Research On Dynamic Loading Method Of Multi-resolution Volume Rendering Data

With the continuous development of the 3D graphics visualization technology.Visualization technology has been applied in many fields,especially in the field of geological exploration.Visualization of geoscience data provides a real picture of the interior of the earth.By three seismic data visualization technology,we can visually observe the internal structure of the body data and attribute information.And the seismic data can be analyzed and explained by the clear graphic image formed by rendering.Rather than relying solely on numerical tables.With the continuous progress of technology,the experimental data in the field of geological exploration increases through the rapid growth of dozens of GB or even TB level.In the process of data visualization,Seismic data can not be fully loaded into memory for processing.Traditional rendering mode,which all body data will be fully loaded into the memory and the rendering module only obtain data from memory,is relatively inefficient in the massive three-dimensional seismic data rendering process.Therefore,the multi-resolution technique based on hierarchical detail block is needed to be deeping study as the key technology in the process of massive data volume drawing.While the storage and loading process management of the large-scale three-dimensional data is also a problem to be solved.Multi-resolution volume rendering technology divide the volume data.By dividing the volume data,volume find areas where the rate of change is relatively low.By sampling these areas to a certain extent,multi-resolution volume rendering algorithm obtain the scalar data with different resolutions.This effectively reduces the amount of data used for volume renderingThis paper analyzes and introduces the method of three-dimensional data volume drawing in detail,including direct volume rendering,parallel drawing and multi-resolution volume rendering.Compare Octree representation based on hierarchical partitioning with multi-resolution representation based on uniform hierarchical partitioning in multi-resolution volume rendering algorithm.Based on large data background,analysis the data storage,memory management,data loading and other large data processing process of large-scale data.All of the research is used to optimize some of the modules in the three-dimension geoscience data visualization toolkit Open Probe.Based on the Open Probe geology project,improving the Open Probe data loading efficiency and solve the problem of the resolution of the image display process of change is not smooth,no dynamic issues.The article studies the LDM file format,and compared LDM with the traditional seismic data file format SEG-Y.At the same time,through the study of the large-scale data octree tree structure and the rapid loading mechanism of large-scale data,design to achieve multi-threaded loading,multi-priority cache replacement strategy loading mechanism.Setting flag mechanism to ensure the rationality of data block repalcement in the memory replacement strategy.At the same time,through the study of multi-resolution experience drawing method based on octagonal tree hierarchy.During the user interaction,when the resolution changes,using the strategy that double-threaded,double-linked list,and a replacement where the minimum number of accesses is replaced.And realizes the dynamic and real-time performance of the rendering and display of the volume data when the resolution changes.Optimize the process of Open Probe original rendering in a certain degree.