BrailleBench found general-purpose vision models read Braille poorly, and that synthetic training data can hide the failure almost completely
AspireAI community · arXiv
*Braille is a real accessibility task that multimodal models handle badly, and it turns out the usual fix can make the problem look solved when it is not.* BrailleBench is a manually curated benchmark of 259 real-world Grade-1 and Grade-2 Braille images. Evaluating proprietary, open-weight, OCR-specialized and tool-assisted systems, standalone general-purpose models transcribe Braille poorly while tool-assisted systems do much better. A 2B VLM trained on a synthetic Braille pipeline with diverse layouts and perturbations reaches 87 percent exact match on Grade-1 and 61 percent on Grade-2, beating standalone VLMs and posting the highest Grade-2 exact-match score among evaluated systems.
The more useful finding is the warning: models trained on prior synthetic data reach up to 96 percent on their own synthetic validation set but at most 3.26 percent on the real Grade-1 BrailleBench. The limitation is scale - 259 images is a small benchmark, and the real-world claim rests on that curated set rather than on a broad survey.
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