Semantic Segmentation of LiDAR Points Clouds: Rasterization Beyond Digital Elevation Models

LiDAR point clouds are receiving a growing interest in remote sensing as they provide rich information to be used independently or together with optical data sources, such as aerial imagery. However, their nonstructured and sparse nature make them difficult to handle, conversely to raw imagery for which many efficient tools are available. To overcome this specific nature of LiDAR point clouds, the standard approach relies on converting the point cloud into a digital elevation model, represented as a 2-D raster. Such a raster can then be used similarly as optical images, e.g., with 2-D convolutional neural networks (CNNs) for semantic segmentation. In this letter, we show that LiDAR point clouds provide more information than only the digital elevation model and that considering alternative rasterization strategies helps to achieve better semantic segmentation results. We illustrate our findings on the IEEE Data Fusion Contest (DFC) 2018 data set.