OCR-D/core

Python modules implementing OCR-D specs and related tools

• Introduction
• Installation
• Command line tools
  • ocrd CLI
  • ocrd-dummy CLI
• Packages
  • ocrd_utils
  • ocrd_models
  • ocrd_modelfactory
  • ocrd_validators
  • ocrd
• bash library
  • bashlib API
  • ocrd__raise
  • ocrd__log
  • ocrd__minversion
  • ocrd__dumpjson
  • ocrd__usage
  • ocrd__parse_argv
• Testing
• See Also

Introduction

This repository contains the python packages that form the base for tools within the OCR-D ecosphere.

All packages are also published to PyPI.

Installation

NOTE Unless you want to contribute to OCR-D/core, we recommend installation as part of ocrd_all which installs a complete stack of OCR-D-related software.

The easiest way to install is via pip:

pip install ocrd

# or just the functionality you need, e.g.

pip install ocrd_modelfactory

All python software released by OCR-D requires Python 3.6 or higher.

NOTE Some OCR-D-Tools (or even test cases) might reveal an unintended behavior if you have specific enviroment modifications, like:

• using a custom build of ImageMagick, whose format delegates are different from what OCR-D supposes
• custom Python logging configurations in your personal account

Command line tools

NOTE: All OCR-D CLI tools support a --help flag which shows usage and supported flags, options and arguments.

ocrd CLI

• OCR-D user guide
• Introduction to ocrd workspace

ocrd-dummy CLI

A minimal OCR-D processor that copies from -I/-input-file-grp to -O/-output-file-grp

Packages

ocrd_utils

Contains utilities and constants, e.g. for logging, path normalization, coordinate calculation etc.

See README for ocrd_utils for further information.

ocrd_models

Contains file format wrappers for PAGE-XML, METS, EXIF metadata etc.

See README for ocrd_models for further information.

ocrd_modelfactory

Code to instantiate models from existing data.

See README for ocrd_modelfactory for further information.

ocrd_validators

Schemas and routines for validating BagIt, ocrd-tool.json, workspaces, METS, page, CLI parameters etc.

See README for ocrd_validators for further information.

ocrd

Depends on all of the above, also contains decorators and classes for creating OCR-D processors and CLIs.

Also contains the command line tool ocrd.

See README for ocrd for further information.

bash library

Builds a bash script that can be sourced by other bash scripts to create OCRD-compliant CLI.

bashlib API

ocrd__raise

Raise an error and exit.

ocrd__log

Delegate logging to ocrd log

ocrd__minversion

Ensure minimum version

ocrd__dumpjson

Output ocrd-tool.json.

Requires $OCRD_TOOL_JSON and $OCRD_TOOL_NAME to be set:

export OCRD_TOOL_JSON=/path/to/ocrd-tool.json
export OCRD_TOOL_NAME=ocrd-foo-bar

Output file resource content.

Output file resources names.

ocrd__usage

Print usage

ocrd__parse_argv

Expects an associative array ("hash"/"dict") ocrd__argv to be defined:

declare -A ocrd__argv=()

usage: pageId=$(ocrd__input_file 3 pageId)

Testing

Download assets (make assets)

Test with local files: make test

• Test with remote assets:
  • make test OCRD_BASEURL='https://github.com/OCR-D/assets/raw/master/data/'

See Also

• OCR-D Specifications (Repo)
• OCR-D core API documentation (built here via make docs)
• OCR-D Website (Repo)