CVPR 2024 论文列表

We present Multi-Baseline Radiance Fields (MuRF) a general feed-forward approach to solving sparse view synthesis under multiple different baseline settings (small and large baselines and different number of input views). To render a target novel view we discretize the 3D space into planes parallel to the target image plane and accordingly construct a target view frustum volume. Such a target volume representation is spatially aligned with the target view which effectively aggregates relevant information from the input views for high-quality rendering. It also facilitates subsequent radiance field regression with a convolutional network thanks to its axis-aligned nature. The 3D context modeled by the convolutional network enables our method to synthesis sharper scene structures than prior works. Our MuRF achieves state-of-the-art performance across multiple different baseline settings and diverse scenarios ranging from simple objects (DTU) to complex indoor and outdoor scenes (RealEstate10K and LLFF). We also show promising zero-shot generalization abilities on the Mip-NeRF 360 dataset demonstrating the general applicability of MuRF.

Generalizability in deep neural networks plays a pivotal role in medical image segmentation. However deep learning-based medical image analyses tend to overlook the importance of frequency variance which is critical element for achieving a model that is both modality-agnostic and domain-generalizable. Additionally various models fail to account for the potential information loss that can arise from multi-task learning under deep supervision a factor that can impair the model's representation ability. To address these challenges we propose a Modality-agnostic Domain Generalizable Network (MADGNet) for medical image segmentation which comprises two key components: a Multi-Frequency in Multi-Scale Attention (MFMSA) block and Ensemble Sub-Decoding Module (E-SDM). The MFMSA block refines the process of spatial feature extraction particularly in capturing boundary features by incorporating multi-frequency and multi-scale features thereby offering informative cues for tissue outline and anatomical structures. Moreover we propose E-SDM to mitigate information loss in multi-task learning with deep supervision especially during substantial upsampling from low resolution. We evaluate the segmentation performance of MADGNet across six modalities and fifteen datasets. Through extensive experiments we demonstrate that MADGNet consistently outperforms state-of-the-art models across various modalities showcasing superior segmentation performance. This affirms MADGNet as a robust solution for medical image segmentation that excels in diverse imaging scenarios. Our MADGNet code is available in GitHub Link.

Many existing motion prediction approaches rely on symbolic perception outputs to generate agent trajectories such as bounding boxes road graph information and traffic lights. This symbolic representation is a high-level abstraction of the real world which may render the motion prediction model vulnerable to perception errors (e.g. failures in detecting open-vocabulary obstacles) while missing salient information from the scene context (e.g. poor road conditions). An alternative paradigm is end-to-end learning from raw sensors. However this approach suffers from the lack of interpretability and requires significantly more training resources. In this work we propose tokenizing the visual world into a compact set of scene elements and then leveraging pre-trained image foundation models and LiDAR neural networks to encode all the scene elements in an open-vocabulary manner. The image foundation model enables our scene tokens to encode the general knowledge of the open world while the LiDAR neural network encodes geometry information. Our proposed representation can efficiently encode the multi-frame multi-modality observations with a few hundred tokens and is compatible with most transformer-based architectures. To evaluate our method we have augmented Waymo Open Motion Dataset with camera embeddings. Experiments over Waymo Open Motion Dataset show that our approach leads to significant performance improvements over the state-of-the-art.

N:M sparsity has received increasing attention due to its remarkable performance and latency trade-off compared with structured and unstructured sparsity. However existing N:M sparsity methods do not differentiate the relative importance of weights among blocks and leave important weights underappreciated. Besides they directly apply N:M sparsity to the whole network which will cause severe information loss. Thus they are still sub-optimal. In this paper we propose an efficient and effective Multi-Axis Query methodology dubbed as MaxQ to rectify these problems. During the training MaxQ employs a dynamic approach to generate soft N:M masks considering the weight importance across multiple axes. This method enhances the weights with more importance and ensures more effective updates. Meanwhile a sparsity strategy that gradually increases the percentage of N:M weight blocks is applied which allows the network to heal from the pruning-induced damage progressively. During the runtime the N:M soft masks can be precomputed as constants and folded into weights without causing any distortion to the sparse pattern and incurring additional computational overhead. Comprehensive experiments demonstrate that MaxQ achieves consistent improvements across diverse CNN architectures in various computer vision tasks including image classification object detection and instance segmentation. For ResNet50 with 1:16 sparse pattern MaxQ can achieve 74.6% top-1 accuracy on ImageNet and improve by over 2.8% over the state-of-the-art. Codes and checkpoints are available at https://github.com/JingyangXiang/MaxQ.

Inspired by the success of general-purpose models in NLP recent studies attempt to unify different vision tasks in the same sequence format and employ autoregressive Transformers for sequence prediction. They apply uni-directional attention to capture sequential dependencies and generate task sequences recursively. However such autoregressive Transformers may not fit vision tasks well as vision task sequences usually lack the sequential dependencies typically observed in natural languages. In this work we design Masked AutoDecoder (MAD) an effective multi-task vision generalist. MAD consists of two core designs. First we develop a parallel decoding framework that introduces bi-directional attention to capture contextual dependencies comprehensively and decode vision task sequences in parallel. Second we design a masked sequence modeling approach that learns rich task contexts by masking and reconstructing task sequences. In this way MAD handles all the tasks by a single network branch and a simple cross-entropy loss with minimal task-specific designs. Extensive experiments demonstrate the great potential of MAD as a new paradigm for unifying various vision tasks. MAD achieves superior performance and inference efficiency compared to autoregressive counterparts while obtaining competitive accuracy with task-specific models. Code will be released at https://github.com/hanqiu-hq/MAD.

In Visual Question Answering (VQA) recognizing and localizing entities pose significant challenges. Pretrained vision-and-language models have addressed this problem by providing a text description as the answer. However in visual scenes with multiple entities textual descriptions struggle to distinguish the entities from the same category effectively. Consequently the VQA dataset is limited by the limitations of text description and cannot adequately cover scenarios involving multiple entities. To address this challenge we introduce a Mask for Align (Mask4Align) method which can determine the entity's position in the given image that best matches the user-input question. This method incorporates colored masks into the image enabling the VQA model to handle discrimination and localization challenges associated with multiple entities. To process an arbitrary number of similar entities Mask4Align is designed hierarchically to discern subtle differences achieving precise localization. Since Mask4Align directly utilizes pre-trained models it does not introduce additional training overhead. Extensive experiments conducted on both the gaze target prediction task dataset and our proposed multi-entity localization dataset showcase the superiority of Mask4Align.

Despite the emergence of successful NeRF inpainting methods built upon explicit RGB and depth 2D inpainting supervisions these methods are inherently constrained by the capabilities of their underlying 2D inpainters. This is due to two key reasons: (i) independently inpainting constituent images results in view-inconsistent imagery and (ii) 2D inpainters struggle to ensure high-quality geometry completion and alignment with inpainted RGB images. To overcome these limitations we propose a novel approach called MVIP-NeRF that harnesses the potential of diffusion priors for NeRF inpainting addressing both appearance and geometry aspects. MVIP-NeRF performs joint inpainting across multiple views to reach a consistent solution which is achieved via an iterative optimization process based on Score Distillation Sampling (SDS). Apart from recovering the rendered RGB images we also extract normal maps as a geometric representation and define a normal SDS loss that motivates accurate geometry inpainting and alignment with the appearance. Additionally we formulate a multi-view SDS score function to distill generative priors simultaneously from different view images ensuring consistent visual completion when dealing with large view variations. Our experimental results show better appearance and geometry recovery than previous NeRF inpainting methods.

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.

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

Multi-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.

Adapting models pre-trained on large-scale datasets to a variety of downstream tasks is a common strategy in deep learning. Consequently parameter-efficient fine-tuning methods have emerged as a promising way to adapt pre-trained models to different tasks while training only a minimal number of parameters. While most of these methods are designed for single-task adaptation parameter-efficient training in Multi-Task Learning (MTL) architectures is still unexplored. In this paper we introduce MTLoRA a novel framework for parameter-efficient training of MTL models. MTLoRA employs Task-Agnostic and Task-Specific Low-Rank Adaptation modules which effectively disentangle the parameter space in MTL fine-tuning thereby enabling the model to adeptly handle both task specialization and interaction within MTL contexts. We applied MTLoRA to hierarchical-transformer-based MTL architectures adapting them to multiple downstream dense prediction tasks. Our extensive experiments on the PASCAL dataset show that MTLoRA achieves higher accuracy on downstream tasks compared to fully fine-tuning the MTL model while reducing the number of trainable parameters by 3.6x. Furthermore MTLoRA establishes a Pareto-optimal trade-off between the number of trainable parameters and the accuracy of the downstream tasks outperforming current state-of-the-art parameter-efficient training methods in both accuracy and efficiency.

Deep neural networks have shown exemplary performance on semantic scene understanding tasks on source domains but due to the absence of style diversity during training enhancing performance on unseen target domains using only single source domain data remains a challenging task. Generation of simulated data is a feasible alternative to retrieving large style-diverse real-world datasets as it is a cumbersome and budget-intensive process. However the large domain-specific inconsistencies between simulated and real-world data pose a significant generalization challenge in semantic segmentation. In this work to alleviate this problem we propose a novel Multi-Resolution Feature Perturbation (MRFP) technique to randomize domain-specific fine-grained features and perturb style of coarse features. Our experimental results on various urban-scene segmentation datasets clearly indicate that along with the perturbation of style-information perturbation of fine-feature components is paramount to learn domain invariant robust feature maps for semantic segmentation models. MRFP is a simple and computationally efficient transferable module with no additional learnable parameters or objective functions that helps state-of-the-art deep neural networks to learn robust domain invariant features for simulation-to-real semantic segmentation. Code is available at https://github.com/airl-iisc/MRFP.

It is a long-lasting goal to design an embodied system that can solve long-horizon open-world tasks in human-like ways. However existing approaches usually struggle with compound difficulties caused by the logic-aware decomposition and context-aware execution of these tasks. To this end we introduce MP5 an open-ended multimodal embodied system built upon the challenging Minecraft simulator which can decompose feasible sub-objectives design sophisticated situation-aware plans and perform embodied action control with frequent communication with a goal-conditioned active perception scheme. Specifically MP5 is developed on top of recent advances in Multimodal Large Language Models (MLLMs) and the system is modulated into functional modules that can be scheduled and collaborated to ultimately solve pre-defined context- and process-dependent tasks. Extensive experiments prove that MP5 can achieve a 22% success rate on difficult process-dependent tasks and a 91% success rate on tasks that heavily depend on the context. Moreover MP5 exhibits a remarkable ability to address many open-ended tasks that are entirely novel.

Different from a unimodal model whose input is from a single modality the input (called multi-modal input) of a multi-modal model is from multiple modalities such as image 3D points audio text etc. Similar to unimodal models many existing studies show that a multi-modal model is also vulnerable to adversarial perturbation where an attacker could add small perturbation to all modalities of a multi-modal input such that the multi-modal model makes incorrect predictions for it. Existing certified defenses are mostly designed for unimodal models which achieve sub-optimal certified robustness guarantees when extended to multi-modal models as shown in our experimental results. In our work we propose MMCert the first certified defense against adversarial attacks to a multi-modal model. We derive a lower bound on the performance of our MMCert under arbitrary adversarial attacks with bounded perturbations to both modalities (e.g. in the context of auto-driving we bound the number of changed pixels in both RGB image and depth image). We evaluate our MMCert using two benchmark datasets: one for the multi-modal road segmentation task and the other for the multi-modal emotion recognition task. Moreover we compare our MMCert with a state-of-the-art certified defense extended from unimodal models. Our experimental results show that our MMCert outperforms the baseline.

Pre-trained Vision-Language Models (VLMs) have served as excellent foundation models for transfer learning in diverse downstream tasks. However tuning VLMs for few-shot generalization tasks faces a discrimination -- generalization dilemma i.e. general knowledge should be preserved and task-specific knowledge should be fine-tuned. How to precisely identify these two types of representations remains a challenge. In this paper we propose a Multi-Modal Adapter (MMA) for VLMs to improve the alignment between representations from text and vision branches. MMA aggregates features from different branches into a shared feature space so that gradients can be communicated across branches. To determine how to incorporate MMA we systematically analyze the discriminability and generalizability of features across diverse datasets in both the vision and language branches and find that (1) higher layers contain discriminable dataset-specific knowledge while lower layers contain more generalizable knowledge and (2) language features are more discriminable than visual features and there are large semantic gaps between the features of the two modalities especially in the lower layers. Therefore we only incorporate MMA to a few higher layers of transformers to achieve an optimal balance between discrimination and generalization. We evaluate the effectiveness of our approach on three tasks: generalization to novel classes novel target datasets and domain generalization. Compared to many state-of-the-art methods our MMA achieves leading performance in all evaluations. Code is at https://github.com/ZjjConan/Multi-Modal-Adapter

Recent advancements in post-hoc and inherently interpretable methods have markedly enhanced the explanations of black box classifier models. These methods operate either through post-analysis or by integrating concept learning during model training. Although being effective in bridging the semantic gap between a model's latent space and human interpretation these explanation methods only partially reveal the model's decision-making process. The outcome is typically limited to high-level semantics derived from the last feature map. We argue that the explanations lacking insights into the decision processes at low and mid-level features are neither fully faithful nor useful. Addressing this gap we introduce the Multi-Level Concept Prototypes Classifier (MCPNet) an inherently interpretable model. MCPNet autonomously learns meaningful concept prototypes across multiple feature map levels using Centered Kernel Alignment (CKA) loss and an energy-based weighted PCA mechanism and it does so without reliance on predefined concept labels. Further we propose a novel classifier paradigm that learns and aligns multi-level concept prototype distributions for classification purposes via Class-aware Concept Distribution (CCD) loss. Our experiments reveal that our proposed MCPNet while being adaptable to various model architectures offers comprehensive multi-level explanations while maintaining classification accuracy. Additionally its concept distribution-based classification approach shows improved generalization capabilities in few-shot classification scenarios.

We present M&M VTO-a mix and match virtual try-on method that takes as input multiple garment images text description for garment layout and an image of a person. An example input includes: an image of a shirt an image of a pair of pants "rolled sleeves shirt tucked in" and an image of a person. The output is a visualization of how those garments (in the desired layout) would look like on the given person. Key contributions of our method are: 1) a single stage diffusion based model with no super resolution cascading that allows to mix and match multiple garments at 1024x512 resolution preserving and warping intricate garment details 2) architecture design (VTO UNet Diffusion Transformer) to disentangle denoising from person specific features allowing for a highly effective finetuning strategy for identity preservation (6MB model per individual vs 4GB achieved with e.g. dreambooth finetuning); solving a common identity loss problem in current virtual try-on methods 3) layout control for multiple garments via text inputs finetuned over PaLI-3 for virtual try-on task. Experimental results indicate that M&M VTO achieves state-of-the-art performance both qualitatively and quantitatively as well as opens up new opportunities for virtual try-on via language-guided and multi-garment try-on.

In recent years anchor-based methods have achieved promising progress in multi-view clustering. The performances of these methods are significantly affected by the quality of the anchors. However the anchors generated by previous works solely rely on single-view information ignoring the correlation among different views. In particular we observe that similar patterns are more likely to exist between similar views so such correlation information can be leveraged to enhance the quality of the anchors which is also omitted. To this end we propose a novel plug-and-play anchor enhancement strategy through view correlation for multi-view clustering. Specifically we construct a view graph based on aligned initial anchor graphs to explore inter-view correlations. By learning from view correlation we enhance the anchors of the current view using the relationships between anchors and samples on neighboring views thereby narrowing the spatial distribution of anchors on similar views. Experimental results on seven datasets demonstrate the superiority of our proposed method over other existing methods. Furthermore extensive comparative experiments validate the effectiveness of the proposed anchor enhancement module when applied to various anchor-based methods.

Recently many approaches directly operate on point clouds for different tasks. These approaches become more computation and storage demanding when point cloud size is large. To reduce the required computation and storage one possible solution is to sample the point cloud. In this paper we propose the first Learnable Task-Agnostic Point Cloud Sampling (LTA-PCS) framework. Existing task-agnostic point cloud sampling strategy (e.g. FPS) does not consider semantic information of point clouds causing degraded performance on downstream tasks. While learning-based point cloud sampling methods consider semantic information they are task-specific and require task-oriented ground-truth annotations. So they cannot generalize well on different downstream tasks. Our LTA-PCS achieves task-agnostic point cloud sampling without requiring task-oriented labels in which both the geometric and semantic information of points is considered in sampling. Extensive experiments on multiple downstream tasks demonstrate the effectiveness of our LTA-PCS.