COMPARISON BETWEEN RGB AND LIDAR POINT CLOUDS: STRUCTURE METRICS IN RESTORED FOREST

The use of Light Detection and Ranging (LiDAR) sensors onboard Remotely Piloted Aircraft Systems (RPAS) has proven to be capable to monitor forest restoration by analyzing forest structure. However, such systems often require substantial investments. Overtime, the access to RPAS with high resolution RGB sensors was facilitated. This study sought to explore the potential of monitoring tropical forest restoration using digital aerial photogrammetry as opposed to LIDAR technology. Thus, a comparison was established between 6 structural metrics calculated from RGB and LiDAR data. The products were compared through linear regressions modeled for each variable. Results show great relationship between both sensors (R²=0.48-0.98), diverging only for 2 metrics (RMSE of 5.6 and 13.05; and MAE of 4.2 and 9.857). Therefore, the products of digital photogrammetry achieved results similar to those provided by LiDAR technology. However, we highlight the limitation of RGB data for generating the Digital Terrain Model and the need to spatially adjust the images. Finally, considering these limitations, the use of commercial RGB RPAS proves to be a viable and cost-effective option for monitoring restoration initiatives.