DocSeeker: Structured Visual Reasoning with Evidence Grounding for Long Document Understanding

Fuente: arXiv
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Main Authors: Yan, Hao, Liu, Yuliang, Liu, Xingchen, Zhang, Yuyi, Liao, Minghui, Wu, Jihao, Chen, Wei, Bai, Xiang
Format: Preprint
Published: 2026
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author Yan, Hao
Liu, Yuliang
Liu, Xingchen
Zhang, Yuyi
Liao, Minghui
Wu, Jihao
Chen, Wei
Bai, Xiang
author_facet Yan, Hao
Liu, Yuliang
Liu, Xingchen
Zhang, Yuyi
Liao, Minghui
Wu, Jihao
Chen, Wei
Bai, Xiang
contents Existing Multimodal Large Language Models (MLLMs) suffer from significant performance degradation on the long document understanding task as document length increases. This stems from two fundamental challenges: 1) a low Signal-to-Noise Ratio (SNR), with crucial evidence buried in irrelevant pages; and 2) supervision scarcity, as datasets offering only final short answers provide a weak learning signal. In this paper, we address these challenges by proposing a paradigm that requires the model to execute a structured Analysis, Localization and Reasoning workflow. To instill this capability, we design a two-stage training framework: we first perform Supervised Fine-Tuning on high-quality data generated via an efficient knowledge distillation strategy. Subsequently, we employ an Evidence-aware Group Relative Policy Optimization which jointly optimizes for both evidence localization and answer accuracy. Additionally, we introduce a Evidence-Guided Resolution Allocation strategy to mitigate memory constraints of training on multi-pages documents. Extensive experiments demonstrate that DocSeeker achieves superior performance on both in-domain and out-of-domain tasks. We show it robustly generalizes from short-page training to ultra-long documents and is naturally synergistic with visual Retrieval-Augmented Generation systems, serving as a solid foundation for their implementation.
format Preprint
id arxiv_https___arxiv_org_abs_2604_12812
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle DocSeeker: Structured Visual Reasoning with Evidence Grounding for Long Document Understanding
Yan, Hao
Liu, Yuliang
Liu, Xingchen
Zhang, Yuyi
Liao, Minghui
Wu, Jihao
Chen, Wei
Bai, Xiang
Artificial Intelligence
Existing Multimodal Large Language Models (MLLMs) suffer from significant performance degradation on the long document understanding task as document length increases. This stems from two fundamental challenges: 1) a low Signal-to-Noise Ratio (SNR), with crucial evidence buried in irrelevant pages; and 2) supervision scarcity, as datasets offering only final short answers provide a weak learning signal. In this paper, we address these challenges by proposing a paradigm that requires the model to execute a structured Analysis, Localization and Reasoning workflow. To instill this capability, we design a two-stage training framework: we first perform Supervised Fine-Tuning on high-quality data generated via an efficient knowledge distillation strategy. Subsequently, we employ an Evidence-aware Group Relative Policy Optimization which jointly optimizes for both evidence localization and answer accuracy. Additionally, we introduce a Evidence-Guided Resolution Allocation strategy to mitigate memory constraints of training on multi-pages documents. Extensive experiments demonstrate that DocSeeker achieves superior performance on both in-domain and out-of-domain tasks. We show it robustly generalizes from short-page training to ultra-long documents and is naturally synergistic with visual Retrieval-Augmented Generation systems, serving as a solid foundation for their implementation.
title DocSeeker: Structured Visual Reasoning with Evidence Grounding for Long Document Understanding
topic Artificial Intelligence
url https://arxiv.org/abs/2604.12812