電腦視覺三維建模的精確度，仰賴影像中對應點的準確性。以前的研究大多採取兩張影像，透過極線轉換(epipolar transfer)取得影像間基礎矩陣(fundamental matrix)的關係，然後進行比對或過濾不良的對應點以求取精確的對應點。然極線轉換存在退化的問題，如何避免此退化問題以及降低兩張影像之間轉換錯誤的累積，成為求取精確三維建模中極待解決的課題。 本論文中，我們提出一套機制，透過三焦張量(trifocal tensor)的觀念來過濾影像間不良的對應點，提高整體對應點的準確度，從而能計算較精確的投影矩陣進行三維建模。我們由多視角影像出發，先透過Bundler求取對應點，然後採用三焦張量過濾Bundler產生的對應點，並輔以最小中值平方法(LMedS)提升選點之準確率，再透過權重以及重複過濾等機制來調節並過濾對應點，從而取得精確度較高的對應點組合，最後求取投影矩陣進行電腦視覺中的各項應用。 實作中，我們測詴了三組資料，包含一組以3ds Max自行建置的資料與兩組網路中取得的資料。我們先從三張影像驗證三焦張量的幾何特性與其過濾對應點的可行性，再將此方法延伸至多張影像，同樣也能證實透過三焦張量確實能提升對應點的準確度，甚至可以過濾出輸入資料中較不符合彼此間幾何性的影像。 / The accuracy of 3D model constructions in computer vision depends on the accuracy of the corresponding points extracted from the images. Previous studies in this area mostly use two images and compute the fundamental matrix through the use of the epipolar geometry and then proceed for corresponding point matching and filtering out the outliers in order to get accurate corresponding points. However, the epipoler transform suffers from the degenerate problems and, also, the accumulated conversion errors during the corresponding matches both will degrade the model accuracy. Solving these problems become crucial in reconstructing accurate 3D models from multiple images. In this thesis, we proposed a mechanism to obtain accurate corresponding points for 3D model reconstruction from multiple images. The concept of trifocal tensor is used to remove the outliers in order to improve the overall accuracy of the corresponding points. We first use Bundler to search the corresponding points in the feature points extracted from multiple view images. Then we use trifocal tensor to determine and remove the outliers in the corresponding points generated by Bundler. LMedS is used in these processes to improve the accuracy of the selected points. One can also improve the accuracy of the corresponding points through the use of weighting function as well as repeated filtering mechanism. With these high precision corresponding points, we can compute more accurate fundamental matrix in order to reconstruct the 3D models and other applications in computer vision. We have tested three sets of data, one of that is self-constructed data using the 3ds Max and the other two are downloaded from the internet. We started by demonstrating the geometric properties of trifocal tensor associated with three images and showed that it can be used to filter out the bad corresponding points. Then, we successfully extended this mechanism to more images and successfully improved the accuracy of the corresponding points among these images.

熱像儀，能感測可見光感測器無法取得的訊息，因此若能透過熱像儀器進行環境偵測，便能得到一般可見光感測器無法獲取的資料。本研究擬以四旋翼UAS酬載熱像儀得到局部區域高解析度之地面熱資訊以便作為地溫研究之背景資料使用。而一般地溫研究區，不易佈設控制點，因此本研究除於無人機上酬載熱像儀之外，並將搭載Trimble BD970 GNSS OEM接收模組，嘗試以少量地面控制點、以及GNSS動態後處理的方式取得取像時對應的GNSS觀測量輔助熱像定位定向。本研究中針對國立政治大學旁的指南溪實驗區與陽明山國家公園的小油坑實驗區，使用AI-RIDER YJ-1000-HC四旋翼UAS分別酬載熱像儀FLIR Tau 640和巨哥XM6，並且同時搭載Trimble BD970 GNSS OEM接收模組、以及GNSS動態後處理的方式取得取像時對應的GNSS觀測量搭配少量地面控制點輔助熱像定位定向，過程中透過三焦張量剔除自動匹配之誤匹配連結點。實驗結果顯示，兩實驗區所產製之DSM於不易變動區域精度經現有資料檢核均在±1m，而指南溪實驗區產製出地面解析度11公分的數值表面模型(Digital Surface Model, DSM)與正射熱像，且正射熱像平面精度達為47公分；小油坑實驗區產製出地面解析度14公分之DSM與正射熱像，正射熱像平面精度則為67公分，雖然DSM和正射熱像精度無法符合一般常規的測量規範，但成果仍然可以證明熱像直接產製DSM以及正射熱像之可行性，兩實驗區最後皆生成數值溫度表面模型(Digital Surface Temparature Model, DSTM)，顯示本研究所提方法之可行性，所生成之成果可供後續地溫研究使用。 / Thermal infrared images show the temperature change of sensed scenes. Therefore, thermal infrared camera can sense some important information that optical digital cameras cannot do for the environment monitoring. In this study, the Quadcopter UAS for thermal image collection applied to geothermal study will be developed. FIIR Tau 640 and Magnity Eletric XM6 thermal infrared sensor will be used in this thermal image collection system separately two test areas, Zhinan River nearby NCCU and Xiaoyoukeng, in the Yangmingshan National Park. Additionally, Trimble BD970 GNSS OEM board will be carried on the Quadcopter UAS to collect dual-frequency GNSS observations for determining the flying trajectory by Post-processed kinematic (PPK) technique to support the positioning and orientating of collected thermal images, and the trifocal tensor will be used to delete wrong matching tie images points. From the tests, the differences between produced DSM and existing DSM data are ± 1 m on uneasy change ground surface in two test areas. The resolution of produced DSM and thermal orthoimages are about 11 cm in Zhinan River, and 14cm in Xiaoyoukeng area. The accuracy of thermal orthoimages is 47cm in Zhinan River and 67cm in Xiaoyoukeng area. The accuracy of thermal orthoimages may not comply with a normal surveying standard, but it proves the possibility of DSM and orthorectifed thermal images generated from thermal images directly. Digital Surface Temparature Model (DSTM) produced in both tests can be used for volcanic geothermal monitoring in the future.