ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences
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Articles | Volume V-2-2020
ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci., V-2-2020, 373–380, 2020
https://doi.org/10.5194/isprs-annals-V-2-2020-373-2020
ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci., V-2-2020, 373–380, 2020
https://doi.org/10.5194/isprs-annals-V-2-2020-373-2020

  03 Aug 2020

03 Aug 2020

OPACITY-BASED EDGE HIGHLIGHTING FOR TRANSPARENT VISUALIZATION OF 3D SCANNED POINT CLOUDS

K. Kawakami1, K. Hasegawa1, L. Li1, H. Nagata1, M. Adachi2, H. Yamaguchi3, F. I. Thufail4, S. Riyanto5, Brahmantara6, and S. Tanaka1 K. Kawakami et al.
  • 1College of Information Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
  • 2Shrewd Design Co. Ltd, Fushimi-ku, Kyoto, Kyoto 612-8362, Japan
  • 3Nara National Research Institute for Cultural Properties, Nijo-cho, Nara City, 630-8577, Japan
  • 4Research Center for Area Studies, Indonesian Institute of Sciences (P2W-LIPI), Jakarta, Indonesia
  • 5Yogyakarta Archaelogy Office (Balai Arkeologi DIY), Yogyakarta, Indonesia
  • 6Borobudur Conservation Office, Magelang, Jawa Tengah, Indonesia

Keywords: 3D Scanned Point Clouds, Transparent Visualization, 3D Edges, Opacity-based Edge Highlighting

Abstract. The recent development of 3D scanning technologies has made it possible to quickly and accurately record various 3D objects in the real world. The 3D scanned data take the form of large-scale point clouds, which describe complex 3D structures of the target objects and the surrounding scenes. The complexity becomes significant in cases that a scanned object has internal 3D structures, and the acquired point cloud is created by merging the scanning results of both the interior and surface shapes. To observe the whole 3D structure of such complex point-based objects, the point-based transparent visualization, which we recently proposed, is useful because we can observe the internal 3D structures as well as the surface shapes based on high-quality see-through 3D images. However, transparent visualization sometimes shows us too much information so that the generated images become confusing. To address this problem, in this paper, we propose to combine “edge highlighting” with transparent visualization. This combination makes the created see-through images quite understandable because we can highlight the 3D edges of visualized shapes as high-curvature areas. In addition, to make the combination more effective, we propose a new edge highlighting method applicable to 3D scanned point clouds. We call the method “opacity-based edge highlighting,” which appropriately utilizes the effect of transparency to make the 3D edge regions look clearer. The proposed method works well for both sharp (high-curvature) and soft (low-curvature) 3D edges. We show several experiments that demonstrate our method’s effectiveness by using real 3D scanned point clouds.