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Document intelligence

Documents bind language to layout and graphics. This chapter separates recognition, grounding, reasoning, schema decoding, and exact structural validity.

19 maintained papers · literature reviewed through 2 October 2026

Documents bind words to two-dimensional layout, reading order, tables, figures, charts, and schemas. OCR pipelines, OCR-free encoders, screenshot parsing, and multimodal LLMs differ in where recognition errors enter and how structure is represented. Evaluation must isolate text reading, layout grounding, reasoning, and exact serialization.

Prerequisite contract

How the field developed

  1. 2019–2020

    Text-aware VQA

    OCR-VQA, TextVQA, and M4C expose reading and copying text from natural scenes and images.

    Key papers in this section

    OrderPrimary paper · authors · year · venue/statusCore idea and why to read itOfficial resources
    01.01OCR-VQA: Visual Question Answering by Reading Text in Images2019 · ICDAR · Peer reviewedAnand Mishra et al.OCR-VQA–200K turns 207,572 book-cover images and their catalog metadata into 1,002,146 question-answer pairs about titles, authors, genres, years, and editions. Questions begin from templates, receive human paraphrases, and are paired with metadata-derived answers; images are randomly split before the accompanying OCR-plus-VQA baseline is trained. The central contribution is a large reading-oriented benchmark, not the claim that its baseline solves open-ended text reasoning. Memory line: cover plus metadata, template plus paraphrase, image split, OCR bottleneck.—
    01.02Towards VQA Models That Can Read2019 · CVPR · Peer reviewedAmanpreet Singh et al.TextVQA is an open-ended benchmark for questions whose answer requires reading text in an everyday photograph and often reasoning about that text. It contains 45,336 questions on 28,408 Open Images v3 images, with ten human answers per question and image-disjoint train, validation, and test partitions. The accompanying LoRRA baseline adds OCR-token attention and a dynamic copy space to a conventional VQA system, but model architecture is evidence about the benchmark—not the benchmark itself. Memory line: look at objects, read scene text, reason, then generate or copy.—
    01.03Iterative Answer Prediction With Pointer-Augmented Multimodal Transformers for TextVQA2020 · CVPR · Peer reviewedRonghang Hu et al.M4C answers questions about text inside an image by jointly contextualizing question tokens, detected visual objects, and OCR tokens, then generating a multiword answer with a pointer-augmented autoregressive decoder. At every step it can emit a frequent word from a fixed 5,000-word answer vocabulary or copy one of the image's OCR tokens. This changes TextVQA from one-shot selection of one answer or one OCR token into conditional sequence generation. Memory line: embed three modalities, self-attend once, copy or generate repeatedly.—

    Work: Trace OCR candidates, spatial features, copying, vocabulary decoding, and answer normalization.

    Exit evidence: Separate OCR recall, grounding, reasoning, and answer parsing errors.

  2. 2020–2022

    Layout-aware document pretraining

    LayoutLM adds two-dimensional positions to OCR tokens; LayoutLMv2 adds page pixels; DocFormer instead uses shared spatial encodings and multimodal self-attention; LayoutLMv3 unifies masked text and image modelling with word–patch alignment.

    Key papers in this section

    OrderPrimary paper · authors · year · venue/statusCore idea and why to read itOfficial resources
    02.01LayoutLM: Pre-training of Text and Layout for Document Image Understanding2020 · KDD · Peer reviewedYiheng Xu, Minghao Li, Lei Cui, Shaohan Huang, Furu Wei, and Ming ZhouLayoutLM extends BERT-style document pretraining by representing each OCR word with both its text embedding and its normalized two-dimensional bounding-box coordinates. Masked visual-language modeling then learns words in the context of neighboring language and page geometry; an optional Faster R-CNN image feature adds appearance during fine-tuning. The central insight is that document meaning depends on where text appears, not only on token order.Official implementation and models
    02.02LayoutLMv2: Multi-modal Pre-training for Visually-rich Document Understanding2021 · ACL-IJCNLP · Peer reviewedYang Xu, Yiheng Xu, Tengchao Lv, Lei Cui, Furu Wei, Guoxin Wang, Yijuan Lu, Dinei Florencio, Cha Zhang, Wanxiang Che, Min Zhang, and Lidong ZhouLayoutLMv2 jointly encodes OCR text, two-dimensional bounding boxes, and page pixels. Text tokens receive ordinary sequence and 2D layout embeddings; a CNN-FPN converts the document image into visual tokens; a multimodal Transformer mixes both streams with spatial-aware attention. Pretraining masks text, tests whether text lines align with image regions, and classifies whether an image and text page match, forcing the model to learn content, geometry, and appearance together.Official implementation
    02.03DocFormer: End-to-End Transformer for Document Understanding2021 · ICCV · Peer reviewedSrikar Appalaraju, Bhavan Jasani, Bhargava Urala Kota, Yusheng Xie, and R. ManmathaDocFormer is an encoder-only document Transformer that keeps visual, language, and spatial streams distinct while making them interact at every layer. ResNet page features and OCR word embeddings each attend with modality-specific projections; shared spatial-attention weights tie their page geometry, and the two attended streams are added into a common hidden state. Multimodal language, image-reconstruction, and image–text matching objectives force the representation to use more than text alone.—
    02.04LayoutLMv3: Pre-training for Document AI with Unified Text and Image Masking2022 · ACM Multimedia · Peer reviewedYupan Huang, Tengchao Lv, Lei Cui, Yutong Lu, and Furu WeiLayoutLMv3 simplifies multimodal document pretraining by representing page images as linearly projected patches and training text and image with parallel masking objectives in one Transformer. Masked language modeling recovers OCR words, masked image modeling predicts discrete visual tokens, and word–patch alignment asks whether the image patch corresponding to a word was masked. The result is one backbone intended for both text-centric extraction and image-centric layout analysis.Official implementation and models

    Work: Hold OCR, pages, downstream heads, and splits fixed while ablating text, pixels, two-dimensional coordinates, attention interface, and pretraining losses.

    Exit evidence: Attribute each document gain to text, layout, pixels, or objective rather than to a model name.

  3. 2021–2022

    Document, table, and chart benchmarks

    DocVQA and ChartQA test question answering under distinct evidence contracts; PubTables-1M supplies canonicalized table detection, structure-recognition, and functional-analysis labels at scale.

    Key papers in this section

    OrderPrimary paper · authors · year · venue/statusCore idea and why to read itOfficial resources
    03.01DocVQA: A Dataset for VQA on Document Images2021 · WACV · Peer reviewedMinesh Mathew et al.DocVQA reframes document understanding as purpose-driven question answering: given a scanned document image and a natural-language question, return a text span found on that page. Its 50,000 manually annotated questions cover 12,767 page images sampled from 6,071 historical industry documents. The benchmark sits between visual question answering and extractive reading comprehension because success requires OCR, layout and structure, question-conditioned retrieval, and exact answer extraction rather than generic document classification.—
    03.02PubTables-1M: Towards Comprehensive Table Extraction From Unstructured Documents2022 · CVPR · Peer reviewedBrandon Smock, Rohith Pesala, and Robin AbrahamPubTables-1M is a large scientific-document resource for table detection, table structure recognition, and functional analysis. Its defining contribution is not only scale—about 948,000 tables—but canonicalization: logically equivalent yet differently authored markup is transformed into one consistent grid representation, with cell content, topology, locations, row/column structure, headers, projected row headers, and spanning cells. The resource makes annotation consistency measurable rather than assuming source markup is ground truth.Official dataset, code, and Table Transformer models
    03.03ChartQA: A Benchmark for Question Answering about Charts with Visual and Logical Reasoning2022 · Findings of ACL · Peer reviewedAhmed Masry et al.ChartQA is a real-world chart-question benchmark built to require both visual reference resolution and logical or arithmetic reasoning. Its human track contains 9,608 questions over 4,804 charts collected from Statista, Pew Research, Our World in Data, and OECD; a second track adds 23,111 machine-generated questions over 17,141 Statista charts. The paper evaluates both an oracle setting with the underlying data table and a realistic pipeline that must extract that table from the chart image, making perception error and reasoning error separately visible.—

    Work: Separate OCR, layout, table topology, graphical marks, arithmetic, and answer normalization without changing evaluation data.

    Exit evidence: Report structural validity and evidence grounding separately from final string accuracy.

  4. 2022–2026

    OCR-free parsing, visual retrieval, and harder charts

    Donut and Pix2Struct decode structures from pixels; ColPali retrieves page images with token-level late interaction; ChartQAPro and PolyChartQA broaden chart complexity and evaluation.

    Key papers in this section

    OrderPrimary paper · authors · year · venue/statusCore idea and why to read itOfficial resources
    04.01OCR-Free Document Understanding Transformer2022 · ECCV · Peer reviewedGeewook Kim et al.Donut treats document understanding as direct image-to-sequence generation: a Swin image encoder converts the page into visual tokens and a BART-style autoregressive decoder emits a task-specific structured string. It removes the external OCR engine and its bounding boxes from the inference path, so recognition and semantic parsing are optimized together. “OCR-free” describes deployment; part of pre-training still uses pseudo text produced by a commercial OCR system.Official code
    04.02Pix2Struct: Screenshot Parsing as Pretraining for Visual Language Understanding2023 · ICML · Peer reviewedKenton Lee et al.Pix2Struct pre-trains an image encoder–text decoder by masking regions of web-page screenshots and asking it to generate the corresponding simplified HTML subtree. The page remains pixels: no OCR tokens, DOM tree, or boxes are supplied downstream. A variable-resolution patch sequence preserves aspect ratio under a fixed patch budget, letting one model process documents, charts, UI screenshots, and natural images.—
    04.03ColPali: Efficient Document Retrieval with Vision Language Models2025 · ICLR · Peer reviewedManuel Faysse, Hugues Sibille, Tony Wu, Bilel Omrani, Gautier Viaud, Céline Hudelot, and Pierre ColomboColPali retrieves a document page directly from its rendered image instead of first extracting OCR text, layout blocks, tables, and captions. PaliGemma contextualizes 1,024 visual patch tokens and query text tokens in a shared language-conditioned space; a learned projection keeps one 128-dimensional vector per patch or query token. At search time, ColBERT-style late interaction lets every query token choose its best-matching page patch, then sums those maxima. The page index is computed offline, so fine-grained query–patch matching remains fast enough for retrieval while preserving text, layout, figures, and tables.Official code · Official ViDoRe models and benchmark
    04.04ChartQAPro: A More Diverse and Challenging Benchmark for Chart Question Answering2025 · Findings of ACL · Peer reviewedAhmed Masry et al.ChartQAPro is a test-only stress benchmark with 1,341 static chart images and 1,948 human-written, human-verified questions. It replaces the narrow source and question distribution of earlier chart QA with 99 represented online sources, dashboards, infographics, multi-chart layouts, optional context paragraphs, five main question categories, and an orthogonal set of unanswerable cases. The headline is not a new model: it is a harder measurement surface for perception, instruction following, and quantitative reasoning.—
    04.05POLYCHARTQA: Benchmarking Large Vision-Language Models with Multilingual Chart Question Answering2026 · ACL · Peer reviewedYichen Xu et al.PolyChartQA is a multilingual chart-QA benchmark and companion training corpus that renders chart text, structured data, and questions in ten languages across sixteen chart types. PolyChartQA-Test contains 22,606 chart images and 26,151 QA pairs; PolyChartQA-Train contains 131,515 images and 751,363 QA pairs. Its key scientific question is whether a model that can reason over an English chart still succeeds when the chart itself and the question use other scripts and languages.—

    Work: Compare OCR-pipeline, end-to-end, and visual-retrieval models under scan, font, language, layout, and schema shifts.

    Exit evidence: Report retrieval relevance, exact structure validity, and field-level error under their separate contracts.

  5. 2026

    Open OCR with structural visual tests

    olmOCR combines large-scale supervised document training with reinforcement learning over visual unit tests and an exact structural benchmark; selected tests do not establish complete semantic correctness.

    Key papers in this section

    OrderPrimary paper · authors · year · venue/statusCore idea and why to read itOfficial resources
    05.01The olmOCR Project: Building Fully Open OCR using VLMs2026 · ACL System Demonstrations · Peer reviewedJake Poznanski, Kyle Lo, and Luca SoldainiPeer-reviewed ACL 2026 system demonstration and Best Demonstration Paper award recipient.olmOCR is an open PDF-to-structured-text system built around a 7B vision-language model. PDF pages are rendered as images, paired with document metadata and prompts, decoded into reading-order text with layout and table structure, and validated before assembly. Training combines supervised examples from roughly 260K pages with reinforcement learning over visual unit tests, while olmOCR-Bench checks selected structural properties on about 1.4K documents and 7K tests.Official implementation and models

    Work: Run olmOCR and OCR-pipeline baselines on pinned document images with exact structural tests for reading order, tables, equations, lists, headers, and serialization, plus blinded semantic error review.

    Exit evidence: Report training and test provenance, unit-test coverage, exact and field-level scores, language/layout strata, compute, parser tolerance, contamination checks, and errors not expressible by the tests.

  6. 2025–2026

    Reasoning budgets, executable outputs and scientific edits

    Test-time scaling studies how extra reasoning changes perception and mathematics; EmbedCopilot checks whether plausible embedded-system answers actually execute; GRADE requires domain-correct and readable image edits. Together they motivate measuring compute, implementation success and constraint satisfaction rather than judging prose alone.

    Key papers in this section

    OrderPrimary paper · authors · year · venue/statusCore idea and why to read itOfficial resources
    06.01GRADE: Benchmarking Discipline-Informed Reasoning in Image Editing2026 · ECCV · Accepted · proceedings pendingMingxin Liu, Ziqian Fan, Zhaokai Wang, Leyao Gu, Zirun Zhu, Yiguo He, Yuchen Yang, Changyao Tian, Xiangyu Zhao, Ning Liao, Shaofeng Zhang, Qibing Ren, Zhihang Zhong, Xuanhe Zhou, Junchi Yan, and Xue YangECCV 2026 Spotlight verified in the official Vision-Language Models & Visual Foundation Models session; manuscript #2706 checked on 2026-09-12. Publisher version of record was not independently verified.GRADE evaluates whether an image editor can use disciplinary knowledge to make a scientifically correct visual change, preserve relevant context, and keep the result logically readable. Its 520 image–instruction–reference triplets span ten academic disciplines. The central distinction is between drawing a plausible image and rendering the right answer to a domain-specific problem.ECCV Spotlight program · Conference manuscript · Official project or implementation

    Work: What external test can falsify a persuasive explanation: a perception answer, a running circuit, or a scientifically valid image?

    Exit evidence: More tokens can reduce perceptual accuracy. Judge scores and physical execution use different protocols; GRADE strict accuracy is a conjunction of three maxima, not its mean reasoning score.

  7. 2025–2026

    Document understanding needs component and layout-aware evaluation

    OmniDocBench separates end-to-end parsing from text, formula, table and reading-order evaluation across document types. Matching rules and ignored elements matter as much as the leaderboard. The original paper and later benchmark releases must be cited as distinct versions.

    Key papers in this section

    OrderPrimary paper · authors · year · venue/statusCore idea and why to read itOfficial resources
    07.01OmniDocBench: Benchmarking Diverse PDF Document Parsing with Comprehensive Annotations2025 · CVPR · Peer reviewedLinke Ouyang et al.Review pins the CVPR 2025 paper and supplement (981 pages). The live repository has later data, matching and scoring revisions; its current leaderboard is not the paper benchmark.OmniDocBench evaluates document parsing as structured extraction rather than just readable OCR. It separates text, tables, formulas and reading order, then breaks results down by page type and visual attributes. The paper benchmark contains 981 pages; newer repository versions are separate evaluation configurations.Proceedings PDF · Supplement · Author code and version history

    Work: Does a better overall parser still fail on the document type or element your application needs?

    Exit evidence: The reviewed CVPR paper uses 981 pages; newer releases change coverage and scoring. Parsing fidelity does not establish factual, clinical or scientific correctness of a generated answer.

  8. 2026

    Retrieve evidence inside the answer-generating model

    URaG uses early shared MLLM states for ColBERT-style page ranking, retains selected page tokens and all query tokens, then continues deeper generation. Its staged retrieval and LoRA training connect evidence selection to answer modeling without a separate retrieval backbone.

    Key papers in this section

    OrderPrimary paper · authors · year · venue/statusCore idea and why to read itOfficial resources
    08.01URaG: Unified Retrieval and Generation in Multimodal LLMs for Efficient Long Document Understanding2026 · AAAI · Peer reviewedYongxin Shi, Jiapeng Wang, Zeyu Shan, Dezhi Peng, Zening Lin, and Lianwen JinAAAI 2026 proceedings paper; FLOP reductions are not measured latency. Code repository states non-commercial research use.URaG makes page retrieval an internal operation of a multimodal language model. Early layers contextualize the full document and question; a lightweight head ranks pages, and deeper layers see only selected page tokens plus the query. This preserves fine-grained tokens on retained pages while removing irrelevant pages, rather than compressing every page uniformly or running an independent external retriever.Proceedings PDF · Author code and usage terms

    Work: Where should evidence be selected so detailed tokens survive without paying full deep-layer cost?

    Exit evidence: Joint training always keeps ground-truth evidence pages; inference must select them. FLOP tests extend documents by duplication and are not latency measurements. Multi-page reasoning and WSI transfer need separate evidence.

Research branches

Layout and document structure

How are reading order, two-dimensional positions, fields, tables, and hierarchy represented?

LayoutLM: Pre-training of Text and Layout for Document Image Understanding · LayoutLMv2: Multi-modal Pre-training for Visually-rich Document Understanding · DocFormer: End-to-End Transformer for Document Understanding · LayoutLMv3: Pre-training for Document AI with Unified Text and Image Masking · PubTables-1M: Towards Comprehensive Table Extraction From Unstructured Documents · DocVQA: A Dataset for VQA on Document Images · OCR-Free Document Understanding Transformer · Pix2Struct: Screenshot Parsing as Pretraining for Visual Language Understanding

Comparison table

Document-system interfaces
Family or stageScientific distinctionMain riskAnchors
OCR and layout-aware pipelineRecognizes text first, then combines tokens and two-dimensional boxes, optionally with page pixels and shared multimodal attention.Recognition and box errors cascade; OCR can still discard non-text evidence.2020 · 2020 · 2021 · 2021 · 2022 · 2021
Table detection and structurePredicts table regions, rows, columns, headers, and spanning cells under a canonical topology.Dataset conversion and canonicalization can dominate apparent structural accuracy.2022
OCR-free generationMaps pixels directly to serialized target structures.Decoder validity and memorized templates hide recognition errors.2022 · 2023
OCR-free visual retrievalEmbeds each page as multiple visual-language vectors and scores query–page token interactions.Storage, corpus construction, and relevance labels can dominate retrieval comparisons.2025
Chart reasoningCombines graphical perception, data extraction, and operations.Template and synthetic-chart shortcuts inflate reasoning scores.2022 · 2025
Open OCR with structural visual testsolmOCR combines large-scale supervised document parsing with reinforcement learning over visual unit tests and an exact structural benchmark.Optimizing a selected test suite can miss semantically wrong text, unsupported layouts, language failures, or tolerance-sensitive serialization errors.2026
Reasoning budgets, executable outputs and scientific editsTest-time scaling studies how extra reasoning changes perception and mathematics; EmbedCopilot checks whether plausible embedded-system answers actually execute; GRADE requires domain-correct and readable image edits. Together they motivate measuring compute, implementation success and constraint satisfaction rather than judging prose alone.More tokens can reduce perceptual accuracy. Judge scores and physical execution use different protocols; GRADE strict accuracy is a conjunction of three maxima, not its mean reasoning score.2026
Document understanding needs component and layout-aware evaluationOmniDocBench separates end-to-end parsing from text, formula, table and reading-order evaluation across document types. Matching rules and ignored elements matter as much as the leaderboard. The original paper and later benchmark releases must be cited as distinct versions.The reviewed CVPR paper uses 981 pages; newer releases change coverage and scoring. Parsing fidelity does not establish factual, clinical or scientific correctness of a generated answer.2025
Retrieve evidence inside the answer-generating modelURaG uses early shared MLLM states for ColBERT-style page ranking, retains selected page tokens and all query tokens, then continues deeper generation. Its staged retrieval and LoRA training connect evidence selection to answer modeling without a separate retrieval backbone.Joint training always keeps ground-truth evidence pages; inference must select them. FLOP tests extend documents by duplication and are not latency measurements. Multi-page reasoning and WSI transfer need separate evidence.2026

Concept lineage

Failure modes to audit

  • Leaking document templates or organizations across splits.
  • Scoring normalized strings while ignoring wrong grounding.
  • Using OCR text that includes test annotations.
  • Treating valid JSON as semantically correct extraction.
  • Ignoring multilingual fonts, handwriting, and scan degradation.

Questions for every paper

  1. Which evidence comes from pixels, OCR, or layout?
  2. What output schema is required?
  3. How is grounding verified?
  4. Which document shifts are tested?

19 canonical readings · 2019–2026· route reviewed through October 2, 2026.

This is the complete structured list for this chapter, ordered chronologically from earlier foundations toward current work. The explanatory ladder above highlights the shortest conceptual route; this list also includes important branches, benchmarks, and current endpoints. It is generated from the same deduplicated catalog used by the AI background registry and My Library, so a future catalog update appears here automatically.

Show all 19 readings in maintained order
  1. #172026ECCVAccepted · proceedings pendingL3

    GRADE: Benchmarking Discipline-Informed Reasoning in Image Editing

    Mingxin Liu, Ziqian Fan, Zhaokai Wang, Leyao Gu, Zirun Zhu, Yiguo He, Yuchen Yang, Changyao Tian, Xiangyu Zhao, Ning Liao, Shaofeng Zhang, Qibing Ren, Zhihang Zhong, Xuanhe Zhou, Junchi Yan, and Xue Yang

    ECCV 2026 Spotlight verified in the official Vision-Language Models & Visual Foundation Models session; manuscript #2706 checked on 2026-09-12. Publisher version of record was not independently verified.

    Official artifacts: ECCV Spotlight program · Conference manuscript · Official project or implementation

    Metadata checked