Aimed at tackling the difficulty in extracting facade from point cloud derived from dense matching of multi-angle airborne oblique images, this paper proposes a facade extraction method considering point cloud geometrical and color information. This method calculates normal vector for each point in the point cloud, and then uses the orientation of the normal vector for initial facade segmentation. After that, color information is used to remove point cloud about vegetation. On the basis of the initial result, the remaining ground points are removed. Finally, clustering analysis is used to refine the result, and facade point cloud can be obtained. Two groups of data sets are used for experiments, and the results reveal that the proposed method can automatically extract the facade of the building, with the completeness and correctness up to 90%, and the accuracy is more than 83%, thus providing the basis for the subsequent facade reconstruction.
[1] Musialski P,Wonka P,Aliaga D G,et al.A survey of urban reconstruction[J].Computer Graphics Forum,2013,32(6):146-177.
[2] Xiong X H,Adan A,Akinci B,et al.Automatic creation of semantically rich 3D building models from laser scanner data[J].Automation in Construction,2013,31:325-337.
[3] 李必军,方志祥,任娟.从激光扫描数据中进行建筑物特征提取研究[J].武汉大学学报:信息科学版,2003,28(1):65-70. Li B J,Fang Z X,Ren J.Extraction of building's feature from laser scanning data[J].Geomatics and Information Science of Wuhan University,2003,28(1):65-70.
[4] Li B J,Li Q Q,Shi W Z,et al.Feature extraction and modeling of urban building from vehicle-borne laser scanning data[C]//International Archives of the Photo-grammetry,Remote Sensing and Spatial Information Sciences.Istanbul:ISPRS,2004:934-939.
[5] 魏征,杨必胜,李清泉.车载激光扫描点云中建筑物边界的快速提取[J].遥感学报,2012,16(2):291-296. Wei Z,Yang B S,Li Q Q.Automated extraction of building footprints from mobile LIDAR point clouds[J].Journal of Remote Sensing,2012,16(2):286-290.
[6] Shahzad M,Zhu X X.Robust reconstruction of building facades for large areas using spaceborne TomoSAR point clouds[J].IEEE Transactions on Geoscience and Remote Sensing,2015,53(2):752-769.
[7] Hohmann B,Havemann S,Krispel U,et al.A GML shape grammar for semantically enriched 3D building models[J].Computers & Graphics,2010,34(4):322-334.
[8] Musialski P,Wimmer M,Wonka P.Interactive coherence-based façade modeling[J].Computer Graphics Forum,2012,31(2pt3):661-670.
[9] Teeravech K,Nagai M,Honda K,et al.Discovering repetitive patterns in facade images using a RANSAC-style algorithm[J].ISPRS Journal of Photogrammetry and Remote Sensing,2014,92:38-53.
[10] Xiao J,Gerke M,Vosselman G.Building extraction from oblique airborne imagery based on robust façade detection[J].ISPRS Journal of Photogrammetry and Remote Sensing,2012,68:56-68.
[11] 黄敏儿,杜志强,朱庆,等.利用像素高度图的三维建筑物屋顶和立面提取方法[J].武汉大学学报:信息科学版,2014,39(10):1221-1224. Huang M E,Du Z Q,Zhu Q,et al.3D building facade and roofs objects extraction from pixel height map[J].Geomatics and Information Science of Wuhan University,2014,39(10):1221-1224.
[12] Axelsson P.DEM generation from laser scanner data using adaptive tin models[J].International Archives of Photogrammetry and Remote Sensing,2000,33:110-117.
[13] Rau J Y,Jhan J P,Hsu Y C.Analysis of oblique aerial images for land cover and point cloud classification in an urban environment[J].IEEE Transactions on Geoscience and Remote Sensing,2015,53(3):1304-1319.
[14] 熊仕勇.一种新型的基于密度和栅格的聚类算法[J].计算机应用研究,2011,28(5):1721-1723,1727. Xiong S Y.Novel clustering algorithm based on grid and density[J].Application Research of Computers,2011,28(5):1721-1723,1727.
[15] Pu S,Rutzinger M,Vosselman G,et al.Recognizing basic structures from mobile laser scanning data for road inventory studies[J].ISPRS Journal of Photogrammetry and Remote Sensing,2011,66(6):S28-S39.