基于观测角信息的HJ-1A/B卫星光学影像几何精纠正

High precision geometric rectification of HJ-1A/B CCD imagery based on satellite observation angle information

现有国产环境卫星光学影像标准数据产品为二级影像,采用系统几何纠正的方法生成,未消除地形起伏引起的影像变形;而这种二级影像产品不包含严格成像模型信息,对地形起伏较大的区域,难以采用现有纠正方法可靠地进行几何精纠正。针对这一问题,提出一种基于观测角信息的几何纠正方法。采用标准影像产品附带的观测角数据恢复影像光束,建立近似成像几何模型,使该卫星光学影像标准数据产品可按正射纠正的方式进行几何精纠正,从而有效消除地形起伏的影响。实验表明,方法相对于现有精纠正方法,提高了中等空间分辨率卫星影像几何纠正的精度和稳定性。

The available standard products of the domestic satellite HJ-1 A/B CCD image are level II images,which are generated with systematic correction without considering the distortions caused by terrain undulation.Lacking of the geometric imaging model,it is difficult to do a reliable image rectification on the level II image with the existing methods in the range with big terrain undulation. To solve this problem,the authors propose a method to reconstruct the imaging geometric model based on the observation angle information,which is stored in a Sat Angle. txt file. With the reconstructed RPC model,the HJ-1 A/B CCD image can be orthorectified just like an original image with rigorous imaging geometric model. The experimental results show that the proposed method can effectively improve the rectification precision and the stability of geometric model fitting.