半全域匹配法於福衛二號立體影像之數值地表模型重建

Semi-Global Matching for DSM Generation using Formosat-2 Stereo Images

張智安(Tee-Ann Teo) ； 郭怡伶(I-Ling Kuo)

《航測及遙測學刊》 22卷3期 (2017/09) Pp. 181-191

https://doi.org/10.6574/JPRS.2017.22(3).3

摘要

像空間半全域匹配法(Semi-global matching, SGM)需使用核影像像對進行核線幾何約制，若使用線列式掃描器成像之衛星影像進行SGM，便須解決其核幾何與像幅式影像不同之問題，因此本研究提出物空間半全域演算法(Object-based SGM, OSGM)重建數值地表模型(Digital Surface Model, DSM)。研究中比較特徵式匹配及物空間半全域演算法於數值地表模型重建之差異，其中特徵式匹配僅針對特徵點進行匹配，再將匹配成功的特徵點三維點雲網格化為DSM，而OSGM則是在物空間逐點式密匹配，直接產生影像正射化所需的DSM。本研究使用福衛二號同軌立體像對進行實驗分析，特徵式匹配之三維點雲為OSGM的15%；分別使用特徵式匹配及OSGM DSM建立正射影像，正射影像視差之標準偏差分別為3.07像元及1.94像元，代表OSGM建立的DSM具有較佳的精密度。

關鍵字

半全域匹配 ； 數值地表模型 ； 福衛二號

並列摘要

Image-based semi-global matching (SGM) utilizes epipolar images as a geometrical constrain in image matching. However, the epipolar geometric of frame camera and push-broom satellite images are not the same. Therefore, the traditional image-based SGM cannot be applied to push-broom satellite images directly. This study proposed an object-based SGM (OSGM) to overcame the problem of non-linear epipolar line for push-broom satellite image. The aim of this study is to generate the digital surface model (DSM) for image orthoretification using proposed OSGM. This study also compare the DSM generated from feature-based matching and OSGM. The feature-based matching only performs the image matching on particular feature points. Then, the 3D coordinates of feature points are interpolated into DSM. The experimental images are Formosat-2 in-track stereo images, the number of 3D points generated from feature-based matching is 15% of OSGM. We use these two DSMs to produce orthoimages, the standard deviations of disparity between orthoimages are 3.07pixels and 1.94pixels, respectively. The DSM generated from OSGM show higher relatively accurate than the one from feature-based matching.

並列關鍵字

Semi-Global Matching (SGM) ； Digital Surface Model (DSM) ； Formosat-2