数字地球中的显示处理技术研究

Study of processing and display technologies for 3D digital earth

提出了边界线等线型目标的分层处理方法,首先计算线型目标与各级地块相邻网格的交点、线段与面片三角形斜边的交点,再对其进行分层处理.接着介绍如何实现地球表面地形的测量显示,主要通过计算旋转轴、旋转矩阵和地形高度,使得计算的测量线紧贴各级地形的三角面片.最后介绍了红蓝立体成像显示实现方法,通过将视点放在左右眼位置分别渲染输出到两个纹理图中,再交由绘图芯片(GPU)由可程序化流程(shader)处理并最终输出红蓝立体影像.应用这些技术开发的基于数字地球的飞行仿真系统,为飞行训练提供了有力支持.

The layered approach for the linear object,such as the boundary lines for digital earth,is proposed.Before the linear object is divided into LOD,the intersection points of the linear object and block adjacent grid at all levels need to be calculated,and then the intersection points of the linear object line segment and triangle.Then how to measure the terrain of Earth＇s surface is described.By calculating the rotation axis,the rotation matrix and the terrain height,the calculated measure line is close to terrain triangles at all levels.Finally,the display method of red and blue stereographic images is detailed.The view point focuses on the left and right eye locations,and GPU outputs to two texture maps.The GPU shader processes and outputs red and blue stereo images.The flight simulation system on the digital earth,which is developed based on these technologies,provides strong support for flight training.