scholarly journals An Accurate Linear Method for 3D Line Reconstruction for Binocular or Multiple View Stereo Vision

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 658
Author(s):  
Lijun Zhong ◽  
Junyou Qin ◽  
Xia Yang ◽  
Xiaohu Zhang ◽  
Yang Shang ◽  
...  
Keyword(s):  
Stereo Vision ◽  
Linear Method ◽  
Accurate Method ◽  
Multiple Camera ◽  
Multiple View ◽  
Camera Systems ◽  
Lower Accuracy ◽  
Simulation Results ◽  
Intersection Method

For the problem of 3D line reconstruction in binocular or multiple view stereo vision, when there are no corresponding points on the line, the method called Direction-then-Point (DtP) can be used, and if there are two pairs of corresponding points on the line, the method called Two Points 3D coordinates (TPS) can be used. However, when there is only one pair of corresponding points on the line, can we get the better accuracy than DtP for 3D line reconstruction? In this paper, a linear and more accurate method called Point-then-Direction (PtD) is proposed. First, we used the intersection method to obtain the 3D point’s coordinate from its corresponding image points. Then, we used this point as a position on the line to calculate the direction of the line by minimizing the image angle residual. PtD is also suitable for multiple camera systems. The simulation results demonstrate that PtD increases the accuracy of both the direction and the position of the 3D line compared to DtP. At the same time, PtD achieves a better result in direction of the 3D line than TPS, but has a lower accuracy in the position of 3D lines than TPS.

Generalized Orthogonal Iterative Algorithm for Pose Estimation of Multiple Camera Systems

2009 ◽  
Vol 29 (1) ◽  
pp. 72-77 ◽  
Author(s):  
许允喜 Xu Yunxi ◽  
蒋云良 Jiang Yunliang ◽  
陈方 Chen Fang
Keyword(s):  
Iterative Algorithm ◽  
Pose Estimation ◽  
Multiple Camera ◽  
Camera Systems ◽  
Generalized Orthogonal

Autonomous rendezvous and robotic capturing of non-cooperative target in space

Robotica ◽  
2009 ◽  
Vol 28 (5) ◽  
pp. 705-718 ◽  
Author(s):  
Wenfu Xu ◽  
Bin Liang ◽  
Cheng Li ◽  
Yangsheng Xu
Keyword(s):  
Stereo Vision ◽  
Joint Angle ◽  
Attitude Measurement ◽  
Stereo Match ◽  
Line Extraction ◽  
Autonomous Rendezvous ◽  
Navigation And Control ◽  
Measurement Algorithm ◽  
Simulation Results ◽  
And Control

SUMMARYThe technologies of autonomous rendezvous and robotic capturing of non-cooperative targets are very crucial for the future on-orbital service. In this paper, we proposed a method to achieve this aim. Three problems were addressed: the target recognition and pose (position and attitude) measurement based on the stereo vision, the guidance, navigation and control (GNC) of the chaser, and the coordinated plan and control of space robot (CP&C). The pose measurement algorithm includes image filtering, edge detection, line extraction, stereo match and pose computing, et al. Based on the measured values, a certain GNC algorithm was designed for the chaser to approach and rendezvous with the target. Then the CP&C algorithm, which is proved to be advantageous over the traditional separated method, was used to plan and track the trajectories of the base pose and the joint angle. At last, a 3D simulation system was developed to evaluate the proposed method. Simulation results verified the corresponding algorithms.

Algorithm of Marriage in Honey Bees Optimization Coperate with Linear Method

2013 ◽  
Vol 871 ◽  
pp. 330-337
Author(s):  
Chen Guang Yang ◽  
Qiao Ge Liu
Keyword(s):  
Honey Bees ◽  
Linear Method ◽  
Local Characteristic ◽  
Evaluation Functions ◽  
Markov Chain Theory ◽  
Computation Process ◽  
Public Evaluation ◽  
Convergence Performance ◽  
Chain Theory ◽  
Simulation Results

Marriage in Honey Bees Optimization (MBO) is a new swarm-intelligence method, but it has the shortcomings of low speed and complex computation process. By changing the structure of MBO and utilizing a linear method to perform the local characteristic, we propose a new optimization algorithm. The global convergence characteristic of the proposed algorithm is proved by using the Markov Chain theory. And then some simulations are done on Traveling Salesman Problem (TSP) and several public evaluation functions. By comparing the proposed algorithm with MBO and Genetic Algorithm, simulation results show that the proposed algorithm has better convergence performance.

scholarly journals Semantically Synchronizing Multiple-Camera Systems with Human Pose Estimation

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2464
Author(s):  
Zhe Zhang ◽  
Chunyu Wang ◽  
Wenhu Qin
Keyword(s):  
Pose Estimation ◽  
Energy Function ◽  
Human Pose Estimation ◽  
Frame Synchronization ◽  
Camera System ◽  
Multiple Camera ◽  
Camera Systems ◽  
Benchmark Datasets ◽  
Improved Performance ◽  
Human Pose

Multiple-camera systems can expand coverage and mitigate occlusion problems. However, temporal synchronization remains a problem for budget cameras and capture devices. We propose an out-of-the-box framework to temporally synchronize multiple cameras using semantic human pose estimation from the videos. Human pose predictions are obtained with an out-of-the-shelf pose estimator for each camera. Our method firstly calibrates each pair of cameras by minimizing an energy function related to epipolar distances. We also propose a simple yet effective multiple-person association algorithm across cameras and a score-regularized energy function for improved performance. Secondly, we integrate the synchronized camera pairs into a graph and derive the optimal temporal displacement configuration for the multiple-camera system. We evaluate our method on four public benchmark datasets and demonstrate robust sub-frame synchronization accuracy on all of them.

scholarly journals Análisis de estabilidad de convertidores de segundo orden con la metodología de optimización de suma de polinomios cuadráticos

2020 ◽  
Vol 1 (1) ◽  
pp. 49-58
Author(s):  
Jhon Jairo Herrera-Pérez ◽  
Alejandro Garcés-Ruiz
Keyword(s):  
Output Voltage ◽  
Equilibrium Points ◽  
Linear Method ◽  
Pi Controller ◽  
Quadratic Lyapunov Function ◽  
Boost Converters ◽  
Dc Microgrids ◽  
Practical Applications ◽  
Simulation Results ◽  
The Stability

This paper presents a non-linear method based on sum-of-squares (SOS), to determine the stability of equilibrium points for the Buck, Boost, Buck-Boost and non-inverter Buck-Boost converters. These converters share a similar structure with a PI controller to regulate the output voltage. A quadratic Lyapunov function is proposed in all cases, and the conditions for stability are evaluated using convex optimization based on SOS models. The methodology is useful for academic purposes but also in practical applications like DC microgrids. Simulation results shows the advantages of the proposed method.

Semi-Automatic Multiple Camera Systems

2021 ◽  
pp. 11-19
Author(s):  
Alejandro Bastida-Castillo ◽  
José Pino-Ortega ◽  
Markel Rico-González ◽  
Carlos D. Gómez-Carmona
Keyword(s):  
Multiple Camera ◽  
Camera Systems

scholarly journals Distributed Asynchronous Fusion Algorithm for Sensor Networks with Packet Losses

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Tianpeng Chu ◽  
Guoqing Qi ◽  
Yinya Li ◽  
Andong Sheng
Keyword(s):  
Sensor Networks ◽  
Estimation Method ◽  
Distributed Estimation ◽  
Fusion Algorithm ◽  
Packet Losses ◽  
Packet Dropouts ◽  
Covariance Intersection ◽  
Measurement Equations ◽  
Simulation Results ◽  
Intersection Method

This paper is concerned with the problem of distributed estimation fusion over peer-to-peer asynchronous sensor networks with random packet dropouts. A distributed asynchronous fusion algorithm is proposed via the covariance intersection method. First, local estimator is developed in an optimal batch fashion by constructing augmented measurement equations. Then the fusion estimator is designed to fuse local estimates in the neighborhood. Both local estimator and fusion estimator are developed by taking into account the random packet losses. The presented estimation method improves local estimates and reduces the estimate disagreement. Simulation results validate the effectiveness of the proposed distributed asynchronous fusion algorithm.

Evaluation on the Accuracies of Sump Depth Measurements during DC Casting Process of 7050 Alloy

2016 ◽  
Vol 877 ◽  
pp. 78-83
Author(s):  
Kang Cai Yu ◽  
Shi Jie Guo ◽  
Hiromi Nagaumi
Keyword(s):  
Steady State ◽  
Measurement Accuracy ◽  
Liquid Surface ◽  
Casting Process ◽  
Accurate Method ◽  
Direct Chill ◽  
Free Liquid Surface ◽  
Dc Casting ◽  
Simulation Results ◽  
Temperature Time

Present work was carried out to investigate the measurement accuracy of the sump depth for 7050 billet in direct chill (DC) casting process. Three measuring methods were applied: (i) Al-30wt.% Cu melt was poured into the mold at the steady state of the casting attempting to record the profile of billet sump; (ii) two steel rods were vertically dipped into the centreline and the edge of the billet attempting to measure the distances between the solidus and the free liquid surface in the hot-top; (iii) several ordered thermocouples were pre-arranged onto the starting block and they were solidified into the billet as it was cast, and a series of temperature-time curves was recorded after casting. For the purposes of comparison and evaluation, a numerical model based on the same experiment parameters was also built and the simulation results were compared with measured results by above methods. It indicates that the sump depth measured by thermocouples has the best consistency with numerical results. The most accurate method is temperature recoding by thermocouples. The Al-Cu melt pouring method is more accurate than the rods dipping method, and the sump depths measured by later two methods were the positions about the solid fraction (fs) depths of 0.8 to 0.9.

Comparative Study of Stereo Correspondence Techniques for Underwater Images

2020 ◽  
pp. 230-261
Author(s):  
Prabhakar C. J.
Keyword(s):  
Computer Vision ◽  
Comparative Study ◽  
3D Reconstruction ◽  
Stereo Vision ◽  
Stereo Correspondence ◽  
Stereo Images ◽  
Visual Comparison ◽  
Simulation Results ◽  
Vision Technique

The aim of the chapter is to provide an overview of the computer vision techniques involved in stereo correspondence of underwater images, which is one of the important steps in the 3D reconstruction of underwater objects and scenes. The author provide briefly the various categories of techniques for 3D reconstruction of objects. Also, the author provides steps involved in the 3D reconstruction of objects using stereo vision technique, particularly, more focused on stereo correspondence step and its techniques available in the literature. Further, they present some of the local and global stereo correspondence methods employed for underwater stereo images with simulation results. Finally, the author presents a visual comparison of local and global stereo correspondence techniques employed for underwater stereo images.

Sign in / Sign up

Export Citation Format

Share Document