【摘要】：近年來(lái),基于全球性的三維地形漫游系統(tǒng)受到大家的熱切關(guān)注,已廣泛應(yīng)用于地理信息系統(tǒng)(GIS)、國(guó)防軍事、城市規(guī)劃等領(lǐng)域。然而,隨著現(xiàn)代數(shù)據(jù)采集能力的提升和人們對(duì)需求質(zhì)量的進(jìn)一步提高,繪制全球性的三維地形漫游系統(tǒng)所需處理的數(shù)據(jù)已經(jīng)達(dá)到了幾十、幾百GB甚至是TB級(jí)了。那么如何在計(jì)算機(jī)硬件條件有限的情況下實(shí)現(xiàn)大規(guī)模球形地形實(shí)時(shí)繪制就成了當(dāng)前的研究熱點(diǎn)。本文圍繞球形地形數(shù)據(jù)組織、球形地形數(shù)據(jù)調(diào)度和球形地形漫游三大模塊,對(duì)基于外存和網(wǎng)絡(luò)的球形地形繪制與漫游關(guān)鍵技術(shù)展開(kāi)研究。本文的主要工作和研究成果包括以下幾個(gè)方面:(1)針對(duì)球形地形數(shù)據(jù)組織進(jìn)行了深入細(xì)致的研究。設(shè)計(jì)了一種針對(duì)球形地形的四叉樹(shù)多分辨率地面構(gòu)建模型以及相對(duì)應(yīng)的地形塊編碼方式;綜合比較了文件和數(shù)據(jù)庫(kù)兩種數(shù)據(jù)存儲(chǔ)與管理方式的優(yōu)劣,選定了以文件的方式來(lái)存儲(chǔ)和管理地形數(shù)據(jù);提出了地形塊數(shù)據(jù)組合的數(shù)據(jù)組織優(yōu)化方式來(lái)減少數(shù)據(jù)I/O時(shí)間,同時(shí)根據(jù)球形地形高程數(shù)據(jù)的特有情況,剔除了一部分高程數(shù)據(jù),減少了地形數(shù)據(jù)處理量,提高了地形繪制效率。(2)針對(duì)球形地形數(shù)據(jù)調(diào)度進(jìn)行了深入細(xì)致的研究。在基于平面地形的視錐裁剪技術(shù)基礎(chǔ)上,提出了一種改進(jìn)的基于球形地形的視錐裁剪技術(shù);在權(quán)衡了繪制效率和繪制效果后,設(shè)計(jì)了一種粗略估算節(jié)點(diǎn)投影面積的計(jì)算方法來(lái)做節(jié)點(diǎn)誤差評(píng)價(jià),并實(shí)現(xiàn)了球形地形多分辨率的節(jié)點(diǎn)遍歷和更新算法;提供了數(shù)據(jù)預(yù)加載和多線程數(shù)據(jù)調(diào)度兩種地形繪制加速方案;另外,為了增強(qiáng)球形地形繪制系統(tǒng)的應(yīng)用范圍,還設(shè)計(jì)了一種本地和網(wǎng)絡(luò)相結(jié)合的數(shù)據(jù)調(diào)度方式。(3)針對(duì)球形地形漫游做了較為詳盡的研究。其中包括視線平移、球面平移、球體普通旋轉(zhuǎn)、球體加速旋轉(zhuǎn)、物體觀察中的視線追蹤和位置追蹤、各種情況下的視點(diǎn)切換過(guò)渡等等。
[Abstract]:In recent years, 3D terrain roaming system based on global has been paid close attention to, and has been widely used in (GIS), national defense, urban planning and other fields. However, with the improvement of modern data acquisition ability and the further improvement of people's demand for quality, the data needed to be processed by the global 3D terrain roaming system has reached tens, hundreds of GB or even TB level. So how to realize real-time rendering of large-scale spherical terrain under limited computer hardware conditions has become a hot research topic at present. This paper focuses on three modules: spherical terrain data organization, spherical terrain data scheduling and spherical terrain roaming. The key technologies of spherical terrain rendering and roaming based on external memory and network are studied in this paper. The main work and research results of this paper include the following aspects: (1) the detailed research on spherical topographic data organization is carried out. A quadtree multi-resolution ground construction model for spherical terrain and the corresponding terrain block coding method are designed, and the advantages and disadvantages of file and database data storage and management are comprehensively compared. In this paper, we choose to store and manage topographic data in the form of files, propose an optimized method of data organization and optimization of topographic block data combination to reduce the I / O time of data, and eliminate a part of elevation data according to the special situation of spherical topographic elevation data. The processing capacity of terrain data is reduced and the efficiency of terrain rendering is improved. (2) the detailed research on the scheduling of spherical terrain data is carried out. In this paper, an improved conical clipping technique based on spherical terrain is proposed, which is based on planar terrain, and after balancing the rendering efficiency and rendering effect, In this paper, a rough calculation method of node projection area is designed to evaluate the node error, and the node traversal and update algorithm with multi-resolution of spherical terrain is realized. In order to enhance the application scope of spherical terrain rendering system, two kinds of accelerated topographic rendering schemes, data preloading and multithread data scheduling, are provided. A data scheduling method combining local and network is also designed. (3) A detailed study on spherical terrain roaming is carried out. It includes line of sight translation, spherical translation, sphere general rotation, sphere acceleration rotation, line of sight tracking and position tracking in object observation, transition of view switching in various situations, etc.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：P208;TP391.41

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 尤克非,明德烈,王廣君,田金文,柳健;基于局部熵和四叉樹(shù)結(jié)構(gòu)的地形簡(jiǎn)化算法[J];中國(guó)圖象圖形學(xué)報(bào);2002年10期

相關(guān)博士學(xué)位論文 前1條

1 杜瑩;全球多分辨率虛擬地形環(huán)境關(guān)鍵技術(shù)的研究[D];中國(guó)人民解放軍信息工程大學(xué);2005年

，

本文編號(hào)：2246076