Sampling locally, hypothesis globally: accurate 3D point cloud registration with a RANSAC variant

Self-supervised rigid transformation equivariance for accurate 3D point cloud registration

The 3D reconstruction and modeling of face, objects and surrounding environment etc., has gained significant attention from the research community in recent days. Availability of depth data from various active and passive sensors have accelerated the work in 3D domain. It finds various applications in robotics, Human Computer Interaction (HCI), medical analysis etc. The major challenge in this area is accurate and real time 3D pose estimation which forms the basis for alignment of multi-view point cloud data. Noise in the depth data due to sensor irregularities significantly affects the accuracy of pose estimation. The main idea of this paper is to compute 2D A-KAZE feature correspondence and map to 3D for obtaining more reliable 3D sparse points. The 2D-3D correspondence is used to estimate accurate pose by formulating a graph optimization problem. The experimental results of this approach is evaluated against well known Iterative Closest Point (ICP) and Singular Value Decomposition (SVD) methods for point cloud registration on face and object data obtained using stereo camera. The results shows that the algorithm is able to estimate the accurate pose with least alignment error as compared with ICP and SVD methods.

Three‐dimensional (3D) point cloud registration is a fundamental key issue in 3D reconstruction, 3D object recognition and augmented reality. In this study, the authors propose a novel local feature descriptor called local angle statistics histogram (LASH) for efficient 3D point cloud registration. LASH forms a description of local shape geometries by encoding their properties on angles between the normal vector of the point and the vector formed by the point and other points in its local neighbourhood. In addition, they propose a 3D point cloud registration algorithm based on LASH. The registration algorithm firstly detects triangle matching points with consistent similarity ratios, and then aggregates each pair of triangular matching points into a set of matching points. They can use these matching sets to calculate multiple transformations between two point clouds. Finally, they use the error function to identify the best transformation and to achieve coarse alignment of the two point clouds. Experiments and comparisons with other global algorithms demonstrate that the proposed approach can be applied to register point clouds with considerable or limited overlaps and is robust to noise.

An automatic 3D point cloud registration method based on regional curvature maps

RCFI-Net: A reliable correspondences evaluation and feature interaction network for fast and accurate point cloud registration

For 3D point cloud registration, how to improve the local feature correlation of two point clouds is a challenging problem. In this paper, we propose a cascaded mutual information attention registration network. The network improves the accuracy of point cloud registration by stacking residual structure and using lateral connection.

This paper presents a patch-based approach for pose estimation from single images using a kernelized density voting scheme. We introduce a boosting-like algorithm that models the density using a mixture of weighted 'weak' estimators. The 'weak' density estimators and corresponding weights are learned iteratively from a training set, providing an efficient method for feature selection. Given a query image, voting is performed by reference patches similar in appearance to query image patches. Locality in the voting scheme allows us to handle occlusions and reduces the size of the training set required to cover the space of possible poses and appearance. Finally, the pose is estimated as the dominant mode in the density. Multimodality can be handled by looking at multiple dominant modes. Experiments carried out on face and articulated body pose databases show that our patch-based pose estimation algorithm generalizes well to unseen examples, is robust to occlusions and provides accurate pose estimation.

For robot-assisted assembly of complex optical systems, the alignment is facilitated by an accurate pose estimation of its components. However, wavefront-based pose estimation is typically ill-conditioned due to the inherent geometry of conventional industrially manufactured optical components. Therefore, we propose a novel approach in this paper to increase wavefront-based pose estimation accuracy via the design of freeform optics. For this purpose, an optimization problem is derived that parameterizes the component's surfaces by a predetermined freeform surface model. To show the efficacy of our approach, we provide simulation results to compare the pose estimation accuracy for a variety of optical designs. As an application example for the resulting improved pose estimation, a hand-eye calibration of a wavefront sensor is performed. This calibration originates from the field of robotics and represents the identification of a sensor coordinate system with respect to a global reference frame. For quantitative evaluation, the calibrating results are first presented with the aid of simulation data. Finally, the practical feasibility is demonstrated using a conventional industrial robot and additively manufactured freeform lenses.

The 3D laser scanning technology has been widely adopted in the field of workshop automatic assembly. Among them, the point cloud registration is a crucial part of the 3D data processing. Among the 3D data processing steps, point cloud registration is an important one. However, existing 3D point cloud registration methods have issues such as mismatching of feature point pairs, long registration time, and poor registration accuracy. In this paper, an LM-NDT point cloud registration algorithm based on 3D shape context feature (3DSC) is proposed.Firstly, the key points of the 3D point cloud are extracted through the intrinsic shape signature (ISS) to enhance the registration efficiency. Then, the features of the key points are described by the 3D shape context feature. According to the feature points, the error pair is processed using the median distance method, and the initial transformation matrix is calculated through SVD decomposition. Finally, the alignment is accomplished by the LM-NDT algorithm. Compared with the NDT algorithm, the proposed algorithm is more accurate and robust when the initial pose transformation is more significant. The test results demonstrate that the accuracy of the algorithm in the shoe and sole can reach 0.019cm, which remarkably improves the registration efficiency of the traditional SAC-IA and LM-NDT algorithms and has certain engineering application value.

In recent years, due to the wide application of 3D vision in the fields of autonomous driving, robot navigation, and the protection of cultural heritage, 3D point cloud registration has received much attention. However, most current methods are time-consuming and are very sensitive to noises and outliers, resulting in low registration accuracy. Therefore, we propose a two-stage framework based on graph neural network and attention—TSGANet, which is effective in registering low-overlapping point cloud pairs and is robust to variable noises as well as outliers. Our method decomposes rigid transformation estimation into two stages: global estimation and fine-tuning. At the global estimation stage, multilayer perceptrons are employed to estimate a seven-dimensional vector representing rigid transformation directly from the fusion of two initial point cloud features. For the fine-tuning stage, we extract contextual information through an attentional graph neural network consisting of attention and feature-enhancing modules. A mismatch-suppression mechanism is also proposed and applied to keep our method robust to partially visible data with noises and outliers. Experiments show that our method yields a state-of-the-art performance on the ModelNet40 dataset.

In the context of new power systems, there is a growing demand for digital and intelligent modeling of power equipment. Recent advances in 3D point cloud registration (PCR) have significantly facilitated the development of digital twin models for power equipment. Nevertheless, automated 3D modeling of power transformers (PT) still faces substantial challenges, primarily due to the lack of high-quality 3D datasets, the absence of dedicated preprocessing methods, and the limited adaptability of existing feature extractors to complex PT morphologies. To address these challenges, this paper proposes Morpheus, a morphology-aware deep registration network for 3D PT digital modeling. We first construct TR3D, a dataset comprising 420 transformer models across approximately 50 categories. Statistical analysis shows that TR3D contains significantly more edges than general 3D datasets. Building on this observation, we design a salient point sampling (SPS) to preserve fine-grained geometric details, and propose a multi-scale feature extractor (MSFE) to enhance feature representation. Finally, a graph matching method is employed to solve the Euclidean transform. Experimental results on PT data demonstrate that compared with the baseline method, Morpheus's comprehensive registration accuracy is improved by 61.13%, and it has the potential to be used for high-precision digital twin construction and automated modeling in the power sector. Project page: <uri xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">https://github.com/pupupuOUO/TR3D</uri>.

The present work proposes a new method Reg3DFacePtCd for registration of point clouds. The key contribution of the present method is that an unknown face in 3D point cloud form is given to the system and is registered to the already existing known 3D face point clouds using a fast 3D face registration method. The novelty of the present technique is that at first the alignment and registration parameters are found out by initially registering eight key points of the unknown source model to that of the known model. Next, the rest of the point clouds of the unknown model are registered to that of the known model using the same parameters found as above. The main method used for alignment is iterative closest point (ICP) using point-based technique followed by registration in the least squares sense. Mainly there are two significant contributions. Firstly, we have developed a new mathematical model facial landmark point based model across poses to obtain the target or the known model to which all the unknown models will be registered. Secondly, a novel way to accelerate point cloud matching by reducing the number of points has been proposed. Using a small number of points necessarily would speed up the registration process but may inculcate errors. So, to determine the registration quality of the fundamental eight key points on which the entire registration process is based, a new robust metric namely ICV (ICP certainty vector) consisting of several key components have been used. Finally, we have addressed several important face registration issues like pre-processing, convergence and quality of registration of the entire facial point cloud based on the eight key points. Extensive experimentation on Frav3D, GavabDB, and the Bosphorus databases on a high-performance computing environment show the novelty and robustness of the method.

Marker-based 3D motion capture systems, widely used for gait analysis, are accurate but have disadvantages such as cost and accessibility. Whereas markerless pose estimation has emerged as a convenient and cost-effective alternative for gait analysis, challenges remain in achieving optimal accuracy. Given the limited research on the effects of camera location and orientation on data collection accuracy, this study investigates how camera placement affects gait assessment accuracy utilizing five smartphones. This study aimed to explore the differences in data collection accuracy between marker-based systems and pose estimation, as well as to assess the impact of camera location and orientation on accuracy in pose estimation. The results showed that the differences in joint angles between pose estimation and marker-based systems are below 5°, an acceptable level for gait analysis, with a strong correlation between the two datasets supporting the effectiveness of pose estimation in gait analysis. In addition, hip and knee angles were accurately measured at the front diagonal of the subject and ankle angle at the lateral side. This research highlights the significance of careful camera placement for reliable gait analysis using pose estimation, serving as a concise reference to guide future efforts in enhancing the quantitative accuracy of gait analysis.

Joint object recognition and pose estimation using multiple-anchor triplet learning of canonical plane

We propose and demonstrate an efficient pose estimation method, specifically small tilt angle variation, for visual servo control system design using a monocular camera, eliminating the need for iterative computations. This paper addresses the challenges associated with accurately estimating the relative pose between a chaser, equipped with a monocular camera, and a target that provides visual cues, particularly in scenarios where the captured image shows only minimal variations in the target's tilt angle. Traditional approaches often rely on direct feedback methods from image data or designs for pose estimation and control separately, necessitating computationally expensive iterations for pose estimation or complex implementation of visual servoing. To address these challenges, we adopt an extended Kalman filter, known as a robust nonlinear observer, and propose a non‐iterative approach that integrates motion dynamics models and control inputs into pose estimation from image data. This approach enables efficient integration of pose estimation and control solely relying on a monocular camera, reducing computational costs and improving robustness. Experimental validation using the ball‐and‐plate system demonstrates the effectiveness of our proposed method. In our setup, the camera is deliberately positioned directly above the pose estimation target, creating a scenario with minimal image variation in the tilt angle. Despite this condition, our approach achieves efficient and accurate pose estimation, demonstrating its feasibility for high‐speed pose estimation and control without iterative computations.