khocr-gen

Synthetic OCR training data generator for mixed Khmer/English text.

Installation

pip install khocr-gen

Requirements

• Python >= 3.12
• Rust toolchain (cargo/rustc, edition 2021) - only needed to build the optional acceleration extension

Quick Start

1. Prepare fonts

fonts/
├── khmer/     <- .ttf / .otf Khmer fonts
└── english/   <- .ttf / .otf English fonts

Fonts placed directly in fonts/ (not in a subdirectory) are added to both pools as fallbacks.

2. Prepare corpus

A plain UTF-8 text file, one string per line:

សួស្តី
Hello World
ស្វាគមន៍ Welcome

3. Generate a dataset

khocr-gen generate --corpus corpus/corpus.txt --fonts fonts --output data --copies 3 --storage lmdb

4. View generated images

# Summary of an LMDB database
khocr-gen view --lmdb data/train/lmdb

# Extract images
khocr-gen view --lmdb data/train/lmdb --output-dir extracted

# Show labels only
khocr-gen view --lmdb data/train/lmdb --labels-only

Configuration

All generation parameters can be specified via CLI flags, a YAML config file, or both (CLI overrides YAML). See CONFIG.md for details. Example: generate.yml

Config loading order (highest priority wins):

1. argparse built-in defaults
2. YAML config file values
3. Explicit CLI flags

CLI Reference

See CLI_REFERENCE.md for complete command documentation.

Acknowledgments

khocr-gen builds on excellent open-source libraries:

• khmernormalizer (MIT) - Khmer text normalization
• OpenCV (Apache 2.0) - Image processing and augmentation
• Pillow (HPND) - Font rendering and image creation
• Albumentations (MIT) - Augmentation primitives
• NumPy (BSD-3-Clause) - Numerical operations
• LMDB (OpenLDAP 2.8) - Embedded database for training pipelines

License

MIT