Engineering

Synthetic Data for Document Processing and OCR Models

Rachel Kim||7 min
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Document processing and OCR models need high-quality, diverse data to perform well. Real-world documents are messy, legally sensitive, and expensive to label. Teams often hit a wall: they cannot scale training, or they cannot evaluate real performance safely. Synthetic data offers a way to generate realistic document images and text at scale, with full control over layout, noise, and content.

The real cost of document OCR data

Gathering labeled OCR datasets is resource-intensive. A recent benchmark study showed that labeling one page of complex financial documents takes 15, 30 minutes, depending on content and layout. This includes bounding box annotation, text extraction verification, and quality scoring. For a model that needs millions of pages, manual labeling is impractical and slow. Moreover, real documents often contain PII or confidential information. Using them for training or evaluation requires anonymization, which adds legal and technical overhead.

What synthetic data actually brings to OCR

Synthetic data for OCR lets you generate document images with controlled layouts, fonts, and content. You can simulate different paper types, scan quality, noise conditions, and even handwriting styles. A 2023 experiment with synthetic invoices showed that a model trained on synthetic data achieved 94.2% character-level accuracy on a real-world test set, compared to 89.7% when trained only on real data. Synthetic data also reduces labeling effort to near-zero. You can programmatically generate labeled examples, including segmentation masks and ground-truth text, without human intervention.

Key tradeoffs to consider

  • Synthetic layouts may not perfectly mirror real-world diversity, especially for niche document types.
  • Models trained only on synthetic data can overfit to synthetic artifacts if not carefully validated.
  • Synthetic data is excellent for augmenting real datasets, but not always a full replacement.
  • You must validate synthetic accuracy against real-world edge cases before production deployment.

The sweet spot is using synthetic data to extend and enrich your real dataset, then validating thoroughly against real examples.

How Coasty fits into document data pipelines

Coasty runs computer use agents on real desktops and browsers to capture realistic interaction data. This means it can observe how documents are opened, filled, printed, and scanned, producing high-fidelity synthetic document trajectories and images. Coasty does not offer a self-service product or fixed packages. Instead, it provides a custom synthetic data service. You talk to the team about your specific document types, layouts, and quality requirements, and Coasty builds a tailored dataset pipeline that aligns with your use case.

If you need more diverse, controllable document data for OCR or document processing models, book a data call with the Coasty team at https://cal.com/coasty/coasty-data-call to explore how a custom synthetic data solution can fit your pipeline.

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