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
Что это такое?Tesseract — это OCR-движок с открытым исходным кодом: он поставляется в виде библиотеки libtesseract и консольной программы tesseract, которая распознаёт текст на изображениях.
Там есть графический интерфейс, или это только командная строка?GUI в этом проекте нет — вы работаете с командой tesseract, а сторонние графические оболочки перечислены в документации 3rdParty.
Как выглядит базовый запуск после установки?Установите готовый бинарный пакет или соберите из исходников, затем запустите tesseract imagename outputbase, при необходимости добавив -l для языка, а также --oem и --psm.
Как именно он читает мои файлы изображений?Для открытия входных изображений, таких как PNG, JPEG и TIFF, используется библиотека Leptonica; документы вроде PDF напрямую он не открывает.
Мой скан не очень качественный — распознавание всё равно будет чистым?Часто нет: во многих случаях, чтобы получить лучшие результаты OCR, нужно сначала улучшить качество изображения, которое вы подаёте на вход.
Он будет работать на Windows, macOS и Linux?Да: готовые бинарные пакеты есть для основных настольных систем, а CI проекта собирается с autotools на macOS и Linux и с CMake на 64-битной Windows.
Всё в нём под одной лицензией открытого исходного кода?Код Tesseract распространяется под Apache License 2.0, но зависимости другие — Leptonica, которая используется для ввода изображений, лицензирована по сути под BSD 2-clause.
Сколько языков он распознаёт «из коробки»?Более 100 языков, с поддержкой unicode (UTF-8); Tesseract также можно обучить распознавать дополнительные языки.
В каких форматах можно получить результат?Обычный текст, hOCR (HTML), PDF, PDF только с невидимым текстовым слоем, TSV, ALTO и PAGE.
Чем отличаются движки LSTM и legacy?В Tesseract 4 появился нейросетевой движок (LSTM), ориентированный на распознавание строк; старый движок Tesseract 3 распознаёт шаблоны символов и включается через --oem 0 с файлами traineddata, поддерживающими legacy.
Можно вызывать его из Python или других языков?Да, через обёртки: libtesseract предоставляет C и C++ API, а привязки для других языков перечислены в документации AddOns.
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
53.6 MB
Stars
77.1K
Updated
CommitOct 19Release5.5.3Jul 24
Age
12y
Commits · 90 Days