HEROS: Hierarchical Exploration with Online Subregion Updating for 3D Environment Coverage

We present an autonomous exploration system for efficient coverage of unknown environments. First, a rapid environment preprocessing method is introduced to provide environmental information for subsequent exploration planning. The exploration space is then divided into multiple subregion cells with varying levels of detail, capable of online decomposition and updating to adaptively represent dynamic unknown regions. Finally, a hierarchical planning strategy treats subregions as basic units, computing an efficient global coverage path. The local path is refined under the guidance of the global path to sequentially visit the viewpoint set, providing an executable trajectory for the robot. This coarse-to-fine planning reduces complexity while enhancing exploration efficiency. Compared with state-of-the-art methods in benchmark environments, the proposed approach achieves superior exploration efficiency with lower computational costs.