Software

• OCR as a Service

  • tesseract-web-service - An implementation of RESTful web service for tesseract-OCR using tornado.
  • docker-ocropy - A Docker container for running the [ocropy OCR system](htps://github.com/tmbdev/ocropy).
  • nidaba - An expandable and scalable OCR pipeline
  • gamera - A meta-framework for building document processing applications, e.g. OCR
  • ocr-tools - Project to provide CLI and web service interfaces to common OCR engines
  • ocrad-docker - Run the [ocrad](http://www.gnu.org/software/ocrad/) OCR engine in a docker container
  • kraken-docker - Run the [kraken](https://github.com/mittagessen/kraken) OCR engine in a docker container
  • OCR4all - Provides OCR services through web applications. Included Projects: [LAREX](https://github.com/chreul/LAREX), [OCRopus](https://github.com/tmbdev/ocropy), [calamari](https://github.com/ChWick/calamari) and [nashi](https://github.com/andbue/nashi).
  • ABBYY Cloud OCR SDK Code samples - Code samples for using the proprietary commercial ABBYY OCR API.
  • gamera - A meta-framework for building document processing applications, e.g. OCR
  • Konfuzio - Free Online OCR up to 2.000 pages per month and OCR API by [@atraining], see https://youtu.be/NZKUrKyFVA8 (code is not open)

• OCR CLI

  • Ocrocis - Project manager interface for Ocropy, see also [external project homepage](http://cistern.cis.lmu.de/ocrocis/)
  • Pdf2PdfOCR - A tool to OCR a PDF (or supported images) and add a text "layer" (a "pdf sandwich") in the original file making it a searchable PDF. GUI included. Tesseract and cuneiform supported.
  • tesseract-recognize - Tesseract-based tool that outputs result in Page XML format ([docker image](https://hub.docker.com/r/mauvilsa/tesseract-recognize)).
  • OCRmyPDF - OCRmyPDF adds an OCR text layer to scanned PDF files, allowing them to be searched

• OCR engines

  • gocr - OCR engine under the GNU Public License led by Joerg Schulenburg.
  • Ocrad - The GNU OCR. `GPL`
  • RWTH-OCR - The RWTH Aachen University Optical Character Recognition System
  • tesseract - The definitive Open Source OCR engine `Apache 2.0`
  • EasyOCR - OCR engine built on PyTorch by JaidedAI, `Apache 2.0`
  • ocropus 0.4 - Older v0.4 state of Ocropus, with tesseract 2.04 and iulib, C++
  • kraken - Ocropus fork with sane defaults
  • ocular - Machine-learning OCR for historic documents
  • attention-ocr - OCR engine using visual attention mechanisms
  • Calamari - OCR Engine based on OCRopy and Kraken
  • doctr - A seamless & high-performing OCR library powered by Deep Learning
  • SwiftOCR - fast and simple OCR library written in Swift
  • simple-ocr-opencv - ocr-opencv) - A simple pythonic OCR engine using opencv and numpy
  • ocropus - OCR engine based on LSTM, `Apache 2.0`

• OCR evaluation

  • ISRI OCR Evaluation Tools - ocr-evaluation-tools/blob/HEAD/user-guide.pdf)
  • ngram-ocr-eval - Brute and simple OCR evaluation using ngrams
  • ancientgreekocr-evaluation-tools - further development by [@nickjwhite](https://github.com/nickjwhite) (2013, 2014)
  • ocrevalUAtion - Cross-format evaluation, CLI and GUI
  • quack - Quality-Assurance-tool for scans with corresponding ALTO-files
  • ISRI OCR Evaluation Tools - ocr-evaluation-tools/blob/HEAD/user-guide.pdf)
  • isri-ocr-evaluation-tools - further development by [@eddieantonio](https://github.com/eddieantonio) (2015, 2016)

• OCR file formats

  • abby2hocr.xslt XSLT script
  • TEI SIG on Libraries - Best Practices for TEI in Libraries
  • GDZ - METS/TEI-based GDZ document format
  • PAGE-XML Schema - XML schema of the PAGE XML format along with documentation and examples
  • omni:us Pages Format (OPF) - XML schema very similar to PAGE XML that has some additional features.
  • hocr-spec - hOCR 1.2 specification
  • hocr-parser - hOCR Specification Python Parser
  • hOCRTools - hOCR to ALTO conversion XSLT
  • ALTO XML Schema - XML Schema and development of the ALTO XML format
  • ALTO XML Documentation - Documentation and use cases for ALTO
  • alto-tools - Various tools to work with ALTO files, Python
  • AbbyyToAlto - PHP script converting from Abbyy 6 to ALTO XML
  • TEI-OCR - TEI customization for OCR generated layout and content information
  • py-pagexml - Python library for handling PAGE XML and OPF files.
  • ocr-conversion-scripts
  • hocr-tools - Tools for doing various useful things with hOCR files, `Apache 2.0`
  • ocr-transform - CLI tool to convert between hOCR and ALTO, `MIT`

• OCR GUI

  • VietOCR - A Java/.NET GUI frontend for Tesseract OCR engine, including [jTessBoxEditor](http://vietocr.sourceforge.net/training.html) a graphical Tesseract [box data](https://github.com/tesseract-ocr/tesseract/wiki/Make-Box-Files) editor
  • OCRFeeder - GTK graphical user interface that allows the users to correct characters or bounding boxes, ODT export and more.
  • moz-hocr-editor - Firefox Addon for editing hOCR files **Discontinued**
  • qt-box-editor - QT4 editor of tesseract-ocr box files.
  • ocr-gt-tools - Client-Server application for editing OCR ground truth.
  • Paperwork - Using scanners and OCR to grep paper documents the easy way.
  • gImageReader - gImageReader is a simple Gtk/Qt front-end to tesseract-ocr.
  • PoCoTo - Fast interactive batch corrections of complete OCR error series in OCR'ed historical documents.
  • PRImA PAGE Viewer - Java based viewer for PAGE XML files (layout + text content). Also supports ALTO XML, FineReader XML, and HOCR.
  • archiscribe - Web application for transcribing OCR ground truth from Archive.org. Deployed instance available at https://archiscribe.jbaiter.de/, results are available in [@jbaiter/archiscribe-corpus](https://github.com/jbaiter/archiscribe-corpus).
  • nw-page-editor - Simple app for visual editing of Page XML files. Provides desktop and [server docker-based](https://hub.docker.com/r/mauvilsa/nw-page-editor-web) versions.
  • Paperless - Scan, index, and archive all of your paper documents.
  • VietOCR - A Java/.NET GUI frontend for Tesseract OCR engine, including [jTessBoxEditor](http://vietocr.sourceforge.net/training.html) a graphical Tesseract [box data](https://github.com/tesseract-ocr/tesseract/wiki/Make-Box-Files) editor
  • LAREX - A semi-automatic open-source tool for Layout Analysis and Region EXtraction on early printed books.

• OCR libraries by programming language

  • leptess - Productive and safe Rust bindings/wrappers for tesseract and leptonica.
  • tesseract-ocr - A Crystal wrapper for tesseract-ocr.
  • tesseract_ocr - Elixir library wrapping the tesseract executable.
  • gosseract - Golang OCR library, wrapping Tesseract-ocr.
  • Tess4J - Java Native Access bindings to Tesseract.
  • tess-two - Tools for compiling Tesseract on Android and Java API.
  • tesseract for .net - A .Net wrapper for tesseract-ocr.
  • TTesseractOCR4 - Object Pascal binding for tesseract-ocr 4.x.
  • Tesseract OCR for PHP - Tesseract PHP bindings.
  • pytesseract - A Python wrapper for Google Tesseract.
  • ocrodjvu - A library and standalone tool for doing OCR on DjVu documents, wrapping Cuneiform, gocr, ocrad, ocropus and tesseract
  • tesserocr - A Python wrapper for the tesseract-ocr API
  • ocracy - pure javascript lstm rnn implementation based on ocropus
  • gocr.js - Javascript port (emscripten) of gocr
  • ocrad.js - Javascript port (emscripten) of ocrad
  • tesseract.js - Javascript port (emscripten) of Tesseract
  • node-tesseract-ocr - A simple wrapper for the Tesseract OCR package.
  • node-tesseract-native - C++ module for node providing OCR with tesseract and leptonica.
  • rtesseract - Ruby library wrapping the tesseract and imagemagick executables.
  • ruby-tesseract - Native Tesseract bindings for Ruby MRI and JRuby
  • ocr_space - API wrapper for free ocr service ocr.space. Includes CLI
  • tesseract.rs - Rust bindings for tesseract OCR.
  • tesseract - R bindings for tesseract OCR.
  • Tesseract OCR iOS - Swift and Objective-C wrapper for Tesseract OCR.
  • ocrodjvu - A library and standalone tool for doing OCR on DjVu documents, wrapping Cuneiform, gocr, ocrad, ocropus and tesseract

• OCR Preprocessing

  • NoiseRemove.java in MathOCR - Java implementation of Adaptive degraded document image binarization by B. Gatos , I. Pratikakis, S.J. Perantonis
  • binarize.c in ZBar - C implementations of two binarization algorithms, based on Sauvola
  • Whiteboard Picture Cleaner - Shell one-liner/script to clean up and beautify photos of whiteboards
  • textcleaner - Processes a scanned document of text to clean the text background
  • localcontrast - Fast O(1) local contrast optimization
  • typeface-corpus - A repository for typefaces to train Tesseract and OCRopus for natural history collections and digital humanities.
  • binarizewolfjolion - Comparison of binarization algorithms. [Blog post](http://zp-j.github.io/2013/10/04/document-binarization/)
  • `crop_morphology.py` in oldnyc - Cropping a page to just the text block
  • textcleaner - Processes a scanned document of text to clean the text background
  • binarizewolfjolion - Comparison of binarization algorithms. [Blog post](http://zp-j.github.io/2013/10/04/document-binarization/)

• OCR training tools

  • glyph-miner - A system for extracting glyphs from early typeset prints
  • ocrodeg - Document image degradation for OCR data augmentation

• Older and possibly abandoned OCR engines

  • Cuneiform - CuneiForm OCR was developed by Cognitive Technologies
  • Eye - an experimental Java OCR (image-to-text) application
  • kognition - An omnifont OCR software for KDE
  • OCRchie - Modular Optical Character Recognition Software
  • ocre - o.c.r. easy
  • xplab - A GTK 2 tool for pattern matching
  • hebOCR - Hebrew character recognition library (previously named hocr, see [Wikipedia article](https://de.wikipedia.org/wiki/HebOCR)) `GPL`
  • Clara OCR - Open source OCR in C `GPL`
  • xplab - A GTK 2 tool for pattern matching
  • Clara OCR - Open source OCR in C `GPL`