【作者】 周娟；

【导师】 周治国；

【作者基本信息】 南京农业大学 ， 地图学与地理信息系统， 2009， 硕士

【摘要】 本文基于2005～2007年棉花品种、播期、氮素、水分和DPC化控试验,将系统分析方法和数学建模技术应用于棉花形态建成的研究,通过对棉花形态数据的定量分析,构建了棉花形态建成模型。结合OpenGL技术,在Visual C++6.0平台上实现了棉花虚拟生长系统VGSC (Virtual Growth System for Cotton)。1.棉花形态模型的构建应用2005年试验数据,在综合考虑氮素、水分、化控等因子影响的基础上,通过对棉花形态数据的定量分析,采用Logistic方程描述各器官尺寸随GDD(生长度日,℃·d)的变化过程及其与氮素、水分及DPC的关系,构建棉花形态建成模型,主要包括：主茎叶长和宽、主茎叶柄长、主茎节间长和粗、果枝叶长和宽、果枝叶柄长、果节长和粗以及棉铃长和宽等模型。利用2006年的试验数据对模型进行检验,棉花主茎叶长宽、主茎叶柄长、主茎节间长粗、果枝叶长宽、果枝叶柄长、果节长粗以及棉铃长宽的观测值与模拟值的根均方差分别为0.85 cm、0.82 cm、0.87 cm、0.57 cm、0.86mm、0.65 cm、0.74 cm、0.8 cm、0.73 cm、0.16 mm、0.36 cm、0.4 cm,模型预测性好。此外,为了虚拟显示的需要,利用2007年试验数据,建立了棉花的叶色模型。2.棉花各器官的可视化模拟根据棉花器官的三维形态特征,利用NURBS曲面描述叶片的几何结构,基于拍摄的叶片照片,选取几张典型的图片(一个裂片、三个裂片、五个裂片),通过photoshop7.0勾勒出反映叶片轮廓的控制点,借助NURBS曲面模拟叶片形状,然后以GDD为主线,以叶片形态模型为基本算法,计算出叶片实际尺寸,再结合已绘制图形进行缩放变形,实现虚拟叶片的伸长。通过叶色模型,完成棉花生长过程中叶色变化的虚拟实现。用圆柱体构建叶柄、节间、果节等形态简单的器官,以柱体的长度和上下底面的直径分别表示茎(节)的长和粗,其取值通过建立的棉花节间形态模型(棉花果节形态模型)获得,将形态模型模拟的茎(节)长和粗数据转化为显示模型中各点的坐标,然后选择合适的绘制模式进行绘制,实现茎(节)形态的可视化输出。最后根据棉花各器官间的拓扑结构将各个器官组合在一起,利用形态模型中各个器官的同伸关系,实现整株棉花的虚拟生长显示。结果表明,该方法具有可控性高、灵活度高等特点,是一种适合于棉花器官三维造型的好方法。3.棉花虚拟生长系统利用棉花的三维形态几何模型,采用面向对象的方法及OpenGL技术设计实现了棉花三维可视化系统。系统主要由参数输入、模型计算、存储系统、结果输出等几大部分组成。模型计算是本系统的核心部分,主要完成棉花的虚拟建成。数据库中存有品种数据、棉花形态特征参数最大值以及初始化的最优栽培参数值等,用户即可在不输入任何数据的情况下直接实现棉花的虚拟生长,也可根据实际情况,修改数据库中各影响因子参数值,然后调用形态模型为可视化模型提供形态特征参数,实现棉花各器官、单株和群体的三维静态建模及生长过程动态模拟。更多还原

【Abstract】 Based on the potted plant research of cotton variety, sowing date, nitrogen, water and DPC in the summer seasons of 2005,2006 and 2007, with the systematic analysis principle and mathematical modeling technique applied to cotton morphogenesis, a morphological model was developed by the quantitative analyses of experimental data. And a virtual growth system for cotton was implemented with usage of OpenGL for 3D graphic and MFC for graphical user interface.1. Construction of morphogenesis model for cottonBased on the pot experiment of cotton in 2005, with the consideration of nitrogen, water and DPC, a morphological model for cotton, which includes several sub-models of leaf, stem, boll, and so on, was developed by the quantitative analyses of measured data, that the dynamic change of each organ size could be characterized by logistic equation in relation to GDD, nitrogen, water and DPC. The model was validated by the data from 2006, and the mean RMSEs were 0.85cm,0.82cm,0.87cm,0.57cm,0.86mm,0.65cm,0.74cm, 0.8cm,0.73cm,0.16mm,0.36cm, and 0.4cm for stem leaf length and width, stem leafstalk length, stem internode length and diameter, fruiting branch leaf length and width, fruiting branch leafstalk length, fruiting node length and diameter, and boll length and width, respectively. Meantime, color model of cotton leaf was analyzed as to the need of virtual display by the data from 2007.2. Visual simualtion of cotton organsVisual simulation of cotton organ is realized by three-dimensional morphological characteristic of cotton organ. The shape of leaf was modeled with the aid of NURBS. we first got a set of points which represented leaf outlines from picture using Photoshop 7.0, then we used NURBS function to simulate the shape of leaf based on these points. At last, based on the morphogenesis of leaf, the actual size was got, and we combined it with the drawn graphic for scaling deformation. Used the leaf color model, the virtual change of leaf color in the process of leaf growth was fulfilled. The column shaped internode and petiole could be naturally captured by length-to-diameter which was got from their morphogenesis model. Using the growth relationship in each organ and integrating each organ according to structure character in cotton, the system fulfilled virtual growth show of the whole cotton. The results show characteristics of the methodology are high controllability and large agility and etc. It is a good way for geometry modeling in cotton organ.3. Realization of virtual growth system for cottonBased on the cotton morphological model, a virtual growth system was realized by the usage of OOP and OpenGL.This system included input module, model module, database module and output module. As central part, model module was used to fulfill cotton virtual show. Database contained variety data, maximum value of organ size, the best parameter of cultivation, and so on. The system could realize virtual growth of cotton with no input, or could take a static model for cotton stem, leaf and boll and realize the demonstration of cotton dynamic growth relied on the input of physiological parameter and cotton morphological model.更多还原