【作者】 骆兴江；

【导师】 顾松山； 魏鸣；

【作者基本信息】 南京信息工程大学 ， 大气物理学与大气环境， 2008， 硕士

【摘要】 随着多普勒天气雷达的应用越来越广泛,业务应用和理论研究的快速发展,雷达资料的分析处理水平也得到了很大的提高。本文设计的多普勒天气雷达产品终端系统既满足了业务上的需求,实现了雷达回波实时显示、雷达远程控制、任意两点测距、鼠标联动、基数据放大、游标读值、产品动画、基数据备份、地图编辑、危险天气警报、产品交互(VAD、弱回波区、多层CAPPI、垂直剖面、等值线)等功能,丰富了气象算法、美化了系统界面、简化了操作步骤;同时也满足科研的需求,对基数据进行标准化处理以兼容不同的数据格式,对标准格式的数据进行了多种预处理以提高数据质量,对气象算法进行动态链接库封装并用插件技术进行组装以提高气象算法增减和升级的便利性。整套系统采用多线程、多窗口、多任务、交互式、模块化、插件化等技术,具有较好的兼容性、可移植性、可扩展性,系统运行稳定,操作简便。目前我国大部分雷达气象产品还是以二维的形式来表示三维结构,其最具代表性的产品就是RHI,WER,多层CAPPI。这些产品虽然可以部分的解决对回波三维结构的分析难题,但还是不够细致,不够方便。光线投射(Ray-Casting)算法能产生三维数据场的整体图像,包括每一个细节,其原理简单、易于实现、可以生成高质量的显示图像,但计算时间较长。本文通过一系列的方法来加速光速投射算法,例如:确定体数据在屏幕上的投影面积来确定投射光线的数量,并采用间隔投射再插值的办法来减少光线投射的次数;通过计算投射光线与体数据的交点来确定初始采样点,使用基于空间跳跃技术的Proximity Clouds算法来确定体数据中的采样点,并设定不透明度阈值来提前结束采样,从而有效减少了投射光线上的合成计算。结合其他一些加速操作,有效地提高了绘制速度,并且保证了较高好的图像质量。更多还原

【Abstract】 With the more and more broad application of Doppler weather radar, and rapid development of radar forecast operational application and theory study, the level of Doppler data analysis has increased greatly. To fulfill the operational application and the scientific research requirements, the Doppler weather radar production terminal is designed in this paper. The terminal realizes many functions such as radar echoes real-time display, radar remote control, random two-point ranging, mouse linkage, raw data magnification, cursor valuation, product animation, raw data backup, map edit, dangerous weather alerting, interactive product(VAD, WER, M-CAPPI, VCS, Contour) and others, expands meteorology algorithms, beautifies system’s GUI, simplifies operational steps, all of these meet the needs of operational application. The terminal also has many preferable designs to fulfill the scientific research requirements, such as standardization of raw data to integrate different raw data formats, many pre-processing methods are used to control the data quality, meteorology algorithms are encapsulated with dynamic link library and assembled with plug-in technique to promote the convenience of meteorology algorithms’ adding, reducing and upgrading. Multi-thread, multi-window, multi-task, interaction, modularization, plug-in, and other techniques are adopted in the whole terminal system. The system can be expanded and transplanted. Besides, it’s a convenient system which has better compatibility, stability and convenient.Most radar products are displayed in two-dimension at home which can’t exhibit radar echoes’ three-dimension structure in focus, the most representational products are RHI(Range Height Indicator), WER(Weak Echo Region), M-CAPPI(Multi-Constant Altitude Plan Position Indicator). These products partly resolved the difficult of analyzing echoes’ 3-D structure, but it’s not precise or convenient. Ray-Casting algorithm can get the whole image of 3-D data with every details, it has some other advantages, like simple principle, easy realization and high quality image, but its calculation is too large. A series of methods are adopted in this paper to accelerate ray-casting algorithm. Confirming the stared out number of ray by calculating data projective aero on screen, interpolating after interval stares out rays are used to reduce the frequency of staring out rays. Confirming the start point of re-sample by calculate point of intersection of ray and data set, confirming the re-sample points in the data set by proximity clouds algorithm based on space leaping, finishing re-sample by setting opacity threshold, all of above are used to reduce re-sample calculation of ray. Other accelerated techniques are also adopted to improve the rendering speed and maintain high image quality.更多还原