A Survey of State Representation Learning for Deep Reinforcement Learning
It provides a taxonomy for researchers in reinforcement learning, but is incremental as it synthesizes existing work.
This survey categorizes state representation learning methods in deep reinforcement learning to address complex observation spaces, organizing them into six classes to improve understanding and guide researchers.
Representation learning methods are an important tool for addressing the challenges posed by complex observations spaces in sequential decision making problems. Recently, many methods have used a wide variety of types of approaches for learning meaningful state representations in reinforcement learning, allowing better sample efficiency, generalization, and performance. This survey aims to provide a broad categorization of these methods within a model-free online setting, exploring how they tackle the learning of state representations differently. We categorize the methods into six main classes, detailing their mechanisms, benefits, and limitations. Through this taxonomy, our aim is to enhance the understanding of this field and provide a guide for new researchers. We also discuss techniques for assessing the quality of representations, and detail relevant future directions.