DT2IT-MRM: Debiased Preference Construction and Iterative Training for Multimodal Reward Modeling

arXiv cs.AI / 4/22/2026

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Key Points

  • The paper introduces DT2IT-MRM, a multimodal reward modeling approach aimed at improving how multimodal LLMs are aligned with human preferences.
  • It addresses key issues in existing preference data—insufficient granularity of preference strength, textual style bias, and unreliable preference signals—by proposing a debiased preference construction pipeline and a new text-to-image (T2I) preference reformulation.
  • The method includes an iterative training framework designed to curate and reduce noise in existing open-source multimodal preference datasets in a scalable way.
  • Experiments report new state-of-the-art overall performance across three benchmarks: VL-RewardBench, Multimodal RewardBench, and MM-RLHF-RewardBench.

Abstract

Multimodal reward models (MRMs) play a crucial role in aligning Multimodal Large Language Models (MLLMs) with human preferences. Training a good MRM requires high-quality multimodal preference data. However, existing preference datasets face three key challenges: lack of granularity in preference strength, textual style bias, and unreliable preference signals. Besides, existing open-source multimodal preference datasets suffer from substantial noise, yet there is a lack of effective and scalable curation methods to enhance their quality. To address these limitations, we propose \textbf{DT2IT-MRM}, which integrates a \textbf{D}ebiased preference construction pipeline, a novel reformulation of text-to-image (\textbf{T2I}) preference data, and an \textbf{I}terative \textbf{T}raining framework that curates existing multimodal preference datasets for \textbf{M}ultimodal \textbf{R}eward \textbf{M}odeling. Our experimental results show that DT2IT-MRM achieves new \textbf{state-of-the-art} overall performance on three major benchmarks: VL-RewardBench, Multimodal RewardBench, and MM-RLHF-RewardBench.