OCRd

OCRd is a daemonized software component designed to automate optical character recognition tasks within document processing workflows. It is intended for server environments that handle large volumes of scanned pages or PDFs, providing automated OCR, metadata capture, and integration with digitization pipelines.

Operating as a background service, OCRd monitors input sources such as watch directories or event queues and coordinates OCR jobs across pluggable backends. Engines supported by OCRd typically include open-source options like Tesseract and Kraken, among others accessible via a plugin interface. The daemon can perform optional preprocessing steps—such as deskew, denoise, and binarization—and routes results to output repositories in standard formats, including PAGE XML, ALTO, or plain text, along with provenance and processing metadata.

Architecturally, OCRd follows a modular design with a core controller, a suite of worker plugins (one per OCR engine or task), and a storage/metadata layer. Configuration is managed through human-readable files or a REST API, facilitating scalable deployment and easy integration with existing digitization and archival workflows. Reliability features typically include retry policies, error handling, and comprehensive logging.

Common use cases include library and archive digitization programs, automated ingestion pipelines for digital repositories, and research workflows requiring reproducible OCR processing. OCRd-oriented deployments emphasize adherence to open standards and interoperability frameworks to support long-term accessibility and data reuse.

Licensing and community status vary by implementation, but many OCRd-like projects are released under permissive licenses and maintained by open-source communities that provide documentation, issue trackers, and contribution guidelines to encourage collaboration.