tesseract README

The project's README from github.com/tesseract-ocr/tesseract. As one markdown file: README.md.

Tesseract OCR

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About

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.

Stefan Weil is the current lead developer. Ray Smith was the lead developer until 2017. 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 image formats including PNG, JPEG and TIFF.

Tesseract supports various output formats: plain text, hOCR (HTML), PDF, invisible-text-only PDF, TSV, ALTO and PAGE.

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 documentation.

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 UK and at Hewlett-Packard Co, Greeley Colorado USA 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. From 2006 until August 2017 it was developed by Google.

Major version 5 is the current stable version and started with release 5.0.0 on November 30, 2021. Newer minor versions and bugfix versions are available from GitHub.

Latest source code is available from main branch on GitHub. Open issues can be found in issue tracker, and planning documentation.

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.

Before building Tesseract from source, please check that your system has a compiler which is one of the supported compilers.

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 documentation.

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 in the AddOns documentation.

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

Support

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

For support, first read the documentation, 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.

Mailing-lists:

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

License

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

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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 the Leptonica library which essentially uses a BSD 2-clause license.

Dependencies

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

Latest Version of README

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

https://github.com/tesseract-ocr/tesseract/blob/main/README.md

tesseract (tesseract-ocr/tesseract)

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Tesseract
What is this?Tesseract is an open source OCR engine: it ships as the libtesseract library plus a command line program called tesseract that reads text out of images.
Do I get a graphical app, or is it command line only?There is no GUI in this project - you drive the tesseract command, and third-party GUI frontends are listed in the 3rdParty documentation.
What does a basic run look like once it's installed?Install a pre-built binary or build from source, then run tesseract imagename outputbase, optionally passing -l for the language plus --oem and --psm.
How does it actually read my image files?It uses the Leptonica library to open input images such as PNG, JPEG and TIFF; documents like PDFs are not what it opens directly.
My scan is a bit low quality - will the recognition still be clean?Often it won't: in many cases you need to improve the quality of the image you feed it to get better OCR results.
Will it run on Windows, macOS and Linux?Yes: pre-built binary packages exist for the major desktop systems, and the project's CI builds with autotools on macOS and Linux and with CMake on 64-bit Windows.
Is everything in it under one open source license?The Tesseract code is Apache License 2.0, but its dependencies differ - Leptonica, which it uses for image input, is essentially BSD 2-clause licensed.
How many languages can it recognize out of the box?More than 100 languages, with unicode (UTF-8) support; you can also train Tesseract to recognize additional languages.
What output formats can I get?Plain text, hOCR (HTML), PDF, invisible-text-only PDF, TSV, ALTO and PAGE.
What is the difference between the LSTM and legacy engines?Tesseract 4 added a neural net (LSTM) engine focused on line recognition; the legacy Tesseract 3 engine recognizes character patterns and is enabled with --oem 0 plus legacy-capable traineddata files.
Can I call it from Python or other languages?Yes, via wrappers: libtesseract exposes a C and C++ API, and bindings for other languages are listed in the AddOns documentation.
What are similar projects?EasyOCR, OCRmyPDF, SimdPaddleOCR, tesseract.js, openalpr, liteparse, dlib, faceai
Which topics is it in?tesseract, text-extraction, lstm, unicode, ocr, neural-network, multilingual, image-processing, pdf, computer-vision, cpp, c++
Creator
tesseract-ocr
Size
53.5 MB
Stars
77.1K
Updated
CommitOct 10Release5.5.3Jul 24
Age
12y
Commits · 90 Days