Locate-then-Sparsify: Attribution Guided Sparse Strategy for Visual Hallucination Mitigation

Fuente: arXiv
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Main Authors: Dang, Tiantian, Bi, Chao, Shen, Shufan, Liu, Jinzhe, Huang, Qingming, Wang, Shuhui
Format: Preprint
Published: 2026
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author Dang, Tiantian
Bi, Chao
Shen, Shufan
Liu, Jinzhe
Huang, Qingming
Wang, Shuhui
author_facet Dang, Tiantian
Bi, Chao
Shen, Shufan
Liu, Jinzhe
Huang, Qingming
Wang, Shuhui
contents Despite the significant advancements in Large Vision-Language Models (LVLMs), their tendency to generate hallucinations undermines reliability and restricts broader practical deployment. Among the hallucination mitigation methods, feature steering emerges as a promising approach that reduces erroneous outputs in LVLMs without increasing inference costs. However, current methods apply uniform feature steering across all layers. This heuristic strategy ignores inter-layer differences, potentially disrupting layers unrelated to hallucinations and ultimately leading to performance degradation on general tasks. In this paper, we propose Locate-Then-Sparsify for Feature Steering (LTS-FS), a plug-and-play framework which controls the steering intensity according to the hallucination relevance of each layer. We first construct a dataset comprising token-level and sentence-level hallucination cases. Based on this dataset, we introduce an attribution method based on causal interventions to quantify the hallucination relevance of each layer. With the attribution scores across layers, we propose a layerwise strategy that converts these scores into feature steering intensities for individual layers, enabling more precise adjustments specifically on hallucination-relevant layers. Extensive experiments across multiple LVLMs and benchmarks demonstrate that LTS-FS effectively mitigates hallucination while preserving strong performance. Codes are available at https://github.com/huttersadan/LTS-FS.
format Preprint
id arxiv_https___arxiv_org_abs_2603_16284
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Locate-then-Sparsify: Attribution Guided Sparse Strategy for Visual Hallucination Mitigation
Dang, Tiantian
Bi, Chao
Shen, Shufan
Liu, Jinzhe
Huang, Qingming
Wang, Shuhui
Computer Vision and Pattern Recognition
Machine Learning
Despite the significant advancements in Large Vision-Language Models (LVLMs), their tendency to generate hallucinations undermines reliability and restricts broader practical deployment. Among the hallucination mitigation methods, feature steering emerges as a promising approach that reduces erroneous outputs in LVLMs without increasing inference costs. However, current methods apply uniform feature steering across all layers. This heuristic strategy ignores inter-layer differences, potentially disrupting layers unrelated to hallucinations and ultimately leading to performance degradation on general tasks. In this paper, we propose Locate-Then-Sparsify for Feature Steering (LTS-FS), a plug-and-play framework which controls the steering intensity according to the hallucination relevance of each layer. We first construct a dataset comprising token-level and sentence-level hallucination cases. Based on this dataset, we introduce an attribution method based on causal interventions to quantify the hallucination relevance of each layer. With the attribution scores across layers, we propose a layerwise strategy that converts these scores into feature steering intensities for individual layers, enabling more precise adjustments specifically on hallucination-relevant layers. Extensive experiments across multiple LVLMs and benchmarks demonstrate that LTS-FS effectively mitigates hallucination while preserving strong performance. Codes are available at https://github.com/huttersadan/LTS-FS.
title Locate-then-Sparsify: Attribution Guided Sparse Strategy for Visual Hallucination Mitigation
topic Computer Vision and Pattern Recognition
Machine Learning
url https://arxiv.org/abs/2603.16284