to integrate the powerful pretrained models into federated learning frameworks to simultaneously reduce communication costs and promote local training on insufficient data. Despite these efforts current federated prompt learning methods lack specialized designs to systematically address severe data heterogeneities e.g. data distribution with both label and feature shifts involved. To address this challenge we present Federated Prompts Cooperation via Optimal Transport (FedOTP) which introduces efficient collaborative prompt learning strategies to capture diverse category traits on a per-client basis. Specifically for each client we learn a global prompt to extract consensus knowledge among clients and a local prompt to capture client-specific category characteristics. Unbalanced Optimal Transport is then employed to align local visual features with these prompts striking a balance between global consensus and local personalization. By relaxing one of the equality constraints FedOTP enables prompts to focus solely on core image patch regions. Extensive experiments on datasets with various types of heterogeneities have demonstrated that our FedOTP outperforms the state-of-the-art methods.

It is challenging for Neural Radiance Fields (NeRFs) in the few-shot setting to reconstruct high-quality novel views and depth maps in 360^\circ outward-facing indoor scenes. The captured sparse views for these scenes usually contain large viewpoint variations. This greatly reduces the potential consistency between views leading NeRFs to degrade a lot in these scenarios. Existing methods usually leverage pretrained depth prediction models to improve NeRFs. However these methods cannot guarantee geometry consistency due to the inherent geometry ambiguity in the pretrained models thus limiting NeRFs' performance. In this work we present P\textsuperscript 2 NeRF to capture global and hierarchical geometry consistency priors from pretrained models thus facilitating few-shot NeRFs in 360^\circ outward-facing indoor scenes. On the one hand we propose a matching-based geometry warm-up strategy to provide global geometry consistency priors for NeRFs. This effectively avoids the overfitting of early training with sparse inputs. On the other hand we propose a group depth ranking loss and ray weight mask regularization based on the monocular depth estimation model. This provides hierarchical geometry consistency priors for NeRFs. As a result our approach can fully leverage the geometry consistency priors from pretrained models and help few-shot NeRFs achieve state-of-the-art performance on two challenging indoor datasets. Our code is released at https://github.com/XT5un/P2NeRF.

A recent trend among generalizable novel view synthesis methods is to learn a rendering operator acting over single camera rays. This approach is promising because it removes the need for explicit volumetric rendering but it effectively treats target images as collections of independent pixels. Here we propose to learn a global rendering operator acting over all camera rays jointly. We show that the right representation to enable such rendering is a 5-dimensional plane sweep volume consisting of the projection of the input images on a set of planes facing the target camera. Based on this understanding we introduce our Convolutional Global Latent Renderer (ConvGLR) an efficient convolutional architecture that performs the rendering operation globally in a low-resolution latent space. Experiments on various datasets under sparse and generalizable setups show that our approach consistently outperforms existing methods by significant margins.

Pedestrian trajectory prediction is a well-established task with significant recent advancements. However existing datasets are unable to fulfill the demand for studying minute-level long-term trajectory prediction mainly due to the lack of high-resolution trajectory observation in the wide field of view (FoV). To bridge this gap we introduce a novel dataset named GigaTraj featuring videos capturing a wide FoV with ~ 4 x10^4 m^2 and high-resolution imagery at the gigapixel level. Furthermore GigaTraj includes comprehensive annotations such as bounding boxes identity associations world coordinates group/interaction relationships and scene semantics. Leveraging these multimodal annotations we evaluate and validate the state-of-the-art approaches for minute-level long-term trajectory prediction in large-scale scenes. Extensive experiments and analyses have revealed that long-term prediction for pedestrian trajectories presents numerous challenges indicating a vital new direction for trajectory research. The dataset is available at www.gigavision.ai.

We present GigaPose a fast robust and accurate method for CAD-based novel object pose estimation in RGB images. GigaPose first leverages discriminative "templates" rendered images of the CAD models to recover the out-of-plane rotation and then uses patch correspondences to estimate the four remaining parameters. Our approach samples templates in only a two-degrees-of-freedom space instead of the usual three and matches the input image to the templates using fast nearest-neighbor search in feature space results in a speedup factor of 35x compared to the state of the art. Moreover GigaPose is significantly more robust to segmentation errors. Our extensive evaluation on the seven core datasets of the BOP challenge demonstrates that it achieves state-of-the-art accuracy and can be seamlessly integrated with existing refinement methods. Additionally we show the potential of GigaPose with 3D models predicted by recent work on 3D reconstruction from a single image relaxing the need for CAD models and making 6D pose object estimation much more convenient. Our source code and trained models are publicly available at https://github.com/nv-nguyen/gigaPose

The lightweight "local-match-global" matching introduced by SRe2L successfully creates a distilled dataset with comprehensive information on the full 224x224 ImageNet-1k. However this one-sided approach is limited to a particular backbone layer and statistics which limits the improvement of the generalization of a distilled dataset. We suggest that sufficient and various "local-match-global" matching are more precise and effective than a single one and has the ability to create a distilled dataset with richer information and better generalization. We call this perspective "generalized matching" and propose Generalized Various Backbone and Statistical Matching (G-VBSM) in this work which aims to create a synthetic dataset with densities ensuring consistency with the complete dataset across various backbones layers and statistics. As experimentally demonstrated G-VBSM is the first algorithm to obtain strong performance across both small-scale and large-scale datasets. Specifically G-VBSM achieves a performance of 38.7% on CIFAR-100 with 128-width ConvNet 47.6% on Tiny-ImageNet with ResNet18 and 31.4% on the full 224x224 ImageNet-1k with ResNet18 under images per class (IPC) 10 50 and 10 respectively. These results surpass all SOTA methods by margins of 3.9% 6.5% and 10.1% respectively.

Event cameras capture the world at high time resolution and with minimal bandwidth requirements. However event streams which only encode changes in brightness do not contain sufficient scene information to support a wide variety of downstream tasks. In this work we design generalized event cameras that inherently preserve scene intensity in a bandwidth-efficient manner. We generalize event cameras in terms of when an event is generated and what information is transmitted. To implement our designs we turn to single-photon sensors that provide digital access to individual photon detections; this modality gives us the flexibility to realize a rich space of generalized event cameras. Our single-photon event cameras are capable of high-speed high-fidelity imaging at low readout rates. Consequently these event cameras can support plug-and-play downstream inference without capturing new event datasets or designing specialized event-vision models. As a practical implication our designs which involve lightweight and near-sensor-compatible computations provide a way to use single-photon sensors without exorbitant bandwidth costs.

As a significant step for human face modeling editing and generation face landmarking aims at extracting facial keypoints from images. A generalizable face landmarker is required in practice because real-world facial images e.g. the avatars in animations and games are often stylized in various ways. However achieving generalizable face landmarking is challenging due to the diversity of facial styles and the scarcity of labeled stylized faces. In this study we propose a simple but effective paradigm to learn a generalizable face landmarker based on labeled real human faces and unlabeled stylized faces. Our method learns the face landmarker as the key module of a conditional face warper. Given a pair of real and stylized facial images the conditional face warper predicts a warping field from the real face to the stylized one in which the face landmarker predicts the ending points of the warping field and provides us with high-quality pseudo landmarks for the corresponding stylized facial images. Applying an alternating optimization strategy we learn the face landmarker to minimize i) the discrepancy between the stylized faces and the warped real ones and ii) the prediction errors of both real and pseudo landmarks. Experiments on various datasets show that our method outperforms existing state-of-the-art domain adaptation methods in face landmarking tasks leading to a face landmarker with better generalizability. Code is available at https://plustwo0.github.io/project-face-landmarker.

Most multimodal large language models (MLLMs) learn language-to-object grounding through causal language modeling where grounded objects are captured by bounding boxes as sequences of location tokens. This paradigm lacks pixel-level representations that are important for fine-grained visual understanding and diagnosis. In this work we introduce GROUNDHOG an MLLM developed by grounding Large Language Models to holistic segmentation. GROUNDHOG incorporates a masked feature extractor and converts extracted features into visual entity tokens for the MLLM backbone which then connects groundable phrases to unified grounding masks by retrieving and merging the entity masks. To train GROUNDHOG we carefully curated M3G2 a grounded visual instruction tuning dataset with Multi-Modal Multi-Grained Grounding by harvesting a collection of segmentation-grounded datasets with rich annotations. Our experimental results show that GROUNDHOG achieves superior performance on various language grounding tasks without task-specific fine-tuning and significantly reduces object hallucination. GROUNDHOG also demonstrates better grounding towards complex forms of visual input and provides easy-to-understand diagnosis in failure cases.

Large Multimodal Models (LMMs) extend Large Language Models to the vision domain. Initial LMMs used holistic images and text prompts to generate ungrounded textual responses. Recently region-level LMMs have been used to generate visually grounded responses. However they are limited to only referring to a single object category at a time require users to specify the regions or cannot offer dense pixel-wise object grounding. In this work we present Grounding LMM (GLaMM) the first model that can generate natural language responses seamlessly intertwined with corresponding object segmentation masks. GLaMM not only grounds objects appearing in the conversations but is flexible enough to accept both textual and optional visual prompts (region of interest) as input. This empowers users to interact with the model at various levels of granularity both in textual and visual domains. Due to the lack of standard benchmarks for the novel setting of visually Grounded Conversation Generation (GCG) we introduce a comprehensive evaluation protocol with our curated grounded conversations. Our proposed GCG task requires densely grounded concepts in natural scenes at a large-scale. To this end we propose a densely annotated Grounding-anything Dataset (GranD) using our proposed automated annotation pipeline that encompasses 7.5M unique concepts grounded in a total of 810M regions available with segmentation masks. Besides GCG GLaMM also performs effectively on several downstream tasks e.g. referring expression segmentation image and region-level captioning and vision-language conversations.

As wearable cameras become more popular an important question emerges: how to identify camera wearers within the perspective of conventional static cameras. The drastic difference between first-person (egocentric) and third-person (exocentric) camera views makes this a challenging task. We present PersonEnvironmentNet (PEN) a framework designed to integrate information from both the individuals in the two views and geometric cues inferred from the background environment. To facilitate research in this direction we also present TF2023 a novel dataset comprising synchronized first-person and third-person views along with masks of camera wearers and labels associating these masks with the respective first-person views. In addition we propose a novel quantitative metric designed to measure a model's ability to comprehend the relationship between the two views. Our experiments reveal that PEN outperforms existing methods. The code and dataset are available at https://github.com/ziweizhao1993/PEN.

We present FoundationPose a unified foundation model for 6D object pose estimation and tracking supporting both model-based and model-free setups. Our approach can be instantly applied at test-time to a novel object without finetuning as long as its CAD model is given or a small number of reference images are captured. Thanks to the unified framework the downstream pose estimation modules are the same in both setups with a neural implicit representation used for efficient novel view synthesis when no CAD model is available. Strong generalizability is achieved via large-scale synthetic training aided by a large language model (LLM) a novel transformer-based architecture and contrastive learning formulation. Extensive evaluation on multiple public datasets involving challenging scenarios and objects indicate our unified approach outperforms existing methods specialized for each task by a large margin. In addition it even achieves comparable results to instance-level methods despite the reduced assumptions. Project page: https://nvlabs.github.io/FoundationPose/

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.

Periocular and face are complementary biometrics for identity management albeit with inherent limitations notably in scenarios involving occlusion due to sunglasses or masks. In response to these challenges we introduce Flexible Biometric Recognition (FBR) a novel framework designed to advance conventional face periocular and multimodal face-periocular biometrics across both intra- and cross-modality recognition tasks. FBR strategically utilizes the Multimodal Fusion Attention (MFA) and Multimodal Prompt Tuning (MPT) mechanisms within the Vision Transformer architecture. MFA facilitates the fusion of modalities ensuring cohesive alignment between facial and periocular embeddings while incorporating soft-biometrics to enhance the model's ability to discriminate between individuals. The fusion of three modalities is pivotal in exploring interrelationships between different modalities. Additionally MPT serves as a unifying bridge intertwining inputs and promoting cross-modality interactions while preserving their distinctive characteristics. The collaborative synergy of MFA and MPT enhances the shared features of the face and periocular with a specific emphasis on the ocular region yielding exceptional performance in both intra- and cross-modality recognition tasks. Rigorous experimentation across four benchmark datasets validates the noteworthy performance of the FBR model. The source code is available at https://github.com/MIS-DevWorks/FBR.