2016 International Conference on Materials, Manufacturing and Mechanical Engineering(MMME2016)
ISBN: 978-1-60595-413-4,pp 334-343
Modeling and Simulation of Leaf Color Based on Virtual Rice
Wenlong YI
1,2
, Huojiao HE
1,*
,
Liping WANG
1
, Hongyun YANG
1
1
School of Software Engineering, Jiangxi Agricultural University, Nanchang, China
2
Faculty of Computer Science and Technology, Saint Petersburg Electrotechnical University "LETI",
Saint Petersburg, Russia
*Corresponding author
Keywords: Leaf color of Virtual Rice, SPAD, RGB, Light rendering, Visualization model.
Abstract. With the color changes of main stem leaves of two kinds of rice variety as the research objects, this
study analyzes the RGB value changes of leaf color with the dynamic changes of SPAD value under different
growth periods and different nitrogen levels, so as to build RGB-SPAD mathematic models of rice leaf color.
This paper focally explores the space simulation of rice leaf color and the rendering method for the rice leaf
color model and analyzes the model in light rendering simulation under four illumination variations of emitted
light, ambient light, diffuse reflection and specular reflection respectively. As the rice leaf belongs to a
semi-transparent and nonluminous material, this paper studies the surface reflection simulation and the diffuse
reflection of the rice leaf according to the illumination models and formulas proposed by previous scholars. By
building the relation formulas for the color and RGB through BRDF diffuse reflection formula, the leaf
rendering equation could be obtained. Under programming environment of Visual Studio 2008, the C++
language combined with OpenGL graphics library is applied to realize this algorithm. Consequently, the
different leaf appearances of rice leaf produced by reflection and diffuse reflection under different SPAD
values and parameter values could be visualized, achieving the rice leaf rendering combined with rice leaf
physiological knowledge and physical light knowledge and building a visualized model with the strongly real
sense, which illustrates how the rice leaf color varies with the changes of SPAD value.
1. Introduction
As an important component of the visualization system for virtual rice, the leaf color model of virtual rice
studies and establishes rice leaf color model based on the virtual rice morphologic model to further perfect the
3D visualization model of virtual rice, which not only improves the authenticity and practicability of the model,
but also enriches the plant modeling theory. As the research of modeling technology promotes the
development of agricultural information technology, the leaf color model of rice is of great theoretical and
practical significance.
In recent years, some researchers have analyzed the plant growing states through tracking the leaf color
changes at different periods during the plant physio-ecological process, and established leaf color models
conforming to the plant physiological knowledge based on theoretical knowledge and computer graphic
techniques[1,2]. Relying on the rendering through the physiological models (changes of pigment
concentrations in leaves) and fractal models on color changes of maple leaves in autumn, Mochizuki et al. [3]
proposed the logic coloring time in autumn through calculating the sunlight quantity absorbed by the leaves.
Taking this time as the indicator for coloring in autumn and verifying the model parameters through
experimental physiological data, this paper succeeded in obtaining the rendering effects of vivid maple leaf
changes in autumn via the chaos game algorithm and the random iterative algorithm. Similarly through the