Study On Three-dimensional Modeling Of Virtual Plant Fruit

Virtual plant is the technology of simulating the plant's growth in virtual reality environment. Virtual plant is a comprehensive research project and also a current research focus, which involves applied mathematics, computer science, agro forestry, ecology, and so on. Virtual plant has a good prospect, and it has some advantages over traditional methods, especially in agriculture test, such as the long-term observation experiment, grafted plants test, wide-ranging cultivation tests. In addition, virtual plant is of great value in the fields of entertainment, education, digital simulation and so on. Based on these applications, this study has completed the following tasks:(1) Since there are some problems in the current modeling approaches, such as lack of authenticity, time-consuming issues, the study in this thesis proposed image-based virtual plant fruit modeling method. The advantages and disadvantages of the current modeling method are analyzed in the thesis and some researches have been done on the basic theory of projective geometry. With the characteristics that the local surface of fruits has smooth continuity, we generated match points clusters by employing the theory of matching spread. These match point clusters generated quasi-dense matched point through homographic. Then the dense matched points are used to reconstruct three-dimensional model. We integrated three dimensional coordinates of model and used triangulation theory to realize point cloud which generated the surfaces of fruits. Finally the surface texture of the fruit was rendered by the original images. The Experimental results proved that our method can efficiently solve the deficiency of fruit surface reality.(2) We have found the solution to introduce plant organs into the 3d virtual platform. In the implementation, the plant organs were transformed into vrml data so as to achieve the transformation and communication between Plantlab system and plant organs. This research could not only complete the mapping between plant organs and Plantlab internal representation, but display some plants with the existing organ model in the virtual platform. Experimental results proved the fruits of model can be reused.(3) Based on the existed fruit model, we simulated the growth model by means of Plantlab which is based on L-systems. In L-system, the plant is represented by the combination of some single organs, and the combination would gradually change in different growth stages. Through iterative changes of the strings, L-system achieved the combination of organs. According to the plant growth law, the paper used the existing plant organs to simulate plant growth. Experimental results showed that the existing plant growth models can truly simulate the plant growth processes.In addition, the thesis also discussed the main methods of texture rendering. We have also done some researches on details of the surface of plant organs. The research in this thesis shows us a tree with some fruits which has high sense of reality.