手持式三維掃描儀於坑道測量之可行性分析

過去受限於技術與設備，只能將三維空間資訊投影在二維地圖上展現；近年來拜電腦軟硬體突飛猛進之賜，三維空間資訊的展現已經可以用虛擬實境(Virtual Reality, VR)甚至擴增實境(Augmented Reality, AR)的方式展現，不僅更直覺，也更詳實而精確。坑道測量受限於封閉環境，過去僅以平板儀或經緯儀測繪平面圖表示。以近景攝影測量測繪坑道三維模型，必須大量佈標、廣設控制點及光源，需大量人力且花費時間。地面光達(Light Detection and Ranging, LiDAR)搭配相機攝像，可以快速獲取坑道三維點雲(Point Cloud)，是最適合坑道三維測量的選項。但地面光達所費不貲，且彎彎曲曲的坑道必須分別設站掃描，再將各場景連接起來，需要高階的電腦及專業的人力才能處理。近來有廠商推出手持式三維掃描儀，採用結構光(Structured Light)原理，可快速擷取近距離（約4 m內）三維點雲，理應相當適用於坑道三維測量。因此本研究採用DotProduct公司出品的DPI-8手持掃描儀作為實驗組，並以FARO公司出品的Focus3D地面光達作為對照組，於花蓮七星潭四八高地下方坑道進行測量。將兩者所得的三維點雲，透過開源軟體Recap360以及CloudCompare進行三維資料的比較，了解手持掃描儀於狹小且缺乏光源的坑道中進行測量工作的可行性。

關鍵字

手持式三維掃描儀；地面光達；坑道測量

並列摘要

Traditionally, 3D spatial information can only be projected on the 2D maps for visualization due to the limitation of equipment and technology. Benefit from the rapid development of computer hardware and software, 3D visualization of the 3D spatial information can be achieved either by virtual reality (VR) or by augmented reality (AR). The 3D visualization is not only much more ocular for human, but also much more detailed and accurate. Due to the close environment and the spatial limitation, the tunnel survey is usually carried out by the plan table or the theodolite. The 3D tunnel is projected on the 2D map. Although close-range photogrammetry can be used to reconstruct the 3D model and to survey 3D coordinates of the tunnel, it requires many artificial targets as control points. Additional light sources are also necessary for shooting clear photographs. These requirements leads to huge labor work and consumes time. The terrestrial light detecting and ranging (LiDAR) integrated with a camera is capable of acquiring 3D point cloud in an efficient way, and therefore, is very suitable for tunnel survey. However, the terrestrial LiDAR is too expensive to be adopt by non-surveyors. In addition, due to the winding design of the military tunnel, it will require much more station setups to scan the whole tunnel. The connection of every scanning scene requires a powerful computer and professional human interaction. Recently, the handheld 3D scanners are developed based on the structured light approach, which can rapidly scan 3D point cloud within a short distance (within 4 meters). In this study, we apply a DotProduct DPI-8 handheld 3D scanner and a FARO Focus3D terrestrial LiDAR in the tunnel survey under the 48 Highland in Ci Sin Tan, Hualien. We compare the requirements, the operating procedures, and the results of the handheld 3D scanner and of the terrestrial LiDAR. The results show that the handheld 3D scanner is very suitable for the tunnel survey.

並列關鍵字

Unmanned Aerial Vehicle (UAV) ； Multi-scale Segmentation ； Object-oriented

參考文獻

花蓮縣新城鄉七星潭社區發展協會，2015。花蓮縣新城鄉七星潭社區農村再生計畫，https://ep.swcb.gov.tw/ep/File/REGENERATION/%E4%B8%83%E6%98%9F%E6%BD%AD%E7%A4%BE%E5%8D%80%E8%BE%B2%E6%9D%91%E5%86%8D%E7%94%9F%E8%A8%88%E7%95%AB_201512081513552712.pdf，引用 2018/02/12。 [Ci Sing Tan Community Development Association, 2015. Rural Rejuvenation Project of Ci SingTang Community, Sin Cheng Township, Hualien County, Available at: https://ep.swcb.gov.tw/ep/File/REGENERATION/%E4%B8%83%E6%98%9F%E6%BD%AD%E7%A4%BE%E5%8D%80%E8%BE%B2%E6%9D%91%E5%86%8D%E7%94%9F%E8%A8%88%E7%95%AB_201512081513552712.pdf , Accessed February 12, 2018. (in Chinese)]