JavaScripting

Tesseract.js is a javascript library that gets words in almost any language out of images. (Demo)

Image Recognition

Video Real-time Recognition

Tesseract.js wraps a webassembly port of the Tesseract OCR Engine. It works in the browser using webpack, esm, or plain script tags with a CDN and on the server with Node.js. After you install it, using it is as simple as:

import { createWorker } from 'tesseract.js';

(async () => {
  const worker = await createWorker('eng');
  const ret = await worker.recognize('https://tesseract.projectnaptha.com/img/eng_bw.png');
  console.log(ret.data.text);
  await worker.terminate();
})();

When recognizing multiple images, users should create a worker once, run worker.recognize for each image, and then run worker.terminate() once at the end (rather than running the above snippet for every image).

Installation

Tesseract.js works with a <script> tag via local copy or CDN, with webpack via npm and on Node.js with npm/yarn.

CDN

<!-- v5 -->
<script src='https://cdn.jsdelivr.net/npm/tesseract.js@5/dist/tesseract.min.js'></script>

After including the script the Tesseract variable will be globally available and a worker can be created using Tesseract.createWorker.

Alternatively, an ESM build (used with import syntax) can be found at https://cdn.jsdelivr.net/npm/tesseract.js@5/dist/tesseract.esm.min.js.

Node.js

Requires Node.js v14 or higher

# For latest version
npm install tesseract.js
yarn add tesseract.js

# For old versions
npm install tesseract.js@3.0.3
yarn add tesseract.js@3.0.3

Documentation

• Workers vs. Schedulers
• Examples
• Supported Image Formats
• API
• Local Installation
• FAQ

Major changes in v5

Version 5 changes are documented in this issue. Highlights are below.

• Significantly smaller files by default (54% smaller for English, 73% smaller for Chinese)
  • This results in a ~50% reduction in runtime for first-time users (who do not have the files cached yet)
• Significantly lower memory usage
• Compatible with iOS 17 (using default settings)
• Breaking changes:
  • createWorker arguments changed
    • Setting non-default language and OEM now happens in createWorker
      • E.g. createWorker("chi_sim", 1)
  • worker.initialize and worker.loadLanguage functions now do nothing and can be deleted from code
  • See this issue for full list

Upgrading from v2 to v5? See this guide.

Major changes in v4

Version 4 includes many new features and bug fixes--see this issue for a full list. Several highlights are below.

• Added rotation preprocessing options (including auto-rotate) for significantly better accuracy
• Processed images (rotated, grayscale, binary) can now be retrieved
• Improved support for parallel processing (schedulers)
• Breaking changes:
  • createWorker is now async
  • getPDF function replaced by pdf recognize option

Major changes in v3

• Significantly faster performance
  • Runtime reduction of 84% for Browser and 96% for Node.js when recognizing the example images
• Upgrade to Tesseract v5.1.0 (using emscripten 3.1.18)
• Added SIMD-enabled build for supported devices
• Added support:
  • Node.js version 18
• Removed support:
  • ASM.js version, any other old versions of Tesseract.js-core (<3.0.0)
  • Node.js versions 10 and 12

Use tesseract.js the way you like!

• Electron Version: https://github.com/Balearica/tesseract.js-electron
• Typescript: https://github.com/Balearica/tesseract.js-typescript
• Chrome Extension (with Manifest V3): https://github.com/Tshetrim/Image-To-Text-OCR-extension-for-ChatGPT
• Converting PDF to text: https://github.com/racosa/pdf2text-ocr

The following are old examples that use depreciated versions of Tesseract.js. Updating to Tesseract.js v5 is highly recommended. Users are encouraged to create updated examples (or make entirely new ones) and submit them as pull requests.

• Offline Version: https://github.com/jeromewu/tesseract.js-offline
• Firefox Extension: https://github.com/gnonio/korporize
• With Vue: https://github.com/jeromewu/tesseract.js-vue-app
• With Angular: https://github.com/jeromewu/tesseract.js-angular-app
• With React: https://github.com/jeromewu/tesseract.js-react-app
• Video Real-time Recognition: https://github.com/jeromewu/tesseract.js-video

React Native is not supported as it does not support Webassembly.

Contributing

Development

To run a development copy of Tesseract.js do the following:

# First we clone the repository
git clone https://github.com/naptha/tesseract.js.git
cd tesseract.js

# Then we install the dependencies
npm install

# And finally we start the development server
npm start

The development server will be available at http://localhost:3000/examples/browser/demo.html in your favorite browser. It will automatically rebuild tesseract.min.js and worker.min.js when you change files in the src folder.

Online Setup with a single Click

You can use Gitpod(A free online VS Code like IDE) for contributing. With a single click it will launch a ready to code workspace with the build & start scripts already in process and within a few seconds it will spin up the dev server so that you can start contributing straight away without wasting any time.

Building Static Files

To build the compiled static files just execute the following:

npm run build

This will output the files into the dist directory.

Contributors

Code Contributors

This project exists thanks to all the people who contribute. [Contribute].

Financial Contributors

Become a financial contributor and help us sustain our community. [Contribute]

Individuals

Organizations

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