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Multi-task Learning of Semantic Segmentation and Height Estimation for Multi-modal Remote Sensing Images 被引量:2
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作者 Mengyu WANG Zhiyuan YAN +2 位作者 Yingchao FENG Wenhui DIAO Xian SUN 《Journal of Geodesy and Geoinformation Science》 CSCD 2023年第4期27-39,共13页
Deep learning based methods have been successfully applied to semantic segmentation of optical remote sensing images.However,as more and more remote sensing data is available,it is a new challenge to comprehensively u... Deep learning based methods have been successfully applied to semantic segmentation of optical remote sensing images.However,as more and more remote sensing data is available,it is a new challenge to comprehensively utilize multi-modal remote sensing data to break through the performance bottleneck of single-modal interpretation.In addition,semantic segmentation and height estimation in remote sensing data are two tasks with strong correlation,but existing methods usually study individual tasks separately,which leads to high computational resource overhead.To this end,we propose a Multi-Task learning framework for Multi-Modal remote sensing images(MM_MT).Specifically,we design a Cross-Modal Feature Fusion(CMFF)method,which aggregates complementary information of different modalities to improve the accuracy of semantic segmentation and height estimation.Besides,a dual-stream multi-task learning method is introduced for Joint Semantic Segmentation and Height Estimation(JSSHE),extracting common features in a shared network to save time and resources,and then learning task-specific features in two task branches.Experimental results on the public multi-modal remote sensing image dataset Potsdam show that compared to training two tasks independently,multi-task learning saves 20%of training time and achieves competitive performance with mIoU of 83.02%for semantic segmentation and accuracy of 95.26%for height estimation. 展开更多
关键词 multi-modAL MULTI-TASK semantic segmentation height estimation convolutional neural network
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Visual Motion Segmentation in Crowd Videos Based on Spatial-Angular Stacked Sparse Autoencoders
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作者 Adel Hafeezallah Ahlam Al-Dhamari Syed Abd Rahman Abu-Bakar 《Computer Systems Science & Engineering》 SCIE EI 2023年第10期593-611,共19页
Visual motion segmentation(VMS)is an important and key part of many intelligent crowd systems.It can be used to figure out the flow behavior through a crowd and to spot unusual life-threatening incidents like crowd st... Visual motion segmentation(VMS)is an important and key part of many intelligent crowd systems.It can be used to figure out the flow behavior through a crowd and to spot unusual life-threatening incidents like crowd stampedes and crashes,which pose a serious risk to public safety and have resulted in numerous fatalities over the past few decades.Trajectory clustering has become one of the most popular methods in VMS.However,complex data,such as a large number of samples and parameters,makes it difficult for trajectory clustering to work well with accurate motion segmentation results.This study introduces a spatial-angular stacked sparse autoencoder model(SA-SSAE)with l2-regularization and softmax,a powerful deep learning method for visual motion segmentation to cluster similar motion patterns that belong to the same cluster.The proposed model can extract meaningful high-level features using only spatial-angular features obtained from refined tracklets(a.k.a‘trajectories’).We adopt l2-regularization and sparsity regularization,which can learn sparse representations of features,to guarantee the sparsity of the autoencoders.We employ the softmax layer to map the data points into accurate cluster representations.One of the best advantages of the SA-SSAE framework is it can manage VMS even when individuals move around randomly.This framework helps cluster the motion patterns effectively with higher accuracy.We put forward a new dataset with itsmanual ground truth,including 21 crowd videos.Experiments conducted on two crowd benchmarks demonstrate that the proposed model can more accurately group trajectories than the traditional clustering approaches used in previous studies.The proposed SA-SSAE framework achieved a 0.11 improvement in accuracy and a 0.13 improvement in the F-measure compared with the best current method using the CUHK dataset. 展开更多
关键词 Visual motion segmentation crowd behavior analysis trajectory analysis crowd dynamics autoencoders motion patterns
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Multi-modality hierarchical fusion network for lumbar spine segmentation with magnetic resonance images
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作者 Han Yan Guangtao Zhang +1 位作者 Wei Cui Zhuliang Yu 《Control Theory and Technology》 EI CSCD 2024年第4期612-622,共11页
For the analysis of spinal and disc diseases,automated tissue segmentation of the lumbar spine is vital.Due to the continuous and concentrated location of the target,the abundance of edge features,and individual diffe... For the analysis of spinal and disc diseases,automated tissue segmentation of the lumbar spine is vital.Due to the continuous and concentrated location of the target,the abundance of edge features,and individual differences,conventional automatic segmentation methods perform poorly.Since the success of deep learning in the segmentation of medical images has been shown in the past few years,it has been applied to this task in a number of ways.The multi-scale and multi-modal features of lumbar tissues,however,are rarely explored by methodologies of deep learning.Because of the inadequacies in medical images availability,it is crucial to effectively fuse various modes of data collection for model training to alleviate the problem of insufficient samples.In this paper,we propose a novel multi-modality hierarchical fusion network(MHFN)for improving lumbar spine segmentation by learning robust feature representations from multi-modality magnetic resonance images.An adaptive group fusion module(AGFM)is introduced in this paper to fuse features from various modes to extract cross-modality features that could be valuable.Furthermore,to combine features from low to high levels of cross-modality,we design a hierarchical fusion structure based on AGFM.Compared to the other feature fusion methods,AGFM is more effective based on experimental results on multi-modality MR images of the lumbar spine.To further enhance segmentation accuracy,we compare our network with baseline fusion structures.Compared to the baseline fusion structures(input-level:76.27%,layer-level:78.10%,decision-level:79.14%),our network was able to segment fractured vertebrae more accurately(85.05%). 展开更多
关键词 Lumbar spine segmentation Deep learning multi-modality fusion Feature fusion
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The Research of ECG Signal Automatic Segmentation Algorithm Based on Fractal Dimension Trajectory
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作者 Yin-jing GUO~1,Qian Cao~1,Peng Gao~1,Zhi-xin Cheng~1,Wei Xia~2 (1.School of information and electrical engineeringShandong University of Science and Technology Qingdao,China 2.Shandong Fengyuan Coal Industry & Electric Power CO.,LTDZaozhuang,China) 《Journal of Measurement Science and Instrumentation》 CAS 2010年第S1期139-142,共4页
In this paper a kind of ECG signal automatic segmentation algorithm based on ECG fractal dimension trajectory is put forward.First,the ECG signal will be analyzed,then constructing the fractal dimension trajectory of ... In this paper a kind of ECG signal automatic segmentation algorithm based on ECG fractal dimension trajectory is put forward.First,the ECG signal will be analyzed,then constructing the fractal dimension trajectory of ECG signal according to the fractal dimension trajectory constructing algorithm,finally,obtaining ECG signal feature points and ECG automatic segmentation will be realized by the feature of ECG signal fractal dimension trajectory and the feature of ECG frequency domain characteristics.Through Matlab simulation of the algorithm,the results showed that by constructing the ECG fractal dimension trajectory enables ECG location of each component displayed clearly and obtains high success rate of sub-ECG,providing a basis to identify the various components of ECG signal accurately. 展开更多
关键词 ECG fractal theory fractal dimension trajectory automatic segmentation
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Trajectory Time Series Compression Algorithm Based on Unsupervised Segmentation
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作者 Shuang SUN Yan CHEN Zaiji PIAO 《Journal of Systems Science and Information》 CSCD 2024年第3期360-378,共19页
Aiming at the problem of ignoring the importance of starting point features of trajecory segmentation in existing trajectory compression algorithms,a study was conducted on the preprocessing process of trajectory time... Aiming at the problem of ignoring the importance of starting point features of trajecory segmentation in existing trajectory compression algorithms,a study was conducted on the preprocessing process of trajectory time series.Firstly,an algorithm improvement was proposed based on the segmentation algorithm GRASP-UTS(Greedy Randomized Adaptive Search Procedure for Unsupervised Trajectory Segmentation).On the basis of considering trajectory coverage,this algorithm designs an adaptive parameter adjustment to segment long-term trajectory data reasonably and the identification of an optimal starting point for segmentation.Then the compression efficiency of typical offline and online algorithms,such as the Douglas-Peucker algorithm,the Sliding Window algorithm and its enhancements,was compared before and after segmentation.The experimental findings highlight that the Adaptive Parameters GRASP-UTS segmentation approach leads to higher fitting precision in trajectory time series compression and improved algorithm efficiency post-segmentation.Additionally,the compression performance of the Improved Sliding Window algorithm post-segmentation showcases its suitability for trajectories of varying scales,providing reasonable compression accuracy. 展开更多
关键词 trajectory time series unsupervised segmentation trajectory compression greedy ran-domized adaptive search
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Application Research of an Intelligent Detection Algorithm for Vehicle Trajectory Route Deviation
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作者 Jianfei Luo Yadong Xing +2 位作者 Cheng Chen Weiqing Zhang Zhongcheng Wu 《Journal of Computer and Communications》 2023年第10期1-11,共11页
In the vehicle trajectory application system, it is often necessary to detect whether the vehicle deviates from the specified route. Trajectory planning in the traditional route deviation detection is defined by the d... In the vehicle trajectory application system, it is often necessary to detect whether the vehicle deviates from the specified route. Trajectory planning in the traditional route deviation detection is defined by the driver through the mobile phone navigation software, which plays a more auxiliary driving role. This paper presents a method of vehicle trajectory deviation detection. Firstly, the manager customizes the trajectory planning and then uses big data technologies to match the deviation between the trajectory planning and the vehicle trajectory. Finally, it achieves the supervisory function of the manager on the vehicle track route in real-time. The results show that this method could detect the vehicle trajectory deviation quickly and accurately, and has practical application value. 展开更多
关键词 Vehicle Positioning Terminal Vehicle trajectory Route Deviation Real-Time segmentation Analysis Algorithm
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虚实坐标智能匹配与自适应三维轨迹规划
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作者 孟月波 王宙 +2 位作者 韩九强 刘光辉 徐胜军 《控制工程》 CSCD 北大核心 2024年第8期1468-1477,共10页
针对数字孪生增材修复任务中,物件仿真与真实坐标对应困难、三维轨迹误差较大的问题,提出虚实坐标智能匹配与自适应三维轨迹规划方法。采用图像分割方法获取实际场景下物件的分割图像,通过最小外接矩形预估物件真实坐标,仿真端据此执行... 针对数字孪生增材修复任务中,物件仿真与真实坐标对应困难、三维轨迹误差较大的问题,提出虚实坐标智能匹配与自适应三维轨迹规划方法。采用图像分割方法获取实际场景下物件的分割图像,通过最小外接矩形预估物件真实坐标,仿真端据此执行旋转与平移操作,调整仿真物件的模型位置,实现坐标智能匹配;为最小化虚实坐标误差,设计基于Attention的多尺度残差UNet图像分割模型,利用多尺度残差模块获取物件多尺度特征,通过Attention策略增强网络对位置信息的描述。三维轨迹规划部分,设计融合特征高度的自适应分层算法,减少分层高度偏移,缩减阶梯误差;根据分层结果进行轮廓提取、填充,生成三维轨迹。结果表明,坐标匹配误差小于1mm,三维修复轨迹规划质量较高。 展开更多
关键词 增材修复机器人 虚实坐标匹配 三维轨迹规划 图像分割 数字孪生
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基于点云的航发叶片分割及打磨轨迹规划方法
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作者 马国庆 刘启畅 +1 位作者 刘珺玮 曲合拉•金恩斯 《现代制造工程》 CSCD 北大核心 2024年第4期102-108,共7页
针对航发叶片打磨过程中点云分割效果差和轨迹规划中曲面拟合所带来的计算量大的问题,提出了一种基于点云的航发叶片分割及打磨轨迹规划方法,旨在改善点云分割效果并降低计算量。通过结构光相机采集待打磨叶片点云,进行滤波等预处理,并... 针对航发叶片打磨过程中点云分割效果差和轨迹规划中曲面拟合所带来的计算量大的问题,提出了一种基于点云的航发叶片分割及打磨轨迹规划方法,旨在改善点云分割效果并降低计算量。通过结构光相机采集待打磨叶片点云,进行滤波等预处理,并对随机采样一致性(Random Sample Consensus,RANSAC)平面分割算法进行改进,提升算法效率。设计一种结合点云颜色信息的区域生长分割算法,实现叶片待打磨区域的稳定分割。提出一种直接基于点云的三重截面法,配合B样条曲线拟合算法生成预打磨轨迹,并基于等残高算法优化行距,完成打磨轨迹规划。经实验验证,平面分割算法相较于传统方法效率提升40.25%,数据处理效率大大提高。此外,通过改进的区域生长分割算法,叶片打磨轨迹规划效率得到明显提高,其实现效果显著增强。 展开更多
关键词 叶片打磨 平面分割 叶片点云分割 轨迹规划
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基于稀疏采样数据的复杂路网地图匹配算法 被引量:1
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作者 黄银峰 李艳红 +1 位作者 姚静怡 罗昌银 《中南民族大学学报(自然科学版)》 CAS 2024年第4期522-531,共10页
地图匹配是指将GPS定位坐标正确匹配到数字地图的道路上.离线地图匹配是从记录和存储的轨迹数据中寻找车辆行驶的真实路径.采样频率和复杂路网是影响地图匹配正确率的两个最重要的因素.为了提高现有的隐马尔可夫模型地图匹配算法在复杂... 地图匹配是指将GPS定位坐标正确匹配到数字地图的道路上.离线地图匹配是从记录和存储的轨迹数据中寻找车辆行驶的真实路径.采样频率和复杂路网是影响地图匹配正确率的两个最重要的因素.为了提高现有的隐马尔可夫模型地图匹配算法在复杂路网上的正确率,提出了分段验证匹配方法(SV算法).考虑到每一段子轨迹会有k条候选路径,引入一个适应度来评判候选路径与轨迹的吻合程度,选取具有最高适应度的候选路径作为局部最佳匹配路径.此外,所提算法还考虑了路段方向和车辆行驶方向的角度差和路段限速,通过这些约束条件过滤候选路段和候选点,以提高算法效率. 展开更多
关键词 轨迹分段 隐马尔可夫模型 采样频率 复杂路网
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共享电动自行车路段超速风险影响因素分析
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作者 张晓龙 边扬 +2 位作者 赵晓华 黄建玲 尹璐瑶 《东南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第1期214-223,共10页
为探究电动自行车超速行为影响作用机制,基于共享电动自行车GPS轨迹数据,对超速行为进行精准辨识和风险等级划分.考虑土地利用、道路、交通等风险要素,在构建基于机器学习算法的路段超速风险识别模型基础上,通过部分依赖图解析各因素对... 为探究电动自行车超速行为影响作用机制,基于共享电动自行车GPS轨迹数据,对超速行为进行精准辨识和风险等级划分.考虑土地利用、道路、交通等风险要素,在构建基于机器学习算法的路段超速风险识别模型基础上,通过部分依赖图解析各因素对路段超速风险的影响规律.结果表明:相较于随机森林,CatBoost对于路段超速风险的识别效果更好;随着土地利用密度、路侧停车密度的降低,公交线路密度、道路等级、人行道宽度、非机动道宽度的增加,超速风险增加;同时,单向路、非物理隔离的人行道与非机动车道、平峰时段存在较大的路段超速风险.该研究为电动自行车风险骑行行为辨识及影响因素分析提供了一种新的方法,并为非机动车交通安全管理提供了有效的技术支持. 展开更多
关键词 电动自行车 路段超速风险 轨迹数据 机器学习 影响因素分析
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基于渔船轨迹数据的进出港区域识别方法
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作者 崔彤彤 徐硕 刘慧媛 《计算机技术与发展》 2024年第6期155-163,共9页
针对当前渔船进出港区域获取方法成本高、更新周期长等问题,提出了一种基于渔船轨迹数据的渔船进出港区域识别方法。首先,提出基于多特征融合下轨迹点间相似性的轨迹划分算法,将渔船轨迹划分为不同渔船行为的轨迹段;然后,提出特征距离加... 针对当前渔船进出港区域获取方法成本高、更新周期长等问题,提出了一种基于渔船轨迹数据的渔船进出港区域识别方法。首先,提出基于多特征融合下轨迹点间相似性的轨迹划分算法,将渔船轨迹划分为不同渔船行为的轨迹段;然后,提出特征距离加权-K均值聚类算法(Feature Distance Weighted-K-means clustering algorithm,FDW-K-means),将上一步得到的轨迹段特征作为聚类对象,实现渔船进出港轨迹段的提取。最后,综合运用DBSCAN(Density-Based Spatial Clustering of Applications with Noise)聚类算法和Del-Alpha-Shape算法对聚集的渔船进出港轨迹段轨迹点集进行边界提取获得渔船进出港区域。以椒江渔港和博贺渔港2021年3月的渔船轨迹数据为例,识别到椒江渔港和博贺渔港的渔船进出港区域的正确率分别为94.2%和95.8%。与使用K-means聚类算法或传统基于对各特征设定约束条件思想提取轨迹段的方法相比,该方法识别到的渔港渔船进出港区域正确率分别提高了10.7%,8.7%和9.5%,6.6%。实验结果表明所提方法能够有效识别渔船进出港区域,其结果能为渔船进出港监管提供科学参考。 展开更多
关键词 渔船轨迹数据 多特征融合 轨迹划分 K-MEANS 进出港轨迹段 进出港区域
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基于路网复杂度分区的轨迹分段地图匹配方法
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作者 王庆庆 郭杜杜 +2 位作者 王洋 周飞 秦音 《计算机工程与应用》 CSCD 北大核心 2024年第15期261-269,共9页
针对现有大多数地图匹配方法在城市复杂环境下难以有效平衡匹配速度和精度的问题,提出了一种基于路网复杂度分区的轨迹分段地图匹配方法。该方法包括路网分区和轨迹分段匹配两个部分。通过构建的路网复杂度分区模型将路网划分为复杂区... 针对现有大多数地图匹配方法在城市复杂环境下难以有效平衡匹配速度和精度的问题,提出了一种基于路网复杂度分区的轨迹分段地图匹配方法。该方法包括路网分区和轨迹分段匹配两个部分。通过构建的路网复杂度分区模型将路网划分为复杂区域和非复杂区域;对复杂区域内的轨迹段采用改进的隐马尔可夫模型进行匹配,非复杂区域内的轨迹段采用基于几何拓扑的快速匹配模型进行匹配;将不同区域内匹配的轨迹段进行拼接,得到完整轨迹的匹配结果。为得到路网复杂度分区模型的最优参数,进行了11组不同参数设置的对比实验,并将最终结果与ST-matching和传统隐马尔可夫模型两种地图匹配方法匹配的结果进行对比。结果表明,在三个数据集的匹配准确率均在96%以上,比其他两种对比算法匹配时间减少了60%,在保证匹配准确率的前提下有效提升了匹配效率。 展开更多
关键词 地图匹配 路网分区 轨迹分段 隐马尔可夫模型 几何拓扑
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非机动车超越行为轨迹分段识别与分析方法
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作者 张蕊 段予 +1 位作者 孔令争 侯先磊 《交通运输系统工程与信息》 EI CSCD 北大核心 2024年第3期323-332,共10页
非机动车超越次数是非机动车道服务水平评价的重要参数,随着路侧高位视频设备的应用普及,为非机动车超越行为识别提供了良好的视频数据来源。目前有关轨迹分段方法的研究难以适应非机动车行驶角度变化频繁且超越轨迹较长的特点。本文提... 非机动车超越次数是非机动车道服务水平评价的重要参数,随着路侧高位视频设备的应用普及,为非机动车超越行为识别提供了良好的视频数据来源。目前有关轨迹分段方法的研究难以适应非机动车行驶角度变化频繁且超越轨迹较长的特点。本文提出基于片段轨迹时长和分割间隔时间两个参数的轨迹分段方法,根据视频获取的640条超越轨迹数据,分析非机动车各类超越行为的特性,选取纵向平均速度、纵向速度标准差、横向平均速度、横向速度标准差作为特征参数,基于K最近邻(K-Nearest Neighbor, KNN)算法建立非机动车超越分类模型。根据超越行为持续时间平均值确定自行车片段轨迹时长取值为[4, 9] s,分割间隔时间取值为[1, 8] s;电动自行车的片段轨迹时长取值为[4, 8] s,分割间隔时间取值为[1, 7] s,利用分类模型对各参数组合分段获得的非机动车轨迹片段进行识别。研究结果表明:自行车片段轨迹时长为8 s,分割间隔时间为6 s;电动自行车片段轨迹时长为6 s,分割间隔时间为4 s时,对应的识别误差百分比最低,分段效果最佳。 展开更多
关键词 城市交通 超越行为识别 轨迹分段 非机动车 片段轨迹时长 分割间隔时间
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基于信息熵的非机动车超越轨迹分段方法
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作者 张蕊 王子轩 +1 位作者 孔令争 侯先磊 《交通信息与安全》 CSCD 北大核心 2024年第2期115-123,共9页
通过自行车轨迹识别超越行为是评价非机动车交通服务水平的重要工作之一。针对基于阈值分段方法中需对不同轨迹确定不同的阈值问题,引入信息熵对非机动车超越轨迹进行分段。根据实测视频提取了780条非机动车超越轨迹数据,包括了在视频... 通过自行车轨迹识别超越行为是评价非机动车交通服务水平的重要工作之一。针对基于阈值分段方法中需对不同轨迹确定不同的阈值问题,引入信息熵对非机动车超越轨迹进行分段。根据实测视频提取了780条非机动车超越轨迹数据,包括了在视频中可能存在的11种超越轨迹情形,并通过对超越过程中各阶段的特征参数分析,最终选取横向加速度、横向偏移距离、偏移角度作为基于信息熵分段的特征参数,通过引入信息熵理论,提出基于信息熵的非机动车超越轨迹分段方法和分段判断条件。根据信息熵理论中,分段后的2段子轨迹中的特征参数概率密度相较分割前更接近时熵增的定律,同时考虑非机动车超越轨迹的特征参数特征,提出适用于非机动车超越轨迹的信息熵分段标准。以实测路段非机动车超越轨迹数据为实验样本,将基于各特征参数的信息熵分段结果与基于时间、速度阈值的分段结果分别带入K最近邻(K-nearest neighbor,KNN)分类算法中进行超越轨迹识别,并利用轨迹覆盖度指标评价不同分段方法的超越轨迹分段效果。实验结果表明:基于信息熵超越轨迹分段方法的超越轨迹覆盖度平均为83.0%,优于基于阈值分段方法的轨迹覆盖度平均值79.7%,且基于横向加速度信息熵分段法的平均轨迹覆盖度为85.1%,分段效果相较于其他特征参数信息熵分段方法效果最优。 展开更多
关键词 交通工程 轨迹分段 非机动车超越行为 信息熵 特征参数选取 轨迹覆盖度
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基于S-Transformer的多模态船舶轨迹预测
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作者 柯研 陈姚节 《计算机系统应用》 2024年第3期273-280,共8页
船舶轨迹预测是实现船舶智能航行的前提与基础.目前,针对船舶轨迹预测的研究大多仅依赖于船舶自动识别系统(AIS)历史数据,而未利用到船舶上其他传感器信息.于是本文提出了一种多模态轨迹预测模型——S-Transformer.在该网络中,电子海图... 船舶轨迹预测是实现船舶智能航行的前提与基础.目前,针对船舶轨迹预测的研究大多仅依赖于船舶自动识别系统(AIS)历史数据,而未利用到船舶上其他传感器信息.于是本文提出了一种多模态轨迹预测模型——S-Transformer.在该网络中,电子海图中的海水/陆地被分割作为辅助训练目标与真实舟山港AIS数据加以综合从而对模型进行训练,并对船舶未来航行轨迹进行预测;其中,本文还引入segment recurrence来捕获AIS数据的长期依赖关系.实验结果表明,S-Transformer在不同的船舶行驶情况中都有优秀的预测结果,并优于相关预测任务的单模态基准模型. 展开更多
关键词 轨迹预测 多模态 TRANSFORMER 语义分割
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直角坐标机器人轨迹自适应NURBS曲线插补算法
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作者 潘忠英 王玉清 《机械设计与制造》 北大核心 2024年第8期307-311,共5页
为了提升直角坐标机器人轨迹的分段精度,提出了一种直角坐标机器人轨迹自适应分段NURBS曲线插补算法。基于NURBSS曲线自适应速度调整原理,通过加减速区域分析和分段预处理,找出曲线上的曲率极大值,分辨这些点是否为速度敏感点,并通过前... 为了提升直角坐标机器人轨迹的分段精度,提出了一种直角坐标机器人轨迹自适应分段NURBS曲线插补算法。基于NURBSS曲线自适应速度调整原理,通过加减速区域分析和分段预处理,找出曲线上的曲率极大值,分辨这些点是否为速度敏感点,并通过前瞻处理,逆向插补每个速度敏感点,规划敏感区的进给速度,使各个轴的加减速限制与弓高误差可同时得到满足,并确定减速点位置,实时插补处理根据进给速度与当前插补点的位置,计算下一插补点的位置,实现实时插补。实验表明:该算法具有较高的分段精度与分段效率;可满足分段加减速的要求;速度波动率最低且始终在给定的速度范围内,能够良好地控制进给速度;前瞻处理后插补速度减速效果较好;插补计算耗时仅为0.6/ms。 展开更多
关键词 直角坐标 机器人轨迹 自适应分段 NURBS 曲线插补算法 进给速度
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改进DeepLabV3+网络的指针轨迹图像识别
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作者 袁帅 蒋强 饶兵 《沈阳理工大学学报》 CAS 2024年第1期50-54,60,共6页
指针式机械记录仪通常用于记录精密设备运输过程中的震动轨迹图像,为了更好地监测运输过程中车辆颠簸对仪器设备的影响,提出一种改进DeepLabV3+网络的指针轨迹图像语义分割方法。首先将骨干网络替换为MobileNetV3,实现模型的轻量化;然... 指针式机械记录仪通常用于记录精密设备运输过程中的震动轨迹图像,为了更好地监测运输过程中车辆颠簸对仪器设备的影响,提出一种改进DeepLabV3+网络的指针轨迹图像语义分割方法。首先将骨干网络替换为MobileNetV3,实现模型的轻量化;然后将解码器中4倍上采样替换为2次2倍上采样,增强图像中像素的连续性,使预测结果更接近原始图像。在自制数据集上进行对比实验,结果表明:改进DeepLabV3+网络的平均交并比(MIoU)达到85.84%,比原始DeepLabV3+网络提高了3.57%,单位时间内检测图片数量(FPS)提高了3.58 s^(-1);改进DeepLabV3+网络在识别精度和速度上具有明显的优势,可为精密仪器检测提供数据支持。 展开更多
关键词 改进DeepLabV3+ 语义分割 轨迹图像识别 轻量化
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Segmentation of Head and Neck Tumors Using Dual PET/CT Imaging:Comparative Analysis of 2D,2.5D,and 3D Approaches Using UNet Transformer
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作者 Mohammed A.Mahdi Shahanawaj Ahamad +3 位作者 Sawsan A.Saad Alaa Dafhalla Alawi Alqushaibi Rizwan Qureshi 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第12期2351-2373,共23页
The segmentation of head and neck(H&N)tumors in dual Positron Emission Tomography/Computed Tomogra-phy(PET/CT)imaging is a critical task in medical imaging,providing essential information for diagnosis,treatment p... The segmentation of head and neck(H&N)tumors in dual Positron Emission Tomography/Computed Tomogra-phy(PET/CT)imaging is a critical task in medical imaging,providing essential information for diagnosis,treatment planning,and outcome prediction.Motivated by the need for more accurate and robust segmentation methods,this study addresses key research gaps in the application of deep learning techniques to multimodal medical images.Specifically,it investigates the limitations of existing 2D and 3D models in capturing complex tumor structures and proposes an innovative 2.5D UNet Transformer model as a solution.The primary research questions guiding this study are:(1)How can the integration of convolutional neural networks(CNNs)and transformer networks enhance segmentation accuracy in dual PET/CT imaging?(2)What are the comparative advantages of 2D,2.5D,and 3D model configurations in this context?To answer these questions,we aimed to develop and evaluate advanced deep-learning models that leverage the strengths of both CNNs and transformers.Our proposed methodology involved a comprehensive preprocessing pipeline,including normalization,contrast enhancement,and resampling,followed by segmentation using 2D,2.5D,and 3D UNet Transformer models.The models were trained and tested on three diverse datasets:HeckTor2022,AutoPET2023,and SegRap2023.Performance was assessed using metrics such as Dice Similarity Coefficient,Jaccard Index,Average Surface Distance(ASD),and Relative Absolute Volume Difference(RAVD).The findings demonstrate that the 2.5D UNet Transformer model consistently outperformed the 2D and 3D models across most metrics,achieving the highest Dice and Jaccard values,indicating superior segmentation accuracy.For instance,on the HeckTor2022 dataset,the 2.5D model achieved a Dice score of 81.777 and a Jaccard index of 0.705,surpassing other model configurations.The 3D model showed strong boundary delineation performance but exhibited variability across datasets,while the 2D model,although effective,generally underperformed compared to its 2.5D and 3D counterparts.Compared to related literature,our study confirms the advantages of incorporating additional spatial context,as seen in the improved performance of the 2.5D model.This research fills a significant gap by providing a detailed comparative analysis of different model dimensions and their impact on H&N segmentation accuracy in dual PET/CT imaging. 展开更多
关键词 PET/CT imaging tumor segmentation weighted fusion transformer multi-modal imaging deep learning neural networks clinical oncology
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基于视觉检测定位的刷头上料系统设计
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作者 王化明 朱雄伟 +2 位作者 杨雪峰 徐轲 于金龙 《江苏大学学报(自然科学版)》 CAS 北大核心 2023年第4期431-436,共6页
针对传统刷头上料系统结构复杂、效率低下的问题,研发了一种基于视觉检测定位的刷头上料系统.通过最大类间方差法和基于图像的矩对刷头进行分割和姿态计算;对刷头头部进行椭圆拟合,以椭圆中心作为刷头的位置,并通过支持向量机判断刷头正... 针对传统刷头上料系统结构复杂、效率低下的问题,研发了一种基于视觉检测定位的刷头上料系统.通过最大类间方差法和基于图像的矩对刷头进行分割和姿态计算;对刷头头部进行椭圆拟合,以椭圆中心作为刷头的位置,并通过支持向量机判断刷头正反;采用3-4-5次多项式运动规律进行轨迹规划,控制机器人平稳运行;构建了刷头上料系统,试验结果表明:系统可以快速准确地检测定位刷头中心,误差不超过0.3 mm,能以5 s/支的节拍进行上料,满足实际需求. 展开更多
关键词 牙刷 刷头分割 姿态识别 位置计算 轨迹规划
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基于相机朝向变化的增量式位姿图分段算法
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作者 范涵奇 王劭靖 《计算机科学》 CSCD 北大核心 2023年第7期152-159,共8页
位姿图优化是估计相机轨迹过程中减少累积误差的重要方法,但随着相机的不断运动,位姿图的规模会不断增大导致优化速度下降,使得轨迹估计难以应用于AR/VR(Augmented Reality/Virtual Reality)等实时性要求较高的领域。针对此问题,文中提... 位姿图优化是估计相机轨迹过程中减少累积误差的重要方法,但随着相机的不断运动,位姿图的规模会不断增大导致优化速度下降,使得轨迹估计难以应用于AR/VR(Augmented Reality/Virtual Reality)等实时性要求较高的领域。针对此问题,文中提出了一种基于相机朝向变化的增量式位姿图分段算法。所提算法能够将位姿图在相机发生朝向变化较大的时刻进行分段,从而只对这些朝向变化较大的相机进行位姿图优化,以有效减小位姿图优化的规模,提高优化速度。针对其余未进行位姿图优化的每个相机,分别将其所在轨迹段的起始相机和终止相机作为参考相机,将根据不同参考相机估计出的不同位姿进行加权平均,从而求解出相机的最终位姿,既避免了非线性优化的大量计算,又降低了噪声的影响,达到了较高的精度。在EuRoC,TUM和KITTI数据集上进行了实验,结果表明,所提算法在减小位姿图优化规模的基础上保证了相机轨迹的精度。 展开更多
关键词 位姿图 相机朝向 轨迹分段 加权平均 增量式
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