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An image registration method based on multi-resolution morphology contour detection
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作者 彭向前 《Journal of Chongqing University》 CAS 2012年第2期88-96,共9页
Combined with the printing application,an image registration method based on the multi-resolution morphology contour detection was proposed.First,a direction based multi-resolution gray morphology in the scheme was pr... Combined with the printing application,an image registration method based on the multi-resolution morphology contour detection was proposed.First,a direction based multi-resolution gray morphology in the scheme was proposed to realize the contour extraction.Then,based on the contour features,the subspace image registration was proposed to deal with issues of the computing complexity appeared in the traditional image registration methods.The proposed image registration was efficiently applied in the defect inspection of printing images. 展开更多
关键词 contour detection multi-resolution morphology image registration
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Study on Productivity Model of Herringbone-Like Laterals Wells and Optimization of Morphological Parameters Considering Threshold Pressure Gradient in Heavy Oil Reservoirs
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作者 Enhui Sun Jie Tan +2 位作者 Dong Zhang Wei Wang Songru Mu 《World Journal of Engineering and Technology》 2019年第2期302-313,共12页
Compared with conventional well, herringbone-like laterals wells can increase the area of oil release, and can reduce the number of wellhead slots of platforms,?and?also can greatly improve the development efficiency.... Compared with conventional well, herringbone-like laterals wells can increase the area of oil release, and can reduce the number of wellhead slots of platforms,?and?also can greatly improve the development efficiency. Based on threshold pressure gradient in heavy oil reservoir,?and?the applied principle of mirror reflection and superposition, the pressure distribution equation of herringbone-like laterals wells is obtained in heavy oil reservoir. Productivity model of herringbone-like laterals wells is proposed by reservoir-wellbore steady seepage. The example shows that the productivity model is great accuracy?to?predict the productivity of herringbone-like laterals wells. The model is used to analyze the branching length, branching angle, branching symmetry, branching position and spacing and their effects on productivity of herringbone-like laterals wells. The principle of optimizing the well shape of herringbone-like laterals wells is proposed. 展开更多
关键词 Threshold Pressure gradient Herringbone-Like Laterals WELLS Heavy Oil RESERVOIRS PRODUCTIVITY Model Optimization of morphological Parameters
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Impacts of ontogenetic and altitudinal changes on morphological traits and biomass allocation patterns of Fritillaria unibracteata 被引量:4
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作者 XU Bo WANG Jin-niu SHI Fu-sun 《Journal of Mountain Science》 SCIE CSCD 2020年第1期83-94,共12页
Environmental variations and ontogeny may affect plant morphological traits and biomass allocation patterns that are related to the adjustments of plant ecological strategies. We selected 2-, 3-and 4-year-old Fritilla... Environmental variations and ontogeny may affect plant morphological traits and biomass allocation patterns that are related to the adjustments of plant ecological strategies. We selected 2-, 3-and 4-year-old Fritillaria unibracteata plants to explore the ontogenetic and altitudinal changes that impact their morphological traits(i.e., plant height, single leaf area,and specific leaf area) and biomass allocations [i.e.,biomass allocations of roots, bulbs, leaves, stems, and flowers] at relatively low altitudinal ranges(3400 m to 3600 m asl) and high altitudinal ranges(3600 m to4000 m asl). Our results indicated that plant height,root biomass allocation, and stem biomass allocation significantly increased during the process of individual growth and development, but single leaf area, specific leaf area, bulb biomass allocation, and leaf biomass allocation showed opposite trends.Furthermore, the impacts of altitudinal changes on morphological traits and biomass allocations had no significant differences at low altitude, except for single leaf area of 2-year-old plants. At high altitude,significantly reduced plant height, single leaf area and leaf biomass allocation for the 2-year-old plants,specific leaf area for the 2-and 4-year-old plants, and stem biomass allocation were found along altitudinal gradients. Significantly increased sexual reproductive allocation and relatively stable single leaf area and leaf biomass allocation were also observed for the 3-and 4-year-old plants. In addition, stable specific leaf area for the 3-year-old plants and root biomass allocation were recorded. These results suggested that the adaptive adjustments of alpine plants, in particular F. unibracteata were simultaneously influenced by altitudinal gradients and ontogeny. 展开更多
关键词 Alpine plants morphological traits Biomass allocation patterns Ontogenetic drifts Altitudinal gradients
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Lotus Leaf‑Derived Gradient Hierarchical Porous C/MoS2 Morphology Genetic Composites with Wideband and Tunable Electromagnetic Absorption Performance 被引量:10
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作者 Fei Pan Zhicheng Liu +4 位作者 Baiwen Deng Yanyan Dong Xiaojie Zhu Chuang Huang Wei Lu 《Nano-Micro Letters》 SCIE EI CAS CSCD 2021年第3期22-38,共17页
Inspired by the nature,lotus leaf-derived gradient hierarchical porous C/MoS2 morphology genetic composites(GHPCM)were successfully fabricated through an in situ strategy.The biological microstructure of lotus leaf wa... Inspired by the nature,lotus leaf-derived gradient hierarchical porous C/MoS2 morphology genetic composites(GHPCM)were successfully fabricated through an in situ strategy.The biological microstructure of lotus leaf was well preserved after treatment.Different pores with gradient pore sizes ranging from 300 to 5μm were hierarchically distributed in the composites.In addition,the surface states of lotus leaf resulted in the Janus-like morphologies of MoS2.The GHPCM exhibit excellent electromagnetic wave absorption performance,with the minimum reflection loss of−50.1 dB at a thickness of 2.4 mm and the maximum effective bandwidth of 6.0 GHz at a thickness of 2.2 mm.The outstanding performance could be attributed to the synergy of conductive loss,polarization loss,and impedance matching.In particularly,we provided a brand-new dielectric sum-quotient model to analyze the electromagnetic performance of the non-magnetic material system.It suggests that the specific sum and quotient of permittivity are the key to keep reflection loss below−10 dB within a certain frequency range.Furthermore,based on the concept of material genetic engineering,the dielectric constant could be taken into account to seek for suitable materials with designable electromagnetic absorption performance. 展开更多
关键词 morphology genetic materials Lotus leaf Electromagnetic wave absorption gradient hierarchical porous structure Dielectric sum-quotient model
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Efficient Morphological Segmentation of Brain Hemorrhage Stroke Lesion Through MultiResUNet 被引量:1
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作者 R.Shijitha P.Karthigaikumar A.Stanly Paul 《Computers, Materials & Continua》 SCIE EI 2022年第3期5233-5249,共17页
Brain Hemorrhagic stroke is a serious malady that is caused by the drop in blood flow through the brain and causes the brain to malfunction.Precise segmentation of brain hemorrhage is crucial,so an enhanced segmentati... Brain Hemorrhagic stroke is a serious malady that is caused by the drop in blood flow through the brain and causes the brain to malfunction.Precise segmentation of brain hemorrhage is crucial,so an enhanced segmentation is carried out in this research work.The brain image of various patients has taken using an MRI scanner by the utilization of T1,T2,and FLAIR sequence.This work aims to segment the Brain Hemorrhagic stroke using deep learning-based Multi-resolution UNet(multires UNet)through morphological operations.It is hard to precisely segment the brain lesions to extract the existing region of stroke.This crucial step is accomplished by this proposed MMU-Net methodology by precise segmentation of stroke lesions.The proposed method efficiently determines the hemorrhagic stroke with improved accuracy of 95%compared with the existing segmentation techniques such as U-net++,ResNet,Multires UNET and 3D-ResU-Net and also provides improved performance of 2D and 3D U-Net with an enhanced outcome.The performancemeasure of the proposed methodology acquires an improved accuracy,precision ratio,sensitivity,and specificity rate of 0.07%,0.04%,0.04%,and 0.05%in comparison to U-net,ResNet,Multires UNET and 3D-ResU-Net techniques respectively. 展开更多
关键词 Brain hemorrhage magnetic resonance imaging segmentation multi-resolutional U-Net morphological operations
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COALESCENCE INDUCED GRADIENT MORPHOLOGY NEAR A WALL IN PHASE SEPARATED POLYMER BLENDS DURING QUIESCENT ANNEALING
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作者 Wei Yu Chi-xing Zhou De-lu Zhao Department of Polymer Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 China State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences Beijing 100080, China 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2002年第6期543-550,共8页
A fast coalescence mechanism is proposed to account for the wall effect on the formation of gradient morphology in phase separated polymer blends during quiescent annealing. The existence of solid wall with high polar... A fast coalescence mechanism is proposed to account for the wall effect on the formation of gradient morphology in phase separated polymer blends during quiescent annealing. The existence of solid wall with high polarity is believed to change the potential field around the dispersed particles near the wall. This additional potential interaction between the solid wall and the dispersed particles causes faster coalescence of the dispersed particles near the wall than in the bulk. The gradient phase morphology thus formed can be predicted by combining the wall-particle interaction and the touch-coalescence mechanism. The effect of interfacial tension on the gradient morphology is also discussed. 展开更多
关键词 gradient morphology wall effect COALESCENCE polymer blends interfacial tension
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Changes in morphology and soil nutrient patterns of nebkhas in arid regions along a precipitation gradient
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作者 WeiCheng Luo WenZhi Zhao +1 位作者 Bing Liu Heng Ren 《Research in Cold and Arid Regions》 CSCD 2021年第3期256-267,共12页
Nebkhas, discrete mounds of sand and vegetation, are a common landscape feature critical to the stability of desert ecosystems and supported by limited precipitation. Nebkha morphology and spatial pattern vary in land... Nebkhas, discrete mounds of sand and vegetation, are a common landscape feature critical to the stability of desert ecosystems and supported by limited precipitation. Nebkha morphology and spatial pattern vary in landscapes, but it is unclear how they change along precipitation gradients in arid and semi-arid regions. In this study we determined morphology and soil nutrient patterns of nebkha from different regions of northwestern China. The objective of this study was to understand zonal differences among nebkhas and how morphological characteristics and soil nutrient patterns of nebkha change along a precipitation gradient in northwestern China. Our results shows that mean annual precipitation(MAP) had significant effects on morphological characteristics of nebkhas such as height, area, and volume which significantly decreased with an increase in MAP. MAP had significant positive effects on shrub cover and species richness of nebkha. Soil nutrients such as soil organic matter(SOM), total carbon(TC), total nitrogen(TN), and total phosphorus(TP) in the 0-10 cm layer increased with an increase of MAP, and soil nutrient content within nebkhas was higher than in inter-nebkha areas.We concluded that nebkhas are "fertile islands" with an important role in ecosystem dynamics in study regions. Further,MAP is a key factor which determined zonal differences, morphological, and soil nutrients patterns of nebkhas. However,disturbance, such as animal grazing, and planted sand-stabilizing vegetation accelerated the degeneration of nebkha landscapes. We recommend implementation of protective measures for nebkhas in arid and semi-arid areas of China. 展开更多
关键词 Nebkha morphologY soil nutrient precipitation gradient arid and semi-arid lands
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基于频率域峭度谱迭代阈值的多尺度形态学轴承故障诊断方法
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作者 钱贾伟 成梁 李梦婕 《山东工业技术》 2024年第2期111-119,共9页
在复杂恶劣的环境中,存在滚动轴承故障信息难以准确提取的问题。因此,引用多尺度数学形态学对滚动轴承故障诊断开展研究。由于小尺度形态学滤波能较好的保存信号的细节特征,大尺度形态学滤波能有效抑制噪声,因此为了能更好的兼顾噪声抑... 在复杂恶劣的环境中,存在滚动轴承故障信息难以准确提取的问题。因此,引用多尺度数学形态学对滚动轴承故障诊断开展研究。由于小尺度形态学滤波能较好的保存信号的细节特征,大尺度形态学滤波能有效抑制噪声,因此为了能更好的兼顾噪声抑制和故障特征信息保存,采用迭代阈值的方法选取尺度范围,运用频率域峭度谱方法计算出阈值,然后通过迭代自适应获取最佳尺度区间。多尺度形态学信号重构加权方法引用加权多尺度形态梯度算法,该方法能保证小尺度具有较小的权重,大尺度具有大权重。通过仿真和实验表明:多尺度形态学有效检测出滚动轴承故障信号,深度挖掘滚动轴承故障特征信息。 展开更多
关键词 多尺度数学形态学 迭代阈值 频率域峭度谱 加权多尺度形态梯度算法
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Distribution pattern of Caragana species under the influence of climate gradient in the Inner Mongolia region, China 被引量:7
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作者 LiNa XIE ChengCang MA +2 位作者 HongYu GUO QingFang LI YuBao GAO 《Journal of Arid Land》 SCIE CSCD 2014年第3期311-323,共13页
There is a strong climate gradient in the Inner Mongolia region, China, with solar radiation and air temperature increasing but precipitation decreasing gradually from the northeast to the southwest. Sixteen Cara- gan... There is a strong climate gradient in the Inner Mongolia region, China, with solar radiation and air temperature increasing but precipitation decreasing gradually from the northeast to the southwest. Sixteen Cara- gana species exist in the Inner Mongolia region. These Caragana species exhibit a distribution pattern across moisture zones and form a geographical replacement series. In order to examine the mechanisms responsible for Caragana species distribution pattern, we selected 12 Caragana species that exhibit a distinct distribution pattern across multiple moisture zones in the Inner Mongolia region, and determined the relationships between the leaf ecological and physiological traits of these Caragana species and the aridity index and solar radiation. Along with the climatic drought gradient and the solar radiation intensification from the northeast to the southwest, leaf eco- logical characteristics of Caragana species changed drastically, i.e. the leaf shape gradually turned from flat into tegular or tubbish; the leaf hair became denser, longer and lighter in color; the leaf area, leaf biomass and specific leaf area (SLA) decreased significantly; the leaf thickness and the ratio of leaf thickness to leaf area increased sig- nificantly; and the leaf chlorophyll content decreased significantly. As the climatic drought stress increased, osmotic potentials of the main osmotic adjustment substances and the cytoplasmic ion concentration of Caragana species increased significantly. Meanwhile, the total and free water contents and water potential of leaves decreased sig- nificantly; the ratio of bound to free water increased significantly; the stomatal conductance and transpiration rate reduced significantly; and the water use efficiency (WUE) increased significantly. In addition, with the intensification of climatic drought stress, peroxidase (POD) and superoxide dismutase (SOD) activities in leaves increased significantly. As a result, the malondialdehyde (MDA) content increased while the oxygen free radical content decreased. Our results showed that most of the leaf ecological and physiological traits of the 12 Caragana species varied in accordance with the climatic drought gradient in the Inner Mongolia region, which reflected the adaptation of the Caragana species to the local climate conditions. With relatively more active metabolism and faster growth, the Caragana species in the northeast had strong competitive abilities; on the other hand, with stronger resistance to climatic drought stress, the Caragana species in the southwest could survive in harsh environments. Based on our results, we con- cluded that both the environmental gradients and the adaptive responses of Caragana species to their environments played important roles in the formation of the Caragana species distribution pattern across the Inner Mongolia region. 展开更多
关键词 ADAPTATION climatic gradient morphological trait osmotic potential water state water metabolism antioxidative enzyme
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Morphology Change of Metastable Regrown Graphite with Boron Additive under HPHT
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作者 Chuanyi Zang Xiaozhou Chen +3 位作者 Qiang Hu Wei Guo Guofeng Huang Xiaopeng Jia 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2009年第4期539-542,共4页
By temperature gradient method under high pressure and high temperature (HPHT), with NiMnCo alloy as the solvent metal, at diamond-stable region of about 5.4 GPa and 1500 K, metastable regrown graphite crystals of d... By temperature gradient method under high pressure and high temperature (HPHT), with NiMnCo alloy as the solvent metal, at diamond-stable region of about 5.4 GPa and 1500 K, metastable regrown graphite crystals of different morphology were synthesized. With B as an additive incorporated into the NiMnCo-C system, metastable regrown graphite crystals of sphere-like shape were firstly obtained under HPHT. If the growth system does not contain B, sheet-like regrown graphite crystals, most with regular hexagonal morphology, are grown upwards and standing vertically in the metal solvent. When B additive of 1.0 wt pct was added into carbon source (graphite powder), all metastable regrown graphite crystals took on the habit of regular sphere-like morphology, and were grown by a spiral layer growth mechanism. 展开更多
关键词 GRAPHITE High pressure and high temperature Temperature gradient method morphologY
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The Influence Factors Analysis to Improve the Compatibility and the Mechanical Behavior of IPN, Gradient IPN and BaTiO<sub>3</sub>Filled IPN
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作者 Yudi Guo Dongyan Tang Ying Wang 《Materials Sciences and Applications》 2012年第9期606-611,共6页
Interpenetrating polymer network (IPN), gradient IPN and BaTiO3 filled IPN, composed of poly(ethylene glycol urethane) (PEGPU) and unsaturated polyester resin (UP) curing at room temperatures were prepared. Then the e... Interpenetrating polymer network (IPN), gradient IPN and BaTiO3 filled IPN, composed of poly(ethylene glycol urethane) (PEGPU) and unsaturated polyester resin (UP) curing at room temperatures were prepared. Then the effect of soft/hard segment ratio in polyurethane (PU), component ratio of PU to UP in IPN, adding amount of BaTiO3 in filled IPN, the component sequences and interval times between each IPN for gradient IPN, on morphology and mechanical behavior of IPN and BaTiO3/IPN nanocomposites with different molecular weight of PU were studied systematically. Moreover, the investigation on the relationship between the morphologies and the mechanical properties indicated that the IPN with finer morphology exhibited an excellent consistency of the higher strengths and elongations. 展开更多
关键词 Poly(ethylene GLYCOL Urethane) (PEGPU) gradient Interpenetrating Polymer Networks (gradient IPN) BaTiO3 morphology Mechanical Property
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典型荒漠灌木叶片功能性状特征随降水梯度的变化研究 被引量:5
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作者 李瑞 单立山 +3 位作者 解婷婷 马丽 杨洁 李全刚 《干旱区研究》 CSCD 北大核心 2023年第3期425-435,共11页
自然降水是干旱地区植被重要的水分来源,为了探明荒漠灌木叶片在降水变化的应对对策,以典型荒漠灌木为研究对象,测定不同降水条件下叶片形态性状和化学计量指标,分析其叶片功能性状的总体特征及各个功能性状与环境因子的关系。结果表明:... 自然降水是干旱地区植被重要的水分来源,为了探明荒漠灌木叶片在降水变化的应对对策,以典型荒漠灌木为研究对象,测定不同降水条件下叶片形态性状和化学计量指标,分析其叶片功能性状的总体特征及各个功能性状与环境因子的关系。结果表明:(1)红砂(Reaumuria soongorica)叶片肉质化程度和含水量随自然降水量的减少呈逐渐增大的趋势;盐爪爪(Kalidium foliatum)叶片组织密度随自然降水量的减少整体呈增大的趋势;(2)红砂和白刺(Nitraria tangutorum)C含量、白刺和珍珠猪毛菜(Salsola passerina)叶片N含量随自然降水量的减少整体呈增大的趋势;珍珠猪毛菜和盐爪爪叶片N∶P均小于14,即其在生长发育中主要受氮素限制;(3)红砂、白刺和盐爪爪叶片组织密度与年均降水量呈正相关关系;红砂、白刺的比叶面积与海拔呈负相关关系,红砂、白刺、珍珠猪毛菜的P含量与海拔呈负相关关系。综上所述,在干旱环境中,不同的植物表现出不同的生态适应策略,其中盐爪爪通过减小比叶面积、增加叶组织密度,白刺和珍珠猪毛菜通过增加叶片N含量,红砂通过增加叶片的肉质化程度和含水量等来适应干旱少雨的荒漠环境;年均降水量和海拔是影响植物生长发育的主要限制环境因子。 展开更多
关键词 叶片形态性状 化学计量指标 环境因子 降水梯度
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基于波形突变特征的海量行波数据中雷击干扰波形辨识
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作者 曹璞璘 申忠友 +3 位作者 束洪春 马御棠 韩一鸣 朱梦梦 《电力系统自动化》 EI CSCD 北大核心 2023年第17期178-186,共9页
行波装置等高采样率装置已在电力系统得到普遍应用,未来将成为新型电力系统运行数据积累的重要来源。行波装置不仅会记录故障产生的电磁暂态过程,也会记录雷击干扰等其他扰动。雷击干扰虽然会引起绝缘的部分损伤,但由于缺少跳闸记录等... 行波装置等高采样率装置已在电力系统得到普遍应用,未来将成为新型电力系统运行数据积累的重要来源。行波装置不仅会记录故障产生的电磁暂态过程,也会记录雷击干扰等其他扰动。雷击干扰虽然会引起绝缘的部分损伤,但由于缺少跳闸记录等事件记录的支撑,且高采样率数据存在离群点问题,雷击识别存在较大困难。文中提出基于中位数绝对离差法滑动窗口的行波数据预处理方法,消除绝大部分异常坏点并对其暂态细节进行修复,抑制异常坏点引起的波形奇异点,对预处理后行波数据做形态学梯度提取,抑制波形中变化较为平缓部分,放大局部暂态突变细节,从而提取电流行波数据突变的相关特征。采用合成少数类过采样技术平衡少数类样本,利用随机森林无需特征归一化的特点,避免新加入数据造成归一化重置的问题,实现了海量数据中线路扰动数据的初步提取,并通过雷电定位系统完成验证。 展开更多
关键词 电磁暂态 雷击干扰 行波装置 形态学梯度 随机森林
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结合自适应TV模型和分水岭变换的图像分割算法 被引量:1
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作者 关豪然 宋卫东 张丰收 《电子设计工程》 2023年第4期33-37,42,共6页
针对传统分水岭算法对噪声敏感,易出现过分割的现象,提出一种自适应全变分模型和标记分水岭算法相结合的图像分割算法。采用自适应全变分模型对原始图像进行滤波处理,平滑去噪的同时保留图像的边缘信息;求解其多尺度形态学梯度图像,并... 针对传统分水岭算法对噪声敏感,易出现过分割的现象,提出一种自适应全变分模型和标记分水岭算法相结合的图像分割算法。采用自适应全变分模型对原始图像进行滤波处理,平滑去噪的同时保留图像的边缘信息;求解其多尺度形态学梯度图像,并用基于最大熵的扩展极小值技术获得的前景和背景标记并对其多尺度梯度图像修改;对修改后的梯度图像进行分水岭变换,实现准确的分割。对比常用和相似的图像分割算法,实验结果表明,该算法在抗噪性、运行时间和分割交并比上有一定的优势。尤其是在噪声强、灰度值接近的医学图像上能够获得合理有意义的分割区域,效果良好。 展开更多
关键词 图像分割 标记分水岭算法 自适应全变分模型 多尺度形态学梯度图像
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基于小波变换的改进暗通道去雾算法
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作者 王文科 胡红萍 曹胜芳 《科学技术与工程》 北大核心 2023年第15期6528-6535,共8页
针对暗通道先验算法在景深较大处会出现颜色失真,且易受噪声干扰和运行时间久等问题,提出了一种基于多尺度小波变换的改进融合暗通道去雾方法。首先对有雾图像作二级小波分解,再对得到的高频分量利用软阈值去噪,对低频分量利用改进的自... 针对暗通道先验算法在景深较大处会出现颜色失真,且易受噪声干扰和运行时间久等问题,提出了一种基于多尺度小波变换的改进融合暗通道去雾方法。首先对有雾图像作二级小波分解,再对得到的高频分量利用软阈值去噪,对低频分量利用改进的自适应融合暗通道进行去雾。最后利用一个局部线性模型将高低频分量系数关联进行小波重构。实验结果表明,提出的算法具有较高的去雾效率,且能很好地提高去雾图像的质量。 展开更多
关键词 暗通道先验 小波变换 形态学梯度 图像去雾 透射率
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基于VMD形态梯度谱与BAS-RF的变压器绕组松动诊断
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作者 颜锦 马宏忠 +2 位作者 朱昊 张玉良 许洪华 《振动.测试与诊断》 EI CSCD 北大核心 2023年第5期953-959,1040,共8页
为有效提取变压器振动信号中的绕组状态信息,提出一种基于变分模态分解(variational mode decomposition,简称VMD)、形态梯度谱的特征提取,采用天牛须搜索算法优化随机森林(beetle antennae search‑random forest,简称BAS‑RF)识别绕组... 为有效提取变压器振动信号中的绕组状态信息,提出一种基于变分模态分解(variational mode decomposition,简称VMD)、形态梯度谱的特征提取,采用天牛须搜索算法优化随机森林(beetle antennae search‑random forest,简称BAS‑RF)识别绕组松动状态的诊断方法。首先,将实测变压器振动信号经VMD分解得到若干个模态分量;其次,计算多个尺度的形态梯度谱以形成初始特征样本集,为防止维数灾难,使用主成分分析法对初始特征样本集进行降维处理;最后,利用天牛须搜索算法对随机森林中决策树的个数和树的深度进行寻优以构造分类器模型,实现对变压器绕组松动状态的识别。实验结果表明,该方法能有效提取变压器绕组松动故障特征信息,且具有优良的抗噪性能,构建的BAS‑RF模型具有较高的识别准确率和识别速度。 展开更多
关键词 变压器 绕组松动 变分模态分解 形态梯度谱 随机森林
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基于二次振荡波过程的交流电网相继速动判据
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作者 吴宇奇 肖澍昱 +2 位作者 黎钊 李正天 林湘宁 《电工技术学报》 EI CSCD 北大核心 2023年第24期6695-6708,共14页
针对现有的交流电网相继速动保护判据的可靠性能受限于运行工况与系统参数,以及其无法耐受较高过渡电阻的难题,该文首先研究了本级线路盲区故障与下级线路故障时由对端断路器开断产生的二次振荡波过程的差异性,并基于行波模量网络分析... 针对现有的交流电网相继速动保护判据的可靠性能受限于运行工况与系统参数,以及其无法耐受较高过渡电阻的难题,该文首先研究了本级线路盲区故障与下级线路故障时由对端断路器开断产生的二次振荡波过程的差异性,并基于行波模量网络分析了特定故障工况下的特殊波过程;然后,提出了基于数学形态学梯度算法的振荡波头极性辨识判据以及特殊故障工况下的辅助判据,以形成全新的相继速动保护判据;最后,基于PSCAD仿真平台验证了所提保护判据的有效性、灵敏性与可靠性,其适用于三相/单相跳闸方式、适应于所有故障类型、不受系统运行工况与系统参数影响,同时耐受过渡电阻能力高达300Ω。 展开更多
关键词 相继速动 二次振荡波 数学形态学梯度 盲区故障 行波模量网络
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一种基于形态学梯度的多聚焦图像融合方法
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作者 张弼晗 许东辉 +1 位作者 丁德锐 陈子鸿 《信息技术》 2023年第1期22-26,共5页
多聚焦图像融合作为信息融合的一个重要分支,广泛应用于计算机视觉、医学诊断、数字成像等领域。文中针对现有融合算法存在融合图像易出现“块效应”等问题,提出了一种基于形态学梯度的多聚焦图像融合方法。该算法首先对源图像进行形态... 多聚焦图像融合作为信息融合的一个重要分支,广泛应用于计算机视觉、医学诊断、数字成像等领域。文中针对现有融合算法存在融合图像易出现“块效应”等问题,提出了一种基于形态学梯度的多聚焦图像融合方法。该算法首先对源图像进行形态学梯度测量得到对应的得分矩阵,然后对得分矩阵进行四叉树分解得到初始分割图。进而利用形态学滤波和小区域滤波,除去边缘信息和小洞得到期望的决策图。实验测试表明,文中提出算法相对于现有的算法在结构相似度、峰值信噪比等定量指标上皆有较好的表现。 展开更多
关键词 形态学梯度 多聚焦图像融合 四叉树分解 决策图
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基于油石分离的再生集料颗粒形态多尺度变化 被引量:1
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作者 马川义 闫显亮 +1 位作者 吕鑫 张吉哲 《山东交通学院学报》 CAS 2023年第2期95-101,共7页
为研究废旧沥青混合料(recycle asphalt pavement,RAP)再生工艺对集料颗粒形态特征的影响,采用油石分离处置技术制备再生集料,建立考虑再生集料颗粒宏观-细观-微观的多尺度评价指标体系,结合三维扫描仪和集料图像测量系统测量新集料、... 为研究废旧沥青混合料(recycle asphalt pavement,RAP)再生工艺对集料颗粒形态特征的影响,采用油石分离处置技术制备再生集料,建立考虑再生集料颗粒宏观-细观-微观的多尺度评价指标体系,结合三维扫描仪和集料图像测量系统测量新集料、未处置RAP和再生集料颗粒的球度、针片状指数、梯度棱角性和纹理指数等4个形态评价指标,对比分析3种集料颗粒的形态特征与多尺度变化规律。结果表明:相比于新集料颗粒和未处置RAP颗粒,再生集料颗粒的形态特征在宏观尺度上的指标参数变化不大,在微观-细观尺度上的指标变化较大,梯度棱角性平均减小12.5%,纹理指数平均增大14.0%,3种集料的4个形态指标均符合正态分布。相比于未处置RAP颗粒,再生集料颗粒的球度、梯度棱角性和纹理指数的标准差均明显变小,表明油石分离处置技术对改善再生集料颗粒的宏观-微观-细观形态特征的变异性有积极作用。对RAP进行高掺量再生利用时,应考虑再生集料颗粒的梯度棱角性和纹理指数与混合料路用性能的关联关系。 展开更多
关键词 油石分离 再生集料 多尺度评价 颗粒形态 球度 梯度棱角性 纹理指数
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A Multi-Scale Gradient Algorithm Based on Morphological Operators
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作者 LU Guan-ming (Department of Information Engineering, Nanjing University of Posts & Telecommunications, Nanjing 210003, P.R.China) 《The Journal of China Universities of Posts and Telecommunications》 EI CSCD 2000年第1期56-59,共4页
Watershed transformation is a powerful morphological tool for image segmentation. However, the performance of the image segmentation methods based on watershed transformation depends largely on the algorithm for compu... Watershed transformation is a powerful morphological tool for image segmentation. However, the performance of the image segmentation methods based on watershed transformation depends largely on the algorithm for computing the gradient of the image to be segmented. In this paper, we present a multi-scale gradient algorithm based on morphological operators for watershed-based image segmentation, with effective handling of both step and blurred edges. We also present an algorithm to eliminate the local minima produced by noise and quantization errors. Experimental results indicate that watershed transformation with the algorithms proposed in this paper produces meaningful segmentations, even without a region-merging step. 展开更多
关键词 morphological gradient WATERSHED image segmentation mathematical morphology
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