臺灣博碩士論文加值系統

無人飛行載具(UAV)可於空中進行航空攝影，近幾年於各領域發展快速，本研究利用數位影像相關係數法(DIC)來提升航拍影像拼接的精準度與三維數值模型的精度。DIC在本研究中的應用有兩個方面，第一在於應用DIC定出控制點在不同影像上的位置，藉由提高控制點的精度來提高影像拼接與三維數值模型的精度；第二在於利用SURF特徵點提取法提出影像的特徵點，再利用DIC比對出影像間相對應的特徵點影像座標，將這些比對出點做為連結點匯入Pix4Dmapper軟體中增加影像拼接與三維模型製作的精度。
本研究先進行了影像匹配精度實驗，將影像於x和y方向移動不同移動量，對移動前與移動後之影像分別進行了SIFT、SURF、BRISK與DIC匹配，結果顯示SIFT、SURF與BRISK在x與y方向的精度皆在1到0.1個pixel，而DIC則是0.02個pixel，顯示DIC的精度確實高於一些常用的匹配方法。
另外，研究中比較了以人工選定控制點與人工選點再輔以DIC配對的差異，三維階梯實驗結果顯示，利用DIC分析的控制點影像座標，做出來的模型檢核點高程誤差標準差為0.08mm，只利用人工選點的標準差為0.201mm，三維模型實驗結果顯示，利用人工搭配DIC分析的控制點影像座標，做出來的模型檢核點高程誤差標準差為0.48mm，只利用人工選點的標準差為0.696mm，階梯模型與三維模型結果皆顯示在單純將DIC應用於控制點定位上已能改善精度。
最後本研究進行了兩個室內實驗來評估不同數量的DIC連結點與SURF連結點對影像拼接與三維數值模型精度之影響，從階梯模型與三維模型的檢核點誤差得知，加入DIC連結點有助於提升拼接影像與三維數值模型的精度，且改善幅度大致隨點數增加而提高，且效果比SURF比對出的連結點更好。具高精度高程之階梯試體之試驗結果顯示，未匯入連結點的檢核點高程誤差標準差為0.08mm，加入DIC連結點的最佳結果為0.049mm，而由三維模型之試驗結果可得未匯入連結點的高程誤差標準差為0.48mm，匯入DIC連結點的最佳結果為0.27mm。由此顯示，應用DIC確實能有效改善影像拼接與三維數值模型建立之精度。

Unmanned aerial vehicle (UAV) can be used to take aerial photographs, and it has been rapidly developed in many fields in recent years. This study uses digital image correlation method (DIC) to increase precision of image stitching and three-dimensional terrain model. DIC will be applied in two ways. Firstly, DIC is used to locate control points’ image positions in different photos, so that the precision of image stitching and three-dimensional terrain model will increase by raising control points’ precision. Secondly, DIC is used to match feature points which extracted by SURF algorithm and then these points are imported into Pix4dmapper to increase the precision of image stitching and three-dimensional terrain model.
An experiment is carried out to compare the precision of various image matching methods, such as SIFT, SURF, BRISK as well as DIC. The results of different movements in x and y directions show that the precisions of SIFT、SURF and BRISK range from 0.1 to 1 pixel and the precision of DIC is 0.02pixel. It shows that DIC is more accurate than the other methods.
Furthermore, this study compares two different methods adopted to obtain the image coordinates of control points. In one of the method, the control points’ image coordinates are positioned manually. The other method will use DIC method to improve the precision of manually positioned control points. Ladder specimen’s results show that the positioning precision by using DIC is 0.08 mm while the manual positioning precision is 0.201 mm, 3D model specimen’s results show that the positioning precision by using DIC is 0.48 mm while the manual positioning precision is 0.696 mm. It shows that applying DIC to positioning control points can improve the precision.
Eventually, this study carries out two indoor experiments to evaluate the influence of different amounts of DIC connection points and SURF connection points on the precision of image stitching and three-dimensional terrain model. According to the altitude error of check points from ladder specimen and 3D model specimen, we can find that importing DIC connection points can increase the precision of image stitching and three-dimensional terrain model. The magnitude of improvement will be raised as the amount of connection points increases, and its effect is better than importing SURF connection points. Ladder specimen’s result shows that the altitude error is 0.08mm without connection points. The best result is 0.049mm while importing DIC connection points. The 3D model specimen’s result shows that the altitude error is 0.48mm without connection point. The best result is 0.27mm while importing DIC connection points. These results show that applying DIC to image stitching and three-dimensional terrain model establishment can actually improve the precision.

第一章 前言
1.1 研究動機
1.2 研究目的
第二章 文獻回顧
2.1 數位影像相關係數(DIC)
2.2 特徵點提取
2.3 影像匹配
2.4 影像拼接與融合
2.5 文獻總結
第三章 特徵點提取與影像匹配相關理論
3.1 特徵點提取法
3.1.1 特徵點擷取法文獻比較
3.1.2 特徵點提取法抵抗影像旋轉能力評估
3.1.3 特徵點提取法運算速度比較
3.2 SIFT演算法
3.3 SURF演算法
3.4 數位影像相關係數法
第四章 空中三角測量
4.1 相機參數
4.2 空中三角測量原理
4.3 PIX4DMAPPER軟體
第五章 實驗驗證與討論
5.1 影像匹配演算法精度比較實驗
5.1.1 試體
5.1.2 實驗步驟
5.1.3 實驗結果與討論
5.2 三維階梯試體實驗
5.2.1 試體
5.2.2 實驗儀器與配置
5.2.3 實驗步驟
5.2.4 人工選點與DIC定位比較
5.2.5 連結點影響之結果與討論
5.3 三維模型實驗
5.3.1 試體
5.3.2 實驗儀器與配置
5.3.3 實驗步驟
5.3.4 人工選點與DIC定位比較
5.3.5 連結點影響之結果與討論
第六章 結論與建議
6.1 結論
6.2 建議
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