高密度的掃描資料可以詳實地記錄地表及地物的資訊，其中豐富的平面資料可應用於三維地物模型的重建。但數量龐大、且不規則分佈的點雲資料，必須先進行結構化，方能進行後續的空間資訊萃取工作。目前相關研究多以規則網格的方式將點雲資料結構化，但是點雲資料在內插會損失部份空間資訊，且2.5D的規則網格表示法亦難以完整展現點雲資料對地物的細部描述。因此本研究之目的，是在不損失點雲資料細部描述的條件下，將不規則分佈的點雲資料予以結構化，使得後續的資料分析更能掌握掃描資料的三維特性

本研究提出一個集結共平面的點雲資料之結構化方法，將雷射掃描點雲資料依八分樹結構進行分割合併並建立三維空間索引。判定點雲資料是否共平面是以最小二乘理論解算點雲資料所構成之最適平面參數後，以此平面參數為判定八分樹是否分割的依據，如此可將具有相同平面資訊之點群集成同範圍之樹狀結構節點，建立八分樹結構。藉由此結構處理可將資料中隱含的平面資訊萃取出來，地表資訊可被凸顯出來。樹狀結構完成後，再將鄰近且參數相似的平面予以合併，可得到較真實的地表平面資訊。

本研究所處理的點雲資料包括以Leica ALS40空載掃描系統在新竹地區所得之空載掃描資料，以及Optech ILRIS 3D地面掃描儀對台南市孔廟所得之地面掃描資料，針對不同類型的地物或建物，進行分割後樹狀結構中平面資訊與點雲資料的吻合程度與合併成果的分析。經過實驗，本研究所提出之方法可成功萃取隱含之平面資訊，同時也完成了點雲資料結構化之工作，所得資訊與結構化成果可供後續研究應用。

Laser scanning data contain extremely detailed surface information that can be used to construct 3D building models. However, it is required to organize randomly distributed point cloud data obtained from laser scanner for any further study. Interpolating point cloud data to a regular grid structure is currently a common method. Some information originally contained in the point cloud data may be lost due to the interpolation procedure. In addition, 2.5D grid structure cannot preserve the fidelity of true 3D data. Therefore the purpose of this research is to develop a method that can properly organize the point cloud data without losing detail spatial information.

The proposed method can segment scanned points based on a plane fitting condition and will establish an octree structure to organize the data. For the purpose of segmenting point cloud data, we extract the best-fit plane information by means of Least-Squares estimation, so that coplanar point cloud data can be grouped and represented by a node in the octree space. Therefore, the explicit surface information in the randomly distributed point cloud data can be extracted. After splitting we can merge neighboring nodes according to the similarity of best-fit plane information between these nodes.

The test data applied in this research includes a set of airborne laser scanning data covering Hsinchu County by the Leica ALS40 scanning system and a set of ground laser scanning data of Tainan Confucian Temple using the Optech ILRIS 3D scanning system. How much the extracted spatial information fit to the original data and how well the merged results fit to the reality were analyzed. The experimental results demonstrate a successful spatial information extraction and a well organization of point cloud data. This tree-structure will. Be very helpful for the further study of laser scanning data.

傅秉綱，『三維建物模型表面影像敷貼自動化之研究』，國立成功大學測量工程研究所碩士論文，2002。

游勳喬，『空載雷射掃描系統ScaLARS安置角自動化率定之研究』，國立成功大學測量工程研究所碩士論文，2002。

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