基于几何模型的绿萝叶片外部表型参数三维估测

为快速高效获取叶类植物叶片的外部表型参数、掌握植株生长状况,以绿萝叶片为研究对象,提出一种基于几何模型的叶长、叶宽与叶面积的三维估测方法。利用微软Kinect V2相机,自80cm高度垂直位姿获取绿萝叶片局部点云,并进行直通滤波去噪与包围盒精简等预处理,测量得到点云外形参数,输入预先建立的SAE网络分类预测得到几何模型参数,并基于曲面参数方程建立叶片几何模型。采用粒子群优化算法计算几何模型离散点云和局部点云间的空间距离,进行空间匹配,利用遗传算法求解最优匹配模型的内部模型参数,输出最优匹配模型的叶长、叶宽与叶面积作为估测结果。实验共采集150片绿萝叶片的局部点云数据,将估测结果和真实值进行数学统计与线性回归分析,得出叶长、叶宽与叶面积估测的平均误差分别为0.46cm、0.41cm和3.42cm2,叶长估测R2和RMSE分别为0.88和0.52cm,叶宽R2和RMSE分别为0.88和0.52cm,叶面积R2和RMSE分别为0.95和3.60cm2。实验表明,该方法对于绿萝叶片外形参数的估测效果较好,具有较高实用价值。     

基于MRE-PointNet+AE的绿萝叶片外形参数估测算法

为了准确、高效、自动获取植物叶片外形参数,提出一种基于多分辨率编码点云深度学习网络(MRE-PointNet)和自编码器模型的绿萝叶片外形参数估测算法.使用Kinect V2相机以垂直姿态获取绿萝叶片点云数据,采用直通滤波、分割、点云精简算法对数据进行预处理,通过测定的叶片外形参数反演绿萝叶片几何模型,并计算几何模型的...     

基于多角度Kinect v2的羊只三维模型重构方法研究

羊只的体尺参数是衡量其生长发育状况、生产性能和遗传特性的关键指标。重建羊只的三维模型可以为自动化获取多种羊只体尺参数提供数据基础,因此提出一种基于多角度Kinect v2的羊只三维模型重构方法。该方法通过放置在羊只顶部和左右两个侧面的Kinect v2设备,获取羊只的三维点云数据;利用这些数据中的点云之间的相对位置关系,进行点云坐标的转换和初始配准;采用ICP算法进行精确配准建立三维模型。结果表明：当Kinect v2深度相机高度为120 cm、俯视角为30°时,获取的点云质量较高,自动配准的平均误差为0.233 cm,平均耗时为12.89 s。根据模型计算出的羊只体高、体斜长、十字部高和腰脚宽等体尺参数与实际测量平均误差均在5%以内。     

番茄非接触式单果质量估测方法

针对目前非离株番茄果实的非接触式单果质量快速估测困难等问题,提出了一种基于局部点云和卷积神经网络的番茄单果质量估测方法.以浙粉702番茄为试验对象,首先通过深度相机采集50个番茄单果的336块原始点云,并增强至1 344块点云用于构建数据集.通过多种点云分割方法比较,选取三维连续卷积神经网络用于番茄单果分割.于分割后的...     

面向摘取的番木瓜三维重构与特征参数提取

准确获取番木瓜体表三维几何特征信息是研制番木瓜摘取装备的前提与基础。为此,基于逆向工程技术,以广东台农2号一线黄番木瓜为对象,利用Sense 3D激光扫描仪进行点云数据采集,通过Sense软件对点云数据进行预处理,运用Geomagic Studio软件进行三角网格化点云数据,创建格栅并拟合NURBS曲面,实现番木瓜表面的三维重建。对番木瓜曲面模型进行偏差分析,得到最大偏差距离为正0.08mm和负0.08mm,平均偏差距离为0.004mm,标准偏差为0.015mm,表明重构曲面模型满足摘取装置设计精度要求。应用Pro/E软件对岭南和台农2号番木瓜进行三维重构和外形特征参数测量,结果表明:两个品种番木瓜外形和尺寸都具有较好一致性,岭南品种外形为粗短型,台农2号外形为细长型;岭南番木瓜抓取直径大于86.02mm,抓取点距离末端执行机构高度大于89.1mm;台农2号番木瓜抓取直径大于89.07mm,抓取点距离末端执行机构高度大于73.41mm。提取的特征参数为番木瓜采摘末端执行机构提供了设计依据。     

点云模型中孔洞边界曲线多准则提取算法

提取点云模型的孔洞边界曲线是数字几何处理领域的基础技术之一。通过分析点云模型的局部几何属性,提出一种针对点云模型的孔洞自动检测算法。算法首先寻找点云中每个点的邻点并计算点云曲面在该点处的法向,通过综合运用最大角度度量准则、半圆盘度量准则、形状度量准则等,度量相关数据点成为孔洞边界点的概率,再采用搜索最近点的方法对边界点进行连接处理,生成孔洞的边界线。实验表明,该算法运行稳定,鲁棒性好,可检测提取出点云模型上各种孔洞的边界曲线。     

基于逆向工程技术的蜣螂外形数据采集与处理

采用三维激光扫描系统测量了臭蜣螂几何体表外形,获取了臭蜣螂几何体表外形的数据点云。利用逆向工程软件进行数据点云的平滑处理、精简处理及其多视数据的定位与拼接。使用点云数据网格化、曲面特征抽取与数据分片、曲面分割及直接拟合曲面片的造型方法,成功进行了臭蜣螂体表外形三维几何曲面模型的重构。     

基于无人机多维数据集的森林地上生物量估测模型研究

森林地上生物量（Aboveground biomass,AGB）是评价森林生长情况的重要指标。基于数字航空摄影（Digital aerial photography,DAP）生成的二维和三维数据,分别计算了41个点云高度变量和16个可见光植被指数,利用6种回归算法（随机森林（RF）、袋装树（BT）、支持向量回归（SVR）、Cubist、类别型特征提升（CatBoost）、极端梯度提升（XGBoost））分别构建了单一变量集和综合变量集AGB估测模型,探索了不同变量对于AGB估测模型的贡献。研究结果表明光谱数据集和点云数据集AGB预测模型精度最高分别为Cubist和XGBoost,R2分别为0.5309和0.6395。组合数据集最高精度模型为XGBoost,R2达到0.7601, XGBoost模型具有更高的AGB估测稳定性。研究还表明6种机器学习模型的贡献主要取决于所考虑的回归方法,所选择的特征个数和特征对模型的重要性在不同的模型中并不一致。DOM光谱特征在AGB的估测中具有更高的重要性。总体来说,二维和三维数据的结合能够有效提高森林AGB估测精度,基于无人机倾斜摄影获取的RGB影像能够实现森林AGB的快速无损估计。     

基于颜色取样的苹果树枝干点云数据提取方法

为了快速提取苹果树冠层枝干三维点云数据,以不同生长时期苹果树冠层彩色点云数据为研究对象,提出了基于颜色取样的苹果树枝干点云数据提取方法。首先,提出了苹果树冠层彩色点云获取方法,利用Trimble TX8型地面三维激光扫描仪获取冠层点云数据,同轴全景摄像机获取彩色全景图,采用贴图方法着色点云数据;然后,提取全景图像苹果树冠层区域R、G、B颜色分量信息,根据其分布规律建立枝干部分自适应分割阈值,并根据颜色阈值删除冠层中非枝干部分彩色点云数据;最后,在Geomagic软件中经过封装—创建流形—编辑多边形—填充孔—光滑等一系列操作重建枝干三维模型。苹果树提取枝干点云数据实验结果表明,本文方法点云删除率为75. 74%,相对于人工枝干点云数据提取,侧枝数量平均准确率为93. 34%,效率提高200倍以上,大大缩短了冠层枝干三维重建时间。本研究成果可为有叶苹果树枝干动力学模型建立提供技术基础。     

基于点云数据的树木三维重建方法改进

激光点云数据以其详尽、高精度的三维信息,在森林参数估算、精确重建植物形态结构三维模型方面具有特殊优势。为进一步提高三维模型精度,综合集成多种算法,在改进现有PC2Tree软件基础上,基于点云数据进行树木三维重建。首先根据树木局部点云的主方向相似度和局部点云轴向分布密度分离枝干与树叶;其次采取水平集和最小二乘法提取枝干部分的骨架点,通过下采样方法提取冠层部分的特征点;最后根据骨架点和特征点拓扑结构重构树木三维模型。以樟树为例,分析枝叶分割精度,自动分割与手动分割结果相近;以无叶的鸡蛋花树为例,分析重建模型精度,模型主枝长度相对误差范围集中在0~8.0%,半径相对误差范围集中在0~10%;枝条重建过程避免了噪声点的干扰,对噪声点具有一定的不敏感性;重建三维模型与原始点云吻合度高,基本解决了冠层内部枝干遮挡严重带来的三维建模困难的问题;依据模型提取树高、冠幅、胸径、体积等参数,增加了重建模型的应用范围。     

Overland water and salt flows in a set of rice paddies

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.     

瓦房店市水果生产标准化发展研究

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。     

金谷子耐旱TG118引种试种及推广应用

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。     

对《种子法》存在问题的探讨

《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。     

Review of the Egyptian experience in implementing land drainage projects

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.     

和谐社会理论建设的几点哲学思考

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。     

A European irrigation map for spatially distributed agricultural modelling

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.     

粉质仪和拉伸仪在面粉生产中的应用

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。     

农村信息化服务的现状及建设措施

分析当前我国农村信息化服务的现状,提出加强农村信息化服务的新举措。     

车辆ABS控制算法的研究及探讨

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。