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Main Authors: Kim, Jiwan, Kim, Kibum, Kim, Wonjoong, Lee, Byung-Kwan, Park, Chanyoung
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2604.12358
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author Kim, Jiwan
Kim, Kibum
Kim, Wonjoong
Lee, Byung-Kwan
Park, Chanyoung
author_facet Kim, Jiwan
Kim, Kibum
Kim, Wonjoong
Lee, Byung-Kwan
Park, Chanyoung
contents Recently, visual token pruning has been studied to handle the vast number of visual tokens in Multimodal Large Language Models. However, we observe that while existing pruning methods perform reliably on simple visual understanding, they struggle to effectively generalize to complex visual reasoning tasks, a critical gap underexplored in previous studies. Through a systematic analysis, we identify Relevant Visual Information Shift (RVIS) during decoding as the primary failure driver. To address this, we propose Decoding-stage Shift-aware Token Pruning (DSTP), a training-free add-on framework that enables existing pruning methods to align visual tokens with shifting reasoning requirements during the decoding stage. Extensive experiments demonstrate that DSTP significantly mitigates performance degradation of pruning methods in complex reasoning tasks, while consistently yielding performance gains even across visual understanding benchmarks. Furthermore, DSTP demonstrates effectiveness across diverse state-of-the-art architectures, highlighting its generalizability and efficiency with minimal computational overhead.
format Preprint
id arxiv_https___arxiv_org_abs_2604_12358
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Why and When Visual Token Pruning Fails? A Study on Relevant Visual Information Shift in MLLMs Decoding
Kim, Jiwan
Kim, Kibum
Kim, Wonjoong
Lee, Byung-Kwan
Park, Chanyoung
Computer Vision and Pattern Recognition
Recently, visual token pruning has been studied to handle the vast number of visual tokens in Multimodal Large Language Models. However, we observe that while existing pruning methods perform reliably on simple visual understanding, they struggle to effectively generalize to complex visual reasoning tasks, a critical gap underexplored in previous studies. Through a systematic analysis, we identify Relevant Visual Information Shift (RVIS) during decoding as the primary failure driver. To address this, we propose Decoding-stage Shift-aware Token Pruning (DSTP), a training-free add-on framework that enables existing pruning methods to align visual tokens with shifting reasoning requirements during the decoding stage. Extensive experiments demonstrate that DSTP significantly mitigates performance degradation of pruning methods in complex reasoning tasks, while consistently yielding performance gains even across visual understanding benchmarks. Furthermore, DSTP demonstrates effectiveness across diverse state-of-the-art architectures, highlighting its generalizability and efficiency with minimal computational overhead.
title Why and When Visual Token Pruning Fails? A Study on Relevant Visual Information Shift in MLLMs Decoding
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2604.12358