Construction of indoor obstacle element map based on scene-aware priori obstacle rules

An obstacle element map is the basis of indoor navigation space subdivision. Effective and reasonable indoor space subdivision can improve the fineness of indoor navigation path planning. To divide an indoor navigation space more finely, an indoor obstacle element map construction method based on scene-aware a priori rules for obstacles is proposed. This method divides indoor space into navigable space (N-space), semi-navigable space (SN-space), and non-navigable space (NN-space) based on the flexible space subdivision framework (FSS) and classifies indoor obstacles into four categories, walls, doors, movable obstacles (MOs), and immovable obstacles (IMOs). First, by analyzing the layout and mobility of common indoor elements, the obstacle prior rules for seven types of indoor scenes (including hospitals, residences, classrooms, office buildings, transportation hubs, restaurants, and shopping malls) are formulated, and a method for obtaining obstacle prior rules based on scene recognition is proposed. Then, obstacles and their mobility are extracted from the semantic segmentation results of point clouds based on the acquired rules and mobility indicators. Finally, the extracted obstacles are processed to construct the obstacle element map, wall and door elements are fitted by the random sample consensus (RANSAC) algorithm, and IMOs and MOs are processed by Euclidean clustering. The experimental results show that the proposed method can effectively determine four types of indoor obstacles, and the overall accuracy in simple scenes is 85.22 %, while in complex scenes it is 97.96 %. Under the experimental environment (CPU: Intel Core i7-7700K; Memory: 16 GB and 2400 MHz; OS: Win10) in this paper, the construction of a simple scene obstacle element map can be completed in 5 s. In addition to the spatial information of the indoor elements, the obstacle element map also contains information about whether the elements can be moved, which provides the basis for the subdivision of the indoor space.