Advances in The Characterization of Caves From Spaceborne X-Band VHR Sar Images

Circular sinkholes (i.e., pits) are depressions in the ground caused by the collapse of the surface layer. These type of features are commonly found on Earth and on other celestial bodies such as the Moon and Mars. Sinkholes may provide access to an underground cave system but it is very difficult to understand their accessibility and internal shape from optical images. In this paper, we propose a methodology for characterizing circular sinkholes by exploiting X-Band Very High Resolution (VHR) Spaceborne Synthetic Aperture Radar (SAR) images. The analysis of our experimental results show that a set of bright reflections in the radar image can be attributed to the response of the circular pit vertical walls and interior. Accordingly, it is possible to characterize the internal morphology of the pit. The results of this work have implications for planetary exploration as the proposed methodology can be applied for characterizing planetary pits.