LiDAR-Inertial simultaneous localization and mapping (LI-SLAM) plays a crucial role in various applications such as robot localization and low-cost 3D mapping. However, factors including inaccurate motion distortion e...
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LiDAR-Inertial simultaneous localization and mapping (LI-SLAM) plays a crucial role in various applications such as robot localization and low-cost 3D mapping. However, factors including inaccurate motion distortion estimation and posegraph constraints, and frequent LiDAR feature degeneracy present significant challenges for existing LI-SLAM methods. To address these issues, we propose DALI-SLAM, an accurate and robust LI-SLAM that consists of degeneracy-aware LiDAR-inertial odometry (DA-LIO) with a dual spline-based motion distortion correction (DS-MDC) module, and multi-constraint pose graph optimization (MC-PGO). Considering the cumulative errors of micro-electromechanical systems (MEMS) inertial measurement unit (IMU) integration, two continuous-time trajectories in the sliding window are fitted to update the discrete IMU poses for accurate motion distortion correction. In the LiDAR-inertial fusion stage, LiDAR feature degeneracy is detected by analyzing the Jacobian matrix and a remapping strategy is introduced into the updating of error state Kalman Filter (ESKF) to mitigate the influence of degeneracy. Furthermore, in the back-end optimization stage, three types of submap constraints are accurately built with dedicated strategy through a robust variant of the iterative closest point (ICP) method. The proposed method is comprehensively validated using data collected from a helmet-based laser scanning system (HLS) in representative indoor and outdoor environments. Experiment results demonstrate that the proposed method outperforms the SOTA methods on the test data. Specifically, the proposed DS-MDC module reduces trajectory root mean square errors (RMSEs) by 7.9 %, 5.8 %, and 3.1 %, while the degeneracy-aware update strategy achieves additional reductions of 43.3 %, 17.7%, and 4.9 %, respectively, across three typical sequences compared to existing methods, thereby effectively improving trajectory accuracy. Furthermore, the results of DA-LIO demonstrate a maxi
In this study, we propose a novel approach to graduated non-convexity (GNC) and demonstrate its efficacy through its application in robust pose graph optimization, a key component in SLAM backends. Traditional GNC met...
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In this study, we propose a novel approach to graduated non-convexity (GNC) and demonstrate its efficacy through its application in robust pose graph optimization, a key component in SLAM backends. Traditional GNC methods rely on heuristic methods for GNC schedule, updating control parameter mu for escalating the non-convexity. However, our approach leverages the properties of convex functions and convex optimization to identify the boundary points beyond which convexity is not guaranteed, thereby eliminating redundant optimization steps in existing methodologies and enhancing both speed and robustness. We demonstrate that our method outperforms the state-of-the-art method in terms of speed and accuracy when used for robust back-end pose graph optimization via GNC. Our work builds upon and enhances the open-source riSAM framework. Our implementation can be accessed from: https://***/SNU-DLLAB/EGNC-PGO.
We consider the problem of distributed pose graph optimization (PGO) that has important applications in multirobot simultaneous localization and mapping (SLAM). We propose the majorization minimization (MM) method for...
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We consider the problem of distributed pose graph optimization (PGO) that has important applications in multirobot simultaneous localization and mapping (SLAM). We propose the majorization minimization (MM) method for distributed PGO ( MM-PGO ) that applies to a broad class of robust loss kernels. The MM--PGO method is guaranteed to converge to first-order critical points under mild conditions. Furthermore, noting that the MM-PGO method is reminiscent of proximal methods, we leverage Nesterov's method and adopt adaptive restarts to accelerate convergence. The resulting accelerated MM methods for distributed PGO-both with a master node in the network ( AMM-PGO(& lowast;) ) and without ( AMM-PGO(#) )-have faster convergence in contrast to the MM--PGO method without sacrificing theoretical guarantees. In particular, the AMM-PGO(#) method, which needs no master node and is fully decentralized, features a novel adaptive restart scheme and has a rate of convergence comparable to that of the AMM-PGO(& lowast;)method using a master node to aggregate information from all the nodes. The efficacy of this work is validated through extensive applications to 2-D and 3-D SLAM benchmark datasets and comprehensive comparisons against existing state-of-the-art methods, indicating that our MM methods converge faster and result in better solutions to distributed PGO.
This paper explores the potential of 5G new radio (NR) Time-of-Arrival (TOA) data for indoor drone localization under different scenarios and conditions when fused with inertial measurement unit (IMU) data. Our approa...
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pose graph optimization helps reduce drift accumulated in pure odometry of visual simultaneous localization and mapping (SLAM) systems by solving a nonlinear least square problem, including both sequential constraints...
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pose graph optimization helps reduce drift accumulated in pure odometry of visual simultaneous localization and mapping (SLAM) systems by solving a nonlinear least square problem, including both sequential constraints and loop-closing constraints. However, the covariances of all constraints are set to constant matrices or by manual setting. In this paper, we propose a novel approach to approximate covariances of constraints in pose graph optimization to better represent the true uncertainty of the underlying visual-inertial navigation system (VINS) that fuses inertial measurements and visual observations. Specifically, for sequential constraints, we propose to utilize nonlinear factor recovery to optimally extract covariance matrices from the accumulated visual-inertial odometry (VIO). For loop-closing constraints, we propose a dynamic scale estimation method to approximate the scales of the information matrices. To evaluate the effectiveness and robustness of the proposed method, we conduct extensive experiments on public and self-collected datasets in various environments. Results show that our proposed method achieves higher accuracy compared with naively-formulated pose graph optimization adopted by several state-of-the-art visual-inertial navigation systems.
In this study, we propose a novel methodology for Graduated Non-Convexity (GNC) and validate its effectiveness through its application in robust pose graph optimization, which is a critical element in SLAM (Simultaneo...
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ISBN:
(纸本)9798331517939;9788993215380
In this study, we propose a novel methodology for Graduated Non-Convexity (GNC) and validate its effectiveness through its application in robust pose graph optimization, which is a critical element in SLAM (Simultaneous Localization and Mapping) backends. Conventional GNC techniques typically depend on heuristic strategies for determining the GNC schedule, specifically in the adjustment of the control parameter mu to increase non-convexity. In contrast, our approach utilizes the characteristics of convex functions and convex optimization to ascertain the boundary points where convexity can no longer be assured. This advancement allows for the elimination of superfluous optimization iterations present in traditional methods, thereby improving both the efficiency and robustness of the process. We provide evidence that our method surpasses the current leading techniques in terms of both speed and accuracy when applied to robust back-end pose graph optimization utilizing GNC. Furthermore, our work builds upon and enhances the open-source riSAM framework. The code is available at: https://***/SNU-DLLAB/EGNC-PGO.
The quality of sonar seabed mapping performed using autonomous underwater vehicles depends on the accuracy of the vehicle trajectory estimation. To reduce the accumulated pose estimation errors from dead reckoning, ba...
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The quality of sonar seabed mapping performed using autonomous underwater vehicles depends on the accuracy of the vehicle trajectory estimation. To reduce the accumulated pose estimation errors from dead reckoning, bathymetry observations from sonar sensors are often exploited within the framework of pose graph optimization, while the submaps of the seafloor are used to add loop-closure constraints to the posegraph by iterative closest point. However, matching with the submaps suffers from local minima because the seafloor is mostly flat and featureless. To resolve this issue, we regularized the sub-maps to enhance the spatial variations in the vertical direction;thus, we realized improved matching accuracy. Given these constraints, the posegraph can be optimized in real time and provide a corrected trajectory. The performance of the proposed method is validated through experiments using a surface vessel where the same navigation and sonar systems as used in the underwater vehicles are installed, in addition to a GPS receiver for ground truth acquisition.
Multiple roadside cameras sense and localize autonomous vehicles for Automated Valet Parking. The accurate multi-camera registration into a shared coordinate system is of great importance. Owing to the sparse and dist...
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As an essential core of structure from motion, full optimization and pose graph optimization are widely used in most of state-of-the-art 3D reconstruction systems, to estimate the motion trajectory of camera during sc...
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As an essential core of structure from motion, full optimization and pose graph optimization are widely used in most of state-of-the-art 3D reconstruction systems, to estimate the motion trajectory of camera during scanning. Comparing to full optimization, the pose graph optimization has the advantages of low computational complexity and fast convergence, while the practical accuracy of pose graph optimization in applications is intrinsically limited by simple loss function independent of points in scene. In this paper, we proposed a point-dependent pose graph optimization (PDPGO) to address this problem and take it as core to construct a 3D high-precision reconstruction system. In our pipeline, we first construct a hierarchical posegraph by aligning the input frame to its overlapping frames searched by a spatial hashing scheme, which reduces the computational complexity of pairwise alignment. We then derive a loss function of PDPGO from global geometry loss, which improves the accuracy of previous methods. Our system is validated on public benchmarks, and experimental results demonstrate the competing performance against the state-of-the-art systems. And the average reconstruction accuracy in all scenes of ICL-NUIM is up to 0.9 cm.
Satellite signals are easily lost in urban areas, which causes difficulty in vehicles being located with high precision. Visual odometry has been increasingly applied in navigation systems to solve this problem. Howev...
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Satellite signals are easily lost in urban areas, which causes difficulty in vehicles being located with high precision. Visual odometry has been increasingly applied in navigation systems to solve this problem. However, visual odometry relies on dead-reckoning technology, where a slight positioning error can accumulate over time, resulting in a catastrophic positioning error. Thus, this paper proposes a road-network-map-assisted vehicle positioning method based on the theory of pose graph optimization. This method takes the dead-reckoning result of visual odometry as the input and introduces constraints from the point-line form road network map to suppress the accumulated error and improve vehicle positioning accuracy. We design an optimization and prediction model, and the original trajectory of visual odometry is optimized to obtain the corrected trajectory by introducing constraints from map correction points. The vehicle positioning result at the next moment is predicted based on the latest output of the visual odometry and corrected trajectory. The experiments carried out on the KITTI and campus datasets demonstrate the superiority of the proposed method, which can provide stable and accurate vehicle position estimation in real-time, and has higher positioning accuracy than similar map-assisted methods.
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