A Survey of OCR Evaluation Methods and Metrics and the Invisibility of Historical Documents
Organizations: The Pennsylvania State University University Park, Pennsylvania, USA
Abstract
Optical character recognition (OCR) and document understanding systems increasingly rely on large vision and vision-language models, yet evaluation remains centered on modern, Western, and institutional documents. This emphasis masks system behavior in historical and marginalized archives, where layout, typography, and material degradation shape interpretation. This study examines how OCR and document understanding systems are evaluated, with particular attention to Black historical newspapers. We review OCR and document understanding papers, as well as benchmark datasets, which are published between 2006 and 2025 using the PRISMA framework. We look into how the studies report training data, benchmark design, and evaluation metrics for vision transformer and multimodal OCR systems. During the review, we found that Black newspapers and other community-produced historical documents rarely appear in reported training data or evaluation benchmarks. Most evaluations emphasize character accuracy and task success on modern layouts. They rarely capture structural failures common in historical newspapers, including column collapse, typographic errors, and hallucinated text. To put these findings into perspective, we use previous empirical studies and archival statistics from significant Black press collections to show how evaluation gaps lead to structural invisibility and representational harm. We propose that these gaps occur due to organizational (meso) and institutional (macro) behaviors and structure, shaped by benchmark incentives and data governance decisions.
Figures & tables
| Model | Year | Training Source | Scale | Params | Scripts | Historical Coverage |
|---|---|---|---|---|---|---|
| olmOCR 2 | 2025 | Web PDFs & Internet Archive | ~260K pgs | ~7B | EN+ | Substantial (IA scans; no curation) |
| PaddleOCR-VL | 2025 | Synthetic & web corpora | Undisclosed | ~0.9B | 109+ | Limited (no historical eval) |
| Qwen2.5-VL | 2025 | Web multimodal corpora | Web-scale | 7B/72B | Multi | None reported |
| GOT-OCR 2.0 | 2024 | Synthetic + modern web | ~5M pairs | ~580M | EN | None (synthetic focus) |
| Surya | 2024 | Scanned document images | Undisclosed | Undiscl. | 90+ | Limited (no benchmarks) |
| DocFormer v2 | 2024 | Document imgs (IIT-CDIP) | ~11M imgs | 200–500M | EN | None reported |
| System | Architecture | Historical Scans | Historical Typography | Complex Layouts | Handwriting |
| Generative / VLM (End-to-End Text Generation) | |||||
| olmOCR 2 | VLM (7B) | 82.3% (Math) 47.7% (General) | Supported | 83.7% (Multi-col) | Supported (20k pages) |
| Qwen2.5-VL | VLM (7B+) | 65.5% (Bench) | High (Gen. Cap.) | Strong | Remarkable (Script-agnostic) |
| GOT-OCR 2.0 | Encoder-Dec. | 22.1% (Fail on noise) | Poor | Poor (reported) | Not evaluated |
| Nougat | Transformer | Poor (Hallucinates) | N/A | Academic Only | Poor |
| Donut | Transformer | Poor | Poor | Poor | Weak |
| Benchmark | Languages | Document Types | Annotation Paradigm | Hist. / Archival Coverage | Underrep. Archives |
|---|---|---|---|---|---|
| CC-OCR | Multi (28+) | Web PDF, scene, docs | Plain Text | None (modern web-crawl) | No targeted focus |
| OmniDoc | EN, ZH | Academic, slides, books | Detection & Text | Modern-era (Born-digital) | No targeted focus |
| OCRBench | EN, ZH | 31 scenarios (mixed) | VQA / Key-Value | Limited (Isolated IAM/HKR) | No explicit focus |
| DUDE | Prim. EN | Multi-page business | QA Pairs | Contemporary (Scanned) | No targeted focus |
| DUE | English | Tables, graphs | QA / Classif. | None | No targeted focus |
| DocVQA | English | Industry forms (Tobacco) | QA Pairs (ANLS) | Legacy Litigation (20th C.) | Single-domain |
| Error Regime | Model | Technical Failure | Archival Consequence |
|---|---|---|---|
| Geometric Collapse (Linearity Bias) | Tesseract v5 | Misinterpreted vertical column rules as text; defaulted to left-to-right “Z-pattern” reading order | Semantic merging of distinct content (editorial poetry conflated with civic reports); granular search rendered ineffective |
| Decoding Instability | Surya | High-contrast 19th-c. fonts triggered token collapse; generative repetition of character sequences | Introduction of “garbage tokens” |
| Corrective Hallucination | olmOCR 2 (SOTA VLM) | Overwrote a visual evidence with high-probability tokens (“knowledge bleed?”) | Entities were replaced with a fabricated text; |
| Publication / Series | Years | Layout Topology | Masthead / Header | Non-Text Elements | Typography Complexity | Scan Degradation |
|---|---|---|---|---|---|---|
| The Weekly Advocate & The Colored American (Transitional newspapers) | 1837–1841 | 4 columns, standard grid frequently interrupted by advertisements & spanning headers | High complexity, ribbon banners with multiple embedded text (e.g., “Established for …” & bold serif headers with sub-text | High variance, heavy horizontal rules, woodcut engraving of the U.S. Capitol, & iconographic glyphs in advertisements | Moderate–high, modern serif (Didone), tight leading, archaic ligatures | bleed-through |
| Mirror of Liberty (Quarterly magazine) | 1838–1841 | 2 columns, wider column width, magazine aspect ratio | Low complexity, simple typographic header, outline block type | Minimal, primarily text-heavy, sparse rules | Moderate, larger point size, clear typographic hierarchy | low contrast, character dropout |
| The North Star (Abolitionist) | 1847–1851 | 7 columns, extremely dense layout | Moderate, typographic masthead often obscured by scan artifacts | Structural emphasis, thin and broken vertical rules | Very high, minimal point size, dense setting, italics for emphasis | blur, speckle noise, skew |
| The Impartial Citizen | 1861–1864 | 5 columns, dense grid with slightly wider margins | High, Gothic/Blackletter masthead distinct from Roman body text | Standard, vertical column rules | High, dense text blocks challenge line segmentation | lighting gradients from microfilm |
| The Weekly Anglo-African | 1859–1861 | 7 columns, header-centered structure | Moderate, detailed masthead with integrated text | Integrated artwork, motto embedded in engraving | Mixed, display fonts in header vs. standard body text | cleaner lines than other samples |
Appendix figures & tables1 asset
Supplementary material from the paper’s appendix.
Appendix
| Query Category | Search Query |
|---|---|
| Primary evaluation queries | “OCR evaluation metrics document understanding” |
| “document AI benchmark evaluation” | |
| “OCR benchmark dataset peer reviewed” | |
| “document layout analysis benchmark” | |
| “vision language model OCR evaluation” | |
| Historical & bias-aware queries | “historical document OCR evaluation” |