在遙測應用中，利用衛星影像進行整合分析之有興趣的區域，常包含兩張甚至多張影像的涵蓋範圍。因此，影像的正射化及正射影像鑲嵌為提供大範圍的影像資料並與其他相關資料整合之重要工作。影像正射化之首要程序為影像之方位重建，使用多航帶區域平差進行方位重建可增強重疊區之幾何一致性。資源衛星影像之主要用途為環境監測及資源探測，為求較大的影像覆蓋面積，不同軌道的影像重疊區域很小，且航帶間普遍具有較弱的交會幾何，傳統上以三維定位為考量之光束法平差模式將不適用。 本研究將提出一個新的光束法平差程序，針對弱交會幾何之影像，以數值高程模型作為航帶連結點之高程控制進行光束法平差，藉以降低重疊航帶間共軛點之相對偏移(簡稱相對偏移)，並改善正射影像間銜接之品質。主要工作包括: (1)以光束法區域平差搭配數值高程模型作為高程控制，進行影像方位之重建，(2)以最小二乘過濾進行衛星軌道精密修正，(3)進行衛星影像正射化，最後進行正射影像鑲嵌。 實驗結果顯示，加入航帶連結點進行光束法區域平差，能有效降低重疊航帶間共軛點之相對偏移，並減少鑲嵌影像上重疊區影像錯開之現象。 In various applications, areas of interest sometimes cover two or more satellite images, thus orthorectification and mosaicking for those images becomes important. While orbit adjustment is a prerequisite in the image orthorectification. Performing simultaneous block adjustment for multi-strip images could enhance the geometric consistency among strips. The major applications of the remote sensing images include the detection of natural resources and the monitoring for geoenvironment. In order to acquire largest possible coverage, the overlapping area of satellite images is small in general. In addition, the converging geometry is poor in common. Hence, the traditional 3-D bundle adjustment is not suitable for orientation modeling directly. The objective of this investigation is to propose a modified block adjustment procedure using DEMs as elevation control for multi-orbit satellite images. The major works of the proposed scheme are: (1) bundle adjustment using DEM as an elevation control, (2) least squares filtering to collocate the orientation parameters, and (3) generation of the orthophotos along with mosaicking. Experimental results indicate that block adjustment can reduce the discrepancies for conjugate points between image strips. It is also demonstrated that the mosaicked image is better seamed when tie points are employed in the adjustment.
