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Optimization study of station track utilization in high-speed railroad based on constraints of control in random origin and process
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作者 Yajing Zheng Dekun Zhang 《Railway Sciences》 2024年第3期332-343,共12页
Purpose-The purpose of this paper is to eliminate the fluctuations in train arrival and departure times caused by skewed distributions in interval operation times.These fluctuations arise from random origin and proces... Purpose-The purpose of this paper is to eliminate the fluctuations in train arrival and departure times caused by skewed distributions in interval operation times.These fluctuations arise from random origin and process factors during interval operations and can accumulate over multiple intervals.The aim is to enhance the robustness of high-speed rail station arrival and departure track utilization schemes.Design/methodologylapproach-To achieve this objective,the paper simulates actual train operations,incorporating the fluctuations in interval operation times into the utilization of arrival and departure tracks at the station.The Monte Carlo simulation method is adopted to solve this problem.This approach transforms a nonlinear model,which includes constraints from probability distribution functions and is difficult to solve directly,into a linear programming model that is easier to handle.The method then linearly weights two objectives to optimize the solution.Findings-Through the application of Monte Carlo simulation,the study successfully converts the complex nonlinear model with probability distribution function constraints into a manageable linear programming model.By continuously adjusting the weighting coefficients of the linear objectives,the method is able to optimize the Pareto solution.Notably,this approach does not require extensive scene data to obtain a satisfactory Pareto solution set.Originality/value-The paper contributes to the field by introducing a novel method for optimizing high-speed rail station arrival and departure track utilization in the presence of fluctuations in interval operation times.The use of Monte Carlo simulation to transform the problem into a tractable linear programming model represents a significant advancement.Furthermore,the method's ability to produce satisfactory Pareto solutions without relying on extensive data sets adds to its practical value and applicability in real-world scenarios. 展开更多
关键词 Control in random origin Control in random process High-speed railroad station Arrival and departure track utilization Optimization Paper type Research paper
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Study of image processing for V-shape groove and robotic weld seam tracking based on laser vision 被引量:3
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作者 肖心远 石永华 +1 位作者 王国荣 李鹤喜 《China Welding》 EI CAS 2008年第4期68-73,共6页
Single-stripe laser was applied to acquire V-shape groove contour information. Most of arc light and splash noise was removed and stripe laser image was kept by wavelet transform. Half-threshold algorithm was used for... Single-stripe laser was applied to acquire V-shape groove contour information. Most of arc light and splash noise was removed and stripe laser image was kept by wavelet transform. Half-threshold algorithm was used for image segmentation and stripe laser image was gotten after refining. Weld seam center position was identified and extracted by extreme curvature corner detection method. The location of torch was detected to accord the frequency of computer program with robot program and serial communication program. The tracking experiments of sidelong, reflex and curve weld line show that the system can meet the demand of the tracking precision under normal welding conditions. 展开更多
关键词 laser vision wavelet transform image processing weld seam tracking
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Study on the image processing of laser vision seam tracking system 被引量:1
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作者 申俊琦 胡绳荪 +1 位作者 冯胜强 朱莉娜 《China Welding》 EI CAS 2010年第2期47-50,共4页
Seam image processing is the basis of the realization of automatic laser vision seam tracking system, and it has become one of the important research directions. Adding windows processing, gray processing, fast median... Seam image processing is the basis of the realization of automatic laser vision seam tracking system, and it has become one of the important research directions. Adding windows processing, gray processing, fast median filtering, binary processing and image edge extraction are used to pretreat the seam image. In the post-processing of seam image, the feature points of the target image are succesfully detected by using center line extraction and feature points detection algorithm based on slope analysis. The whole processing time is less than 150 ms, and the real-time processing of seam image can be implemented. 展开更多
关键词 image processing seam tracking laser vision feature points detection
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基于改进YOLOv7-ByteTrack的干制哈密大枣缺陷检测与计数系统
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作者 刘鑫 马本学 +2 位作者 李玉洁 陈金成 喻国威 《农业工程学报》 EI CAS CSCD 北大核心 2024年第3期303-312,共10页
针对目前无法同时对随机多列排布干制哈密大枣进行快速缺陷检测和统计计数问题,该研究设计了一款干制哈密大枣在线检测与计数系统。以干制哈密大枣为研究对象,利用工业相机拍摄传送带上随机排列的多类别缺陷干制哈密大枣视频为数据源,... 针对目前无法同时对随机多列排布干制哈密大枣进行快速缺陷检测和统计计数问题,该研究设计了一款干制哈密大枣在线检测与计数系统。以干制哈密大枣为研究对象,利用工业相机拍摄传送带上随机排列的多类别缺陷干制哈密大枣视频为数据源,采用改进的YOLOv7模型进行干制哈密大枣多类别缺陷检测并将检测结果作为后续多目标跟踪算法的输入;考虑到传送带上干制哈密大枣的外观相似性高以及排列密集等特点,该研究结合ByteTrack多目标跟踪算法的思想,设计了一种多类别干制哈密大枣的画线计数方法,实现了随机排布多类别干制哈密大枣的缺陷检测、准确定位及计数。试验结果表明:1)改进的YOLOv7模型浮点计算量为64.6 G,在干制哈密大枣目标检测数据的测试集上的平均检测精度、召回率、F_(1)平衡分数分别达到了98.03%、93.43%和95.00%,相比YOLOv7模型分别提高了4.40、6.88和7.00个百分点,浮点计算量下降了38.6%;2)基于改进YOLOv7为目标检测器开发的ByteTrack算法计数模型对干制哈密大枣计数的准确率为90.12%。该研究可为干制哈密大枣检测计数和分选分级提供技术支持。 展开更多
关键词 图像处理 目标检测 干制哈密大枣 多目标跟踪 YOLOv7
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Optimal tracking control for automatic transmission shift process 被引量:2
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作者 万国强 李克强 +2 位作者 裴玲 黄英 张付军 《Journal of Beijing Institute of Technology》 EI CAS 2015年第4期458-465,共8页
In order to improve the shift quality, a linear quadratic optimal tracking control algorithm for automatic transmission shift process is proposed. The dynamic equations of the shift process are derived using a Lagrang... In order to improve the shift quality, a linear quadratic optimal tracking control algorithm for automatic transmission shift process is proposed. The dynamic equations of the shift process are derived using a Lagrange method. And a powertrain model is built in the Matlab/Simulink and veri- fied by the measurements. Considering the shift jerk and friction loss during the shift process, the tracking trajectories of the turbine speed and output shaft speed are defined. Furthermore, the linear quadratic optimal tracking control performance index is proposed. Based on the Pontryagin' s mini- mum principle, the optimal control law of the shift process is presented. Finally, the simulation study of the 1 - 2 upshift process under different load conditions is carried out with the powertrain model. The simulation results demonstrate that the shift jerk and friction loss can be significantly re- duced by applying the proposed optimal tracking control method. 展开更多
关键词 POWERTRAIN automatic transmission shift process optimal tracking control
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基于自纠正NMS-ByteTrack的套袋葡萄估产方法
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作者 吕佳 张翠萍 +1 位作者 刘琴 李帅军 《农业工程学报》 EI CAS CSCD 北大核心 2023年第13期182-190,共9页
针对套袋后的葡萄体积增加和葡萄叶片表面积大容易出现重叠遮挡,及人工拍摄视频的速度不稳定可能导致套袋葡萄目标丢失的问题,该研究提出一种基于自纠正NMS(non-maximum suppression)-ByteTrack的套袋葡萄估产方法。该方法首先通过目标... 针对套袋后的葡萄体积增加和葡萄叶片表面积大容易出现重叠遮挡,及人工拍摄视频的速度不稳定可能导致套袋葡萄目标丢失的问题,该研究提出一种基于自纠正NMS(non-maximum suppression)-ByteTrack的套袋葡萄估产方法。该方法首先通过目标检测方法YOLOv5s检测视频中的套袋葡萄,将检测阶段的NMS操作后置到追踪阶段,保留因遮挡而被过滤的果实检测框;其次在ByteTrack的基础上加入相机运动补偿和改进的卡尔曼滤波算法,以自动纠正果实预测框的位置并进行追踪;最后提出一种划线计数策略对套袋葡萄自动计数。试验结果表明,该方法的多目标追踪准确率、多目标追踪精度和ID调和平均数分别为64.6%、82.4%和80.8%,相比ByteTrack分别提高了1.7、1.0和4.1个百分点,平均计数精度达到82.8%。因此,基于自纠正NMS-ByteTrack的估产方法能有效解决套袋葡萄的追踪计数问题,实现对套袋葡萄更精确地估产。 展开更多
关键词 图像处理 农业 目标追踪 视频计数 估产方法 套袋葡萄 Bytetrack 卡尔曼滤波器
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Automatic Determination of Yarn Hairiness Length Based on Image Processing and Analysis Algorithm 被引量:1
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作者 景军锋 黄梦莹 +2 位作者 李鹏飞 张蕾 张宏伟 《Journal of Donghua University(English Edition)》 EI CAS 2016年第4期587-591,共5页
A new algorithm is proposed to determine the actual length and the number of the protruding fibres of yarn based on a combination of image acquisition technology. First, a yarn hairiness image is obtained by the serie... A new algorithm is proposed to determine the actual length and the number of the protruding fibres of yarn based on a combination of image acquisition technology. First, a yarn hairiness image is obtained by the series of image processing procedures that include grayscale transformation,skew correction,yarn binary image acquisition and yarn core binary image obtaining. Then,the hairiness is realized in single pixel width by the usage of thinning algorithm. Finally, a baseline of yarn core margin is obtained,and pixels that match 8-neighbor template correctly are found by row scanning in a certain area. From this,these pixels are judged and the real crossover points of yarn core margin and hairiness,i. e.,the starting points of hairiness,are gained. The real length of the protruding fibres is calculated by tracking hairiness from the starting point constantly. 展开更多
关键词 protruding fibres of yarn image processing procedures hairiness thinning template matching tracking hairiness
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Facies and Fracture Network Modeling by a Novel Image Processing Based Method 被引量:1
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作者 Peyman Mohammadmoradi 《Geomaterials》 2013年第4期156-164,共9页
A wide range of methods for geological reservoir modeling has been offered from which a few can reproduce complex geological settings, especially different facies and fracture networks. Multi Point Statistic (MPS) alg... A wide range of methods for geological reservoir modeling has been offered from which a few can reproduce complex geological settings, especially different facies and fracture networks. Multi Point Statistic (MPS) algorithms by applying image processing techniques and Artificial Intelligence (AI) concepts proved successful to model high-order relations from a visually and statistically explicit model, a training image. In this approach, the patterns of the final image (geological model) are obtained from a training image that defines a conceptual geological scenario for the reservoir by depicting relevant geological patterns expected to be found in the subsurface. The aim is then to reproduce these training patterns within the final image. This work presents a multiple grid filter based MPS algorithm to facies and fracture network images reconstruction. Processor is trained by training images (TIs) which are representative of a spatial phenomenon (fracture network, facies...). Results shown in this paper give visual appealing results for the reconstruction of complex structures. Computationally, it is fast and parsimonious in memory needs. 展开更多
关键词 Filter-Based IMAGE processing Pattern Training IMAGE ENTROPY plot MPS
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The training process: Planning for strength-power training in track and field. Part 2: Practical and applied aspects 被引量:3
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作者 Brad H. DeWeese Guy Hornsby +1 位作者 Meg Stone Michael H. Stone 《Journal of Sport and Health Science》 SCIE 2015年第4期318-324,共7页
在制定田径运动员力量—爆发力训练方案前,首先需要理解训练原则与训练理论。训练原则包括超负荷原则、多样性原则及专项性原则。其中每个原则都应纳入适当的训练体系中。从概念上讲,训练分期围绕训练原则,并为训练计划和方案提供有利条... 在制定田径运动员力量—爆发力训练方案前,首先需要理解训练原则与训练理论。训练原则包括超负荷原则、多样性原则及专项性原则。其中每个原则都应纳入适当的训练体系中。从概念上讲,训练分期围绕训练原则,并为训练计划和方案提供有利条件,使之能够允许训练变量(如训练方法选择、训练强度和训练量)的逻辑整合和控制。运动员的适应和发展与教练员能否制定高效训练方案的能力密不可分。该能力包括:对运动如何影响生理适应和运动表现的理解(例如最大力量、力量发展和爆发力等);如何优化训练效果,确保训练能使运动潜能最大化地转变为运动表现;以及如何在适当水平(宏观、中观、微观)的变化下实施训练中的疲劳管理和运动表现的优化。 展开更多
关键词 力量训练 训练过程 规划 田径 应用 适应能力 训练计划 生理性能
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The training process: Planning for strength-power training in track and field. Part 1: Theoretical aspects 被引量:3
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作者 Brad H. DeWeese Guy Hornsby +1 位作者 Meg Stone Michael H. Stone 《Journal of Sport and Health Science》 SCIE 2015年第4期308-317,共10页
力量—爆发力训练的过程和随后的适应受多种因素影响。这其中包括运动员的基因、形态特征以及教练如何选择、安排及实施、训练和负荷模式。针对上述训练因素的适应能力很大程度上与传授模式,即项目策略有很大关系。有研究证明,运动员在... 力量—爆发力训练的过程和随后的适应受多种因素影响。这其中包括运动员的基因、形态特征以及教练如何选择、安排及实施、训练和负荷模式。针对上述训练因素的适应能力很大程度上与传授模式,即项目策略有很大关系。有研究证明,运动员在训练中表现出的模式和阶段对表现结果有深远的影响。本文讨论了模块式周期性训练的概念以及田径运动中力量—爆发力训练过程的相关方法。 展开更多
关键词 力量训练 训练过程 田径 规划 形态特征 加载模式 编程策略 编程方法
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Cenozoic evolution of tectono-fluid and metallogenic process in Lanping Basin, western Yunnan Province, Southwest China: Constraints from apatite fission track data 被引量:11
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作者 李小明 宋友桂 《Chinese Journal Of Geochemistry》 EI CAS 2006年第4期395-400,共6页
Since the Mesozoic, abundant metal and salt deposits have been formed in the Lanping Basin, western Yunnan Province, Southwest China, constituting a well-known hydrothermal ore belt in China. Most of the deposits are ... Since the Mesozoic, abundant metal and salt deposits have been formed in the Lanping Basin, western Yunnan Province, Southwest China, constituting a well-known hydrothermal ore belt in China. Most of the deposits are meso-epithermal hydrothermal deposits. This paper preliminarily deals with the mineralization ages of hydrothermal deposits in the Lanping Basin by using the apatite fission track method, and integrates the spatial distribution of the deposits and their regional geological backgrounds, to give the preliminary viewpoints as follows: (1) the apatite fission track ages acquired range from 19.9 Ma to 52.8 Ma, much younger than those of their host strata, so they may be considered to be mineralization ages, which represent the late mineralization period; (2) the apatite fission track ages tend to become younger from the west to the middle of the basin, indicating that the latest evolution of tectono-fluid and/or metallogenic processes of the middle basin ended later than that in the west; (3) in the Paleogene, most of the Cu deposits were formed in the western part of the basin; (4) the major metallogenic processes occur between the Paleogene and the Neogene, because the eastern and western edges of the basin were subducted into and collided with its bilateral continental blocks, respectively, and the central fault was strongly activated, which led to the processes of large-scale ore-forming fluids, and their differentiation and transport because of the variation of their physical and chemical properties. Having been squeezed and uplifted, the Lanping Basin became an intermontane basin that contains many kinds of fluid traps resulting in the formation of different types of ore deposits (for example, Pb-Zn, Cu, Ag) of different scales in the middle of the basin. Simultaneously, the fluids with volatile elements such as Hg, Sb and As were transported upwards along the central fault system and diffused into its subordinate fractures, thus leading to the metallogenic processes of Hg, Sb and As in the eastern composite anticline of the Lanping Basin; (5) and later, these ore deposits experienced reformation and oxidization. To summarize,deep giant faults were active in the basin, and metallogenic processes were constrained by the evolution of tectono-fluids in the Lanping Basin. Simultaneously, the occurrence of the metallogenic processes made the nature of fluid and the structural environment change, which led to returning and recycling of the fluids. Multi-stage and zonational metallogenic processes are the characteristics of the ore deposits in the Lanping Basin. 展开更多
关键词 裂变痕迹 时空框架 云南西部 矿化作用
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Complex analysis of the damage caused by geocryologic processes (as exemplified by effects on the Chara-China Railway track, Transbaikal region)
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作者 Irina Chesnokova Dmitry Sergeev 《Research in Cold and Arid Regions》 CSCD 2017年第3期335-338,共4页
The report presents an analysis of a unique data set demonstrating the influence of geocryological processes on the 75-km Chara-China Railway track(northern Transbaikal region).The originality of these investigations ... The report presents an analysis of a unique data set demonstrating the influence of geocryological processes on the 75-km Chara-China Railway track(northern Transbaikal region).The originality of these investigations lies in the study of the influence of natural processes on the road in the absence of any repair works or protective and compensating measures for a long period of time(1998~2014).These conditions allowed assessment of the actual damage to the railroad. 展开更多
关键词 geocryological processES PERMAFROST conditions social-economic DAMAGE Chara-China RAILWAY track
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Insiders' Hedging for Jump Diffusion Processes with Applications to Index Tracking
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作者 苏小囡 王伟 王文胜 《Journal of Donghua University(English Edition)》 EI CAS 2011年第6期571-575,共5页
The hedging problem for insiders is very important in the financial market.The locally risk minimizing hedging was adopted to solve this problem.Since the market was incomplete,the minimal martingale measure was chose... The hedging problem for insiders is very important in the financial market.The locally risk minimizing hedging was adopted to solve this problem.Since the market was incomplete,the minimal martingale measure was chosen as the equivalent martingale measure.By the F-S decomposition,the expression of the locally risk minimizing strategy was presented.Finally,the local risk minimization was applied to index tracking and its relationship with tracking error variance (TEV)-minimizing strategy was obtained. 展开更多
关键词 jump diffusion processes local risk minimization insiders’ hedging index tracking
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Vision Navigation Based PID Control for Line Tracking Robot 被引量:1
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作者 Rihem Farkh Khaled Aljaloud 《Intelligent Automation & Soft Computing》 SCIE 2023年第1期901-911,共11页
In a controlled indoor environment,line tracking has become the most practical and reliable navigation strategy for autonomous mobile robots.A line tracking robot is a self-mobile machine that can recognize and track ... In a controlled indoor environment,line tracking has become the most practical and reliable navigation strategy for autonomous mobile robots.A line tracking robot is a self-mobile machine that can recognize and track a painted line on thefloor.In general,the path is set and can be visible,such as a black line on a white surface with high contrasting colors.The robot’s path is marked by a distinct line or track,which the robot follows to move.Several scientific contributions from the disciplines of vision and control have been made to mobile robot vision-based navigation.Localization,automated map generation,autonomous navigation and path tracking is all becoming more frequent in vision applications.A visual navigation line tracking robot should detect the line with a camera using an image processing technique.The paper focuses on combining computer vision techniques with a proportional-integral-derivative(PID)control-ler for automatic steering and speed control.A prototype line tracking robot is used to evaluate the proposed control strategy. 展开更多
关键词 Line tracking robot vision navigation PID control image processing OPENCV raspberry pi
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Embedded System Development for Detection of Railway Track Surface Deformation Using Contour Feature Algorithm 被引量:1
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作者 Tarique Rafique Memon Tayab Din Memon +1 位作者 Imtiaz Hussain Kalwar Bhawani Shankar Chowdhry 《Computers, Materials & Continua》 SCIE EI 2023年第5期2461-2477,共17页
Derailment of trains is not unusual all around the world,especially in developing countries,due to unidentified track or rolling stock faults that cause massive casualties each year.For this purpose,a proper condition... Derailment of trains is not unusual all around the world,especially in developing countries,due to unidentified track or rolling stock faults that cause massive casualties each year.For this purpose,a proper condition monitoring system is essential to avoid accidents and heavy losses.Generally,the detection and classification of railway track surface faults in real-time requires massive computational processing and memory resources and is prone to a noisy environment.Therefore,in this paper,we present the development of a novel embedded system prototype for condition monitoring of railway track.The proposed prototype system works in real-time by acquiring railway track surface images and performing two tasks a)detect deformation(i.e.,faults)like squats,shelling,and spalling using the contour feature algorithm and b)the vibration signature on that faulty spot by synchronizing acceleration and image data.A new illumination scheme is also proposed to avoid the sunlight reflection that badly affects the image acquisition process.The contour detection algorithm is applied here to detect the uneven shapes and discontinuities in the geometrical structure of the railway track surface,which ultimately detects unhealthy regions.It works by converting Red,Green,and Blue(RGB)images into binary images,which distinguishes the unhealthy regions by making them white color while the healthy regions in black color.We have used the multiprocessing technique to overcome the massive processing and memory issues.This embedded system is developed on Raspberry Pi by interfacing a vision camera,an accelerometer,a proximity sensor,and a Global Positioning System(GPS)sensors(i.e.,multi-sensors).The developed embedded system prototype is tested in real-time onsite by installing it on a Railway Inspection Trolley(RIT),which runs at an average speed of 15 km/h.The functional verification of the proposed system is done successfully by detecting and recording the various railway track surface faults.An unhealthy frame’s onsite detection processing time was recorded at approximately 25.6ms.The proposed system can synchronize the acceleration data on specific railway track deformation.The proposed novel embedded system may be beneficial for detecting faults to overcome the conventional manual railway track condition monitoring,which is still being practiced in various developing or underdeveloped countries. 展开更多
关键词 Railway track surface faults condition monitoring system fault detection contour detection deep learning image processing rail wheel impact
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Multiple-Object Tracking Using Histogram Stamp Extraction in CCTV Environments
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作者 Ye-Yeon Kang Geon Park +1 位作者 Hyun Yoo Kyungyong Chung 《Computers, Materials & Continua》 SCIE EI 2023年第12期3619-3635,共17页
Object tracking,an important technology in the field of image processing and computer vision,is used to continuously track a specific object or person in an image.This technology may be effective in identifying the sa... Object tracking,an important technology in the field of image processing and computer vision,is used to continuously track a specific object or person in an image.This technology may be effective in identifying the same person within one image,but it has limitations in handling multiple images owing to the difficulty in identifying whether the object appearing in other images is the same.When tracking the same object using two or more images,there must be a way to determine that objects existing in different images are the same object.Therefore,this paper attempts to determine the same object present in different images using color information among the unique information of the object.Thus,this study proposes a multiple-object-tracking method using histogram stamp extraction in closed-circuit television applications.The proposed method determines the presence or absence of a target object in an image by comparing the similarity between the image containing the target object and other images.To this end,a unique color value of the target object is extracted based on its color distribution in the image using three methods:mean,mode,and interquartile range.The Top-N accuracy method is used to analyze the accuracy of each method,and the results show that the mean method had an accuracy of 93.5%(Top-2).Furthermore,the positive prediction value experimental results show that the accuracy of the mean method was 65.7%.As a result of the analysis,it is possible to detect and track the same object present in different images using the unique color of the object.Through the results,it is possible to track the same object that can minimize manpower without using personal information when detecting objects in different images.In the last response speed experiment,it was shown that when the mean was used,the color extraction of the object was possible in real time with 0.016954 s.Through this,it is possible to detect and track the same object in real time when using the proposed method. 展开更多
关键词 Data mining deep learning object detection object tracking real-time object detection multiple object image processing
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Multiple Object Tracking through Background Learning
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作者 Deependra Sharma Zainul Abdin Jaffery 《Computer Systems Science & Engineering》 SCIE EI 2023年第1期191-204,共14页
This paper discusses about the new approach of multiple object track-ing relative to background information.The concept of multiple object tracking through background learning is based upon the theory of relativity,th... This paper discusses about the new approach of multiple object track-ing relative to background information.The concept of multiple object tracking through background learning is based upon the theory of relativity,that involves a frame of reference in spatial domain to localize and/or track any object.Thefield of multiple object tracking has seen a lot of research,but researchers have considered the background as redundant.However,in object tracking,the back-ground plays a vital role and leads to definite improvement in the overall process of tracking.In the present work an algorithm is proposed for the multiple object tracking through background learning.The learning framework is based on graph embedding approach for localizing multiple objects.The graph utilizes the inher-ent capabilities of depth modelling that assist in prior to track occlusion avoidance among multiple objects.The proposed algorithm has been compared with the recent work available in literature on numerous performance evaluation measures.It is observed that our proposed algorithm gives better performance. 展开更多
关键词 Object tracking image processing background learning graph embedding algorithm computer vision
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Different response of North Pacific storm tracks in the upper and lower troposphere to jet strength
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作者 Chenming Ma Ming Bao 《Atmospheric and Oceanic Science Letters》 CSCD 2023年第1期1-7,共7页
北太平洋风暴轴的深冬抑制表明风暴轴强度与斜压性之间的线性关系在冬季破裂,本研究基于1979-2019年冷季的再分析数据和拉格朗日跟踪算法,对比分析了高低层扰动的具体生长过程,结果表明太平洋急流的增强有利于高层扰动在急流核东北侧产... 北太平洋风暴轴的深冬抑制表明风暴轴强度与斜压性之间的线性关系在冬季破裂,本研究基于1979-2019年冷季的再分析数据和拉格朗日跟踪算法,对比分析了高低层扰动的具体生长过程,结果表明太平洋急流的增强有利于高层扰动在急流核东北侧产生,但却抑制其在西北太平洋的生成,在急流核上游产生的高层扰动在整个冷季都无法充分发展,只有在急流核下游产生的高层扰动才能正常生长且它们是构成高层太平洋风暴轴的主体,相比之下,低层扰动的生成区和生长区都与斜压区重合,并且它们的生成数量和局部增长率随着斜压性的增强而增强. 展开更多
关键词 深冬抑制 风暴轴 斜压性 生长过程 生成
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紧凑型地波雷达目标检测跟踪一体化实验平台
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作者 孙伟峰 李小彤 《实验室研究与探索》 CAS 北大核心 2024年第3期78-83,共6页
紧凑型地波雷达检测目标时回波信噪比低。应用传统的先检测后跟踪方法进行目标探测时,弱目标回波容易淹没在杂波和噪声中,出现弱目标漏检和虚假点迹误检,导致跟踪时易发生航迹断裂、误跟踪等现象,影响目标跟踪的连续性。为提升紧凑型地... 紧凑型地波雷达检测目标时回波信噪比低。应用传统的先检测后跟踪方法进行目标探测时,弱目标回波容易淹没在杂波和噪声中,出现弱目标漏检和虚假点迹误检,导致跟踪时易发生航迹断裂、误跟踪等现象,影响目标跟踪的连续性。为提升紧凑型地波雷达对海上运动目标的长时跟踪能力,建立检测器与跟踪器之间的信息动态交互机制,提出一种紧凑型地波雷达目标检测跟踪一体化方法。实验结果表明,与先检测后跟踪方法相比,所提方法跟踪得到的平均航迹时长增加了17.52 min。结合工程应用需求,在Matlab R2018b环境下开发了紧凑型地波雷达目标检测跟踪一体化实验平台,为紧凑型地波雷达海上目标探测实验测试提供了平台支撑。 展开更多
关键词 紧凑型地波雷达 弱目标检测 目标跟踪 检测跟踪一体化 点迹-航迹关联
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基于电流多特征融合的窄间隙P-GMAW摆动电弧传感焊缝跟踪方法
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作者 刘文吉 朱鹏飞 +2 位作者 于镇洋 杨嘉昇 肖宇 《传感技术学报》 CAS CSCD 北大核心 2024年第4期612-619,共8页
电弧传感是实现窄间隙焊接焊缝跟踪的主要方式之一。针对电弧传感稳定性差、可靠性低的问题,提出融合摆动周期内电流信息的多个统计学特征进行偏差提取的方法,克服单一数据特征容易受到电弧稳定性影响、导致传感精度下降的问题。首先,... 电弧传感是实现窄间隙焊接焊缝跟踪的主要方式之一。针对电弧传感稳定性差、可靠性低的问题,提出融合摆动周期内电流信息的多个统计学特征进行偏差提取的方法,克服单一数据特征容易受到电弧稳定性影响、导致传感精度下降的问题。首先,提取电流信号的多个时域特征,计算特征矩阵与偏差矢量相关性;然后,取相关性高的特征用主成分分析的方法进行融合,取前两个主成分作为观测数据;最后,基于多分类的支持向量机模型对其进行分类试验。试验结果表明最大误差为0.2 mm,0.1 mm以内的误差占93.75%。该方法对比传统方法精度有所提升,对比神经网络方法,所用训练样本少,训练过程更加简单。 展开更多
关键词 数据处理 焊缝跟踪 特征融合 电弧传感
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