Instruction Lens Score: Your Instruction Contributes a Powerful Object Hallucination Detector for Multimodal Large Language Models

Fuente: arXiv
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Main Authors: Lai, Runhe, Lu, Xinhua, Wu, Yanqi, Ye, Jinlun, Yu, Weijiang, Wang, Ruixuan
Format: Preprint
Published: 2026
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author Lai, Runhe
Lu, Xinhua
Wu, Yanqi
Ye, Jinlun
Yu, Weijiang
Wang, Ruixuan
author_facet Lai, Runhe
Lu, Xinhua
Wu, Yanqi
Ye, Jinlun
Yu, Weijiang
Wang, Ruixuan
contents Multimodal large language models (MLLMs) have achieved remarkable progress, yet the object hallucination remains a critical challenge for reliable deployment. In this paper, we present an in-depth analysis of instruction token embeddings and reveal that they implicitly encode visual information while effectively filtering erroneous information introduced by misleading visual embeddings. Building on this insight, we propose the Instruction Lens Score (InsLen), which combines a Calibrated Local Score with a Context Consistency Score that measures context consistency of the object tokens. The proposed approach serves as a plug-and-play object hallucination detector without relying on auxiliary models or additional training. Extensive experiments across multiple benchmarks and diverse MLLM architectures demonstrate that InsLen consistently outperforms existing hallucination detection methods, highlighting its effectiveness and robustness. The code is available at https://github.com/Fraserlairh/Instruction-Lens-Score.
format Preprint
id arxiv_https___arxiv_org_abs_2605_12258
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Instruction Lens Score: Your Instruction Contributes a Powerful Object Hallucination Detector for Multimodal Large Language Models
Lai, Runhe
Lu, Xinhua
Wu, Yanqi
Ye, Jinlun
Yu, Weijiang
Wang, Ruixuan
Machine Learning
Multimodal large language models (MLLMs) have achieved remarkable progress, yet the object hallucination remains a critical challenge for reliable deployment. In this paper, we present an in-depth analysis of instruction token embeddings and reveal that they implicitly encode visual information while effectively filtering erroneous information introduced by misleading visual embeddings. Building on this insight, we propose the Instruction Lens Score (InsLen), which combines a Calibrated Local Score with a Context Consistency Score that measures context consistency of the object tokens. The proposed approach serves as a plug-and-play object hallucination detector without relying on auxiliary models or additional training. Extensive experiments across multiple benchmarks and diverse MLLM architectures demonstrate that InsLen consistently outperforms existing hallucination detection methods, highlighting its effectiveness and robustness. The code is available at https://github.com/Fraserlairh/Instruction-Lens-Score.
title Instruction Lens Score: Your Instruction Contributes a Powerful Object Hallucination Detector for Multimodal Large Language Models
topic Machine Learning
url https://arxiv.org/abs/2605.12258