3D spatial reasoning using the clock model

A visual, three-dimensional (3D) scene is usually grounded by two-dimensional (2D) views. In order to develop a system able to automatically understand such a 3D scene and to provide high-level specifications of what is this scene, we propose a new computational formalism which allows to perform reasoning simultaneously about the 3D scene and its 2D views. In particular, our approach formalizes both 3D directional relations and 3D far/close spatial relations among objects of interest in the scene. For this purpose, qualitative spatial relations based on the clock model are computed in each of the 2D views capturing the scene and are reconstructed in the 3D space in a semantically meaningful, spherical representation. Our resulting 3D qualitative spatial relations have been successfully tested on real-world dataset and show excellent performance in terms of accurateness and efficiency compatible with real-time applications.