基于光环境的虚拟玉米生长模拟研究

发布时间：2018-04-19 05:32

本文选题：虚拟植物 + 光线跟踪　；参考：《河南师范大学》2017年硕士论文

【摘要】：玉米作为我国主要农产作物之一,然而玉米种植的农业科技转化率并不高。玉米的生长周期较长,过程也较为复杂。玉米的生长除了受内部生理机制影响外,还跟它的生长环境有很大的影响联系,特别是光照环境,这也是一个重要的前沿课题,具有很高的学术意义。在生长过程中,玉米与光环境之间的交互作用时刻进行着。但是,玉米的光分布很难进行试验测定和模拟研究,如果在计算机上建立三维的玉米模型,模拟光线在玉米间的传输、反射等,就能精确直观地对其进行研究。近年来,随着互联信息和计算机硬件技术的进步,虚拟植物技术已逐渐成为一个集合计算机图形学、植物生长学、农学、数学等多学科研究的活跃领域,吸引了各学科专家学者的广泛关注。然而,困扰虚拟植物领域众多学者的难点之一就是如何在计算机上实现环境因素影响下的植物模拟,其困难之处主要是因为植物与外部环境的交互是一个相当复杂的过程,并且涉及较多因素的影响,想要找到一个普适的数学模型来描述之并不容易。本文主要研究的是外部环境因素中对玉米的生长产生主要影响作用的光照环境,重点探讨和研究光环境对玉米生长过程的形态变化及生理影响,建立了一种玉米与环境交互的光照模型,提出了一种光影响下的玉米生长模拟方法,并利用计算机技术动态模拟虚拟玉米与光照之间的交互过程,主要工作如下:(1)首先,结合我国的玉米种植背景,提出了进行基于光环境的玉米生长模拟研究的意义以及研究光环境下虚拟玉米生长模拟的必要性;然后,介绍了光环境下虚拟玉米生长模拟的国内外研究现状,分析各种生长模型的特点,从虚拟植物技术的产生、起源到后来的飞速发展,以及目前的研究重点和将来的研究方向;最后将全文的主要内容和创新点进行简单的阐述。(2)其次,主要介绍了光照模块所要采用的光线跟踪算法的相关基础知识,从经典的光线跟踪算法,到光线跟踪算法的改进以及内包围盒技术的介绍。(3)为了构建逼真有效的玉米生长的光环境,提出了一种基于二分内包围盒的逆光线跟踪算法。首先,在玉米表面建立了二分内包围盒进行预处理,剔除与光线不相交的冗余面,减少光线与玉米的相交运算量;然后,引入了遮挡因子简化光能计算的复杂度;最后,通过调整光能阈值达到光环境逼真度和算法效率的有机统一。(4)为了验证逆光线跟踪算法的快速、有效性,建立了三维立体的玉米模型,对比不同包围盒求交运算的速率,得出二分内包围盒求交运算速度最快,逆光线跟踪算法模拟出的玉米生长效果较为逼真。(5)回顾整文,总结了本文所做的主要工作,指出并分析了存在的缺点,并对未来的研究方向和工作进行了预测展望。
[Abstract]:Maize is one of the main agricultural crops in China, but the conversion rate of agricultural science and technology is not high.The growth cycle of maize is longer and the process is more complicated.The growth of maize is not only influenced by internal physiological mechanism, but also influenced by its growth environment, especially the illumination environment, which is also an important frontier subject and has a high academic significance.During growth, the interaction between maize and light environment occurs at all times.However, the light distribution of maize is difficult to be measured and simulated. If a three-dimensional maize model is built on a computer to simulate the transmission and reflection of light between corn, it can be studied accurately and intuitively.In recent years, with the development of interconnected information and computer hardware technology, virtual plant technology has gradually become a collection of computer graphics, plant growth, agronomy, mathematics and other multidisciplinary research activities.Attracted the extensive attention of various disciplines experts and scholars.However, one of the difficulties for many scholars in the field of virtual plants is how to realize plant simulation under the influence of environmental factors on the computer. The main difficulty is that the interaction between plants and external environment is a very complex process.It is not easy to find a universal mathematical model to describe it because of the influence of many factors.In this paper, the main research is the light environment which has the main effect on the growth of maize in the external environmental factors, especially the morphological changes and physiological effects of the light environment on the growth process of maize.In this paper, an interactive illumination model of maize and environment is established, and a simulation method of maize growth under the influence of light is put forward. The interaction between virtual maize and illumination is simulated dynamically by computer technology. The main work is as follows: 1) first of all,According to the background of maize planting in China, the significance of maize growth simulation based on light environment and the necessity of virtual maize growth simulation in light environment are put forward.This paper introduces the research status of virtual maize growth simulation in light environment at home and abroad, analyzes the characteristics of various growth models, from the emergence of virtual plant technology, its origin to the rapid development later, and the current research focus and future research direction.Finally, the main contents and innovations of the paper are briefly described. Secondly, the basic knowledge of the ray-tracking algorithm used in the illumination module is introduced, and the classical ray-tracking algorithm is introduced.To improve the ray-tracing algorithm and introduce the technology of inner bounding box, in order to construct a realistic and effective light environment for corn growth, an inverse line tracking algorithm based on two-branch inner bounding box is proposed.First of all, a two-minute bounding box is set up on the corn surface to eliminate the redundant surface which is not intersected with light, so as to reduce the computation amount of light intersecting with corn. Then, the occlusion factor is introduced to simplify the complexity of light energy calculation.By adjusting the threshold of light energy to achieve the organic unity of optical environment fidelity and algorithm efficiency. In order to verify the speed and effectiveness of the inverse line tracking algorithm, a three-dimensional corn model is established, and the intersecting rate of different bounding boxes is compared.It is concluded that the intersecting speed of the bounding box is the fastest and the effect of corn growth simulated by the inverse ray tracing algorithm is more realistic. The whole paper is reviewed, the main work done in this paper is summarized, and the shortcomings are pointed out and analyzed.The future research direction and work are forecasted.
【学位授予单位】：河南师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S513;TP391.9

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