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arXiv 2411.19187cs.CL

超越 Logit Lens:利用上下文嵌入实现 VLM 中鲁棒的幻觉检测与定位

Beyond Logit Lens: Contextual Embeddings for Robust Hallucination Detection & Grounding in VLMs

IIT Kanpur(印度理工学院坎普尔分校);IIT Bombay(印度理工学院孟买分校);Adobe Research(奥多比研究院)

Anirudh Phukan, Divyansh, Harshit Kumar Morj, Vaishnavi, Apoorv Saxena, Koustava Goswami

AI总结:

针对 LMM 幻觉问题,本文提出 ContextualLens,利用中间层上下文 token 嵌入实现免训练的鲁棒幻觉检测与精确定位。

摘要:

大型多模态模型(LMMs)的快速发展,通过利用大型语言模型(LLMs)的语言能力并集成特定模态编码器,显著推进了多模态理解。然而,LMMs 受到幻觉困扰,这限制了其可靠性和应用。传统检测和缓解这些幻觉的方法通常涉及高昂的训练成本,或严重依赖外部模型,而近期利用模型内部特征的方法提供了一种有前景的替代方案。本文中,我们批判性评估了最先进的免训练技术 logit lens 在处理泛化视觉幻觉方面的局限性。我们提出 ContextualLens,这是一种改进方法,利用来自 LMMs 中间层的上下文 token 嵌入。该方法在包括动作和 OCR 在内的多种类别上显著改善幻觉检测和定位,同时在空间关系和属性比较等需要上下文理解的任务中表现优异。我们新颖的定位技术可生成高度精确的边界框,推动从零样本对象分割到 grounded Visual Question Answering(基于定位的视觉问答)的转变。我们的贡献为更可靠、更可解释的多模态模型铺平了道路。

英文摘要:

The rapid development of Large Multimodal Models (LMMs) has significantly advanced multimodal understanding by harnessing the language abilities of Large Language Models (LLMs) and integrating modality-specific encoders. However, LMMs are plagued by hallucinations that limit their reliability and adoption. While traditional methods to detect and mitigate these hallucinations often involve costly training or rely heavily on external models, recent approaches utilizing internal model features present a promising alternative. In this paper, we critically assess the limitations of the state-of-the-art training-free technique, the logit lens, in handling generalized visual hallucinations. We introduce ContextualLens, a refined method that leverages contextual token embeddings from middle layers of LMMs. This approach significantly improves hallucination detection and grounding across diverse categories, including actions and OCR, while also excelling in tasks requiring contextual understanding, such as spatial relations and attribute comparison. Our novel grounding technique yields highly precise bounding boxes, facilitating a transition from Zero-Shot Object Segmentation to Grounded Visual Question Answering. Our contributions pave the way for more reliable and interpretable multimodal models.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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