mirror of
https://github.com/tesseract-ocr/tesseract.git
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5da09f241c
Versions 4.1.1 and 5.0.0 still support the legacy engine with the same functionality as 3.05.02, so there is no reason to mention 3.05.02.
143 lines
7.9 KiB
Markdown
143 lines
7.9 KiB
Markdown
# Tesseract OCR
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[](https://travis-ci.org/tesseract-ocr/tesseract)
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[](https://ci.appveyor.com/project/zdenop/tesseract/)
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<br>
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[](https://scan.coverity.com/projects/tesseract-ocr)
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[](https://lgtm.com/projects/g/tesseract-ocr/tesseract/context:cpp)
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[](https://lgtm.com/projects/g/tesseract-ocr/tesseract/alerts)
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[](https://bugs.chromium.org/p/oss-fuzz/issues/list?sort=-opened&can=2&q=proj:tesseract-ocr)
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<br/>
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[](https://raw.githubusercontent.com/tesseract-ocr/tesseract/main/LICENSE)
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[](https://github.com/tesseract-ocr/tesseract/releases/)
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Table of Contents
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=================
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* [Tesseract OCR](#tesseract-ocr)
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* [About](#about)
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* [Brief history](#brief-history)
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* [Installing Tesseract](#installing-tesseract)
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* [Running Tesseract](#running-tesseract)
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* [For developers](#for-developers)
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* [Support](#support)
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* [License](#license)
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* [Dependencies](#dependencies)
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* [Latest Version of README](#latest-version-of-readme)
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## About
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This package contains an **OCR engine** - `libtesseract` and a **command line program** - `tesseract`.
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Tesseract 4 adds a new neural net (LSTM) based OCR engine which is focused
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on line recognition, but also still supports the legacy Tesseract OCR engine of
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Tesseract 3 which works by recognizing character patterns. Compatibility with
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Tesseract 3 is enabled by using the Legacy OCR Engine mode (--oem 0).
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It also needs [traineddata](https://tesseract-ocr.github.io/tessdoc/Data-Files.html) files which support the legacy engine, for example
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those from the tessdata repository.
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The lead developer is Ray Smith. The maintainer is Zdenko Podobny.
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For a list of contributors see [AUTHORS](https://github.com/tesseract-ocr/tesseract/blob/main/AUTHORS)
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and GitHub's log of [contributors](https://github.com/tesseract-ocr/tesseract/graphs/contributors).
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Tesseract has **unicode (UTF-8) support**, and can **recognize more than 100 languages** "out of the box".
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Tesseract supports **various output formats**: plain text, hOCR (HTML), PDF, invisible-text-only PDF, TSV. The main branch also has experimental support for ALTO (XML) output.
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You should note that in many cases, in order to get better OCR results,
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you'll need to **[improve the quality](https://tesseract-ocr.github.io/tessdoc/ImproveQuality.html) of the image** you are giving Tesseract.
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This project **does not include a GUI application**.
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If you need one, please see the [3rdParty](https://tesseract-ocr.github.io/tessdoc/User-Projects-%E2%80%93-3rdParty.html) documentation.
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Tesseract **can be trained to recognize other languages**.
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See [Tesseract Training](https://tesseract-ocr.github.io/tessdoc/Training-Tesseract.html) for more information.
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## Brief history
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Tesseract was originally developed at Hewlett-Packard Laboratories Bristol and
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at Hewlett-Packard Co, Greeley Colorado between 1985 and 1994, with some
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more changes made in 1996 to port to Windows, and some C++izing in 1998.
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In 2005 Tesseract was open sourced by HP. From 2006 until November 2018 it was developed by Google.
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The latest (LSTM based) stable version is **[4.1.1](https://github.com/tesseract-ocr/tesseract/releases/tag/4.1.1)**, released on December 26, 2019.
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Latest source code is available from [main branch on GitHub](https://github.com/tesseract-ocr/tesseract/tree/main).
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Open issues can be found in [issue tracker](https://github.com/tesseract-ocr/tesseract/issues),
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and [planning documentation](https://tesseract-ocr.github.io/tessdoc/Planning.html).
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See **[Release Notes](https://tesseract-ocr.github.io/tessdoc/ReleaseNotes.html)**
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and **[Change Log](https://github.com/tesseract-ocr/tesseract/blob/main/ChangeLog)** for more details of the releases.
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## Installing Tesseract
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You can either [Install Tesseract via pre-built binary package](https://tesseract-ocr.github.io/tessdoc/Home.html)
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or [build it from source](https://tesseract-ocr.github.io/tessdoc/Compiling.html).
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C++17 support is required for building.
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## Running Tesseract
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Basic **[command line usage](https://tesseract-ocr.github.io/tessdoc/Command-Line-Usage.html)**:
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tesseract imagename outputbase [-l lang] [--oem ocrenginemode] [--psm pagesegmode] [configfiles...]
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For more information about the various command line options use `tesseract --help` or `man tesseract`.
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Examples can be found in the [documentation](https://tesseract-ocr.github.io/tessdoc/Command-Line-Usage.html#simplest-invocation-to-ocr-an-image).
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## For developers
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Developers can use `libtesseract` [C](https://github.com/tesseract-ocr/tesseract/blob/main/include/tesseract/capi.h) or
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[C++](https://github.com/tesseract-ocr/tesseract/blob/main/include/tesseract/baseapi.h) API to build their own application.
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If you need bindings to `libtesseract` for other programming languages, please see the
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[wrapper](https://tesseract-ocr.github.io/tessdoc/AddOns.html#tesseract-wrappers) section in the AddOns documentation.
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Documentation of Tesseract generated from source code by doxygen can be found on [tesseract-ocr.github.io](https://tesseract-ocr.github.io/).
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## Support
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Before you submit an issue, please review **[the guidelines for this repository](https://github.com/tesseract-ocr/tesseract/blob/main/CONTRIBUTING.md)**.
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For support, first read the [documentation](https://tesseract-ocr.github.io/tessdoc/),
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particularly the [FAQ](https://tesseract-ocr.github.io/tessdoc/FAQ.html) to see if your problem is addressed there.
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If not, search the [Tesseract user forum](https://groups.google.com/g/tesseract-ocr), the [Tesseract developer forum](https://groups.google.com/g/tesseract-dev) and [past issues](https://github.com/tesseract-ocr/tesseract/issues), and if you still can't find what you need, ask for support in the mailing-lists.
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Mailing-lists:
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* [tesseract-ocr](https://groups.google.com/g/tesseract-ocr) - For tesseract users.
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* [tesseract-dev](https://groups.google.com/g/tesseract-dev) - For tesseract developers.
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Please report an issue only for a **bug**, not for asking questions.
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## License
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The code in this repository is licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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**NOTE**: This software depends on other packages that may be licensed under different open source licenses.
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Tesseract uses [Leptonica library](http://leptonica.com/) which essentially
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uses a [BSD 2-clause license](http://leptonica.com/about-the-license.html).
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## Dependencies
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Tesseract uses [Leptonica library](https://github.com/DanBloomberg/leptonica)
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for opening input images (e.g. not documents like pdf).
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It is suggested to use leptonica with built-in support for [zlib](https://zlib.net),
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[png](https://sourceforge.net/projects/libpng) and
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[tiff](http://www.simplesystems.org/libtiff) (for multipage tiff).
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## Latest Version of README
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For the latest online version of the README.md see:
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https://github.com/tesseract-ocr/tesseract/blob/main/README.md
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