Although Gaussian scene representation has achieved remarkable success in tracking and mapping, most existing methods are confined to single-agent systems. Current multi-agent solutions typically rely on centralized architectures, which struggle to account for communication bandwidth constraints. Furthermore, the inherent depth ambiguity of 3D Gaussian splatting poses notable challenges in maintaining geometric consistency. To address these challenges, we introduce CoMA-SLAM, the first distributed multi-agent Gaussian SLAM framework. By leveraging 2D Gaussian surfels and robust initialization strategy, CoMA-SLAM enhances tracking accuracy and geometry consistency. It efficiently manages communication bandwidth while dynamically scaling with the number of agents. Through the integration of intra- and inter-loop closure, distributed keyframe optimization and submap centric update, our framework ensures global consistency and robustly alignment. Synthetic and real-world experiments demonstrate that CoMA-SLAM outperforms state-of-the-art methods in pose accuracy, rendering fidelity, and geometric consistency while maintaining competitive efficiency across distributed multi-agent systems. Notably, by avoiding data transmission to a centralized server, our method reduces communication bandwidth by 99.8% compared to centralized approaches.

Energy optimization constitutes a paramount design consideration in the realm of embedded systems development since these devices are inherently constrained by finite battery resources. Designing and developing an effective energy-aware scheduling approach is a desirable work to provide excellent processing capability while keeping the energy consumption under control. Although previous approaches can obtain reasonable scheduling solutions for tasks with energy consumption constraints, they are computationally expensive and have deficiencies in effectiveness or efficiency due to unfair or inefficient energy pre-assignment strategies. In this article, we study the energy-aware workflow scheduling problem and present a three-stage list-based approach to minimize the schedule length of workflows in heterogeneous distributed embedded systems. First, the workflow applications and energy consumption of processors are modelled, and the energy-aware workflow scheduling problem is formulated as a non-linear mixed integer programming one with various dependency and energy constraints. Then, with an effective task prioritization strategy and a reasonable energy pre-assignment strategy, a three-stage list-based scheduling approach is proposed to schedule the tasks and minimize the schedule length of workflows. Experiments on randomly-generated and real-life workflows demonstrate that our proposed approach constantly outperforms the existing approaches and our algorithm can, respectively, reduce the normalized schedule length and the deviation ratio by 16.7% and 7.6% in average.

This paper presents a novel collaborative online dense mapping system for multiple Unmanned Aerial Vehicles (UAVs). The system confers two primary benefits: it facilitates simultaneous UAVs co-localization and real-time dense map reconstruction, and it recovers the metric scale even in GNSS-denied conditions. To achieve these advantages, Ultrawideband (UWB) measurements, monocular Visual Odometry (VO), and co-visibility observations are jointly employed to recover both relative positions and global UAV poses, thereby ensuring optimality at both local and global scales. In the proposed methodology, a two-stage optimization strategy is proposed to reduce optimization burden. Initially, relative Sim3 transformations among UAVs are swiftly estimated, with UWB measurements facilitating metric scale recovery in the absence of GNSS. Subsequently, a global pose optimization is performed to effectively mitigate cumulative drift. By integrating UWB, VO, and co-visibility data within this framework, both local geometric consistency and global pose accuracy are robustly maintained. Through comprehensive simulation and empirical real-world testing, we demonstrate that our system not only improves UAV positioning accuracy in challenging scenarios but also facilitates the high-quality, online integration of dense point clouds in large-scale areas. This research offers valuable contributions and practical techniques for precise, real-time map reconstruction using an autonomous UAV fleet, particularly in GNSS-denied environments.

In this paper, we introduce G2-Mapping, a novel method to comprehensively support online monocular, RGB-D, and LiDAR-Inertial-Visual systems, employing 3D gaussian points as scene representation. There are several issues when applying 3d gaussian splatting (3DGS) techniques to simultaneous localization and mapping (SLAM) 1) for monocular, the lack of depth information makes scene initialization difficult and large baseline positioning challenging; 2) differentiable rendering with respect to depth and pose has not been implemented in 3DGS, making it difficult to directly apply to the SLAM system; 3) strategy for updating the scene with incoming online frames is not present, which may lead to memory overflow. In order to overcome problems mentioned above, we formulate a mathematical derivation and propose a differentiable rendering approach that leverages both depth and color to optimize the scene and pose. We introduce a simplified odometry that provides a metric depth estimation for monocular and enhance the low-overlap scene availability. A scale consistency and uncertainty weighted optimization is further proposed to eliminates the impact of inaccurate depth prediction. Our proposed scene updating strategy effectively prevents rapid memory growth. Tracking and mapping are performed alternatively to achieve precise localization and synchronous high-fidelity map reconstruction. Extensive experiments demonstrate that our G2-Mapping surpasses feature-based SLAM in localization precision and exceeds state-of-the-art neural SLAM methods in the fidelity of view synthesis. Note to Practitioners—This paper is dedicated to tackling the efficiency challenges in multi-source SLAM and map reconstruction, aiming to generate pose and high-fidelity maps synchronously. We introduce G2-Mapping, a novel framework that leverages the power of 3D Gaussian points for scene representation, offering a universal solution for monocular, RGB-D, and LiDAR-Inertial-Visual systems. By developing a comprehensive differentiable renderer and presenting a strategy for dynamic scene updating, G2-Mapping significantly advances the state-of-the-art in localization precision and view synthesis fidelity. Although the approach is highly promising, it currently relies on the accuracy of depth prediction networks and requires further optimization for handling sparse LiDAR data. Future research will focus on enhancing these aspects, aiming to seamlessly integrate G2-Mapping into practical applications within robotics, autonomous vehicles, and augmented reality, where robust and efficient SLAM solutions are paramount.

Visual geolocalization is a cost-effective and scalable task that involves matching one or more query images, taken at some unknown location, to a set of geotagged reference images. Existing methods, devoted to semantic features representation, evolving towards robustness to a wide variety between query and reference, including illumination and viewpoint changes, as well as scale and seasonal variations. However, practical visual geolocalization approaches need to be robust in appearance changing and extreme viewpoint variation conditions, while providing accurate global location estimates. Therefore, inspired by curriculum design, human learn general knowledge first and then delve into professional expertise. We first recognize semantic scene and then measure geometric structure. Our approach, termedCurriculumLoc, involves a delicate design of multi-stage refinement pipeline and a novel keypoint detection and description with global semantic awareness and local geometric verification. We rerank candidates and solve a particular cross-domain perspective-n-point (PnP) problem based on these keypoints and corresponding descriptors, position refinement occurs incrementally. The extensive experimental results on our collected dataset,TerraTrackand a benchmark dataset,ALTO, demonstrate that our approach results in the aforementioned desirable characteristics of a practical visual geolocalization solution. Additionally, we achieve new high recall@1 scores of 62.6% and 94.5% on ALTO, with two different distances metrics, respectively. Dataset, code and trained models are publicly available on https://github.com/npupilab/CurriculumLoc.

Traditional change detectors are ill-equipped for incremental learning (IL). Existing IL methods address the problem of catastrophic forgetting by artificially adding categories and utilizing old labels for learning supervision. Current strategies for change detection (CD) are inadequate as they fail to address a crucial aspect of the task: the constant label space throughout each training step, causing label conflicts between background-class pixels (representing unchanged regions) and changed pixels, which can lead to knowledge confusion. In this work, we revisit classical IL methods and propose an effective framework that explicitly addresses this conflict. Furthermore, we design a hierarchical distillation to ensure adequate retention of the learned features. The proposed architecture and distillation method balance acquiring new knowledge and preserving old knowledge effectively. To address the absence of datasets for IL in CD, we design a multidomain CD dataset that encompasses three distinct environments. Our proposed method demonstrates a significant improvement in the performance of IL, as measured by$\Delta _{\text {IoU}}$and$\Delta _{\text {F1}}$. Extensive experiments on this dataset show that our performance is promising compared to state-of-the-art CD methods and incremental methods.

Summary Cloud computing has been widely adopted in practical applications due to its strong calculating ability and high parallel feature. Although cloud computing can achieve significant cost reduction and flexibility enhancement, it results in a serious task scheduling problem. As one of the key techniques for automate management of cloud resources, task scheduling plays an important role in improving system utilization and supporting load balancing. In this article, we focus on the scheduling problem of independent tasks in cloud environment with heterogeneous and distributed resources. First, with models of resources and tasks, we present an exact formulation based on linear programming to fully search solution space and produce optimal allocation schemes for tasks. Then, inspired from the differential evolution method, we propose a population‐based approach to allocate tasks to their suitable resources such that the total time cost would be minimized. Experiments with multi‐task sets are conducted to show the convergence and efficiency of the proposed approach.

Large-scale visual geolocation is a meaningful task that involves locating a query image by comparing it with images in a database and predicting the most similar image. However, the widely used training framework based on contrastive learning cannot fully utilize all data and is difficult to adapt to larger scales. At the same time, the traditional convolutional neural networks (CNNs) and vector of locally aggregated descriptors (VLADs) using aggregated features cannot fully reflect the relationship between the local features of the image. Therefore, a graph neural network (GNN) is designed as the feature extraction network, and then a training framework based on image classification is constructed. Specifically, a data grouping strategy and special loss function are designed for better training results. After training, we adopt an image retrieval strategy based on kNN for position. In addition, considering that existing datasets cannot be adapted to our requirements, two datasets are constructed for experiments, that one contains large-scale satellite images and the other fuses satellite and unmanned aerial vehicle (UAV) images. Results demonstrate that our method outperforms other common methods in both the datasets. The results demonstrate the effectiveness of our approach for UAV visual geolocation and provide ideas for future research in this field.

Inspired by simultaneous localization and mapping (SLAM) style workflow, this article presented an online sequential structure from motion (SfM) solution for high-frequency video and large baseline high-resolution aerial images with high efficiency and novel precision. First, as traditional SLAM systems are not good in processing low overlap images, based on our novel hierarchical feature matching paradigm with multihomography and BoW, we proposed a robust tracking method where the relative pose and its scale are estimated separately followed by a joint optimization by considering both perspective-n-point (PnP) and epipolar constraints. Second, to further optimize the camera poses for the sparse map and dense pointcloud reconstruction, we provided a graph-based optimization with reprojection and GPS constraints, which make the camera trajectory and map georeferenced. We also incrementally generated the dense point cloud in real time from keyframes after local mapping optimization. Finally, we use a publicly available aerial image dataset with sequences of different environments, to evaluate the effectiveness of the proposed method, meanwhile, the robust performance of our solution is demonstrated with applications of high-quality aerial images mosaic and digital surface model (DSM) reconstruction in real time. Compared with the state-of-the-art SLAM and traditional SfM methods, the presented system can output large-scale high-quality ortho-mosaic and DSM in real time with the low computational cost.

Unmanned aerial vehicles (UAVs) have been widely applied in civilian and military applications due to their high autonomy and strong adaptability. Although UAVs can achieve effective cost reduction and flexibility enhancement in the development of large-scale systems, they result in a serious path planning and task allocation problem. Coverage path planning, which tries to seek flight paths to cover all of regions of interest, is one of the key technologies in achieving autonomous driving of UAVs and difficult to obtain optimal solutions because of its NP-Hard computational complexity. In this paper, we study the coverage path planning problem of autonomous heterogeneous UAVs on a bounded number of regions. First, with models of separated regions and heterogeneous UAVs, we propose an exact formulation based on mixed integer linear programming to fully search the solution space and produce optimal flight paths for autonomous UAVs. Then, inspired from density-based clustering methods, we design an original clustering-based algorithm to classify regions into clusters and obtain approximate optimal point-to-point paths for UAVs such that coverage tasks would be carried out correctly and efficiently. Experiments with randomly generated regions are conducted to demonstrate the efficiency and effectiveness of the proposed approach.

For tree counting tasks, since traditional image processing methods require expensive feature engineering and are not end-to-end frameworks, this will cause additional noise and cannot be optimized overall, so this method has not been widely used in recent trends of tree counting application. Recently, many deep learning based approaches are designed for this task because of the powerful feature extracting ability. The representative way is bounding box based supervised method, but time-consuming annotations are indispensable for them. Moreover, these methods are difficult to overcome the occlusion or overlap. To solve this problem, we propose a weakly tree counting network (WTCNet) based on deep segmentation network with only point supervision. It can simultaneously complete tree counting with localization and output mask of each tree at the same time. We first adopt a novel feature extractor network (FENet) to get features of input images, and then an effective strategy is introduced to deal with different mask predictions. In the end, we propose a basic localization guidance accompany with rectification guidance to train the network. We create two different datasets and select an existing challenging plant dataset to evaluate our method on three different tasks. Experimental results show the good performance improvement of our method compared with other existing methods. Further study shows that our method has great potential to reduce human labor and provide effective ground-truth masks and the results show the superiority of our method over the advanced methods.

With the rapidly developing unmanned aerial vehicles, the requirements of generating maps efficiently and quickly are increasing. To realize online mapping, we develop a real-time dense mapping framework named DenseFusion which can incrementally generates dense geo-referenced 3D point cloud, digital orthophoto map (DOM) and digital surface model (DSM) from sequential aerial images with optional GPS information. The proposed method works in real-time on standard CPUs even for processing high resolution images. Based on the advanced monocular SLAM, our system first estimates appropriate camera poses and extracts effective keyframes, and next constructs virtual stereo-pair from consecutive frame to generate pruned dense 3D point clouds; then a novel realtime DSM fusion method is proposed which can incrementally process dense point cloud. Finally, a high efficiency visualization system is developed to adopt dynamic levels of detail (LoD) method, which makes it render dense point cloud and DSM smoothly. The performance of the proposed method is evaluated through qualitative and quantitative experiments. The results indicate that compared to traditional structure from motion based approaches, the presented framework is able to output both large-scale high-quality DOM and DSM in real-time with low computational cost.

SLAM technology has recently seen many successes and attracted the attention of high-technological companies. However, how to unify the interface of existing or emerging algorithms, and effectively perform benchmark about the speed, robustness and portability are still problems. In this paper, we propose a novel SLAM platform named GSLAM, which not only provides evaluation functionality, but also supplies useful toolkit for researchers to quickly develop their SLAM systems. Our core contribution is an universal, cross-platform and full open-source SLAM interface for both research and commercial usage, which is aimed to handle interactions with input dataset, SLAM implementation, visualization and applications in an unified framework. Through this platform, users can implement their own functions for better performance with plugin form and further boost the application to practical usage of the SLAM.

This paper presents an algorithm which can generate live digtial surface model (DSM) during the flight based on simultaneous localization and mapping (SLAM). We process the keyframe which is output by a monocular SLAM system to generate a local DSM, and fuse the local DSM to the global tiled DSM incrementally. During the local DSM generation, a local digital elevation model (DEM) is estimated by projecting the filtered 2D Delaunay mesh to a 3D mesh, and a local orthomosaic is obtained by projecting triangle image patches onto a 2D mesh. During the DSM fusion, both the local DEM and orthomosaic are split into tiles and fused to the global tiled DEM and orthomosaic respectively with multiband algorithm. Both the efficient DSM generation and fusion algorithms contribute to achieving a real-time reconstruction. Qualitative and quantitative experiments on a public aerial image dataset with different scenarios are performed to validate the effectiveness of the proposed method. Compared with traditional structure from motion (SfM) based approaches, the presented system is able to output both large-scale high-quality DEM and orthomosaic in real-time with low computational cost.

Heterogeneous multiprocessor platforms have been widely adopted as an efficient approach to providing high instruction throughput while keeping power and complexity under control. Although this approach can achieve improved performance for large-scale real-time systems, it results in a complex task scheduling problem. All tasks should be scheduled according to a proper strategy such that their deadlines will be met even in the worst case situations. In this work, we study the non-preemptive scheduling problem of periodic tasks with data dependency upon heterogeneous multiprocessor platforms. We first analyze the space, time and precedence constraints of tasks, and propose an exact formulation to determine the schedulability of tasks. Then, inspired from the Heterogeneous Earliest Finish Time (HEFT) algorithm, we present a list-based scheduling heuristic to schedule the jobs generated by the periodic tasks and minimize the jobs' finish time. The proposed approach is efficient and can help in guiding the design of heterogeneous multiprocessor systems.