Calamari OCR vs docTR
Calamari OCR
github.comdocTR
mindee.github.ioSide by side
| Figure | Calamari OCR | docTR |
|---|---|---|
| Price from | — | Free |
| Free plan | — | Yes |
| Free trial | — | — |
| Open source | — | — |
| Windows | — | Yes |
| macOS | — | Yes |
| Linux | Yes | Yes |
| API | Yes | Yes |
| Self-hosted | Yes | Yes |
| Plans published | 0 | 1 |
| Spec score · OCR API Software | 7.4 (#24) | 8.9 (#2) |
| Customization | The engine can be integrated and customized from Python scripts, and the documentation includes a Python API. | Users can train custom detection, recognition, layout, and table structure models when pretrained models do not meet their needs. |
| Input formats | The documentation lists Plain files, PageXML, Abbyy, and HDF5 dataset formats. | docTR can read PDFs, images, and web pages, with HTML input requiring the optional html extra. |
| Installation | The README says Calamari is available on PyPI and gives `pip install calamari-ocr` as the installation command. | The library can be installed with pip or from Git, and official Docker images are available from GitHub Container Registry. |
| License | The GitHub repository identifies its license as GPL-3.0. | The documentation's source code identifies the program as licensed under Apache License 2.0. |
| Purpose | Calamari is a line-based OCR engine based on OCRopy and Kraken, written in Python 3. | docTR is a deep learning OCR library for locating and recognizing text in documents, intended for document automation and research. |
| Support | The project links users to its documentation for further installation and usage instructions. | The contribution guide directs users with questions to GitHub Discussions and also mentions a #doctr channel on Slack. |
Plans
In their own words
Calamari OCR
Calamari OCR has no write-up on Specifiction yet; its figures are above.
docTR
docTR is a free deep-learning OCR library for finding and recognizing text in documents, aimed at document automation and research. Its pretrained OCR predictors first detect text and then recognize it, while a layout predictor identifies regions such as tables, figures, and headers. It reads PDFs and images; web-page input requires the optional HTML extra. Results can be rendered as plain text or exported as a JSON-serializable nested dictionary. The project describes its predictors as optimized for CPU and GPU inference. Users can train custom detection, recognition, layout, and table-structure models when pretrained models are not suitable. Documentation covers loading and sharing models through the Hugging Face Hub, and includes a minimal REST API deployment template and a browser demo. Installation is available through pip, Git, or official Docker images. The library requires Python 3.11 or higher, and pretrained weights download on first use and are cached locally. For AWS Lambda, the guide advises disabling multiprocessing and placing the model cache within /tmp. The project uses the Apache License 2.0.