Research On Illuminating Methods Of Visualizing 3d Flows

After Scientific Visualization was put forward, people are trying to use it in diffident area; some of illumination algorithms were brought forward. So the result of visualization is more convincing. Some features of the datasets are visualized through different illumination algorithms.Based on deeply study of the realistic illumination algorithms and Non-Photorealistic illumination algorithms, we proposed some improved algorithms to solve some practical problem. We also constructed a GPU-based three-dimensional visualization framework for the texture design of the flow field illumination model. The contributions and relevant work in this paper are as follows:Firstly, based on the Cook-Torrance illumination model, we proposed an improved Cook-Torrance illumination algorithm to solve the texture fragments illuminating problem. This algorithm improves the geometric attenuation factor to solve the blocking and shielding between the texture fragments.Secondly, based on the cool/warm illumination model, this paper proposed scumbled cool/warm illumination algorithms, and computed a distance index for every sample point on the streamline. Then, we represent the global concrete orientation of the 3D vector field by using the distance indices to control the variety of cool/warm illumination temperature. In contrast to representing the global orientation of the above method, another illumination approach was proposed to describe the concrete vector direction on each texture fragment.Thirdly, although scumbled cool/warm illumination algorithms can represent the flow direction as a whole, yet it can't reflect the direction from a single LIC streak. This is especially important when users zoom in the view position to investigate some special interested parts in the vector field. So we proposed exquisite cool/warm illumination algorithms, which can reflect the concrete direction of the flow from a single texture streak.Finally, we have developed a prototype framework system based on analyses and realization of algorithms above. This system has been applied to Lorenz attractor data, aircraft data and so on successfully.