LiDAR point cloud registration is a fundamental problem in 3D computer vision. Recent learning-based methods have significantly improved the robustness and accuracy of LiDAR point cloud registration, while most of these methods are designed for global registration. In this paper, we focus on the post-refinement problem of LiDAR point cloud registration, which has been largely overlooked in previous learning-based approaches. To address the correspondence error between LiDAR point clouds, we formulate the transformation refinement problem as a correspondence optimization problem and propose DCR, a diffusion-based correspondence refinement model. DCR is built upon denoising diffusion models and recovers accurate correspondences from noisy initial correspondences estimated by arbitrary global registration methods. To achieve precise correspondence refinement, we employ a residual-based modeling scheme to constrain the output distribution and design a conditional generation paradigm to control the randomness of diffusion models. We combine DCR with both learning-based and traditional global registration methods and perform experiments on three large-scale outdoor LiDAR point cloud datasets to verify the performance. Extensive experimental results demonstrate DCR’s versatility and effectiveness in improving the accuracy of LiDAR point cloud registration.

Collaborative perception seeks to mitigate the limitations of single-vehicle perception, such as occlusions, by facilitating communication and information sharing among connected vehicles. However, most existing works assume a homogeneous scenario where all vehicles share identity sensor types and perception model architectures. In contrast, real-world systems often involve heterogeneous agents with diverse sensor configurations and independently developed models. In such settings, directly exchanging features without proper alignment can significantly degrade performance and hinder effective collaboration. While some methods have been proposed to address heterogeneity, they typically require retraining or access to internal model parameters, making them impractical for scalable deployment. To address these challenges, we propose DiffAlign, a plug-and-play adapter that enables feature alignment across heterogeneous agents in a training-free and model-agnostic manner. DiffAlign treats received BEV features as noisy latent representations and progressively refines them through a pretrained diffusion process. This alignment strategy does not require access to model internals or any retraining, which makes it both scalable and privacy-preserving while supporting diverse sensor modalities and perception backbones. Extensive experiments on simulated OPV2V and real-world V2V4Real datasets demonstrate that DiffAlign consistently improves detection performance in heterogeneous settings, improving CoBEVT by 132.01% and 91.95%, respectively. Our method provides a practical path toward scalable, generalizable, and deployment-ready collaborative perception.

Collaborative perception enhances single-vehicle perception by integrating sensory data from multiple connected vehicles. However, existing studies often assume ideal conditions, overlooking resilience to real-world challenges, such as adverse weather and sensor malfunctions, which is critical for safe deployment. To address this gap, we introduce RCP-Bench, the first comprehensive benchmark designed to evaluate the robustness of collaborative detection models under a wide range of real-world corruptions. RCP-Bench includes three new datasets (i.e., OPV2V-C, V2XSet-C, and DAIR-V2X-C) that simulate six collaborative cases and 14 types of camera corruption resulting from external environmental factors, sensor failures, and temporal misalignments. Extensive experiments on 10 leading collaborative perception models reveal that, while these models perform well under ideal conditions, they are significantly affected by corruptions. To improve robustness, we propose two simple yet effective strategies, RCP-Drop and RCP-Mix, based on training regularization and feature augmentation. Additionally, we identify several critical factors influencing robustness, such as backbone architecture, camera number, feature fusion methods, and the number of connected vehicles. We hope that RCP-Bench, along with these strategies and insights, will stimulate future research toward developing more robust collaborative perception models. Our benchmark toolkit is available at https://github.com/LuckyDush/RCP-Bench.

Collaborative perception is dedicated to tackling the constraints of single-agent perception, such as occlusions, based on the multiple agents' multi-view sensor inputs. However, most existing works assume an ideal condition that all agents' multi-view cameras are continuously available. In reality, cameras may be highly noisy, obscured or even failed during the collaboration. In this work, we introduce a new robust camera-insensitivity problem: how to overcome the issues caused by the failed camera perspectives, while stabilizing high collaborative performance with low calibration cost? To address above problems, we propose RCDN, a Robust Camera-insensitivity collaborative perception with a novel Dynamic feature-based 3D Neural modeling mechanism. The key intuition of RCDN is to construct collaborative neural rendering field representations to recover failed perceptual messages sent by multiple agents. To better model collaborative neural rendering field, RCDN first establishes a geometry BEV feature based time-invariant static field with other agents via fast hash grid modeling. Based on the static background field, the proposed time-varying dynamic field can model corresponding motion vector for foregrounds with appropriate positions. To validate RCDN, we create OPV2V-N, a new large-scale dataset with manual labelling under different camera failed scenarios. Extensive experiments conducted on OPV2V-N show that RCDN can be ported to other baselines and improve their robustness in extreme camera-insensitivity setting. Our code and datasets will be available soon.

Multi-agent collaborative perception (MCP) has recently attracted much attention. It includes three key processes: communication for sharing, collaboration for integration, and reconstruction for different downstream tasks. Existing methods pursue designing the collaboration process alone, ignoring their intrinsic interactions and resulting in suboptimal performance. In contrast, we aim to propose a Unified Collaborative perception framework named UMC, optimizing the communication, collaboration, and reconstruction processes with the Multi-resolution technique. The communication introduces a novel trainable multi-resolution and selective-region (MRSR) mechanism, achieving higher quality and lower bandwidth. Then, a graph-based collaboration is proposed, conducting on each resolution to adapt the MRSR. Finally, the reconstruction integrates the multi-resolution collaborative features for downstream tasks. Since the general metric can not reflect the performance enhancement brought by MCP systematically, we introduce a brand-new evaluation metric that evaluates the MCP from different perspectives. To verify our algorithm, we conducted experiments on the V2X-Sim and OPV2V datasets. Our quantitative and qualitative experiments prove that the proposed UMC outperforms the state-of-the-art collaborative perception approaches.