基于计算机视觉的土壤镉胁迫生菜叶片污染响应分析

为了实现无损检测生菜叶片中重金属镉的污染程度,以计算机视觉技术为研究手段,结合图像处理方法和特征选择方法,对4个梯度重金属镉胁迫的生菜叶片进行识别。首先利用数码相机获取生菜叶片图像,然后使用K-means聚类算法分割图像,对分割出的目标图像提取图像颜色、形状和纹理特征,共获取46个图像特征。为了使模型更简便和减少数据量,利用基于变量组合的变量重要性分析(VIAVC)和竞争性自适应重加权算法(CARS)对图像特征进行降维。采用偏最小二乘法判别分析(PLS-DA)和随机森林(RF)构建模型,用于生菜镉胁迫程度的识别。结果表明,在7个组合特征模型中,颜色形状纹理融合特征所建立的模型给出了最优结果,测试集分类正确率为92%。用VIAVC和CARS对颜色形状纹理融合特征进行特征选择,发现VIAVC的降维效果优于CARS。使用特征选择的变量建立模型,RF模型的训练集分类正确率和预测集分类正确率均高于PLS-DA,其中,基于VIAVC的RF模型的训练集和预测集分类正确率分别为98.0%和96.0%。可见,基于VIAVC的RF模型在大大降低了特征维数的前提下,能够较好地对不同镉胁迫程度的生菜叶片进行识别。     

采摘机器人基于支持向量机苹果识别方法

针对目前苹果采摘机器人果实识别过程误差大、处理时间长等问题,应用支持向量机(SVM)方法对苹果果实进行识别.首先采用矢量中值滤波法对苹果彩色图像进行预处理,然后运用区域生长算法和颜色特征相结合的方法进行图像分割,最后分别对苹果彩色图像的颜色特征、几何形状特征进行提取,并用支持向量机的模式识别方法识别苹果果实.实验结果表明:支持向量机识别方法的识别性能优于神经网络方法;综合颜色特征和形状特征的支持向量机识别方法对苹果果实识别的正确率高于只用颜色特征或形状特征的正确率.     

基于K均值聚类的绿色苹果识别技

针对颜色和背景相近的绿色苹果,提出了一种基于K-均值聚类的苹果图像识别算法.该算法以8×8像素的正方形区域为分割单位.选择颜色差R-B作为颜色特征,选择灰度均值m,标准偏差σ和熵e作为纹理特征,形成特征向量空间.采用间隙统计法确定苹果图像的最佳聚类数. 将特征向量空间和最佳聚类数作为输入,运用本文算法对苹果图像进行聚类和分割.对200幅图像识别实验结果表明,在顺光和逆光情况下,算法均能实现果实与背景的有效分割,果实识别的正确率高于81%.     

基于激光扫描三维图像的树上苹果识别算法

为消除不同光线和复杂背景的影响,提出了一种自动识别树上苹果的算法.使用激光视觉系统获取果树局部的三维图像,参考设定的场景知识对图像背景进行简化;采用基于平滑频率曲线的自动阈值检测方法实现图像的二值化;通过轮廓跟踪技术记录目标边界的走向,据此计算链码和与链码差,并根据两者在果树各部分的变化规律确立相应的准则,以提取苹果的轮廓像素点;利用随机圆环法获得果实的形状特征完成对苹果的识别.实验结果表明,该算法具有较好的实时性,当枝叶遮挡面积小于40％时,果实的正确识别率高于93.75％,且识别效果不受光照条件与果实表面颜色的影响.     

夜间自然环境下荔枝采摘机器人识别技术

利用机器视觉实现自然环境下成熟荔枝的识别,对农业采摘机器人的研究与发展具有重要意义。本文首先设计了夜间图像采集的视觉系统,然后选取了白天和夜间两种自然环境下采集荔枝图像,分析了同一串荔枝在白天自然光照与夜间LED光照下的颜色数据,确定了YIQ颜色模型进行夜间荔枝果实识别的可行性。首先选择夜间荔枝图像的I分量图,利用Otsu算法分割图像去除背景,然后使用模糊C均值聚类算法分割果实和果梗图像,得到荔枝果实图像;再利用Hough圆拟合方法检测出图像中的各个荔枝果实。荔枝识别试验结果表明:夜间荔枝图像识别的正确率为95.3%,识别算法运行的平均时间为0.46 s。研究表明,该算法对夜间荔枝的识别有较好的准确性和实时性,为荔枝采摘机器人的视觉定位方法提供了技术支持。     

近色背景中树上绿色苹果识别方法

为实现大型果园生产中果实产量监控和预测,研究了基于机器视觉的树上绿色苹果识别方法。为彩色相机配备一环形闪光灯用于夜间苹果树的图像采集,设计了以归一化的g分量和HSV颜色空间中H、S分量为特征参数的支持向量机(SVM)分类器和以超绿算子(2G-R-B)为特征的阈值分类器组合而成的混合分类器,实现了绿色苹果在近色背景中的有效识别;针对识别结果中的果实粘连情况,通过计算区域面积以及区域长、短轴之比,识别粘连区域,并对粘连果实区域图像进行欧氏距离变换,进而针对粘连区域距离变换图像采用分水岭算法进行分割,可将大部分粘连果实分开,并最终实现近色背景中绿色苹果的识别与计数。通过对64幅果树图像实验表明,该方法平均识别正确率为89.30%。     

基于RGB-D相机的果树三维重构与果实识别定位

为实现对果园果实机器人采摘提供科学可靠的技术指导,提出了一种基于RGB-D相机的苹果果树三维重构以及进行果实立体识别与定位的方法。使用RGB-D相机快速获取自然光照条件下果树的彩色图像和深度图像,通过融合果树图像彩色信息和深度信息实现了果树的三维重构;对果树的三维点云进行 R-G 的色差阈值分割和滤波去噪处理,获得果实区域的点云信息;基于随机采样一致性的点云分割方法对果实点云进行三维球体形状提取,得到每个果实质心的三维空间位置信息和果实半径。实验结果表明,提出的果树三维重构和果实立体识别与定位方法具有较强的实时性和鲁棒性,在0.8~2.0 m测量范围内,顺光和逆光环境中果实正确识别率分别达95.5%和88.5%;在果实拍摄面的点云区域被遮挡面积超过50%的情况下正确识别率达87.4%;果实平均深度定位偏差为8.1 mm;果实平均半径偏差为4.5 mm。     

基于超像素特征的苹果采摘机器人果实分割方法

针对苹果采摘机器人在自然环境下对着色不均匀果实的识别分割问题,提出了基于超像素特征的苹果采摘机器人果实分割方法。首先,采用简单线性迭代聚类算法将图像分割成内部像素颜色较为一致的若干超像素单元;然后,提取每个超像素的纹理和颜色特征,并采用支持向量机将超像素分为果实和背景两个类别;最后,根据超像素之间的邻接关系对分类结果进行进一步修正。实验表明,该方法能够对大部分超像素单元进行正确分类,平均每幅图像被错误分类的超像素约为2.28个。与采用像素级特征的色差法和采用邻域像素特征的果实分割方法相比,采用超像素特征的果实分割方法具有更好的分割效果。在进行邻接关系修正前,该方法图像分割准确率达0.9214,召回率达0.8565,平均识别分割一幅图像耗时0.6087s,基本满足实时性需求。     

基于SVM和AdaBoost的棉叶螨危害等级识别

针对自然条件下棉叶螨虫害等级识别难的问题,在自然条件下以普通手机采集棉叶图像作为实验对象,首先使用大津法和连通区域标记算法,将棉花叶片图像与背景分离,然后,提取不同棉叶螨危害等级棉叶图像的颜色、纹理和边缘特征数据,使用支持向量机(Support vector machine,SVM)单独进行分类实验,得到平均识别正确率为76. 25%,最后,采用SVM和AdaBoost相结合的算法,生成最优判别模型,实现对棉叶螨危害等级的识别,平均识别正确率为88. 75%。对比实验表明,提出的棉叶螨危害等级识别方法比BP神经网络的平均识别正确率高13. 75个百分点,比单独采用SVM算法高12. 5个百分点,比单独采用AdaBoost算法高8. 75个百分点,SVM和AdaBoost相结合的算法可较好地对棉叶螨危害等级进行识别,为棉叶螨数字化防治和变量喷药提供了数据支持。     

基于深度图像的球形果实识别定位算法

为了解决近色背景果实识别困难问题,针对果实近球形的形态特性,提出了一种利用深度图像从果实形态角度进行果实识别定位的算法。该算法使用深度摄像头获取果树的深度图像,通过深度图像计算出各像素点的梯度向量,将梯度向量看作运动矢量场,并计算出矢量场的散度,根据散度最大原则,从矢量场中搜索出辐散中心点;然后利用果实和叶片等深图像的差异从辐散中心点中筛选出果实中心点,以果实中心点为起点采用八方向搜索方法搜索出果实边界点,将果实边界点依次连接后形成的封闭区域内的果实图像导入点云;最后根据果实图像部分点云利用RANSAC算法求出目标果实的拟合球形,进而得出果实的尺寸以及三维空间位置。该算法无需传统算法需要利用的颜色特征,而仅利用了深度图像中的深度信息进行果实识别定位,能够克服传统算法受色彩、光照等因素影响的弊端,并且由于该算法完全没有利用到彩色图像信息,因此不仅可以实现绿色果实的识别定位,还可以实现采摘机器人在夜间环境下正常工作,为复杂环境下的果实识别定位算法研究提供了技术支撑。     

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。