Scaling Beyond Context: A Survey of Multimodal Retrieval-Augmented Generation for Document Understanding
On the map: Retrieval-augmented generation → Multimodal RAG
Abstract (arXiv)
Document understanding is critical for applications from financial analysis to scientific discovery. Current approaches, whether OCR-based pipelines feeding Large Language Models (LLMs) or native Multimodal LLMs (MLLMs), face key limitations: the former loses structural detail, while the latter struggles with context modeling. Retrieval-Augmented Generation (RAG) helps ground models in external data, but documents' multimodal nature, i.e., combining text, tables, charts, and layout, demands a more advanced paradigm: Multimodal RAG. This approach enables holistic retrieval and reasoning across all modalities, unlocking comprehensive document intelligence. Recognizing its importance, this paper presents a systematic survey of Multimodal RAG for document understanding. We propose a taxonomy based on domain, retrieval modality, and granularity, and review advances involving graph structures and agentic frameworks. We also summarize key datasets, benchmarks, applications and industry deployment, and highlight open challenges in efficiency, fine-grained representation, and robustness, providing a roadmap for future progress in document AI.
Key facts. Cited by 9 papers in the map (data through 7 Oct 2026). Placed in Multimodal RAG, one of 15 directions in Retrieval-augmented generation. Builds on 99 of its 181 references that are in the map. First posted on arXiv 17 Oct 2025.
Builds on
99 of 181 references.
Closest ancestors · 16
Same direction, newest first
- 2025UNIDOC-BENCH: A Unified Benchmark for Document-Centric Multimodal RAG4 Oct
- 2025Enhancing Document VQA Models via Retrieval-Augmented Generation26 Aug
- 2025M2IO-R1: An Efficient RL-Enhanced Reasoning Framework for Multimodal Retrieval Augmented Multimodal Generation8 Aug
- 2025mKG-RAG: Leveraging Multimodal Knowledge Graphs in Retrieval-Augmented Generation for Knowledge-intensive VQA7 Aug
- 2025Vision-Guided Chunking Is All You Need: Enhancing RAG with Multimodal Document Understanding19 Jun
- 2025CoRe-MMRAG: Cross-Source Knowledge Reconciliation for Multimodal RAG3 Jun
- 2025VRAG-RL: Empower Vision-Perception-Based RAG for Visually Rich Information Understanding via Iterative Reasoning with Reinforcement Learning28 May
- 2025A Multi-Granularity Retrieval Framework for Visually-Rich Documents1 May
- 2025VDocRAG: Retrieval-Augmented Generation over Visually-Rich Documents14 Apr
- 2025CollEX -- A Multimodal Agentic RAG System Enabling Interactive Exploration of Scientific Collections10 Apr
- 2025A Survey of Multimodal Retrieval-Augmented Generation26 Mar
- 2025ViDoRAG: Visual Document Retrieval-Augmented Generation via Dynamic Iterative Reasoning Agents25 Feb
4 more
- 2024VisDoM: Multi-Document QA with Visually Rich Elements Using Multimodal Retrieval-Augmented Generation14 Dec
- 2024M3DocRAG: Multi-modal Retrieval is What You Need for Multi-page Multi-document Understanding7 Nov
- 2024Beyond Text: Optimizing RAG with Multimodal Inputs for Industrial Applications29 Oct
- 2024VisRAG: Vision-based Retrieval-augmented Generation on Multi-modality Documents14 Oct
Other references · 83
- 2018BERT: Pre-training of Deep Bidirectional Transformers for Language Understandingcited by 40,204
- 2019RoBERTa: A Robustly Optimized BERT Pretraining Approachcited by 13,266
- 2020Retrieval-Augmented Generation for Knowledge-Intensive NLP Taskscited by 9,160
- 2016SQuAD: 100,000+ Questions for Machine Comprehension of Textcited by 4,115
- 2023Grounding DINO: Marrying DINO with Grounded Pre-Training for Open-Set Object Detectioncited by 3,274
- 2022ChartQA: A Benchmark for Question Answering about Charts with Visual and Logical Reasoningcited by 1,449
- 2024From Local to Global: A Graph RAG Approach to Query-Focused Summarizationcited by 1,411
- 2020DocVQA: A Dataset for VQA on Document Imagescited by 1,288
- 2022Text Embeddings by Weakly-Supervised Contrastive Pre-trainingcited by 1,216
- 2020ColBERT: Efficient and Effective Passage Search via Contextualized Late Interaction over BERTcited by 1,160
- 2023Towards General Text Embeddings with Multi-stage Contrastive Learningcited by 705
- 2015An End-to-End Trainable Neural Network for Image-based Sequence Recognition and Its Application to Scene Text Recognitioncited by 519
38 more
- 2021TAT-QA: A Question Answering Benchmark on a Hybrid of Tabular and Textual Content in Financecited by 402
- 2020Understanding the Behaviour of Contrastive Losscited by 397
- 2019Scene Text Visual Question Answeringcited by 327
- 2024Graph Retrieval-Augmented Generation: A Surveycited by 320
- 2019PlotQA: Reasoning over Scientific Plotscited by 317
- 2021TransVG: End-to-End Visual Grounding with Transformerscited by 269
- 2021DocFormer: End-to-End Transformer for Document Understandingcited by 254
- 2025Agentic Retrieval-Augmented Generation: A Survey on Agentic RAGcited by 242
- 2024mPLUG-DocOwl 1.5: Unified Structure Learning for OCR-free Document Understandingcited by 220
- 2024Mitigating Hallucinations in Large Vision-Language Models with Instruction Contrastive Decodingcited by 198
- 2023SlideVQA: A Dataset for Document Visual Question Answering on Multiple Imagescited by 175
- 2024MMLongBench-Doc: Benchmarking Long-context Document Understanding with Visualizationscited by 174
- 2021VisualMRC: Machine Reading Comprehension on Document Imagescited by 150
- 2023Document Understanding Dataset and Evaluation (DUDE)cited by 132
- 2024mPLUG-DocOwl2: High-resolution Compressing for OCR-free Multi-page Document Understandingcited by 113
- 2024Unifying Multimodal Retrieval via Document Screenshot Embeddingcited by 107
- 2022Unified Pretraining Framework for Document Understandingcited by 85
- 2025A Survey of Graph Retrieval-Augmented Generation for Customized Large Language Modelscited by 85
- 2023Retrieving Multimodal Information for Augmented Generation: A Surveycited by 84
- 2022Towards Complex Document Understanding By Discrete Reasoningcited by 82
- 2024SPIQA: A Dataset for Multimodal Question Answering on Scientific Paperscited by 75
- 2024LongDocURL: a Comprehensive Multimodal Long Document Benchmark Integrating Understanding, Reasoning, and Locatingcited by 70
- 2024Sufficient Context: A New Lens on Retrieval Augmented Generation Systemscited by 69
- 2025MDocAgent: A Multi-Modal Multi-Agent Framework for Document Understandingcited by 66
- 2024Retrieval Augmented Generation (RAG) and Beyond: A Comprehensive Survey on How to Make your LLMs use External Data More Wiselycited by 65
- 2024Typos that Broke the RAG's Back: Genetic Attack on RAG Pipeline by Simulating Documents in the Wild via Low-level Perturbationscited by 64
- 2024Think-on-Graph 2.0: Deep and Faithful Large Language Model Reasoning with Knowledge-guided Retrieval Augmented Generationcited by 63
- 2024VLSBench: Unveiling Visual Leakage in Multimodal Safetycited by 59
- 2020FQuAD: French Question Answering Datasetcited by 58
- 2025SmolDocling: An ultra-compact vision-language model for end-to-end multi-modal document conversioncited by 51
- 2024MAIN-RAG: Multi-Agent Filtering Retrieval-Augmented Generationcited by 43
- 2025Adversarial Attacks against Closed-Source MLLMs via Feature Optimal Alignmentcited by 42
- 2024UDA: A Benchmark Suite for Retrieval Augmented Generation in Real-world Document Analysiscited by 40
- 2025MetaEmbed: Scaling Multimodal Retrieval at Test-Time with Flexible Late Interactioncited by 36
- 2024Boosting Transferability in Vision-Language Attacks via Diversification along the Intersection Region of Adversarial Trajectorycited by 35
- 2024AI Hallucinations: A Misnomer Worth Clarifyingcited by 34
- 2025LessLeak-Bench: A First Investigation of Data Leakage in LLMs Across 83 Software Engineering Benchmarkscited by 34
- 2020A Survey of Deep Learning Approaches for OCR and Document Understandingcited by 32
50 most cited of 83 All 83 (JSON)
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Citing papers per year: 2026: 9.
9 papers.
- 2026Sculpting the Vector Space: Towards Efficient Multi-Vector Visual Document Retrieval via Prune-then-Merge Frameworkcited by 8
- 2026Unlocking Multimodal Document Intelligence: From Current Triumphs to Future Frontiers of Visual Document Retrievalcited by 8
- 2026CausalEmbed: Auto-Regressive Multi-Vector Generation in Latent Space for Visual Document Embeddingcited by 6
- 2026MINER: Mining Multimodal Internal Representation for Efficient Retrievalcited by 2
- 2026Very Efficient Listwise Multimodal Reranking for Long Documentscited by 1
- 2026MM-BizRAG: Rethinking Multimodal Retrieval-Augmented Generation for General Purpose Enterprise Q&Acited by 1
- 2026FLOWREADER: Min-Cost Flow Optimization for Multi-Modal Long Document Q&Acited by 1
- 2026GVD: Governed Versioning and Deduplication for Document Repositoriescited by 0
- 2026Amnesia by Design, Memory By Necessity: Persistent State for Document Intelligencecited by 0
- 2026Amnesia by Design, Memory By Necessity: Persistent State for Document Intelligence25 Sep 2026
- 2026GVD: Governed Versioning and Deduplication for Document Repositories15 Sep 2026
- 2026FLOWREADER: Min-Cost Flow Optimization for Multi-Modal Long Document Q&A5 Jun 2026
- 2026MM-BizRAG: Rethinking Multimodal Retrieval-Augmented Generation for General Purpose Enterprise Q&A2 Jun 2026
- 2026Very Efficient Listwise Multimodal Reranking for Long Documents12 May 2026
- 2026MINER: Mining Multimodal Internal Representation for Efficient Retrieval7 May 2026
- 2026Unlocking Multimodal Document Intelligence: From Current Triumphs to Future Frontiers of Visual Document Retrieval23 Feb 2026
- 2026Sculpting the Vector Space: Towards Efficient Multi-Vector Visual Document Retrieval via Prune-then-Merge Framework23 Feb 2026
- 2026CausalEmbed: Auto-Regressive Multi-Vector Generation in Latent Space for Visual Document Embedding29 Jan 2026
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