BalCapRL: A Balanced Framework for RL-Based MLLM Image Captioning
Researchers introduce BalCapRL, a reinforcement learning framework that improves multimodal image captioning by balancing three competing objectives: utility-aware correctness, reference coverage, and linguistic quality. The method achieves significant performance gains across multiple models by applying reward-decoupled normalization and length-conditional masking, addressing the trade-offs present in existing captioning approaches.