隨著數碼城市的應用逐日增加，對於數碼城市的需求跟著越來越高，以往利用圖庫材質貼圖做為牆面紋理的房屋模型已漸漸無法滿足使用者，這使得仿真數碼城市之建置成了相當重要的研究主題。其中，對於牆面遮蔽偵測補償問題，更是這項研究的重點。因此、本研究針對牆面的部分，提出一套自動化的流程，透過篩選機制選擇交會幾何較佳之影像來產生牆面紋理貼圖，藉此減少人力介入並提高貼圖的品質。研究中針對牆面遮蔽問題則採用向量式遮蔽偵測來判斷牆面是否有遮蔽區，若有則予以移除並以其他角度之影像重建牆面應有之紋理資訊。
首先，針對影像資料獲取的部分，考量了實驗區域範圍的大小以及部分區域無法接近等因素，本研究採用直升機搭載雙傾斜攝影機的攝影系統，藉此加快資料獲取的效率、減少地面物體（如：樹木、汽車、路牌…等）的遮蔽情形，並提高牆面資訊的完整度。其中假設三維房屋模型及影像內外方為參數皆已知，故房屋模型的建置與影像內、外方位參數的求解皆不在本研究的討論範疇內。
接著，以影像為單位對每面牆作分析，透過牆面與影像的相對關係，以及漸進式門檻值的設定剃除不合適的牆面，而剩餘合適的牆面便直接產生貼圖。最後利用遮蔽偵測、遮蔽區標記及遮蔽區填補等步驟，將牆面受到其他建築物遮蔽的部分移除，還原牆面完整且正確的紋理資訊。由實驗結果顯示，透過上述一系列的步驟，可自動化的產生牆面紋理貼圖，並還原牆面遮蔽區應有的資訊，所產生的紋理貼圖，其品質也多能滿足大部分數碼城市的應用。

Due to the applications of cyber-city is getting more and more in recent years, the demand of cyber-city has becoming higher and higher. Thus, the utilization of generic texture library for facade texturing can no longer satisfy the user’s requirement. The generation of a photo-realistic cyber-city is thus becoming an important research topic. In which, the most critical issue is how to cope with the occlusion detection and texture compensation problem for the façade. In this paper, we thus propose an automatic scheme for façade texture mapping according to a mechanism for the selection of better imaging geometry for the purpose of reducing human interference and increasing the texture quality. In the research, the occlusion problem is solved by means of a vector-based occlusion detection algorithm. In case of occlusion, it will be removed and restored from the other images taken from other viewing positions.
First of all, considering the size of test area and somewhere cannot be reached, the image data were acquired by a dual-camera oblique imaging system. The efficiency for data acquisition has increased, the occlusion effect has reduced (such as from the trees, cars, traffic signs, etc.), and the degree of completeness of façades can be improved. In this research, we assumed the 3-D building models and the images’ exterior/interior orientation parameters were existed, thus how to generate this information is out of this paper’s scope.
The proposed algorithm treats each façade one by one. According to the relative relationship between the façade and the image, those images with bad viewing angle will be skipped based on the setup of a progressive incremental threshold. Otherwise, the image suitable for façade texture mapping will be used directly. In the end, the occlusion detection, occlusion area removal, and texture restoration for occlusion area will be performed. Experimental results demonstrate that the proposed scheme can automatically generate the façade texture information when occlusion effect occurred. The texture quality can satisfy most of the cyber-city applications as well.

王聖鐸，以浮測模型理論萃取三維空間資訊－以建物重建為例，國立成功大學，測量及空間資訊學系，博士論文，2005。

朱慶、林琿，數位城市地理資訊系統－虛擬城市環境中的三維城市模型初探，武漢大學出版社，武漢市，pp. 20-25, 2004。

江孟璁，房屋模型面與空載影像之套合，國立中央大學，土木工程所，碩士論文，2009。

成晨光，以網際網路三維地理資訊系統為基礎之仿真數碼城市在不動產市場之應用，國立成功大學，測量及空間資訊學系，碩士論文，2010。

李訢卉，整合房屋、道路及地形模型之高解析影像正射改正，國立中央大學，土木工程所，碩士論文，2007。

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，測量及空間資訊學系，碩士論文，2002。

Al-amri, S., S., Kalyankar, .N. V., and Khamitkar, S. D., Linear and Non-linear Contrast Enhancement Image, IJCSNS International Journal of Computer Science and Network Security, 10(2), pp 139-143, 2010.

Amhar, F., Josef, J., and Ries, C., The Generation of True Orthophotos Using a 3D Building Model in Conjunction with a Conventional DTM, International Archives of Photogrammetry and Remote Sensing, 32(4), pp. 16-22, 1998.

Asai, T., Kanbara, M. and Yokoya, N., 3D Modeling of Outdoor Environments by Integrating Omnidirectional Range and Color Images, Proceedings of the Fifth International Conference on 3-D Digital Imaging and Modeling, pp. 447-454, 2005.

Burigat, S., and Chittaro, L., Location-aware Visualization of VRML Models in GPS-based Mobile Guides, In Proc of the 10th International Conference on 3D Web Technology, ACM Press, New York, pp. 57-64, 2005.

Chen, L. C., Lo, C. Y., and Rau, J. Y., Generation of Digital Orthophotos from IKONOS Satellite Images, Journal of Surveying Engineering, ASCE, 129(2), pp. 73-78, 2003.

Cox, S., Daisy, P., Lake, R., Portele, C. and Whiteside, A, OpenGIS Geography Markup Language (GML3.1), Implementation Specification Version 3.1.0, Recommendation Paper, OGC Document no 03-105r1, 2004.

Dale, P., Introduction to Mathematical Techniques Used in GIS, CRC Press, pp. 30-31, 2005.

Früh, C., and Zakhor, A., Constructing 3D City Models by Merging Ground-Based and Airborne Views. IEEE Computer Graphics and Applications, Special Issue Nov/Dec, pp. 52-61, 2003.

Gonzalez, R.C., and Woods, R.E., Digital Image Processing, Prentice-Hall, New Jersy, pp. 94-102, 2002.

Gröger, G., Kolbe, T.H., Czerwinski, A., and Nagel, C., OpenGIS City Geography Markup Language(CityGML) Encoding Standard, Open Geospatial Consortium, 2008. (Available online at : http://portal.opengeospatial.org/files/index.php?artifact_id=28802&passcode=2j1knmnukhe2pv71gcc2, May, 2010.)

Haala, N., and Kada, M., Panoramic Scenes for Texture Mapping of 3D City Models. International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 36(Part 5/W8), 2005.

Habib, A.F., E.M. Kim, and C.J. Kim, New Methodologies for True Orthophoto Generation, Photogrammetric Engineering and Remote Sensing, 73(1), pp. 25-36, 2007.

Kada, M., Hardware-Based Texture Extraction for Building Facades, IAPRS, 35(B4), pp. 420-425, 2004.

Kolbe, T. H., Gröger, G., and Plümer, L., CityGML – Interoperable Access to 3D City Models. First International Symposium on Geo-Information for Disaster Management GI4DM, 2005.

Karras, G., Grammatikopoulos, L., Kaisperakis, I., and Petsa, E., Generation of Orthoimages and Perspective Views with Automatic Visibility Checking and Texture blending. Photogrammetric Engineering and Remote Sensing, 73(4), pp. 403–411. 2007.

LI Deren, ZHU Qing and Li Xiafei, CyberCity: Conception, Technical Supports and Typical Applications. Geo-Spatial Information Science, 3(4), pp. 1-8, 2000

Rau, J. Y., Chen, N. Y. and Chen, L. C., True Orthophoto Generation of Built-Up Areas Using Multi-View Images, Photogrammetric Engineering & Remote Sensing, 68(6), pp. 581-588, 2002.

Rau, J. Y., and Chen, L. C., Robust Reconstruction of Building Models from Three-Dimensional Line Segments, Photogrammetric Engineering and Remote Sensing, 69(2), pp. 181-188, 2003.

Takase, Y., Sone, A., Hatanaka, T. and Shiroki, M., 2004. A Development of 3D Urban Information System on Web, Proc. of Processing and Visualization Using High-Resolution Images, Pitsanulok, 18-20 November. (on CDROM)

Tsai, F., Lin, H.C., Chen, C.H., Facade Texture Generation and Mapping Using Digital Videos, Journal of Photogrammetry and Remote Sensing, 12(1), pp. 83-92, 2007.

Varshosaz, M., True Realistic 3D Model of Buildings in Urban Areas, Int. Archives of the Photogrammetry, Remotes Sensing and Spatial Information Sciences, XXXIV-5/W1, 2003.

Wang, S., Tseng, Y. H. and Fu, P. K., Automated Texture Mapping on 3D Building Model Using Photogrammetric Images, Journal of Photogrammetry and Remote Sensing, 13(2), pp. 75-84, 2008.

Zhang, Y., Zhang, Z., Zhang, J., and Wu, J., 3D Building Modelling with Digital Map, LIDAR Data and Video Image Sequences, The Photogrammetric Record, 20(111), pp. 285-302, 2005.

Zhang, Z., Wu, J., and Zhang J., Rapid Texture Mapping from Image Sequences for Building Geometry Model, Geo-spatial Information Science (Quarterly), 6(3), pp. 8-15, 2003.