Research Of Ocean Scalar And Vector Data Field Visualization

Scientific visualization is a new subject on the basis of computer graphics.It combines the technologies of computer graphics,computer aided design,human-machine interaction technology and so on.Vector visualization is an important subject in the research of scientific computing visualization,and it has been applied in weather forecast,hydrodynamics,aeronautics and Astronautics,turbine design and so on.The visualization of the scalar and vector data fields intuitively shows the data information to the researchers,transform intangible and complex data into tangible and visible graphics to help them analyze data fields.This dissertation systematically introduced the research of scalar visualization,and focused on research of vector visualization and streamline visualization.Texture-based vector visualization method and streamline uniform placement algorithms were mainly researched.For the texture-based vector visualization method,the efficiency and visualization effect of the line integral convolution algorithm are analyzed,and an improved method is proposed and some extended researches are done.For streamline uniform placement algorithms systematically,a dynamic seed point algorithm based on critical point and grid was proposed.It could not only ensure that the key characteristics of the flow field are not lost,but also obtain uniform placement streamline.On the basis of this,a new form of visualization was proposed.The main innovations and the major tasks completed in this dissertation as follows:(1)The visualization method of the ocean scalar data field was systematically studied and summarized.For the visualization of two dimensional scalar field,color mapping,contour algorithm,height map were implemented.For three-dimensional scalar field visualization,a volume rendering algorithm based on texture mapping was implemented.(2)With regard to the two-dimensional vector fields,the dissertation summarized the current progress of vector visualization technology,and mainly summarized the method based ontexture visualization.For texture visualization(LIC algorithm),a new method of determining the step length and interpolation in the process of line integral convolution was put forward,which improved the efficiency and the effect of the visualization.(3)The texture enhancement based on LIC algorithm was improved.While improving streamline contrast,multiple line integral convolution was used to improve the similarity of streamlines.This Avoided the texture of "black or white",obtained the texture level more abundant and the texture more delicate.(4)Based on the LIC-based texture visualization method,a new visualization form was proposed.In order to simultaneously observe the vector texture,vector size and vector direction in the same picture,we added a stream line with a specific direction on the basis of the texture,and combined the color mapping.(5)Studied the existing common streamline placement algorithm.On the basis of guaranteeing the key features,we proposed the streamline placement algorithm named a dynamic seed points based on critical point and grid.The new method had the advantages of streamline placement uniform,without missing key features,and almost no short streamlines.Finally,based on the study of vector visualization and streamline visualization,the implemented algorithm was integrated into software and a vector visualization system was constructed.