Temporal Scene-Object Graph Learning for Object Navigation

Object navigation tasks require agents to locate target objects within unfamiliar indoor environments. However, the first-person perspective inherently imposes limited visibility, complicating global planning. Hence, it becomes imperative for the agent to cultivate an efficient visual representation from this restricted viewpoint. To address this, we introduce a temporal scene-object graph (TSOG) to construct an informative and efficient ego-centric visual representation. Firstly, we develop a holistic object feature descriptor (HOFD) to fully describe object features from different aspects, facilitating the learning of relationships between observed and unseen objects. Next, we propose a scene-object graph (SOG) to simultaneously learn local and global correlations between objects and agent observations, granting the agent a more comprehensive and flexible scene understanding ability. This facilitates the agent to perform target association and search more efficiently. Finally, we introduce a temporal graph aggregation (TGA) module to dynamically aggregate memory information across consecutive time steps. TGA offers the agent a dynamic perspective on historical steps, aiding in navigation towards the target in longer trajectories. Extensive experiments in AI2THOR and Gibson datasets demonstrate our method's effectiveness and efficiency for ObjectNav tasks in unseen environments.