一种地物关系约束下的线阵影像坐标反投影计算方法

A Back Projection Algorithm for Linear Array Imageries Based on the Constraints of Object-space Relation

坐标反投影计算是线阵影像基于严格模型几何校正的关键步骤。本文在分析线阵摆扫式影像的成像方式及其特点的基础上,针对传统基于像方的顺序或迭代搜索方法效率低下的问题,提出了一种利用地物关系约束的坐标反投影计算方法。首先将当前相邻点的最佳扫描行作为先验值,估算其与当前点最佳扫描行的距离,定位初始最佳扫描行;然后以初始最佳扫描行为中心构建搜索窗口,进行最佳扫描行精确搜索;最后根据最佳扫描行对应的外方位元素进行坐标反投影计算。通过对机载线阵摆扫式模拟影像数据和推扫式真实影像数据的试验,验证了该方法的可行性、准确性和高效性。

Back projection is the key technology for rectification of linear array CCD imageries.On the basis of analyzing the imaging mode and characteristics of linear whiskbroom image,a back projection algorithm based on the constraints of object-space relation was proposed,aiming at the inefficiency of conventional image-based sequential or iterative search methods.The best scan-line of the adjacent point was used as a priori value,to estimate the number of the scan-lines between the adjacent point and the current point,thus locating the initial best scan-line.Then,a search window was constructed by the center of the initial best scan-line,and an accurate searching was implemented.At last,according to the orientation elements of the best scan-line,the coordinates back projection was carried out.The feasibility,accuracy and efficiency of the proposed method were verified by the experimental results of the airborne linear array whiskbroom simulated image data and the pushbroom real image data.