Towards Unseen Triples: Effective Text-Image-joint Learning for Scene Graph Generation

Scene Graph Generation (SGG) aims to structurally and comprehensively represent objects and their connections in images, it can significantly benefit scene understanding and other related downstream tasks. Existing SGG models often struggle to solve the long-tailed problem caused by biased datasets. However, even if these models can fit specific datasets better, it may be hard for them to resolve the unseen triples which are not included in the training set. Most methods tend to feed a whole triple and learn the overall features based on statistical machine learning. Such models have difficulty predicting unseen triples because the objects and predicates in the training set are combined differently as novel triples in the test set. In this work, we propose a Text-Image-joint Scene Graph Generation (TISGG) model to resolve the unseen triples and improve the generalisation capability of the SGG models. We propose a Joint Fearture Learning (JFL) module and a Factual Knowledge based Refinement (FKR) module to learn object and predicate categories separately at the feature level and align them with corresponding visual features so that the model is no longer limited to triples matching. Besides, since we observe the long-tailed problem also affects the generalization ability, we design a novel balanced learning strategy, including a Charater Guided Sampling (CGS) and an Informative Re-weighting (IR) module, to provide tailor-made learning methods for each predicate according to their characters. Extensive experiments show that our model achieves state-of-the-art performance. In more detail, TISGG boosts the performances by 11.7% of zR@20(zero-shot recall) on the PredCls sub-task on the Visual Genome dataset.

ARiADNE: A Reinforcement learning approach using Attention-based Deep Networks for Exploration

In autonomous robot exploration tasks, a mobile robot needs to actively explore and map an unknown environment as fast as possible. Since the environment is being revealed during exploration, the robot needs to frequently re-plan its path online, as new information is acquired by onboard sensors and used to update its partial map. While state-of-the-art exploration planners are frontier- and sampling-based, encouraged by the recent development in deep reinforcement learning (DRL), we propose ARiADNE, an attention-based neural approach to obtain real-time, non-myopic path planning for autonomous exploration. ARiADNE is able to learn dependencies at multiple spatial scales between areas of the agent's partial map, and implicitly predict potential gains associated with exploring those areas. This allows the agent to sequence movement actions that balance the natural trade-off between exploitation/refinement of the map in known areas and exploration of new areas. We experimentally demonstrate that our method outperforms both learning and non-learning state-of-the-art baselines in terms of average trajectory length to complete exploration in hundreds of simplified 2D indoor scenarios. We further validate our approach in high-fidelity Robot Operating System (ROS) simulations, where we consider a real sensor model and a realistic low-level motion controller, toward deployment on real robots.