WildHandBench: A Benchmark for Handwritten Text Understanding that Challenges MLLMs and Humans
Organizations: Baidu Inc.
Abstract
While the top model on OmniDocBench now reaches 96.34% overall on printed-document parsing, the ability of current models to handle challenging handwritten documents remains largely uncharacterized. Existing benchmarks focus on isolated text or formulas, overlook handwritten tables and real-world degradation, and report aggregate accuracy without explaining why models fail. We present WildHandBench, a benchmark containing 500 handwritten documents across three structures (free text, tables, formulas), four languages, and nine real-world scenarios. We introduce a Prior-Driven Error (PDE) metric that quantifies whether errors originate from language priors rather than visual evidence. Evaluating 18 state-of-the-art models together with calibrated human baselines, we find: (1) the best model achieves only 71.85% overall; (2) humans outperform all models yet the gap is narrow (77.09% vs. 71.85%); and (3) model errors are qualitatively different from human errors -- 63-91% of model errors are prior-driven versus only 49% for humans, exposing systematic reliance on language priors that conventional accuracy metrics cannot capture.
Figures & tables
| Benchmark | Lang. | Handwritten | Free Text | Table | Formula | Real Degrad. | Human Baseline |
| IAM | EN | ✓ | ✓ | – | – | – | – |
| CASIA-HWDB | ZH | ✓ | ✓ | – | – | – | – |
| SCUT-EPT / HCCDoc | ZH | ✓ | ✓ | – | – | Partial | – |
| CROHME / MathWriting | Symbol | ✓ | – | – | ✓ | – | – |
| PubTabNet / FinTabNet | EN | – | – | ✓ | – | – | – |
| ICDAR Table | EN | – | – | ✓ | – | – | – |
| Performance Evaluation (%) | Prior-Driven Error (%) | ||||||||||
| Type | Model | Params | Text Edit | Table TEDS | Formula CDM | Overall | Text | Table | Formula | Overall | |
| Proprietary | Claude Opus 4.8 | – | 53.30 | 52.27 | 74.11 | 57.70 | 72.78 | 59.32 | 91.66 | 74.59 | |
| Gemini 3.5 Flash | – | 27.10 | 53.63 | 78.22 | 68.25 | 71.36 | 71.91 | 94.36 | 79.21 | ||
| Gemini 3.1 Pro | – | 24.32 | 60.44 | 79.42 | 71.85 | 71.19 | 66.56 | 94.77 | 77.51 | ||
| Open General | InternVL3.5 | 241B-A28B | 46.80 | 41.22 | 64.00 | 52.80 | 72.62 | 66.38 | 90.03 | 76.34 | |
| Qwen3-VL | 235B-A22B | 34.30 | 51.81 | 69.06 | 62.19 | 70.01 | 62.18 | 91.33 | 74.51 | ||
Appendix figures & tables11 assets
Supplementary material from the paper’s appendix.
Appendix
| Category | zh_hans | en | zh_hant | zh_en_mix | Total |
| Text | 251 | 99 | 12 | 7 | 369 |
| Table | 62 | 16 | 0 | 1 | 79 |
| Formula | 20 | 29 | 0 | 3 | 52 |
| Total | 333 | 144 | 12 | 11 | 500 |
| Scenario | Count |
| Literary essays | 93 |
| Letters & notes | 81 |
| Medical & health | 62 |
| Education & learning | 61 |
| Business documents | 58 |
| Math & science formulas | 55 |
| Model Name | Type | Access | Model ID / Version |
| GPT-5.4 | General VLM | API (OpenAI-compat) | gpt-5.4 |
| Gemini-3.1-Pro | General VLM | API (OpenAI-compat) | gemini-3.1-pro-preview |
| Gemini-3.5-Flash | General VLM | API (OpenAI-compat) | gemini-3.5-flash |
| Claude-Opus-4-8 | General VLM | API (OpenAI-compat) | claude-opus-4-8 |
| Qwen3.5-Plus | General VLM | API (OpenAI-compat) | qwen3.5-plus |
| Qwen3-VL | General VLM | API (vLLM) | qwen3-vl-235b-a22b-thinking |