Tesseract Open Source OCR Engine (Mirror)

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Tesseract OCR

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This package contains an OCR engine - libtesseract and a command line program - tesseract. Tesseract 4 adds a new neural net (LSTM) based OCR engine which is focused on line recognition, but also still supports the legacy Tesseract OCR engine of Tesseract 3 which works by recognizing character patterns. Compatibility with Tesseract 3 is enabled by using the Legacy OCR Engine mode (--oem 0). It also needs traineddata files which support the legacy engine, for example those from the tessdata repository.

The lead developer is Ray Smith. The maintainer is Zdenko Podobny. For a list of contributors see AUTHORS and GitHub's log of contributors.

Tesseract has unicode (UTF-8) support, and can recognize more than 100 languages "out of the box".

Tesseract supports various output formats: plain text, hOCR (HTML), PDF, invisible-text-only PDF, TSV. The master branch also has experimental support for ALTO (XML) output.

You should note that in many cases, in order to get better OCR results, you'll need to improve the quality of the image you are giving Tesseract.

This project does not include a GUI application. If you need one, please see the 3rdParty wiki page.

Tesseract can be trained to recognize other languages. See Tesseract Training for more information.

Brief history

Tesseract was originally developed at Hewlett-Packard Laboratories Bristol and at Hewlett-Packard Co, Greeley Colorado between 1985 and 1994, with some more changes made in 1996 to port to Windows, and some C++izing in 1998. In 2005 Tesseract was open sourced by HP. Since 2006 it is developed by Google.

The latest (LSTM based) stable version is 4.1.0, released on July 7, 2019. Latest source code is available from master branch on GitHub. Open issues can be found in issue tracker, and Planning wiki.

The latest 3.5 version is 3.05.02, released on June 19, 2018. Latest source code for 3.05 is available from 3.05 branch on GitHub. There is no development for this version, but it can be used for special cases (e.g. see Regression of features from 3.0x).

See Release Notes and Change Log for more details of the releases.

Installing Tesseract

You can either Install Tesseract via pre-built binary package or build it from source.

Supported Compilers are:

  • GCC 4.8 and above
  • Clang 3.4 and above
  • MSVC 2015, 2017, 2019

Other compilers might work, but are not officially supported.

Running Tesseract

Basic command line usage:

tesseract imagename outputbase [-l lang] [--oem ocrenginemode] [--psm pagesegmode] [configfiles...]

For more information about the various command line options use tesseract --help or man tesseract.

Examples can be found in the wiki.

For developers

Developers can use libtesseract C or C++ API to build their own application. If you need bindings to libtesseract for other programming languages, please see the wrapper section on AddOns wiki page.

Documentation of Tesseract generated from source code by doxygen can be found on tesseract-ocr.github.io.


Before you submit an issue, please review the guidelines for this repository.

For support, first read the Wiki, particularly the FAQ to see if your problem is addressed there. If not, search the Tesseract user forum, the Tesseract developer forum and past issues, and if you still can't find what you need, ask for support in the mailing-lists.


Please report an issue only for a bug, not for asking questions.


The code in this repository is licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at


Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
See the License for the specific language governing permissions and
limitations under the License.

NOTE: This software depends on other packages that may be licensed under different open source licenses.

Tesseract uses Leptonica library which essentially uses a BSD 2-clause license.


Tesseract uses Leptonica library for opening input images (e.g. not documents like pdf). It is suggested to use leptonica with build-in support for zlib, png and tiff (for w multipage tiff).

Latest Version of README

For the latest online version of the README.md see: