Recovering the order of pen strokes from a photo of handwriting
AspireAI community · arXiv
Handwriting is produced as an ordered sequence of pen movements, but an offline image keeps only the final ink. inkGround is a benchmark for stroke trajectory recovery from full-page, camera-captured handwriting: 537 page images, about 18.7k words and 163k strokes, paired with reference trajectories from a pretrained offline-to-online model filtered by OCR agreement and verified by human raters. Because those references are pseudo-labels representing one plausible pen trajectory, the authors also evaluate on IAM-OnDB, which has recorded pen trajectories. The task is cast as text-conditioned point grounding - given a page image and a target word, output the word's ordered stroke points - scored by trajectory fidelity, readability of the rendered strokes and style similarity. Seven models were benchmarked with a shared in-context prompt, and closed-source models, notably Gemini-3.1-Pro, produced legible trajectories close to the reference, a ranking that held on IAM-OnDB.
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