近景攝影測量於特殊海岸地景監測的可行性評估－－以澎湖大池火山頸柱狀玄武岩為例

Applicability of Close-range Photogrammetry on Coastal Geoheritage Site Monitoring - An Example of Dachi Volcanic Neck

豐富多樣的海岸地景是台灣重要的地景資源，海岸地帶在海洋、陸地與人類活動的交互作用下，形成動態而複雜的環境系統。近年來在數位相機與演算法的進步下，研究已證實近景攝影測量具有高精度的測量成效，本文選擇澎湖大池海岸的火山頸柱狀玄武岩做為實驗對象，嘗試應用近景攝影測量於特殊海岸地景的監測。實驗結果顯示，採用非量測型相機的近景攝影測量方法所建置出的數值地形模型，其最佳的三軸精度可達1.6公分。比較不同拍攝變數的精度結果則發現，共軛點的數量和分布與鏡頭透鏡畸變差的穩定性將影響模型的精度。因此，從本文的實驗結果可證實，使用近景攝影測量於特殊海岸地景的監測是有效且可靠的。後續可應用此技術於特殊海岸地景的變遷偵測與海洋文化地景的數位典藏（如澎湖石滬群），將使此法更具應用價值。

Abundant and diverse coastal landscape is one of the most important landscape resource in Taiwan. However, the interaction among processes of ocean and land, and human activities makes coastal area a dynamic and complex environment system. Recently, under the progress of digital camera and algorithm, photogrammetry is confirmed as a high-precision survey method. We tested the applicability of close-range photogrammetry (CRP) in monitoring coastal geoheritage site, Dachi volcanic neck. We used non-metric SLR digital camera and collocated with the software of CRP to reconstruct digital terrain model (DTM) of the volcanic neck. Results show that the best RMSE (root mean square error) of three-axis is 1.6 cm. The number and distribution of tie-points and constant of lens distortion directly influence the accuracy of digital terrain model. Consequently, we conclude that CRP is applicable and reliable in monitoring basaltic coastal landscape. We also proposed that CRP can be an ideal tool for digital archives of costal cultural landscape, such as Penghu fishing wires.