Researchers from the Aerospace Information Research Institute (AIR) of the Chinese Academy of Sciences (CAS) have found that the proportion of sunlit background visible in remote sensing images controls the vertical distribution of stereoscopic point clouds. The higher the proportion of visible sunlit background, the stronger the ability to detect the understory terrain. The team realized the unique value of satellite-borne stereoscopic observations for measuring forest 3D structure and carried out in-depth research. They confirmed that leaf-on imagery could depict the structure of forest canopy top, while leaf-off imagery had the potential for detecting understory ground elevations. They also developed a stereoscopic observation model of forest, which was used in the design of China's Terrestrial Ecosystem Carbon Inventory Satellite, making it the only satellite in China that is capable of both along-track spectral and multi-angle stereo observations.
