基于自适应导航参数的智能车辆视觉导航

为提高导航路径识别的鲁棒性和实时性,采用了分区阈值二值化、噪声点搜索及滤波等图像处理方法,并对导航路径进行分区逐段识别;在路径跟踪方面,在获取的导航路径图像中选取远端路径和近端路径,以远端路径和近端路径的方位偏差量作为确定目标路径的依据,使提取的导航参数能适应导航路径的变化。根据四轮智能车辆模型进行路径跟踪仿真计算。在此基础上,采用两块数字信号处理器,对基于路径导航的视觉智能车辆进行了设计和试验验证。试验结果表明采用该方法设计的智能车辆具有较好的路径识别和跟踪控制效果。     

农机自动导航车辆采集图像的倾斜校正——基于MATLAB

农业机械的自动导航是现代智能农业的一个重要组成部分,有着广阔的发展前景。但由于地面不平的影响,农机自动导航车辆采集的图像会产生一定的倾斜角度,造成后期导航参数提取的误差。为此,利用MAT-LAB中图像的一般处理和Radon变换,快速地求取采集图像的倾斜角度,并调整图像。试验证明,该方法可以快速和有效地纠正图像的倾角。     

基于机器视觉的非结构化道路导航路径检测方法

针对视觉导航智能机器人,提出了一种非结构化道路导航路径的检测方法。以道路两边缘线的中间线作为导航路径,首先使用亮度分析的方法判断图像中道路的终止位置;然后采用基于扫描线上像素分布的分割方法提取出导航路径上的候选点;最后采用基于一点的改进Hough变换方法提取导航路径的参数,进行非结构化道路的检测。经过对多幅图片的处理,证明该算法具有速度快、抗干扰能力强、准确性高等优点。     

农业车辆杂草环境下视觉导航路径识别方法

在普通环境导航路径识别方法的基础上,分析了株间杂草和垄间杂草对农业车辆导航路径的影响.针对影响较大的垄间杂草环境,提出一种基于BP神经网络的杂草环境下导航路径识别方法.田间实验证明,该方法对杂草的影响具有较好的适应性,能够快速、可靠、准确地提取导航路径特征,识别率为97%,单幅图像平均耗时560ms.     

自动导航系统在农业中的应用及果园适用性分析

自动导航作为现代智能农业车辆的一个重要组成部分,有着广阔的发展前景。为此,综合分析了国内外接触式导航、电磁导航、机械导航、超声波导航、激光导航、GPS导航、视觉导航,以及多传感器融合技术研究进展及在农业车辆的应用现状,并分析了各种导航方式应用于果园机械中的可行性及存在的问题,提出了今后果园智能机械主要的导航方式以及果园导航机械设计研究过程中需要考虑的问题。     

温室环境视觉导航路径的识别

为实现视觉导航的精确性和鲁棒性,研究了温室复杂环境机器人视觉导航路径的识别方法。以温室内西红柿苗垄为研究对象,在地膜、光线和阴影等复杂环境对植物识别的影响下,用Lab色彩空间将绿色植物从背景中分离出来;用基于权重因子的阈值分割算法代替常用的阈值分割算法;用改进的Hough变换的导航线提取方法处理有杂草干扰的作物垄。试验证明,该方法对复杂温室环境下作物垄导航线的提取有较好的适应性,而且算法简单,能够满足实时性的要求。     

智能车辆自主导航神经网络控制器设计

针对自主设计、制造的智能车辆,提出了设计新的神经网络控制器来实现对车辆导航路径的自主跟踪控制。分析了神经网络导向控制器的设计方法,选择了神经网络导向控制器的输入、输出变量,并建立了神经网络导向控制器的结构。在此基础上,采用人工驾车采集的数据对控制器进行了训练。完成了计算机仿真和实际路径跟踪控制试验,试验结果表明该神经网络控制器能够很好地实现对导航路径的自主跟踪控制。     

基于信息融合的多智能体混合体系智能车辆导航

针对智能车辆的结构特点和任务要求,综合体系结构和信息处理两方面设计车辆导航策略.提出了一种基于多智能体且包含了慎思和反应结构的混合体系,根据系统特性设计出多个异构智能体.在现有研究的基础上将图像处理、信息融合方法与该体系相结合.仿真与实验显示,智能车辆在多智能体结构下能充分利用多传感器信息,并获得良好的避障导航效果.     

基于激光雷达的果园行间路径提取与导航

针对车辆果园行间自主导航出现的车辆偏航、非相邻树行干扰、植株缺失、树行弯曲等问题,提出一种基于激光雷达的行间路径提取方法,构建多样化虚拟果园环境仿真行间路径导航过程,评估路径提取算法性能。行间路径提取时,采用二维激光雷达（Light detection and ranging,LiDAR）获取果园树干测量数据,通过中值滤波削弱测量噪声,设计椭圆感兴趣区域（Region of interest,ROI）提取相邻树行,提出两步树行分割法获取相邻树行数据,通过最小二乘法拟合树行直线,将树行中心线作为导航路径。行间导航仿真时,建立虚拟果园环境和LiDAR测量模型,基于仿真测量数据生成导航路径,经过一阶数字低通滤波后实时控制车辆运动。仿真实验中,设置果树种植偏差为±20cm,树干直径偏差为±3cm,LiDAR测量误差为±3cm。实验结果表明,本文方法在车辆偏航、缺树、曲线树行等情况下均能准确提取导航路径,在偏航角不大于15°、横向偏差不大于1m、缺树率不大于25%时均能将车辆轨迹与道路中心线的横向偏差控制在±14cm内。     

基于机器视觉的农田机械导航线提取算法研究

随着科学技术的发展,精细农业已成为现代农业发展的主导方向。农业机械的自动导航技术是精细农业的关键技术之一,也是实施精准农业的基础。机器视觉由于其广泛实用性,已成为农田机械导航线提取的重要方法。目前,机器视觉自动导航线提取易受自然环境干扰,且在实时处理速度上有待提高。为此,研究了一种导航线提取算法,旨在简化图像处理,提高通用性。首先对CCD获取的彩色农田图像,使用改进的过绿色算法进行灰度化,得到目标区分较好的图像;然后使用改进的OTSU算法对图像进行分割,得到二值图像,再采用滤波、腐蚀、膨胀相结合的算法去除图像噪声;最后提取作物行骨架,拟合作物行直线并进行方向校正,计算相机偏差,为实时校正航向提供反馈信息。试验结果表明,该算法处理一幅图像所用时间在200ms左右,可满足农田机械实时导航的要求。     

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。