基于间接校正的高分三号正射影像生成

由于高分三号卫星(gaofen-3 satellite, GF-3)数据问世时间较短、参数不足，现有软件未针对GF-3数据添加传感器支持，导致难以利用现有各类软件生成其正射影像。提出一种基于间接校正的GF-3正射影像生成方法。模拟待校正区域卫星成像过程，采用RD模型利用与该区域对应的DEM数据构建模拟GF-3影像；在模拟与真实GF-3影像中分别提取特征点，并配准提取的特征点对，进而建立两影像间的映射关系；利用模拟GF-3影像分别与DEM数据和真实GF-3影像之间的映射关系，间接完成正射校正，生成正射影像。针对GF-3多成像模式的特点，选取3种具有代表性成像模式的影像进行正射影像生成试验，取得了较好的实验结果。将真实GF-3影像与模拟GF-3影像的对应像元坐标进行比较表明，x和y方向误差均小于一个像元，精度较高。提出算法充分考虑到了GF-3系统的成像特点，在不同的地形细节均取得了较好的结果。定性和定量的分析实验结果验证了提出方法的可行性及有效性。

Generating GF-3 orthophoto image based on indirect rectification

Due to the short time to come out and insufficient parameters of GaoFen-3 satellite(GF-3) data, the existing software does not add sensor support for GF-3 data which makes it difficult to generate its orthophoto images by using existing software. To this end, a method of generating GF-3 orthophoto images based on indirect rectification is presented in this paper. Firstly, the process of satellite imaging in the region to be ortho-corrected is simulated, and the simulated GF-3 image is constructed by using DEM data which corresponds to this region through the RD model. Secondly, feature points are extracted in simulated and real GF-3 images, respectively, the feature point pairs are matched; and then the mapping relationship between the two images is established. Finally, using the mapping relationship between simulated GF-3 image and DEM data as well as real GF-3 image, orthophoto correction is completed indirectly and orthophoto image is generated. In this paper, according to the characteristics of multiple imaging modes of GF-3, the experiment for generating GF-3 orthophoto image generation is carried out with three representative imaging model and good experimental results are obtained. The comparison of corresponding pixel coordinates between real GF-3 image and simulated GF-3 image shows error in x and y direction is less than one pixel. A high precision result has been obtained. The imaging features of SAR system are fully taken into account in the proposed method. Results of different terrain details are good. The experimental results of qualitative and quantitative analysis verify the feasibility and effectiveness of the proposed method.