亚m级卫星TDI CCD立体测绘相机成像仿真

以三角网和贴面纹理影像为精细地面模型的数据构成,以亚m级TDI CCD(time delay and iintegration charge coupled devices)立体测绘相机为仿真对象进行成像仿真。通过建立每个像元的"视线目标索引"判断目标对相机和太阳的可见视性,进而生成阴影。将TDI CCD焦平面细分成很多子CCD,同时将积分时间细分,计算"连续焦面辐照度影像"并实现静态MTF仿真,然后得到"时间平均静态影像"。实现了多级积分条件下的霰粒噪声仿真和TDI CCD多级动态积分成像的仿真。推导了相机安装角和光学节点从平台坐标系到物方坐标系的转换公式,结合姿态参数和CCD畸变参数,实现了任意侧摆角度和相机安装角度的成像仿真。

Imaging Simulation of Sub-meter Satellite TDI CCD Camera for Surveying and Mapping

This paper details a meticulous ground model using triangular networks and furring texture images as well as imaging simulations of TDI CCD cameras for surveying and mapping. The sight target index was built by projecting the ground triangular network to the image，and then evaluated to see if a ground point was visible in the camera and sun direction by "imaging" in these two directions，and creating a shadow. The TDI CCD plane was divided into small CCDs and the irradiance of every small CCD was computed to get the“continuous focal plane irradiance image". The static MTF was simulated by filtering the“continuous focal plane irradiance image" using PSF. The integration time was divided and the filtered static image computed for every sub-time，then the images added for every sub-time to get the "time mean static image". Then，graupel noise was added to every "time mean stat is image" of every line CCD，and then，adding the "time mean static image" of the same target by different CCD lines to get the average energy image，thus realizing TDI CCD multistage dynamic imaging simulation. In this manner，it was possible to derive the camera setting angle and optical panel point transfer function from platform coordinates to object coordinates，realizing an imaging simulation for any incline angle and setting angle by integrating attitude and CCD distortion parameters.