【摘要】：隨著科技的進(jìn)步,計(jì)算機(jī)圖形學(xué)與虛擬技術(shù)得到很大的發(fā)展,利用計(jì)算機(jī)建立虛擬模型也成為一個熱門話題。日常生活中所見到的植物不僅種類繁多,更為整個世界增添了很多色彩,為人們提供了賴以生存的食物。因此,植物虛擬三維模型的建立已成為圖形學(xué)領(lǐng)域的一大熱點(diǎn),而且虛擬植物模型的應(yīng)用前景非常廣泛,比如設(shè)計(jì)數(shù)字化城市、制作游戲場景以及進(jìn)行遙感實(shí)驗(yàn)。對農(nóng)作物進(jìn)行虛擬模型的建立可以進(jìn)行虛擬試驗(yàn)以研究出更高產(chǎn)量的農(nóng)作物,建立虛擬農(nóng)場可以更好地實(shí)現(xiàn)農(nóng)田的管理。本文主要以玉米為目標(biāo)進(jìn)行虛擬模型研究,主要研究內(nèi)容有以下幾個方面:1、幾何參數(shù)建模方法研究。對非均勻B樣條曲面(簡稱NURBS)的概念進(jìn)行闡述,了解NURBS曲面擬合所需條件:控制點(diǎn)和節(jié)點(diǎn)矢量。對玉米植株進(jìn)行測量獲得地上各部分器官的幾何參數(shù),然后根據(jù)控制點(diǎn)相關(guān)算法求取控制葉鞘和葉片組成的NURBS曲面的控制點(diǎn)和節(jié)點(diǎn)矢量,再根據(jù)NURBS擬合算法得到表示葉鞘和葉片的NURBS曲面。根據(jù)得到的莖稈高和半徑,畫圓柱代替玉米的莖稈,最后將兩個模型組合起來得到完整玉米植株的模型。2、點(diǎn)云數(shù)據(jù)建模方法研究。從三個方向?qū)τ衩字仓赀M(jìn)行掃描獲得玉米植株表面點(diǎn)的三維空間坐標(biāo),再對獲得的數(shù)據(jù)進(jìn)行拼接得到完整玉米植株數(shù)據(jù)。由于數(shù)據(jù)量巨大,首先對數(shù)據(jù)進(jìn)行一些預(yù)處理,如去噪、精簡等;另外,玉米的葉片類似于二維空間的一個曲面,而莖稈相當(dāng)于圓柱,為了方便建模,對葉片和莖稈進(jìn)行分割;然后利用區(qū)域增長算法實(shí)現(xiàn)葉片建模,并用圓柱擬合算法實(shí)現(xiàn)莖稈的建模;最后將得到的模型整合在一起組成完整的植株模型。3、時(shí)序插值方法研究。測量兩個時(shí)段玉米植株的幾何參數(shù),然后利用關(guān)鍵幀技術(shù)的插值函數(shù)求出兩個時(shí)段幾何參數(shù)之間的線性關(guān)系,最后利用這個線性關(guān)系得到玉米中間狀態(tài)的生長過程并得到其模型。
[Abstract]:With the progress of science and technology, computer graphics and virtual technology have been greatly developed, the use of computers to build virtual models has become a hot topic. The plants seen in daily life are not only diverse, but also the whole world has added many colors, providing people with food for survival. Therefore, the establishment of virtual 3D models of plants has become a hot topic in the field of graphics, and the application prospect of virtual plant models is very extensive, such as designing digital cities, making game scenes and remote sensing experiments. Virtual experiment can be carried out to study the crops with higher yield, and the management of farmland can be realized better by establishing virtual farm. The main contents of this paper are as follows: 1. Geometric parameter modeling method. The concept of nonuniform B-spline surface (NURBS) is introduced, and the conditions of NURBS surface fitting are obtained: control point and node vector. The geometric parameters of the organs of each part of the ground were measured and the control points and nodal vectors of the NURBS surface composed of the leaf sheath and the leaf were obtained according to the control point correlation algorithm. Based on the NURBS fitting algorithm, the NURBS surfaces representing the sheaths and blades are obtained. According to the height and radius of the stem, the stem of maize was replaced by a cylinder. Finally, the two models were combined to get the model of the whole maize plant. 2. The method of point cloud data modeling was studied. The three dimensional coordinates of the surface points of maize plants were obtained by scanning the maize plants in three directions, and the complete data of maize plants were obtained by splicing the obtained data. Because of the huge amount of data, the data is preprocessed first, such as de-noising, streamlining and so on. In addition, the leaves of maize are similar to a curved surface in two-dimensional space, and the stem is equivalent to a cylinder. In order to facilitate modeling, the leaves and stems are divided. Then the region growth algorithm is used to model the leaves, and the cylindrical fitting algorithm is used to model the stem. Finally, the obtained model is integrated to form a complete plant model. 3, the time series interpolation method is studied. The geometric parameters of corn plants in two periods were measured, and the linear relationship between the geometric parameters of two periods was obtained by using the interpolation function of key frame technique. Finally, the growth process of corn intermediate state is obtained by using this linear relation and its model is obtained.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：S126;S513

【參考文獻(xiàn)】

相關(guān)期刊論文 前2條

1 嚴(yán)濤,陳彥云,吳恩華;一種基于單幅圖像的樹木深度估計(jì)與造型方法[J];計(jì)算機(jī)學(xué)報(bào);2000年04期

2 唐衛(wèi)東;李金忠;劉昌鑫;胡雪華;李萍萍;盧章平;;虛擬植物模型及其構(gòu)建方法研究綜述[J];計(jì)算機(jī)應(yīng)用研究;2012年09期

，

本文編號：2406421