用视觉编码器注意力引导,减少大模型图像生成幻觉。
VEGAS: Mitigating Hallucinations in Large Vision-Language Models via Vision-Encoder Attention Guided Adaptive Steering
- 用视觉编码器注意力图替代模型自身注意力,抑制幻觉。
- 在多个基准上显著降低幻觉率,效果优于现有方法。
- 适合需要高视觉一致性场景的开发者使用。
大型视觉语言模型(LVLM)虽能联合推理视觉与文本输入,但常生成语言流畅却与图像事实不符的幻觉内容。本研究发现:当模型最终视觉注意力未聚焦关键图像对象时,幻觉更易发生;而视觉编码器的注意力图更具集中性,能有效抑制幻觉。进一步分析表明,视觉-文本冲突在语言模型中层达到峰值,将编码器注意力注入这些层可显著抑制幻觉。基于此,提出VEGAS——一种简单有效的推理阶段方法,通过自适应地将视觉编码器注意力融入语言模型中层,引导未聚焦关键物体的词元。在多个基准上的实验表明,VEGAS持续实现领先的去幻觉性能。
原文摘要 · Abstract (English)
Large vision-language models (LVLMs) exhibit impressive ability to jointly reason over visual and textual inputs. However, they often produce outputs that are linguistically fluent but factually inconsistent with the visual evidence, i.e., they hallucinate. Despite growing efforts to mitigate such hallucinations, a key question remains: what form of visual attention can effectively suppress hallucinations during decoding? In this work, we provide a simple answer: the vision encoder's own attention map. We show that LVLMs tend to hallucinate when their final visual-attention maps fail to concentrate on key image objects, whereas the vision encoder's more concentrated attention maps substantially reduce hallucinations. To further investigate the cause, we analyze vision-text conflicts during decoding and find that these conflicts peak in the language model's middle layers. Injecting the vision encoder's attention maps into these layers effectively suppresses hallucinations. Building on these insights, we introduce VEGAS, a simple yet effective inference-time method that integrates the vision encoder's attention maps into the language model's mid-layers and adaptively steers tokens which fail to concentrate on key image objects. Extensive experiments across multiple benchmarks demonstrate that VEGAS consistently achieves state-of-the-art performance in reducing hallucinations.
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