Imaging Chain Modeling and a Scaling Experiment for Optical Remote Sensing of Lunar Surface

Lunar exploration has drawn attention all over the world, and remote sensing of the lunar surface through the satellite's optical camera is one of the most important ways to provide scientific data. Although on-orbit measurement is the ultimate goal, lunar exploration is a huge cost project, so researchers should take on-ground simulations and experiments to evaluate the performance of the optical instrument and provide basic references before launch. In this article, we propose an optical imaging chain modeling algorithm that focuses on the physical imaging process from light scattering among the 3-D lunar surface to the optical instrument's output digital value (DV). Compared to other optical signal measurement simulations, we make progress in considering the 3-D structure of the observed scene, the spectral property of the imaging parameters, and corresponding absolute calibration methods. The proposed method is verified in a scaling experiment for lunar optical remote sensing with a calibrated optical camera, simulated moon soil, and a parallel light source. We compare the imaging simulation results with the experiment results for directly illuminated lunar regions, shadowed lunar regions, and multispectral imaging tasks, and the results show average relative errors (REs) around 2.4%, 11.5%, and 4.3% and coefficients of determination around 0.972, 0.942, and 0.915 for the three cases, respectively. Both the modeling algorithm and the scaling experiment will provide basic analysis for optical imaging in lunar remote sensing before the execution of a real project.