tesseract.js

What is tesseract.js?

tesseract.js is a JavaScript library that provides Optical Character Recognition (OCR) capabilities. It allows you to extract text from images and PDFs directly in the browser or in a Node.js environment.

What are tesseract.js's main functionalities?

Basic OCR

This feature allows you to perform basic OCR on an image file. The code sample demonstrates how to recognize text from an image using the English language.

const Tesseract = require('tesseract.js');

Tesseract.recognize(
  'path/to/image.png',
  'eng',
  {
    logger: m => console.log(m)
  }
).then(({ data: { text } }) => {
  console.log(text);
});

Handling Multiple Languages

This feature allows you to recognize text in multiple languages. The code sample demonstrates how to recognize text from an image using both English and Spanish languages.

const Tesseract = require('tesseract.js');

Tesseract.recognize(
  'path/to/image.png',
  'eng+spa',
  {
    logger: m => console.log(m)
  }
).then(({ data: { text } }) => {
  console.log(text);
});

Progress Reporting

This feature provides real-time progress updates during the OCR process. The code sample demonstrates how to log progress messages to the console.

const Tesseract = require('tesseract.js');

Tesseract.recognize(
  'path/to/image.png',
  'eng',
  {
    logger: m => console.log(m)
  }
).then(({ data: { text } }) => {
  console.log(text);
});

Using Worker for Performance

This feature allows you to use a worker for better performance, especially for large images or multiple OCR tasks. The code sample demonstrates how to create a worker, load the necessary language, perform OCR, and then terminate the worker.

const { createWorker } = require('tesseract.js');

const worker = createWorker({
  logger: m => console.log(m)
});

(async () => {
  await worker.load();
  await worker.loadLanguage('eng');
  await worker.initialize('eng');
  const { data: { text } } = await worker.recognize('path/to/image.png');
  console.log(text);
  await worker.terminate();
})();

Other packages similar to tesseract.js

ocrad.js

ocrad.js is a JavaScript port of the OCRAD OCR library. It is designed to be used in the browser and can recognize text from images. Compared to tesseract.js, ocrad.js is lighter but may not be as accurate or feature-rich.

node-tesseract-ocr

node-tesseract-ocr is a Node.js wrapper for the Tesseract OCR engine. It provides a simpler interface for performing OCR in Node.js environments. While it offers similar functionalities to tesseract.js, it does not support browser usage.

README

Tesseract.js

Tesseract.js v2 is now available and under development in master branch, check support/1.x branch for v1.

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

Tesseract.js works with script tags, webpack, and Node.js. After you install it, using it is as simple as

import { TesseractWorker } from 'tesseract.js';
const worker = new TesseractWorker();

worker.recognize(myImage)
  .progress((p) => { console.log('progress', p);    })
  .then((result) => { console.log('result', result); });

Check out the docs for a full treatment of the API.

Provenance

Tesseract.js wraps an emscripten port of the Tesseract OCR Engine.

Installation

Tesseract.js works with a <script> tag via local copy or CDN, with webpack via npm, and on Node.js via npm. Check out the docs for a full treatment of the API.

CDN

You can simply include Tesseract.js with a CDN like this:

<script src='https://unpkg.com/tesseract.js@v2.0.0-alpha.6/dist/tesseract.min.js'></script>

After including your scripts, the Tesseract variable will be defined globally!

npm

2.x

Major Changes

• Upgrade to tesseract v4
• Support multiple languages, ex: eng+chi_tra
• Support image formats: png, jpg, bmp, pbm

> yarn add tesseract.js@next

or

> npm install tesseract.js@next --save

1.x

> yarn add tesseract.js

or

> npm install tesseract.js --save

Note: Tesseract.js currently requires Node.js v6.8.0 or higher.

Documentation

• Examples
• Image Format
• API
• Local Installation
• FAQ

Contributing

Development

To run a development copy of tesseract.js, first clone this repo.

> git clone https://github.com/naptha/tesseract.js.git

Then, cd tesseract.js && npm install && npm start

> cd tesseract.js
> npm install && npm start

  ... a bunch of npm stuff ...

  Starting up http-server, serving ./
  Available on:
    http://127.0.0.1:3000
    http://[your ip]:3000

Then open http://localhost:3000/examples/browser/demo.html in your favorite browser. The devServer automatically rebuilds tesseract.dev.js and worker.min.js when you change files in the src folder.

Building Static Files

After you've cloned the repo and run npm install as described in the Development Section, you can build static library files in the dist folder with

> npm run build