Research On Plant Growth Simulation And Visualization

Virtual plant is a kind of technology which simulates plant growth and to show the growth process with visualization technologies based on computer. It is a combination of computer, mathematics, botany, agriculture, forestry, ecology and other subjects. It also has potential applications including agriculture, simulation system of large nature landscape, entertainment, scientific research and education. Plant growth simulation and visualization, which have been studied in this dissertation, are the two key technologies and the most important problems of virtual plant research. Based on the initial status of plant, environmental factors and growth rules of plant, the plant growth simulation can calculate out the physiological and geometric attributes of plant in each of the physiological stages during the growth process. Utilizing the information computed by plant growth simulation, visualization technologies can display the geometric changes of a plant during its growth on a computer screen as two-dimensional or three-dimensional graphics. The main studies and contributions in this dissertation are as followings:(1)A virtual organ based plant growth simulation method is presented. Virtual organ is the representation of physiological and geometric attributes of a real plant organ. And the relations among virtual organs are used to describe the structure of plant. The process of plant growth can be realized by changing attributes of virtual organ. The changes of environment controlled by variation rules are simulated by virtual environment. The attributes of virtual organs in the next growth period are determined by growth rules according to the current attributes of virtual organs and environment attributes. Finally 3D graph of visual plant is rendered by 3D engine which reads the attributes of virtual organs to control the rendering process. Experiments show that plant growth with influence of environment can be simulated, and the shortcomings of L system are also overcome.(2)A plant fruit modeling method based on Bezier curve is introduced. The approach uses Bezier curve to construct fruit axis and sectional curve parametric equations which build models of plant fruits, such as eggplant, banana, watermelon and etc. In order to solve the deformation of fruit, perturbation functions are added to curve parametric equations. Morphing technology is also applied to make these models be used for"virtual organ based plant growth simulation", and deformation of fruit model during plant growth can be realized.(3)A PSO based Wang Tiles texture synthesis algorithm is developed. This algorithm improves the effect of Wang Tiles texture synthesis algorithm. It searches and selects image patches which have minor error between patch boundaries by particle swarm optimization. Then these sample patches are used to construct Wang Tiles which are used to synthesize textures by Wang Tiles texture synthesis algorithm. In this dissertation, the texture synthesis algorithm is applied to synthesize textures of plant organs. The difficulty of obtain the surface texture of plant organ and the lack of surface texture are addressed by this proper application. Later, these synthesized textures are applied to improve the render effect of plant organ models by using texture mapping technology. Experiments show that textures of plant organs synthesized in this dissertation can improve the visualized effect of plant organs.(4)A plant growth simulation framework based on"virtual organ based plant growth simulation method"is implemented. And then the processes of capsicum flower, capsicum growth, eggplant growth and capsicum growth with influence of environment are simulated by this framework. These simulations prove that research of this dissertation can simulate plant growth and produce better visualization effect.