Photometric-Constrained Reconstruction of Lunar Landing Site Topography Using Orbiter and Descent Images

In lunar exploration, high-resolution topography is an important basis for safe landing and mission planning. Remote sensing images are the main data sources for the reconstruction of lunar surface topography [1]. Among them, the orbiter images preserve the topographic photometric information under different illumination directions, and the descent images contain high-resolution morphological details of the landing site. In order to integrate the advantages of multi-illumination directions of orbiter images and high resolution of descent images, we propose a joint photometric-constrained method for topography reconstruction using both orbiter and descent images. In the framework of the joint photometric-constrained Shape from Shading (SfS) [2-4], the photometric information in multi-source images illuminated from different directions is added into the cost function as a weighted regular term in topography reconstruction. We focus on the Chang'E-3 landing site. We used the Lunar Reconnaissance Orbiter (LRO) Narrow Angle Camera (NAC) images of the area and Chang'E-3 descent images for experiments, and obtained topographic data of the site with a resolution better than 0.1 m/pixel. Comparing with previously derived topography [5], we verified that our topography is more consistent result with the images in multi-angle illumination rendering [6], integrating the photometric information of the multi-source images and preserving the morphological details such as small-size impact craters. The method proposed in this study not only improves the accuracy of topography reconstruction of the Chang'E-3 landing site, but also provides a new idea for the joint processing of multi-source image data.

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