利用3ＤLiDAR技術應用於結構物監測及地形數化之研究

Using 3D LiDAR Technique in Structure Monitoring and Terrain Modeling

本研究結合地面光達-3D雷射掃描技術及點雲資料處理等方法，選定大溪橋與其周邊河谷為研究區域，嘗試用於不同時期橋樑變形之監測作業及數值高程模型（DEM）之製作。本文主要研究目的有三：（1）了解地面光達運作及後續軟體處理，（2）嘗試以該新型技術取代傳統地面測量來執行結構物監測作業之可行性，（3）比對地面光達與空載光達於數值高程模型之建置。本實驗結果顯示，地面光達所產出的點雲資料，其整體點雲的套合精度可達3mm左右，故針對監測公分級以上變化的結構物，有顯著的效果及可靠的參數；另外在數值高程模型的製作上，利用e-GNSS定位技術獲取公分級誤差的控制點坐標，可將地面光達之點雲成果精確轉換至TWD97坐標系統上，與空載光達所建置之同坐標數值高程模型相比，品質更為細緻，且成本更為便宜。

This research integrates ground LiDAR- 3D scanning technique and point cloud data, selected Daxi Bridge and nearby valley as test areas, attempt to monitoring the bridge deformation in different times, and producing digital elevation model (DEM). The aims of those studies are summarized as follow: (1) Trying to enhance ground LiDAR technique working and point cloud data processing. (2) Replace the traditional surveying with ground LiDAR technique to implement the feasibility of structural monitoring operations. (3) Compared the DEM made in the same area with ground LiDAR and airborne LiDAR.
The results show the accuracy of the point cloud data setting approaches 3 mm. Therefore, the deformation of structures monitoring is over 1 cm, it can be depended on ground LiDAR technique. Besides DEM made, e-GNSS positioning is used to fix control points in this case, and the precision of this system can be reached centimeter level. After fix control points fulfilled, all the point cloud data can be transformed to TWD97 coordinate. Finally, compared with the quality of DEMs made, the benefits of ground LiDAR has that higher resolution and lower costs than those of airborne LiDAR.