| 摘要: | 有鑑於三維城市模型的重要性以及大量的需求，有必要建立一套有效的建築物幾何模塑解決方案。著眼於實用的角度，本文提出一基於半自動化策略進行建築物幾何模塑(Geometrical Modeling)之交談式系統，並且提出一基於完全自動化策略進行影像正射化(Ortho Rectification)之程序，將前者所產生之建築物三維模型應用於都會區真實正射影像(True-Orthophoto)之製程上。 本研究利用人工量測可視之屋緣線段，或者利用現有數值航測製圖所產生的都會區建築物資料，以最少的人力需求來建立三維城市模型。主要核心技術稱為「分割-合併-成形」(Split-Merge-Shape, SMS)演算法。其中「分割-合併」兩步驟主要在重建屋緣線段之間的拓樸關係，以完成封閉多邊形。而「成形」步驟則是利用屋緣之高度資訊，來判定屋頂面為平面或斜面。利用本技術可將傳統數值航測製圖與三維城市模型之製作程序結合，以提昇效率與成果之品質。 在傳統航空像片正射化的過程中，通常僅利用地形高度進行正射糾正，也就是說並未對建築物進行高差移位修正，同時也未對被遮蔽區進行資訊補償，加上建築物所造成之陰影效應，嚴重影響到成果之可用性與正確性。為了有效回復建築物之正確位置以及被遮蔽區與陰影區之資訊，本文提出一自動化程序，利用SMS所產生之多面體房屋模型、多重疊航空像片、數值地形模型與太陽方位等資訊，來進行真實正射影像糾正。同時將建築物高差移位修正、遮蔽區資訊補償、補償區邊緣勻化以及陰影區影像增顯等步驟合而為一，以提昇正射影像之品質。 文中首先對相關文獻在建築物幾何模塑，以及影像正射化方面做一全面性探討。而在建築物幾何模塑方面，針對所提出之SMS技術在邏輯上之建全性、處理效率、成果之準確度等方面，進行量化分析。並將所產生之三維建築物資料，配合數值地形模型，應用在真實正射影像之製作、都市三維景觀模擬以及三維地理資訊系統之查詢上，以展現SMS技術之實用性。 Due to the huge demand and the importance of 3-D city models, an effective solution for geometrical building modeling is indispensable. From the application point of view, an interactive system for geometrical building modeling based on a semi-automatic approach is presented. A true-orthophoto rectification scheme based on the generated building models is also proposed. The data used in the proposed system are 3-D visible roof-edges that have been manually measured from a stereo-model, or the 3-D building outlines from a digital topographic map. The core technology is called the "Split-Merge-Shape" (SMS) method. The SPLIT and MERGE steps are the two main procedures for topology reconstruction from non-related roof-edges. The SHAPE step uses the available roof-edge height information to define an appropriate rooftop. With the SMS method, the topographic mapping of buildings, and geometric building modeling, can be seamlessly integrated into a unified procedure. In a conventional ortho-rectification procedure using a digital terrain model, the correction of relief displacement due to buildings is not considered. Accordingly, any information hidden by buildings or in their shadow is not restored. In order to restore the most complete information and to correct the relief displacement of buildings, a rigorous true-orthophoto rectification scheme is proposed. In the proposed scheme, 3-D building models, multi-view aerial images, digital terrain models, and the sun's orientation are all utilized. Terrain and building relief displacement corrections as well as hidden area compensation, seamless mosaicking, and shadowed area enhancement are integrated into one procedure. This thesis starts with an overview of state-of-the-art technologies on the subject of building modeling and orthoimage rectification. Then, the SMS method is presented, including an evaluation of its feasibility, robustness, efficiency and accuracy. Finally, the generated building models are applied to true-orthophoto generation, 3-D city landscape simulation, and 3-D GIS querying. The applicability of the SMS method is thus demonstrated. |
