arXiv:2412.13949cs.CLcs.CV2024-12ACL被引 33

通过分析注意力头对视觉信息的敏感度,找出大模型幻觉根源并针对性改进。

Cracking the Code of Hallucination in LVLMs with Vision-aware Head Divergence

  • 提出视觉感知注意力分歧度量,定位对视觉敏感的注意力头。
  • 发现模型过度依赖语言先验是导致幻觉的关键原因。
  • 无需训练即可增强视觉注意力,显著降低幻觉率,适合追求高效可靠的开发者。

大型视觉语言模型(LVLMs)在融合语言模型与视觉输入方面取得显著进展,支持复杂的多模态推理。然而,幻觉问题——生成文本未能准确反映视觉内容——持续影响其准确性和可靠性。现有方法主要聚焦于对齐训练或解码优化,但仅处理生成阶段的症状,未深入探究根本原因。本文研究了LVLM中幻觉产生的内部机制,重点关注多头注意力模块。我们提出视觉感知注意力分歧(VHD),量化注意力头输出对视觉上下文的敏感度。研究发现存在对视觉信息更敏感的注意力头,但模型对语言先验的过度依赖与幻觉密切相关。基于此,我们提出无需训练的视觉感知注意力强化(VHR)方法,通过增强视觉感知注意力头的作用来缓解幻觉。大量实验表明,该方法在抑制幻觉方面优于现有先进方法,且额外计算开销极小。

原文摘要 · Abstract (English)

Large vision-language models (LVLMs) have made substantial progress in integrating large language models (LLMs) with visual inputs, enabling advanced multimodal reasoning. Despite their success, a persistent challenge is hallucination-where generated text fails to accurately reflect visual content-undermining both accuracy and reliability. Existing methods focus on alignment training or decoding refinements but primarily address symptoms at the generation stage without probing the underlying causes. In this work, we investigate the internal mechanisms driving hallucination in LVLMs, with an emphasis on the multi-head attention module. Specifically, we introduce Vision-aware Head Divergence (VHD), a metric that quantifies the sensitivity of attention head outputs to visual context. Based on this, our findings reveal the presence of vision-aware attention heads that are more attuned to visual information; however, the model's overreliance on its prior language patterns is closely related to hallucinations. Building on these insights, we propose Vision-aware Head Reinforcement (VHR), a training-free approach to mitigate hallucination by enhancing the role of vision-aware attention heads. Extensive experiments demonstrate that our method achieves superior performance compared to state-of-the-art approaches in mitigating hallucinations, while maintaining high efficiency with negligible additional time overhead.

幻觉抑制注意力机制多模态LVLM

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