线阵推扫式相机高精度在轨几何标定

基于偏置矩阵和探元指向角构建了线阵推扫式相机的在轨几何标定模型,并给出了相应的参数求解方法。分析了线阵推扫式相机物理内参数模型与指向角内参数模型的区别与联系,对物理模型到指向角模型的演化过程进行了推导,分析了偏视场相机与正视场相机在使用指向角模型时的不同,并分别给出了两者的具体计算公式。利用嵩山检校场高精度控制数据和天绘一号高分影像验证了本文的模型和解法。实验结果表明,本文的标定模型和求解方法可解算出稳健可靠的内参数;两次标定结果相比,95%的样本探元沿轨方向的指向差异小于0.1像元,93%的样本探元垂轨方向的指向差异小于0.2像元。经在轨几何标定,影像定位精度显著提升。

High Accuracy On-Orbit Geometric Calibration of Linear Push-broom Cameras

An on-orbit geometric calibration model is established based on an offset matrix and direction angle model,the corresponding solution is presented in this paper. Similarities and differences between the physical distortion model and direction angle distortion model are analyzed. The direction angle distortion model in a linear push-broom camera is derived from the physical distortion model. Differences between the field central camera and field bias one are analyzed and their direction angle model formulas are separately provided. Control data from the Songshan mountain test field and a HR image from the TH-1 satellite are employed to verify this calibration model and solution. Experiments indicate that stable inner parameters can be obtained by this calibration model and solution method. Between the two calibrated inner results, 95 percent of along-track direction angle difference is less than 0.1 pixels and 93 percent of across-track direction angle difference is less than 0.2 pixels. After on-orbit geometric calibration, image positioning accuracy was significantly improved.