基于农学参数的玉米叶片表观建模与可视化方法  

Appearance modeling and visualization of maize leaf with agronomic parameters

作　　者：苗腾[1,2,3,4] 郭新宇 温维亮[1,3,4] 王传宇 肖伯祥[1,3,4] 

机构地区：[1]北京农业信息技术研究中心,北京100097 [2]沈阳农业大学信息与电气工程学院,沈阳110866 [3]国家农业信息化工程技术研究中心,北京100097 [4]数字植物北京市重点实验室,北京100097

出　　处：《农业工程学报》2017年第19期187-195,共9页Transactions of the Chinese Society of Agricultural Engineering

基　　金：北京市自然科学基金(4162028);国家自然科学基金(31501217);北京市农林科学院博士后基金项目;北京市科技计划项目(D151100004215004)

摘　　要：为提高农业题材三维数字媒体内容制作效率,提出基于SPAD(soil and plant analyzer development)和生育期农学参数的作物叶片表观建模与可视化方法,并以玉米为例进行实际验证。将玉米叶片分成叶肉、一级叶脉、二级叶脉3种结构,首先获取主要生育期下各结构表观材质(包括漫反射强度、透射强度、高光反射强度、粗糙度4种参数)及SPAD数据;之后构建各类表观材质参数与SPAD及生育期之间的定量化模型;再对玉米叶片纹理样式进行抽象,构建参数化的玉米纹理结构几何表达,并基于定量化模型为纹理结构分配表观参数;最后整合实时光照计算框架,对大田光环境下玉米表观进行可视化模拟。该文方法搭建了农业知识与三维可视化效果间的桥梁,使用户可以通过调整农学参数实现对作物叶片表观的快速、准确设计与制作,为农业题材的三维数字资源开发提供技术工具。In this paper, we presents a method for modeling and visualization of crop leaves based on agronomic parameters in order to improve the production efficiency of three dimensional digital media for agricultural subjects. The field experiments were conducted in the experiment farm of Beijing Academy of Agricultural and Forestry Sciences, Beijing City. During maize growth periods of jointing stage, horn mouth stage, florescence stage, grouting stage, maturation period and senility period, SPAD values of maize leaves were obtained by using SPAD-502 and four appearance parameters were collected by an apparent image acquisition system using linear light source. The four appearance parameters were diffuse reflectance, transparency, specular reflectance and roughness. In order to finely model the maize leaf appearance, leaf surface was divided into three structures including mesophyll, main vein and secondary vein. With the data, we analyzed the relationship between SPAD, growth period parameters and various kinds of appearance parameters of the three structures, respectively. We applied a variety of mathematical models to fit the data to describe the potential relationship between SPAD, growth period and diffuse, transparency appearance of mesophyll. Based on R2 and RMSE, we selected quadratic function for diffuse reflectance and negative exponential function for transparency. The coefficients of determination for the RGB channels of final diffuse model of mesophyll were 0.913 7, 0.851 1, and 0.614 6, respectively, and their corresponding values of RMSE were 0.0154 9, 0.012 8, and 0.015 33. The coefficients of determination for the transparency model were 0.997 5, 0.991 3, and 0.990 7, respectively, and their corresponding values of RMSE were 0.006 4, 0.009 6, and 0.020 7. Data showed diffuse reflection and transparency of secondary vein could be classified into four sections by SPAD values and there was little difference between each class of appearance values. We used mean values of each section as diffuse and trans

关 键 词：三维 可视化 作物 叶片表观 表观模拟 数字植物 

分 类 号：TP391.4[自动化与计算机技术—计算机应用技术]