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基于车载三维激光雷达的玉米叶面积指数测量 总被引：2，自引：0，他引：2
为使用车载三维激光雷达快速获取作物的株高、叶面积指数(LAI)等作物形态参数,以玉米为研究对象,采用车载三维激光雷达点云数据,提出了一种基于玉米分层点云数量或分层点云数量与地面点云数量比值计算LAI的方法。使用车载平台获取京农科728和农大84玉米的三维点云数据;对点云数据进行预处理,获得已测量LAI真值区域的点云数据;进行玉米植株点云与地面点云分割,根据地面起伏程度,基于随机一致性平面分割算法,将距离阈值设置为0. 06 m;依据玉米垂直结构分布,将玉米植株划分为上、中、下3层,计算每层点云数量并分别标记为H、M和L,同时,将上、中、下每层的点云数量与地面点云数量的比值标记为Hr、Mr和Lr,分别建立H、M、L和Hr、Mr、Lr与LAI真值的线性回归模型。试验结果表明:采用Hr、Mr变量建立的LAI二元线性回归测量模型最优,京农科728玉米训练集R~2为0. 931,验证集R~2为0. 949;农大84玉米训练集R~2为0. 979,验证集R~2为0. 984,本文方法可为田间快速测量LAI提供解决方案。 相似文献
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Kinect获取植物三维点云数据的去噪方法 总被引：4，自引：0，他引：4
为解决Kinect获取的玉米三维点云数据噪声影响三维重建精度的问题,根据Kinect所获取的点云数据特点,采用多帧数据融合的方法获取更完整的三维点云数据并对点云数据进行初步平滑;通过对Kinect所获数据噪声进行分析,提出了一种基于密度分析和深度数据双边滤波的方法,分别对离群点噪声和内部高频噪声进行处理。以Kinect获取的玉米及茄子的三维点云数据进行去噪实验,所用去噪时间仅为传统双边滤波去噪时间的2.71%和1.78%,并且能够达到很好的去噪效果。结果表明,所提方法能够方便、快捷地去除不同尺度的噪声,同时保留边缘数据的完整性,获得良好的植物三维点云数据。 相似文献
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基于自适应半径滤波的农业导航激光点云去噪方法研究 总被引：1，自引：0，他引：1
针对点云数据去噪操作易损失点云细节信息问题,提出了动态半径滤波器,该方法可在保留场景细节信息的同时获得良好去噪效果。此外,提出基于深度卷积神经网络的种植模式判定器,该方法可实时识别当前种植模式,并读取相应的去噪参数。在苹果种植园、白杨树林和旱柳树林完成去噪试验,试验结果表明,本文方法能去除多尺度点云噪声,有效抑制稀疏离群点、目标周围的逸出值和密集噪声,单帧点云(6400点)去噪平均耗时为43.2ms。经自适应半径滤波去噪后,密度聚类的平均精确率为94.3%,平均召回率为78.9%,与原始数据相比,分别提升了40.4%、33.9%。自适应半径滤波具有较高的实时性、通用性和鲁棒性,能较明显地提升聚类效果,为点云后续处理奠定良好基础。 相似文献
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针对枣树的三维轮廓信息重建,搭建了一种基于激光雷达的果树轮廓测量平台。通过在平台上的滑轨移动激光雷达获取果树的三维点云信息,采用MatLab软件对点云数据进行提取与处理。为了降低外部环境对点云数据处理的影响,采用高度统计直方图进行地面滤波实现地面点云的滤除,通过icp算法实现双侧点云的配准,应用欧氏聚类算法分割获取枣树点云数据。为验证研究方法的准确性,从点云轮廓数据中获取果树的冠幅数据与手工测量数据进行线性模型拟合对比,二者的相关系数R=0.91,均方根误差RMSE=0.06,相对误差RE=4.08%,拟合效果较好,说明此方法具有一定的可行性。 相似文献
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基于地面激光雷达点云数据的树种识别方法 总被引：1，自引：0，他引：1
为了能够更有效地利用地面激光雷达的点云数据识别树种,以北京林业大学为研究区域,利用FARO Photon 120型地面激光雷达在研究区内获取4个树种、共92棵树木的点云数据。依据点云的三维坐标值提取研究区内立木的胸径、枝下高、树高、冠高、最长冠幅、垂直最长方向冠幅6个测树因子,同时提取由测树因子组合而成具有鲁棒性的6个树形特征参数,包括冠长树高比、胸径树高比、冠高树高比、分枝角、冠长最大冠幅之比、最长冠幅与垂直方向冠幅之比。分别使用测树因子和组合特征参数,采用支持向量机、分类回归决策树和随机森林的方法,对树种进行冠幅自动识别。研究结果表明：使用测树因子树木识别方法,识别平均准确率为0.765,平均召回率为0.778,3种识别方法中,分类效果较好的依次为分类回归决策树、随机森林、支持向量机;使用组合特征参数树木识别方法,识别平均准确率为0.891,平均召回率为0.896,分类效果较好的方法是随机森林和支持向量机,其次是分类回归决策树;总体上来看,不论是对于单个树种还是总体的准确率和召回率,组合特征参数法均高于测树因子法,而对于3种不同的分类方法,随机森林相对最好。研究结果表明,结合地面激光雷达获取的点云和不同机器学习分类方法进行树种识别分类可以达到满意的效果,且能节省大量时间和人力。 相似文献
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为了快速无损地检测大田作物冠层叶绿素含量,使用便携式多波段光谱探测仪针对农大8号（G1）、郑单（G2）、先玉（G3）和京农科（G4）4种玉米作物品种,在拔节期采集550、650、766、850 nm波长处太阳光信号和作物冠层反射光信号,用于建立玉米冠层叶绿素含量诊断模型。首先,利用作物冠层650 nm和550 nm波长反射率之间的差值 T D 剔除了土壤背景数据点（ T D >0）。然后,组合计算了NDVI、RVI和DVI共12个植被指数,分析各植被指数与叶绿素含量之间的相关关系,结果显示与G1~G4品种叶绿素含量相关性最优的参数分别为RVI(766,550)、 DVI(850,650)、 NDVI(850,550)和RVI(766,550),相关系数均达0.6以上。数据按一定间隔聚类后,相关性分析结果表明多波段光谱探测仪对玉米叶绿素含量检测最优分辨率为0.5 mg/L,且NDVI(850,550)、NDVI(766,550)和RVI(850,550)与叶绿素含量的相关系数分别为0.837 0、0.773 7和0.767 7,达到了强相关水平。最后,建立了多品种通用型玉米拔节期叶绿素含量诊断模型,可为大田玉米拔节期叶绿素含量诊断提供技术支持。 相似文献
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羊胴体自动化分割对于提高羊屠宰加工企业生产效率有重要意义。为实现将羊胴体点云精准高效地分割为多分体,研究了一种基于表面凹凸性的羊胴体点云分割方法。以倒挂状态下的巴美肉羊胴体为研究对象,利用三维激光扫描仪获取羊胴体点云。首先,对羊胴体点云进行预处理,去除离群点噪声和采用体素滤波的方法进行下采样;并将羊胴体点云超体素化,以获取超体素邻接图;然后,对超体素邻接图中相邻点云的公共边进行凹凸性判断,将凹边凸边赋予不同权重;并由得分评估函数计算不同权重点云的得分,将结果与参数Smin作比较;最后,根据比较结果确定分割区域,完成对羊胴体点云的分割。试验结果表明：羊胴体点云分割的平均精确度、平均召回率、平均F1值和平均总体准确率分别为92.3%、91.3%、91.8%、92.1%。各分体的平均分割精确度分别为92.7%、90.7%、92.6%、93.2%、92.5%、92.2%,各分体的平均分割召回率分别为86.0%、93.2%、92.8%、91.6%、90.9%、93.4%,处理单只羊胴体点云的平均时长为18.82 s。通过处理多分体组合点云以及多体型羊胴体点云判断本文方法的适... 相似文献
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无人机搭载激光雷达扫描仪以获取机载点云已成为农作物冠层结构信息提取的理想数据源,基于机载激光雷达点云提取树木、电力塔、电力线等飞行障碍物,为无人机安全飞行提供可靠数据。首先,使用TerraSolid软件对点云进行滤波,分离地面点,提取植被树木、电力塔、电力线等障碍物,根据地物分布进行点云分幅。利用PCL点云库中随机采样一致性及稳健的特征值法构建平面模型,实现分幅后的点云非地面点及飞行障碍物提取。最后,以人工滤波结果和分类结果为参考点云,分别建立基于TIN算法的滤波结果和PCL分割结果的精度验证混淆矩阵,从而对滤波及分割提取障碍物的结果进行精度评价。研究结果表明,TerraSolid软件处理分幅点云效率优于整幅点云数据,TerraSolid及PCL两者对于处理相同分幅点云结果较为相近,其中PCL操作快捷高效,可视性较差。在提取飞行障碍物的过程中,可结合二者优势。 相似文献
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Overland water and salt flows in a set of rice paddies 总被引：1，自引：0，他引：1
E. Playn O. Prez-Coveta A. Martínez-Cob J. Herrero P. García-Navarro B. Latorre P. Brufau J. Garcs 《Agricultural Water Management》2008,95(6):645-658
Cultivation of paddy rice in semiarid areas of the world faces problems related to water scarcity. This paper aims at characterizing water use in a set of paddies located in the central Ebro basin of Spain using experimentation and computer simulation. A commercial field with six interconnected paddies, with a total area of 5.31 ha, was instrumented to measure discharge and water quality at the inflow and at the runoff outlet. The soil was classified as a Typic Calcixerept, and was characterized by a mild salinity (2.5 dS m−1) and an infiltration rate of 5.8 mm day−1. The evolution of flow depth at all paddies was recorded. Data from the 2002 rice-growing season was elaborated using a mass balance approach to estimate the infiltration rate and the evolution of discharge between paddies. Seasonal crop evapotranspiration, estimated with the surface renewal method, was 731 mm (5.1 mm day−1), very similar to that of other summer cereals grown in the area, like corn. The irrigation input was 1874 mm, deep percolation was 830 mm and surface runoff was 372 mm. Irrigation efficiency was estimated as 41%. The quality of surface runoff water was slightly degraded due to evapoconcentration and to the contact with the soil. During the period 2001–2003, the electrical conductivity of surface runoff water was 54% higher than that of irrigation water. However, the runoff water was suitable for irrigation. A mechanistic mass balance model of inter-paddy water flow permitted to conclude that improvements in irrigation efficiency cannot be easily obtained in the experimental conditions. Since deep percolation losses more than double surface runoff losses, a reduction in irrigation discharge would not have much room for efficiency improvement. Simulations also showed that rice irrigation performance was not negatively affected by the fluctuating inflow hydrograph. These hydrographs are typical of turnouts located at the tail end of tertiary irrigation ditches. In fact, these are the sites where rice has been historically cultivated in the study area, since local soils are often saline-sodic and can only grow paddy rice taking advantage of the low salinity of the irrigation water. The low infiltration rate characteristic of these saline-sodic soils (an experimental value of 3.2 mm day−1 was obtained) combined with a reduced irrigation discharge resulted in a simulated irrigation efficiency of 60%. Paddy rice irrigation efficiency can attain reasonable values in the local saline-sodic soils, where the infiltration rate is clearly smaller than the average daily rice evapotranspiration. 相似文献
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瓦房店市是我国重要的水果生产基地,在国内水果生产领域占有重要地位。随着水果市场化的不断深入,如何满足和适应国内外市场需求成为瓦房店市水果生产的关键问题。从瓦房店市水果生产实际出发,阐述了实施水果生产标准化的必要性,提出了发展水果生产标准化的具体措施。 相似文献
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对引进的谷子新品种金谷子耐旱TG118进行品种比较试验和多点试种。结果表明：该品种抗旱、耐瘠、适应性强,稳产、高产、抗病抗风抗倒伏强,品质优良,粮草兼用,种植简单,省工易管;一般产量在6000kg/hm2以上,比当地主栽品种增产20%以上。最高产量达9450kg/hm2,适于在辽西北地区推广应用。 相似文献
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对《种子法》存在问题的探讨 总被引：1，自引：0，他引：1
李鹏 《农业机械化与电气化》2011,(6):129-130
《种子法》是我国种植业第一部法律。自实施以来,为依法加强种子管理提供了有力的法律支撑,促进我国种子产业发生翻天覆地的变化。但随着依法管理工作的深入和种子产业的快速发展,《种子法》及配套规章的一些问题逐步显现出来。对《种子法》及配套规章存在的问题进行深入分析,对需要进一步补充的章节以及需要调整的内容进行深入探讨,以求更加完善和明确。 相似文献
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About 30 years have passed since the Government of Egypt embarked on implementing a series of large scale drainage projects. At present, about 3.8 million acres have been provided with drainage systems on the basis of systematic pre-drainage investigations and designs. The target is to provide drains in approximately 6.4 million acres in the Nile Valley and Delta.The implementation of the subsurface drainage system is carried out by the public sector and private contractors under direct supervision of governmental regional departments. The implementation process depends on many factors related to the drainage material, machinery, manpower, site requirements, farmers and organizations involved. Problems and constraints are sometimes challenging, however, the annual rate of implementation has gradually increased to 170,000 acre/year.This paper discusses the different aspects involved in the implementation process of drainage systems. The development in materials, machinery and construction technologies will be reviewed. Institutional and management factors are going to be also considered. 相似文献
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在新世纪,面对机遇和挑战,党的十六大把“社会更加和谐”作为全面建设更高水平的小康社会的一个重要目标。中国人素有社会和谐的理想;西方人自古也向往社会和谐;借鉴东西方两种和谐社会思想的经验、教训,构建社会主义和谐社会理论。 相似文献
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Gunter Wriedt Marijn van der Velde Alberto Aloe Fayçal Bouraoui 《Agricultural Water Management》2009,96(5):771-789
We present a pan-European irrigation map based on regional European statistics, a European land use map and a global irrigation map. The map provides spatial information on the distribution of irrigated areas per crop type which allows determining irrigated areas at the level of spatial modelling units. The map is a requirement for a European scale assessment of the impacts of irrigated agriculture on water resources based on spatially distributed modelling of crop growth and water balance. The irrigation map was compiled in a two step procedure. First, irrigated areas were distributed to potentially irrigated crops at a regional level (European statistical regions NUTS3), combining Farm Structure Survey (FSS) data on irrigated area, crop-specific irrigated area for crops whenever available, and total crop area. Second, crop-specific irrigated area was distributed within each statistical region based on the crop distribution given in our land use map. A global map of irrigated areas with a 5′ resolution was used to further constrain the distribution within each NUTS3 based on the density of irrigated areas. The constrained distribution of irrigated areas as taken from statistics to a high resolution dataset enables us to estimate irrigated areas for various spatial entities, including administrative, natural and artificial units, providing a reasonable input scenario for large-scale distributed modelling applications. The dataset bridges a gap between global datasets and detailed regional data on the distribution of irrigated areas and provides information for various assessments and modelling applications. 相似文献
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在介绍粉质仪和拉伸仪结构和原理的基础上,探讨了粉质曲线中吸水率、形成时间、稳定时间、弱化度和评价值等指标与面粉品质的关系,以及如何根据拉伸曲线中面团最大拉伸阻力、延伸度和拉伸曲线面积等指标来评价面团品质,并结合生产实际,概述了粉质仪和拉伸仪在面粉生产中的作用。 相似文献
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车辆ABS控制算法的研究及探讨 总被引：1，自引：0，他引：1
对现代汽车的ABS控制算法作了一些简单的介绍,同时指出了它们的一些缺陷,相应地提出了几种对ABS的其它控制方法并加以探讨,其中着重论述了ABS门限值控制算法中参考车速的确定方法和基于附着系数的控制算法。 相似文献