本文選題：虛擬植物 + 光線跟蹤�。� 參考：《河南師范大學(xué)》2017年碩士論文

【摘要】：玉米作為我國主要農(nóng)產(chǎn)作物之一,然而玉米種植的農(nóng)業(yè)科技轉(zhuǎn)化率并不高。玉米的生長周期較長,過程也較為復(fù)雜。玉米的生長除了受內(nèi)部生理機(jī)制影響外,還跟它的生長環(huán)境有很大的影響聯(lián)系,特別是光照環(huán)境,這也是一個(gè)重要的前沿課題,具有很高的學(xué)術(shù)意義。在生長過程中,玉米與光環(huán)境之間的交互作用時(shí)刻進(jìn)行著。但是,玉米的光分布很難進(jìn)行試驗(yàn)測(cè)定和模擬研究,如果在計(jì)算機(jī)上建立三維的玉米模型,模擬光線在玉米間的傳輸、反射等,就能精確直觀地對(duì)其進(jìn)行研究。近年來,隨著互聯(lián)信息和計(jì)算機(jī)硬件技術(shù)的進(jìn)步,虛擬植物技術(shù)已逐漸成為一個(gè)集合計(jì)算機(jī)圖形學(xué)、植物生長學(xué)、農(nóng)學(xué)、數(shù)學(xué)等多學(xué)科研究的活躍領(lǐng)域,吸引了各學(xué)科專家學(xué)者的廣泛關(guān)注。然而,困擾虛擬植物領(lǐng)域眾多學(xué)者的難點(diǎn)之一就是如何在計(jì)算機(jī)上實(shí)現(xiàn)環(huán)境因素影響下的植物模擬,其困難之處主要是因?yàn)橹参锱c外部環(huán)境的交互是一個(gè)相當(dāng)復(fù)雜的過程,并且涉及較多因素的影響,想要找到一個(gè)普適的數(shù)學(xué)模型來描述之并不容易。本文主要研究的是外部環(huán)境因素中對(duì)玉米的生長產(chǎn)生主要影響作用的光照環(huán)境,重點(diǎn)探討和研究光環(huán)境對(duì)玉米生長過程的形態(tài)變化及生理影響,建立了一種玉米與環(huán)境交互的光照模型,提出了一種光影響下的玉米生長模擬方法,并利用計(jì)算機(jī)技術(shù)動(dòng)態(tài)模擬虛擬玉米與光照之間的交互過程,主要工作如下:(1)首先,結(jié)合我國的玉米種植背景,提出了進(jìn)行基于光環(huán)境的玉米生長模擬研究的意義以及研究光環(huán)境下虛擬玉米生長模擬的必要性;然后,介紹了光環(huán)境下虛擬玉米生長模擬的國內(nèi)外研究現(xiàn)狀,分析各種生長模型的特點(diǎn),從虛擬植物技術(shù)的產(chǎn)生、起源到后來的飛速發(fā)展,以及目前的研究重點(diǎn)和將來的研究方向;最后將全文的主要內(nèi)容和創(chuàng)新點(diǎn)進(jìn)行簡(jiǎn)單的闡述。(2)其次,主要介紹了光照模塊所要采用的光線跟蹤算法的相關(guān)基礎(chǔ)知識(shí),從經(jīng)典的光線跟蹤算法,到光線跟蹤算法的改進(jìn)以及內(nèi)包圍盒技術(shù)的介紹。(3)為了構(gòu)建逼真有效的玉米生長的光環(huán)境,提出了一種基于二分內(nèi)包圍盒的逆光線跟蹤算法。首先,在玉米表面建立了二分內(nèi)包圍盒進(jìn)行預(yù)處理,剔除與光線不相交的冗余面,減少光線與玉米的相交運(yùn)算量;然后,引入了遮擋因子簡(jiǎn)化光能計(jì)算的復(fù)雜度;最后,通過調(diào)整光能閾值達(dá)到光環(huán)境逼真度和算法效率的有機(jī)統(tǒng)一。(4)為了驗(yàn)證逆光線跟蹤算法的快速、有效性,建立了三維立體的玉米模型,對(duì)比不同包圍盒求交運(yùn)算的速率,得出二分內(nèi)包圍盒求交運(yùn)算速度最快,逆光線跟蹤算法模擬出的玉米生長效果較為逼真。(5)回顧整文,總結(jié)了本文所做的主要工作,指出并分析了存在的缺點(diǎn),并對(duì)未來的研究方向和工作進(jìn)行了預(yù)測(cè)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.
【學(xué)位授予單位】：河南師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：S513;TP391.9

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