手持式光達與地面光達適用場景之分析比較-以地下停車場、橋梁與周圍建物、礦坑隧道三種場景為例

Abstract

光達(Light Detection and Ranging, LiDAR)是一種光學遙感技術，其原理是利用測量光脈衝的飛行時間，判斷感測器和物體之間的距離，進而獲得物體三維坐標及反射強度資料。隨著光達技術的快速發展，已有許多測繪等級的光達儀器問世，依其掃描方式大致可分為手持式光達、地面光達、車載光達、無人機光達、空載光達等，這些光達儀器並廣泛應用於土地測量、土木工程、災害管理、林業管理、建築設計、隧道監測、文化資產保存維護等領域。近年來，手持式光達更與同時定位與地圖建構(Simultaneous Localization and Mapping, SLAM)技術結合，除了掃描的範圍變大之外，更提升了在現場採集資料的速度，也加快了後續點雲資料的產生。本研究希望能夠進一步了解手持式光達與SLAM技術結合後之效能以及其侷限性，擬試圖回答：如果在同一個環境場景中，從點雲資料採集的時間、採集範圍、取得點雲資料後軟體的處理時間，以及產生的資料成果等幾個面向切入，手持式光達是否可以取代地面光達的作業。本研究擬以SLAM技術用於手持式光達三維掃描儀的空間測量案例進行分析，選擇了三個環境場景作為案例：室內地下停車場、橋梁周圍建物以及礦坑隧道，分別代表空曠室內、戶外空間以及狹長型通道三個空間類型，以高效率較低精度的手持式光達為實驗組，並以高效率高精度的地面光達為對照組，來獲取相同場景的三維點雲資料並比較地面光達與手持式光達的測量原理、測量範圍、測量精度等基本參數，還有在相同場景下，兩者點雲資料在三維點雲視覺化和精度上的比較，對比兩種光達儀器的成本和效益，分析實際應用的可行性和優劣性。本研究得出結論，手持式光達和地面光達所得到的點雲資料特性不同，在某些環境及用途範圍內，手持式光達可以適度取代地面光達的作業。LiDAR (Light Detection and Ranging) is an optical remote sensing technology that uses the measurement of the flight time of light pulses to determine the distance between the sensor and objects, thus obtaining parameter data. With the rapid development of LiDAR technology, various mapping-grade LiDAR scanners have been introduced, which can be broadly categorized into handheld LiDAR, ground-based LiDAR, mobile LiDAR (mounted on vehicles), drone LiDAR, and airborne LiDAR. These LiDAR instruments are widely used in fields such as land surveying, civil engineering, disaster management, forestry management, architectural design, tunnel monitoring, cultural heritage preservation, and more.In recent years, the integration of handheld LiDAR with Simultaneous Localization and Mapping (SLAM) technology has further expanded its scanning range and improved the speed of data collection in the field. It has also accelerated the processing of point cloud data. This study aims to further understand the performance and limitations of handheld LiDAR when combined with SLAM technology. Specifically, it seeks to answer whether handheld LiDAR can replace ground-based LiDAR operations by examining several aspects: the time required for point cloud data collection, the scanning range, the processing time of the acquired point cloud data, and the resulting data products.The research will focus on analyzing spatial measurement cases using SLAM technology with handheld LiDAR 3D scanners. Three environmental scenes have been selected as case studies: an indoor underground parking lot, buildings around a bridge, and a mine tunnel. These scenes represent three types of environments: open indoor, outdoor space, and narrow passages. The experiment will use a high-efficiency but lower-accuracy handheld LiDAR as the experimental group and a high-efficiency and high-accuracy ground-based LiDAR as the control group to obtain 3D point cloud data of the same scenes. The study will compare the basic parameters of both LiDAR instruments, such as measurement principles, measurement ranges, and measurement accuracy. It will also compare the 3D point cloud visualization and accuracy of the two LiDAR datasets within the same scenes. Additionally, the study will analyze the cost-effectiveness of the two LiDAR instruments and assess the feasibility and advantages and disadvantages of their practical applications, aiming to address the research questions of interest. The conclusion of this study indicates that the point cloud data obtained from handheld LiDAR and ground-based LiDAR exhibit different characteristics. Furthermore, the study suggests that within certain environments and application scopes, handheld LiDAR can be used to a reasonable extent as a replacement for ground-based LiDAR operations.