The Design And Implementation Of Visualization System For 3D Data Sets Based On Volume Rendering

Visualization in Scientific Computing(VISC)is a new research field and developed in the 1980 s.By using computer graphics and image processing technology,it converts the mass data and computed result produced in the process of scientific computing to graphics or image which can be shown on the screen and used for interaction.Visualization of three-dimensional data is core part of the scientific computing visualization.And volume rendering technology is a common method of three-dimensional data visualization.Now,it is a hotspot of visual field and has great application prospect and research value.Volume rendering is the core of the paper and the main works are as follows.First,we introduce the concept of scientific computing visualization,simply expound the several methods of three-dimensional data field visualization,analyze their respective characteristics and differences,and analyze the advantages and disadvantages and application environment of several common volume rendering algorithms.After that,we describes the basic concepts and do further study on the key technologies.Second,we focus our study on volume rendering algorithm based on texture mapping.Using three-dimensional texture data,the algorithm draws a three-dimensional image according to the attribute information of voxel.It can greatly improve the speed of volume rendering and generate a higher quality image.In order to improve the universality of volume rendering algorithm based on texture mapping,a method of designing a conversion function called conversion function design method based on the gray distribution and color stick COGAC(Conversion Of Gray And Color)is proposed.According to the gray distribution,we can select the range of the attribution and then using the color stick,the color,transparency and the change mode(gradual or fixed)of the two can be set manually,which can make the visualization results show the distribution of the material in a most reasonable way.Meanwhile,according to the shown mode that has been set,the mode of the other range could be varied dynamically.In the VS2010 development environment,volume rendering based on COGAC texture mapping is implemented by using Open GL.In the experiment,material is classified according to the gray distribution.And based on the COGAC designing method,the 3D texture of the volume data is generated.Then,after the direction of observation is determined and the sampling polygon is get,the mapping relation between polygon and texture coordinate is provided.At last,use texture-mapping hardware to generate the final image.The experiment result shows that volume rendering based on COGAC texture mapping can greatly improve the efficiency of visualization and draw out high quality images,and visualization system based on it has the feasibility and effectiveness.