General and Efficient Visual Goal-Conditioned Reinforcement Learning using Object-Agnostic Masks
Fahim Shahriar, Cheryl Wang, Alireza Azimi, Gautham Vasan, Hany Hamed Elanwar, A. Rupam Mahmood, Colin Bellinger
TL;DR
This paper addresses the challenge of goal representation in visual GCRL by introducing an object-agnostic mask-based goal conditioning and a mask-derived dense reward. The method appends a dynamic binary mask to visual observations and uses three-frame frame stacking to provide progression cues, enabling fast learning and strong generalization to unseen targets. It evaluates SAC and PPO across three robotics environments, demonstrating near-perfect reaching accuracy on training and unseen objects (99.9%), and shows that mask-based rewards can rival distance-based rewards with improved stability. The work also demonstrates sim-to-real transfer and real-world learning from scratch using open-vocabulary detectors (Detic, Grounding DINO), highlighting practical potential for vision-driven robotic manipulation without privileged information.
Abstract
Goal-conditioned reinforcement learning (GCRL) allows agents to learn diverse objectives using a unified policy. The success of GCRL, however, is contingent on the choice of goal representation. In this work, we propose a mask-based goal representation system that provides object-agnostic visual cues to the agent, enabling efficient learning and superior generalization. In contrast, existing goal representation methods, such as target state images, 3D coordinates, and one-hot vectors, face issues of poor generalization to unseen objects, slow convergence, and the need for special cameras. Masks can be processed to generate dense rewards without requiring error-prone distance calculations. Learning with ground truth masks in simulation, we achieved 99.9% reaching accuracy on training and unseen test objects. Our proposed method can be utilized to perform pick-up tasks with high accuracy, without using any positional information of the target. Moreover, we demonstrate learning from scratch and sim-to-real transfer applications using two different physical robots, utilizing pretrained open vocabulary object detection models for mask generation.
