Study On Model-Based Visualization Of Wheat Root Systems

Virtual roots are to simulate roots morphological architecture and growth processes in three-dimensional space visually on computer, which is an important part of virtual crop, and has important realistic significance and wide application prospects in agronomy, ecology and virtual teaching. This paper is on the research of wheat root, based on the different experiments data, a preliminary root morphology model in wheat was established using GDD as a driving factor. Integrated morphological feature parameter outputted from the root morphological model and root topology, using 3d geometrical modeling techniques, a three-dimensional visualization model of root axis in wheat was developed. Then based on the platform of OpenGL, the three-dimensional visualization of root growth in wheat was realized, by integrating the technologies of texture mapping, lighting rendering and collision detection. A digital and visualized wheat root growth system was developed by using components and visualization technology. This study could lay a foundation for further development of a visualization system of whole wheat plant.A systematic observation was performed on wheat root morphology through a greenhouse tub-planting and hydroponic experiment. Morphological structure features like the length of wheat root, branch numbers and intersection angle were extracted by application of 3D digitizer (3Space Fastrak) and root analyzer (WinRhizo). A 3D display model of wheat root axis, including root axis growth model, branch geometric model as well as root axis curve model, were developed by analysis of topology formulation law with 3D geometry modeling technology combining botany theory. Then, by integrating root topology, the corresponding pixel was determined, and the whole 3D root of wheat was re-constructed by using morphological feature parameter outputted from the root morphology model.Based on the established geometrical model, the corresponding pixel was determined by combined the basic model of wheat root growth, using programming in the Visual C++ as well as OpenGL. The whole 3D root of wheat was re-constructed according to the morphological feature parameters outputted from the root morphological model and the experimental results that can calculate the geometric dimensioning and space positions of each radical axis and its root segment in each course of growth. Then based on the three dimensional graphics, the three-dimensional visualization of root growth in wheat was realized by integrating the technologies of texture mapping, lighting rendering, randomicity processing, collision detection and response.Finally, a digital and visual wheat root growth system was developed by using components and visualization technology. The visualization system for 3D morphology on wheat root showed that the output of 3D root from model was vivid, which could realize 3D visualization of wheat roots under different cultivars, water regimes and nitrogen rates. The system interface was designed according to needs of users, the functions of zooming,rotating, transfer, and light and memory of photos can be got easily. The system would lay a foundation for further development of the digital and visual system of whole wheat plant.