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当期目录

2021年, 第3期 刊出日期:2021-09-01 上一期    下一期
本期栏目:
A single camera 360-degree real time vision-based localization method with application to mobile robot trajectory tracking   收藏
Khomsun Singhirunnusorn, Farbod Fahimi, Ramazan Aygun
IET Cyber-Systems and Robotics. 2021 (3): 185-198.   DOI: https://doi.org/10.1049/csy2.12021
摘要( 58 )     PDF(0KB)( 14 )
A method is proposed for real-time vision-based localization in the 360° area around a three-dimensional (3D) reference object with a single camera. The problem is split into three subproblems. First, 360° 3D object recognition is proposed, in which a computer vision solution can recognize a reference object from all possible 360° locations. Second, 360° pose estimation is presented, in which the pose of a robot at all locations is estimated. Third, a 360° localization application is integrated with a closed-loop real-time trajectory tracking controller. The successful results of simulations and real experiments of trajectory tracking are also presented.
PatchMatch Filter-Census: A slanted-plane stereo matching method for slope modelling application   收藏
Weiyong Eng, Voonchet Koo, Tiensze Lim
IET Cyber-Systems and Robotics. 2021 (3): 199-209.   DOI: https://doi.org/10.1049/csy2.12026
摘要( 43 )     PDF(0KB)( 12 )
Image matching is a well-studied problem in computer vision. Conventional image matching is solved using image feature matching algorithms, and later deep learning techniques are also applied to tackle the problem. Here, a slope-modelling framework is proposed by adopting the image matching techniques. First, image pairs of a slope scene are captured and camera calibration as well as image rectification are performed. Then, PatchMatch Filter (PMF-S) and PWC-Net techniques are adapted to solve the matching of image pairs. In the proposed PatchMatch Filter-Census (PMF-Census), slanted-plane modelling, image census transform and gradient difference are employed in matching cost formulation. Later, nine matching points are manually selected from an image pair. Matching point pairs are further used in fitting a transformation matrix to relate the matching between the image pair. Then, the transformation matrix is applied to obtain a ground truth matching image for algorithm evaluation. The challenges in this matching problem are that the slope is of a homogenous region and it has a slanted-surface geometric structure. In this work, it is found out that the error rate of the proposed PMF-Census is significantly lower as compared with the PWC-Net method and is more suitable in this slope-modelling task. In addition, to show the robustness of the proposed PMF-Census against the original PMF-S, further experiments on some image pairs from Middlebury Stereo 2006 dataset are conducted. It is demonstrated that the error percentage by the proposed PMF-Census is reduced significantly especially in the low-texture and photometric distorted region, in comparison to the original PMF-S algorithm. This further verifies the suitability of the PMF-Census in modelling the outdoor low-texture slope scene.
Adaptive constrained population extremal optimisation-based robust proportional-integral-derivation frequency control method for an islanded microgrid   收藏
Kang-Di Lu, Guo-Qiang Zeng, Wuneng Zhou
IET Cyber-Systems and Robotics. 2021 (3): 210-227.   DOI: https://doi.org/10.1049/csy2.12028
摘要( 41 )     PDF(0KB)( 13 )
The expected penetration of renewable sources is driving the islanded microgrid towards uncertainties, which have highly influence the reliability and complexities of frequency control. To alleviate the influence caused by load fluctuations and inherent variability of renewable sources, this article proposes an optimised robust proportional-integral-derivation (PID) frequency control method by taking full advantage of a robust control strategy while simultaneously maintaining the basic characteristics of a PID controller. During the process of iterated optimisation, a weighted objective function is used to balance the tracking error performance, robust stability and disturbance attenuation performance. Then, the robust PID frequency (RPIDF) controller is determined by an adaptive constrained population extremal optimisation algorithm based on self-adaptive penalty constraint-handling technique. The proposed control method is examined on a typical islanded microgrid, and the control performance is evaluated under various disturbances and parametric uncertainties. Finally, the simulation results indicate that the fitness value of the proposed method is 1.7872, which is lower than 2.9585 and 3.0887 obtained by two other evolutionary algorithms-based RPIDF controllers. Moreover, the comprehensive simulation results fully demonstrate that the proposed method is superior to other comparison methods in terms of four performance indices on the most considered scenarios.
A study on preterm birth predictions using physiological signals, medical health record information and low-dimensional embedding methods   收藏
Ejay Nsugbe, Oluwarotimi William Samuel, Ibrahim Sanusi, Mojisola Grace Asogbon, Guanglin Li
IET Cyber-Systems and Robotics. 2021 (3): 228-244.   DOI: https://doi.org/10.1049/csy2.12031
摘要( 45 )     PDF(0KB)( 13 )
Preterm births have been seen to have psychological and financial implications; current surveys suggest that amongst the various methods of preterm prediction, there is yet to exist a reliable and standard means of predicting preterm births. This study investigates the application of electrohysterogram and tocogram signals acquired at various points during the third pregnancy trimester, alongside information from the patients' medical health record regarding the pregnancy, towards preterm prediction and an associated delivery imminency timeline. In addition to this, the impact of both linear and non-linear dimensional embedding methods towards the preterm prediction is explored. The classification exercises were carried out using a support vector machine and decision tree, both of which have a certain degree of model interpretability and have potential to be introduced into a clinical operating framework.
Real time path planning via alternating minimisation through image information   收藏
Zheng Chen, Minjie Zhang, Jiang Zhu, Shiqiang Zhu
IET Cyber-Systems and Robotics. 2021 (3): 245-255.  
摘要( 67 )     PDF(0KB)( 18 )
Real time path planning from image information is of vital importance in the fields of robots as it has various applications in real time navigation, autonomous driving, robot arm manipulation and human robot cooperation and so on. To achieve this task, a two stage approach is proposed. At the first stage, a novel change point detection approach is proposed to process the image to extract the shape of the obstacles. At the second stage, several novel approximations are adopted to make the path planning problem tractable. Firstly, the irregular shapes of the obstacles in the environment are approximated as lines and circles, which simplify the distance constraint significantly. Secondly, the non-convex path planning problem is iteratively decomposed as a sequence of subproblems and alternating minimisation method is proposed to efficiently solve the subproblem. To improve the quality of the solution, good initial points obtained by A* algorithm is provided. Both numerical experiments and real experiments are conducted to demonstrate the effectiveness of the proposed algorithm.
An improved YOLOv3-tiny algorithm for vehicle detection in natural scenes   收藏
Bingqiang Huang, Haiping Lin, Zejun Hu, Xinjian Xiang, Jiana Yao
IET Cyber-Systems and Robotics. 2021 (3): 256-264.   DOI: https://doi.org/10.1049/csy2.12029
摘要( 44 )     PDF(0KB)( 16 )
YOLO (You Only Look Once), as a target detection algorithm with good speed and precision, is widely used in the industry. In the process of driving, the vehicle image captured by the driving camera is detected and it extracts the license plate and the front part of the vehicle. Compared with the network structure of YOLOv3-tiny algorithm, the acquisition method of anchor box is improved by combining the Birch algorithm. In order to improve the real-time performance, the original two-scale detection is added to the multi-scale prediction of three-scale detection to ensure its accuracy. Finally, the experimental results show that the improved YOLOv3-tiny network structure proposed in this study can improve the performance of mean-average-precision, intersection over union and speed by 5.99%, 17.52% and 48.4%, respectively, and the algorithm has certain robustness.
Reservoir inflow predicting model based on machine learning algorithm via multi-model fusion: A case study of Jinshuitan river basin   收藏
Wei Zhang, Hanyong Wang, Yemin Lin, Jianle Jin, Wenjuan Liu, Xiaolan An
IET Cyber-Systems and Robotics. 2021 (3): 265-277.   DOI: https://doi.org/10.1049/csy2.12015
摘要( 39 )     PDF(0KB)( 13 )
Flood prevention and disaster mitigation have a great impact on people's lives and properties, and so it is urgent to realise high-accuracy inflow predictions for flood early warning. To this end, a prediction model based on a machine learning algorithm via a multimodel combination method is proposed to predict the inflow of Jinshuitan reservoir. Firstly, a data formatting scheme called the ’hydrological regime profile‘ is designed for input data. The whole data set is partitioned into a low-flow subset and a high-flow subset. Considering the high dimensions of the complex input data, convolutional neural networks (CNN), EXtreme gradient Boosting model (XGBoost) and a partial least squares model (PLS) are used. In the CNN and XGBoost models, a special loss function weighted on inflow is designed to improve the performance on high-inflow predictions. Finally, a multi-model combination method is proposed to improve the prediction performance. Compared with XGBoost, CNN and PLS, the root mean square error of the combined model is reduced by 41.64%, 72.29% and 3.41%, respectively. As a consequence, the combined model is able to predict the inflows with higher accuracy compared to the single models.