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基于改进PointNet++的中压电力线点云分类方法
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作者 雒建艳 《应用激光》 北大核心 2025年第3期146-158,共13页
针对中压电力线点云分类中存在的噪声干扰、分类精度低和鲁棒性不足的问题,提出一种基于改进PointNet++的中压电力线点云分类方法。首先,通过多种手段提取点云空间信息、几何特征以及局部几何特征等多维度特征,为点云单点构造40维特征向... 针对中压电力线点云分类中存在的噪声干扰、分类精度低和鲁棒性不足的问题,提出一种基于改进PointNet++的中压电力线点云分类方法。首先,通过多种手段提取点云空间信息、几何特征以及局部几何特征等多维度特征,为点云单点构造40维特征向量;然后对PointNet++进行改进,引入了点注意力模块(point attention module,PAM)和组注意力模块(group attention module,GAM),同时与层归一化(layer norm)和残差连接结构组合使用,用以增强其特征的细节捕捉能力,降低复杂环境对分类效果影响;最后采用某地机载采集的10 kV中压电力线走廊数据构建数据集,进行了方法验证。实验结果表明,所提方法在Precision、Recall和F_1-score上均优于传统机器学习方法和基于PointNet、PointNet++的深度学习方法。相较于PointNet++(XYZ+Features),所提方法在Precision、Recall和F_1-score上分别高出1.6个百分点、5.3个百分点和4.6个百分点,且通过可视化结果进一步验证了PAM和GAM的有效性。验证了所提方法在中压电力线点云的提取上更为精确,其结构特征更加清晰,且与周围环境的区分度更高。 展开更多
关键词 激光点云 注意力机制 pointNet++ 中压电力线 点云分类
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基于DI-PointNet的变电站主设备点云高精度语义分割方法 被引量:1
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作者 裴少通 孙海超 +2 位作者 孙志周 胡晨龙 祝雨馨 《电工技术学报》 北大核心 2025年第9期2917-2930,共14页
在变电站机器人巡检任务中,三维点云数据的高精度语义分割是关键技术之一,有助于机器人理解电力设备、障碍物和其他物体的空间布局。然而,现有的点云分割算法在变电站场景中的应用效果有限,准确度较低、计算复杂度高,难以实现对变电站... 在变电站机器人巡检任务中,三维点云数据的高精度语义分割是关键技术之一,有助于机器人理解电力设备、障碍物和其他物体的空间布局。然而,现有的点云分割算法在变电站场景中的应用效果有限,准确度较低、计算复杂度高,难以实现对变电站主设备点云的准确分割。为了解决这一问题,该文提出了一种基于PointNet++的DI-PointNet算法。首先,采用双层连续变换器模块增强点云之间的信息交互,有效地聚合长距离上下文,增大网络有效感受野;其次,通过分层键采样策略生成自注意力机制所需的键值,降低算法复杂度;最后,使用倒置残差模块,通过倒置瓶颈设计和残差连接缓解梯度消失,有效地增加模型的深度,同时降低计算复杂度。此外,该文构建了变电站点云数据集,对DI-PointNet算法进行详细的消融实验,并与主流深度学习算法和电力领域典型点云分割算法进行对比。实验验证结果表明,DI-PointNet算法对变电站主设备点云分割的平均交并比达到82.5%,相比PointNet++算法提高了2.1个百分点,且总体精度提高了3.4个百分点,达到90.1%。DI-PointNet算法为智能电力设备巡检和维护提供了有效的解决方案。 展开更多
关键词 点云语义分割 双层连续变换器 分层键采样 倒置残差 变电站
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基于SwinPoinTr的视角受限下杏鲍菇表型参数测量方法
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作者 谢立敏 黄轶 +2 位作者 吴昊宇 叶大鹏 方兵 《农业机械学报》 北大核心 2025年第3期148-157,共10页
针对菇房内杏鲍菇表型参数测量任务中,由于扫描设备视角受限,扫描的杏鲍菇点云出现残缺问题,基于AdaPoinTr(Adaptive geometry-aware point transformers)提出了改进的SwinPoinTr模型,实现了对残缺杏鲍菇点云的准确补全和杏鲍菇表型参... 针对菇房内杏鲍菇表型参数测量任务中,由于扫描设备视角受限,扫描的杏鲍菇点云出现残缺问题,基于AdaPoinTr(Adaptive geometry-aware point transformers)提出了改进的SwinPoinTr模型,实现了对残缺杏鲍菇点云的准确补全和杏鲍菇表型参数的测量。该方法在使用提出的特征重塑模块的基础上,构建具有几何感知能力的层次化Transformer编码模块,提高了模型对输入点云的利用率和模型捕捉点云细节特征的能力。然后基于泊松重建方法完成了补全点云表面重建,并测量到杏鲍菇表型参数。实验结果表明,本文所提算法在残缺杏鲍菇点云补全任务中,模型倒角距离为1.316×10^(-4),地球移动距离为21.3282,F1分数为87.87%。在表型参数估测任务中,模型对杏鲍菇菌高、体积、表面积估测结果的决定系数分别为0.9582、0.9596、0.9605,均方根误差分别为4.4213 mm、10.8185 cm^(3)、7.5778 cm^(2)。结果证实了该研究方法可以有效地补全残缺的杏鲍菇点云,可以为菇房内杏鲍菇表型参数测量提供基础。 展开更多
关键词 杏鲍菇 智慧菇房 表型参数 点云补全 泊松重建 Swinpointr
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基于改进PointNet++的城市道路点云分类方法
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作者 田晟 熊辰崟 龙安洋 《广西师范大学学报(自然科学版)》 北大核心 2025年第4期1-14,共14页
城市道路场景的点云数据量巨大、类别分布不平衡且密度极不均匀,导致现有的点云分类方法难以满足高精度分类的需求。为了解决现有PointNet++网络对局部特征提取不充分的问题,本文充分考虑场景的上下文信息和点之间的全局依赖性,构建融... 城市道路场景的点云数据量巨大、类别分布不平衡且密度极不均匀,导致现有的点云分类方法难以满足高精度分类的需求。为了解决现有PointNet++网络对局部特征提取不充分的问题,本文充分考虑场景的上下文信息和点之间的全局依赖性,构建融合上下文信息的PointNet++点云分类网络模型。首先,基于注意力机制设计局部特征聚合模块,通过动态地融合邻域点特征以充分捕获局部信息。其次,考虑现有的分类模型不能顾及上下文信息,导致复杂场景下的分类性能受限,本文构建上下文感知模块和双注意力模块,从多个维度提取上下文信息,进一步增强特征的表达能力。实验结果表明:改进模型在大型点云数据集下具有更高的分类精度及更强的泛化性能(总体分类精度在Oakland和Paris公开数据集上分别为98.70%和96.84%),更适用于大规模点云分类。 展开更多
关键词 点云分类 pointNet++ 局部特征 注意力机制 上下文信息 城市道路
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Point-GBLS:结合深宽度学习的三维点云分类网络
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作者 张国有 左嘉欣 +3 位作者 潘理虎 郝志祥 郭伟 张雪楠 《计算机系统应用》 2025年第3期1-13,共13页
基于点云的三维物体识别和检测是计算机视觉和自主导航领域的一个重要研究课题.如今,深度学习算法大大提高了三维点云分类的准确性和鲁棒性.然而,深度学习网络通常存在网络结构复杂、训练过程耗时等问题.本文提出了一种三维点云分类网络... 基于点云的三维物体识别和检测是计算机视觉和自主导航领域的一个重要研究课题.如今,深度学习算法大大提高了三维点云分类的准确性和鲁棒性.然而,深度学习网络通常存在网络结构复杂、训练过程耗时等问题.本文提出了一种三维点云分类网络Point-GBLS,它将深度学习和宽度学习系统结合在一起.网络结构简单,训练时间短.首先通过基于深度学习的特征提取网络提取点云特征,然后用改进的宽度学习系统对其进行分类.ModelNet40和ScanObjectNN数据集上的实验表明,Point-GBLS识别准确率分别达到92%以上和78%以上,训练时间低于同类深度学习方法的50%以上,优于具有相同骨干的深度学习网络. 展开更多
关键词 三维模型分类 点云 深度学习 宽度学习系统
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基于Point Transformer方法的鱼类三维点云模型分类
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作者 胡少秋 段瑞 +3 位作者 张东旭 鲍江辉 吕华飞 段明 《水生生物学报》 北大核心 2025年第2期146-155,共10页
为实现对不同鱼类的精准分类,研究共采集110尾真实鱼类的三维模型,对获取的3D模型进行基于预处理、旋转增强和下采样等操作后,获取了1650尾实验样本。然后基于Point Transformer网络和2个三维分类的对比网络进行数据集的分类训练和验证... 为实现对不同鱼类的精准分类,研究共采集110尾真实鱼类的三维模型,对获取的3D模型进行基于预处理、旋转增强和下采样等操作后,获取了1650尾实验样本。然后基于Point Transformer网络和2个三维分类的对比网络进行数据集的分类训练和验证。结果表明,利用本实验的目标方法Point Transformer获得了比2个对比网络更好的分类结果,整体的分类准确率能够达到91.9%。同时对所使用的三维分类网络进行有效性评估,3个模型对于5种真实鱼类模型的分类是有意义的,其中Point Transformer的模型ROC曲线准确率最高,AUC面积最大,对于三维鱼类数据集的分类最为有效。研究提供了一种可以实现对鱼类三维模型进行精准分类的方法,为以后的智能化渔业资源监测提供一种新的技术手段。 展开更多
关键词 点云处理 point Transformer 三维模型 鱼类分类
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基于Point-Attention点云分类的激光雷达故障诊断方法研究
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作者 谭光兴 程星 陈海峰 《现代电子技术》 北大核心 2025年第20期10-17,共8页
在智能车辆和自主机器人领域,激光雷达传感器因高精度和可靠性,被广泛应用于环境感知和物体检测,因此其故障诊断尤为重要。激光雷达内部的故障往往有固件提醒,而外部环境因素导致的故障检测挑战较大,比如车辆形变、污垢等导致的激光点... 在智能车辆和自主机器人领域,激光雷达传感器因高精度和可靠性,被广泛应用于环境感知和物体检测,因此其故障诊断尤为重要。激光雷达内部的故障往往有固件提醒,而外部环境因素导致的故障检测挑战较大,比如车辆形变、污垢等导致的激光点云遮挡故障,难以直接在固件层面体现,需通过外部检测进行诊断。为此,提出一种基于Point-Attention激光雷达遮挡故障诊断方法。首先,结合多头几何注意力机制模块与CBAM模块、残差连接机制,增强了模型对点云数据中关键特征的提取能力,提高了分类准确性和鲁棒性;在真实的ScanObjectNN数据集和ModelNet40基准数据集上对Point-Attention模型进行了实验。该模型在分类任务上准确率分别达到了93.7%、82.5%。其次,融合了一种时间特征捕捉机制,从而使模型能够更好地适应现实场景中的时间相关性,进而更准确地处理激光雷达的遮挡故障。实验结果表明,所提方法能有效诊断激光雷达遮挡故障,最佳总体精度达99%以上,为激光雷达故障诊断提供了一种高效准确的解决方案。 展开更多
关键词 激光雷达 故障诊断 点云分类 残差连接 遮挡检测 时间特征捕捉
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Optimizing electronic structure through point defect engineering for enhanced electrocatalytic energy conversion
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作者 Wei Ma Jiahao Yao +6 位作者 Fang Xie Xinqi Wang Hao Wan Xiangjian Shen Lili Zhang Menggai Jiao Zhen Zhou 《Green Energy & Environment》 SCIE EI CAS 2025年第1期109-131,共23页
Point defect engineering endows catalysts with novel physical and chemical properties,elevating their electrocatalytic efficiency.The introduction of defects emerges as a promising strategy,effectively modifying the e... Point defect engineering endows catalysts with novel physical and chemical properties,elevating their electrocatalytic efficiency.The introduction of defects emerges as a promising strategy,effectively modifying the electronic structure of active sites.This optimization influences the adsorption energy of intermediates,thereby mitigating reaction energy barriers,altering paths,enhancing selectivity,and ultimately improving the catalytic efficiency of electrocatalysts.To elucidate the impact of defects on the electrocatalytic process,we comprehensively outline the roles of various point defects,their synthetic methodologies,and characterization techniques.Importantly,we consolidate insights into the relationship between point defects and catalytic activity for hydrogen/oxygen evolution and CO_(2)/O_(2)/N_(2) reduction reactions by integrating mechanisms from diverse reactions.This underscores the pivotal role of point defects in enhancing catalytic performance.At last,the principal challenges and prospects associated with point defects in current electrocatalysts are proposed,emphasizing their role in advancing the efficiency of electrochemical energy storage and conversion materials. 展开更多
关键词 point defect engineering DOPING VACANCY ELECTROCATALYSIS Electronic structure
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Nomenclature and location of acupuncture points for laboratory animals Part 2 被引量:1
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作者 《World Journal of Acupuncture-Moxibustion》 2025年第2期163-165,共3页
This paper introduces part of the content in the association standard,T/CAAM0002–2020 Nomenclature and Location of Acupuncture Points for Laboratory Animals Part 2:Rat.This standard was released by the China Associat... This paper introduces part of the content in the association standard,T/CAAM0002–2020 Nomenclature and Location of Acupuncture Points for Laboratory Animals Part 2:Rat.This standard was released by the China Association of Acupuncture and Moxibustion on May 15,2020,implemented on October 31,2020,and published by Standards Press of China.The standard was drafted by the Institute of Acupuncture and Moxibustion,China Academy of Chinese Medical Sciences,and the Nanjing University of Chinese Medicine.Principal draftsmen:Xiang-hong JING and Xing-bang HUA.Participating draftsmen:Wan-Zhu BAI,Bin XU,Dong-sheng XU,Yi GUO,Tie-ming MA,Xin-jun WANG,and Sheng-feng LU. 展开更多
关键词 acupuncture points STANDARD NOMENCLATURE rat association standardt caam LOCATION acupuncture moxibustion
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Coincidence Point and Common Fixed Point Theorems on b-Metric-like Spaces
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作者 LUO Ting 《应用数学》 北大核心 2025年第3期831-840,共10页
In this paper,we establish common fixed point theorems for expansive map?pings on b-metric-like space and coincidence point for f-weakly isotone increasing mappings in partially ordered b-metric-like space.The main re... In this paper,we establish common fixed point theorems for expansive map?pings on b-metric-like space and coincidence point for f-weakly isotone increasing mappings in partially ordered b-metric-like space.The main results generalize and extend several well-known comparable results from the existing literature.Moreover,some examples are provided to illustrate the main results. 展开更多
关键词 b-metric-like space Partially ordered b-metric-like space Expansive mapping f-weakly isotone mapping Coincidence point Common fixed point
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The(Homotopy)Fixed Point Set of S^(1)-Actions on Rationally Elliptic 4-Manifolds
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作者 Chen Huimin Liu Xiugui 《南开大学学报(自然科学版)》 北大核心 2025年第3期32-37,共6页
Let X be a closed simply connected rationally elliptic 4-manifold.The rational homotopy type of homotopy fixed point sets X^(hS^(1))is determined,and based on some relations between X^(hS^(1))and X^(S^(1)),the rationa... Let X be a closed simply connected rationally elliptic 4-manifold.The rational homotopy type of homotopy fixed point sets X^(hS^(1))is determined,and based on some relations between X^(hS^(1))and X^(S^(1)),the rational homotopy type of the fixed point set X^(S^(1))is determined. 展开更多
关键词 rationally elliptic 4-manifolds rational homotopy type homotopy fixed point set fixed point set
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基于改进PointNet++的船舶管路重建方法
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作者 冯彦淏 邓志杰 +2 位作者 刘维 沈彬 王皓 《机械设计与研究》 北大核心 2025年第5期86-92,共7页
船舶的管路系统是船舶可靠运行的保障,具有零部件种类多和结构复杂的特点。针对船舶管路系统在维护与替换过程中重建效率低和精度差的问题,对经典的点云深度学习网络PointNet++进行了改进,提出了一种船舶管路的重建方法。通过构建管路... 船舶的管路系统是船舶可靠运行的保障,具有零部件种类多和结构复杂的特点。针对船舶管路系统在维护与替换过程中重建效率低和精度差的问题,对经典的点云深度学习网络PointNet++进行了改进,提出了一种船舶管路的重建方法。通过构建管路部件分割数据集,生成了高质量训练样本;对PointNet++模型采取多尺度采样半径调整和损失均衡化的改进策略,使其能够准确和均衡地捕捉各类部件的局部特征;根据分割结果求解出零部件特征参数和零部件之间的连接关系,实现了拓扑结构的恢复和管路的重建。实验结果显示,改进后的PointNet++模型在管路部件分割精度上取得了提升,对少数类部件的识别和分割更为精准;在管路重建方面实现了较高的精度,同时也保证了安装精度和可替换性,验证了所提方法可以满足实际船舶维修中高精度、自动化重建管路的需求,有效提升了管路替换的生产效率和可靠性。 展开更多
关键词 管路重建 虚拟数据集 点云分割 pointNet++
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Therapeutic Effects of 35 kDa Hyaluronan Injection at Trigger Points in the Treatment of Myofascial Pain Syndrome
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作者 Enkhbat Purevsuren Dylan Treger +5 位作者 Zhaohui Ma Xiaoxiao Jia Taivanbat Ganbaatar Munkh-Amgalan Gantumur Mizhou Hui Davaajargal Nkhtuvshin 《International Journal of Clinical Medicine》 2025年第1期1-15,共15页
Objectives: This study aimed to evaluate the prolonged therapeutic effects of a 35 kDa molecular weight hyaluronan fragment (HA35) in alleviating pain associated with myofascial pain syndrome (MPS). Hyaluronan interac... Objectives: This study aimed to evaluate the prolonged therapeutic effects of a 35 kDa molecular weight hyaluronan fragment (HA35) in alleviating pain associated with myofascial pain syndrome (MPS). Hyaluronan interacts with various receptors in the human body, including CD44, LYVE-1, RHAMM, and TLR2, and is well-known for its analgesic effects when used in intra-articular or ultrasound-guided nerve trunk injections. Studies have shown that hyaluronidase cleaves high molecular weight HA to generate HA35, a low molecular weight fragment with enhanced tissue permeability, capable of binding to HA receptors on cell surfaces to produce broad-spectrum analgesic effects. Methods: Ten patients diagnosed with MPS were treated and assessed in this study. HA35 was administered through injection at a dosage of 100 mg daily for 15 days. Patients evaluated their MPS, overall pain levels, and treatment satisfaction using the Numerical Pain Rating Scale (NPRS), the Global Pain Scale (GPS), and the Treatment Satisfaction Questionnaire for Medication (TSQM 1.4). Follow-up evaluations were performed three months post-treatment to assess the duration of therapeutic effects. Results: Significant improvements were observed in NPRS, GPS, and TSQM scores both during and after the treatment period (P Conclusions: HA35 provides effective and sustained relief from pain associated with MPS, demonstrating a prolonged therapeutic benefit. 展开更多
关键词 35 kDa Hyaluronan Fragment HA35 PAIN Myofascial Pain Syndrome Myofascial Trigger points
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Research on the Development of the Grade Point Average System in Higher Education-Re-understand the Connotation and Function of GPA
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作者 Wenxiu Zhang 《Journal of Contemporary Educational Research》 2025年第9期225-231,共7页
With the continuous advancement of the internationalization of higher education in China,the Grade Point Average(GPA)has become a primary indicator for evaluating academic performance in universities,playing a positiv... With the continuous advancement of the internationalization of higher education in China,the Grade Point Average(GPA)has become a primary indicator for evaluating academic performance in universities,playing a positive role in educational management.However,as it is closely tied to students’immediate interests,such as awards,exemptions from entrance exams for postgraduate recommendations,and domestic or international further education,certain new issues have emerged in its practical application.These problems have hindered the effective functioning of the GPA system,attracting widespread attention.This paper examines the origin,connotation,and theoretical assumptions of the GPA system,discusses its positive functions and existing challenges,and proposes recommendations for further improving academic evaluation. 展开更多
关键词 point system Grade point average(GPA) Academic evaluation Educational management
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Nomenclature and location of acupuncture points for laboratory animals Part 3:Mouse
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作者 《World Journal of Acupuncture-Moxibustion》 2025年第2期160-162,共3页
This paper introduces part of the content in the association standard,T/CAAM0002–2020 Nomenclature and Location of Acupuncture Points for Laboratory Animals Part 3:Mouse.This standard was released by the China Associ... This paper introduces part of the content in the association standard,T/CAAM0002–2020 Nomenclature and Location of Acupuncture Points for Laboratory Animals Part 3:Mouse.This standard was released by the China Association of Acupuncture and Moxibustion on May 15,2020,implemented on October 31,2020,and published by Standards Press of China.The standard was drafted by the Institute of Acupuncture and Moxibustion,China Academy of Chinese Medical Sciences,and the Nanjing University of Chinese Medicine.Principal draftsmen:Xiang-hong JING and Xing-bang HUA.Participating draftsmen:Wan-zhu BAI,Bin XU,Dong-sheng XU,Yi GUO,Tie-ming MA,Xin-jun WANG,and Sheng-feng LU. 展开更多
关键词 acupuncture points STANDARD MOUSE NOMENCLATURE location acupuncture points association standardt caam LOCATION acupuncture moxibustion
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Research on Airborne Point Cloud Data Registration Using Urban Buildings as an Example
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作者 Yajun Fan Yujun Shi +1 位作者 Chengjie Su Kai Wang 《Journal of World Architecture》 2025年第4期35-42,共8页
Airborne LiDAR(Light Detection and Ranging)is an evolving high-tech active remote sensing technology that has the capability to acquire large-area topographic data and can quickly generate DEM(Digital Elevation Model)... Airborne LiDAR(Light Detection and Ranging)is an evolving high-tech active remote sensing technology that has the capability to acquire large-area topographic data and can quickly generate DEM(Digital Elevation Model)products.Combined with image data,this technology can further enrich and extract spatial geographic information.However,practically,due to the limited operating range of airborne LiDAR and the large area of task,it would be necessary to perform registration and stitching process on point clouds of adjacent flight strips.By eliminating grow errors,the systematic errors in the data need to be effectively reduced.Thus,this paper conducts research on point cloud registration methods in urban building areas,aiming to improve the accuracy and processing efficiency of airborne LiDAR data.Meanwhile,an improved post-ICP(Iterative Closest Point)point cloud registration method was proposed in this study to determine the accurate registration and efficient stitching of point clouds,which capable to provide a potential technical support for applicants in related field. 展开更多
关键词 Airborne LiDAR point cloud registration point cloud data processing Systematic error
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Perceptual point cloud quality assessment for immersive metaverse experience
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作者 Baoping Cheng Lei Luo +2 位作者 Ziyang He Ce Zhu Xiaoming Tao 《Digital Communications and Networks》 2025年第3期806-817,共12页
Perceptual quality assessment for point cloud is critical for immersive metaverse experience and is a challenging task.Firstly,because point cloud is formed by unstructured 3D points that makes the topology more compl... Perceptual quality assessment for point cloud is critical for immersive metaverse experience and is a challenging task.Firstly,because point cloud is formed by unstructured 3D points that makes the topology more complex.Secondly,the quality impairment generally involves both geometric attributes and color properties,where the measurement of the geometric distortion becomes more complex.We propose a perceptual point cloud quality assessment model that follows the perceptual features of Human Visual System(HVS)and the intrinsic characteristics of the point cloud.The point cloud is first pre-processed to extract the geometric skeleton keypoints with graph filtering-based re-sampling,and local neighboring regions around the geometric skeleton keypoints are constructed by K-Nearest Neighbors(KNN)clustering.For geometric distortion,the Point Feature Histogram(PFH)is extracted as the feature descriptor,and the Earth Mover’s Distance(EMD)between the PFHs of the corresponding local neighboring regions in the reference and the distorted point clouds is calculated as the geometric quality measurement.For color distortion,the statistical moments between the corresponding local neighboring regions are computed as the color quality measurement.Finally,the global perceptual quality assessment model is obtained as the linear weighting aggregation of the geometric and color quality measurement.The experimental results on extensive datasets show that the proposed method achieves the leading performance as compared to the state-of-the-art methods with less computing time.Meanwhile,the experimental results also demonstrate the robustness of the proposed method across various distortion types.The source codes are available at https://github.com/llsurreal919/Point Cloud Quality Assessment. 展开更多
关键词 Metaverse point cloud Quality assessment point feature histogram Earth mover’s distance
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A Method for Automatic Feature Points Extraction of Pelvic Surface Based on PointMLP_RegNet
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作者 Wei Kou Rui Zhou +5 位作者 Hongmiao Zhang Jianwen Cheng Chi Zhu Shaolong Kuang Lihai Zhang Lining Sun 《CAAI Transactions on Intelligence Technology》 2025年第3期716-727,共12页
The success of robot-assisted pelvic fracture reduction surgery heavily relies on the accuracy of 3D/3D feature-based registration.This process involves extracting anatomical feature points from pre-operative 3D image... The success of robot-assisted pelvic fracture reduction surgery heavily relies on the accuracy of 3D/3D feature-based registration.This process involves extracting anatomical feature points from pre-operative 3D images which can be challenging because of the complex and variable structure of the pelvis.PointMLP_RegNet,a modified PointMLP,was introduced to address this issue.It retains the feature extraction module of PointMLP but replaces the classification layer with a regression layer to predict the coordinates of feature points instead of conducting regular classification.A flowchart for an automatic feature points extraction method was presented,and a series of experiments was conducted on a clinical pelvic dataset to confirm the accuracy and effectiveness of the method.PointMLP_RegNet extracted feature points more accurately,with 8 out of 10 points showing less than 4 mm errors and the remaining two less than 5 mm.Compared to PointNettt and PointNet,it exhibited higher accuracy,robustness and space efficiency.The proposed method will improve the accuracy of anatomical feature points extraction,enhance intra-operative registration precision and facilitate the widespread clinical application of robot-assisted pelvic fracture reduction. 展开更多
关键词 automatic feature points extraction feature points intra-operative registration pointMLP_RegNet robot-assisted pelvic fracture reduction surgery
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基于三维点云和改进PointNet++的大田烟株叶片计数方法
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作者 南德旺 李军营 +3 位作者 梁虹 马二登 张宏 肖恒树 《中国烟草科学》 北大核心 2025年第3期89-97,共9页
烟草植株叶片数是估计烟叶产量的重要表型参数之一。针对传统人工烟株叶片计数困难问题,提出一种结合三维点云和改进PointNet++的大田烟株叶片计数方法。该方法利用无人机倾斜摄影获取大田烟株图片进而生成三维点云,然后利用改进的Point... 烟草植株叶片数是估计烟叶产量的重要表型参数之一。针对传统人工烟株叶片计数困难问题,提出一种结合三维点云和改进PointNet++的大田烟株叶片计数方法。该方法利用无人机倾斜摄影获取大田烟株图片进而生成三维点云,然后利用改进的PointNet++算法实现叶片点云分割,该算法应用KAN网络代替MLP提高算法学习能力,减少训练损失;并提出一种融合DGST网络和DBB多元分支块的DGSTD注意力机制提升准确性;此外,引入Varifocal loss解决各类别点云比例不平衡问题;最后采用MeanShift聚类算法实现叶片点云聚类,对应得到叶片数。结果表明,该算法点云分割的准确率为92.55%,平均交并比为76.33%,较原始模型分别提高2.06、2.81百分点;叶片估测精确率为94.35%,在三维空间内实现了大田烟株叶片计数。 展开更多
关键词 大田烟株 叶片计数 pointNet++ 三维点云 无人机倾斜摄影
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Universality of percolation at dynamic pseudocritical point
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作者 Qiyuan Shi Shuo Wei +1 位作者 Youjin Deng Ming Li 《Chinese Physics B》 2025年第4期304-310,共7页
Universality,encompassing critical exponents,scaling functions,and dimensionless quantities,is fundamental to phase transition theory.In finite systems,universal behaviors are also expected to emerge at the pseudocrit... Universality,encompassing critical exponents,scaling functions,and dimensionless quantities,is fundamental to phase transition theory.In finite systems,universal behaviors are also expected to emerge at the pseudocritical point.Focusing on two-dimensional percolation,we show that the size distribution of the largest cluster asymptotically approaches to a Gumbel form in the subcritical phase,a Gaussian form in the supercritical phase,and transitions within the critical finite-size scaling window.Numerical results indicate that,at consistently defined pseudocritical points,this distribution exhibits a universal form across various lattices and percolation models(bond or site),within error bars,yet differs from the distribution at the critical point.The critical polynomial,universally zero for two-dimensional percolation at the critical point,becomes nonzero at pseudocritical points.Nevertheless,numerical evidence suggests that the critical polynomial,along with other dimensionless quantities such as wrapping probabilities and Binder cumulants,assumes fixed values at the pseudocritical point that are independent of the percolation type(bond or site)but vary with lattice structures.These findings imply that while strict universality breaks down at the pseudocritical point,certain extreme-value statistics and dimensionless quantities exhibit quasi-universality,revealing a subtle connection between scaling behaviors at critical and pseudocritical points. 展开更多
关键词 PERCOLATION UNIVERSALITY extreme-value statistics pseudocritical point
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