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.
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.
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.
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 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.
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 or plain script tags with a CDN and on the server with Node.js.
After you install it, using it is as simple as:
importTesseractfrom'tesseract.js';
Tesseract.recognize(
'https://tesseract.projectnaptha.com/img/eng_bw.png',
'eng',
{ logger: m =>console.log(m) }
).then(({ data: { text } }) => {
console.log(text);
})
Or using workers (recommended for production use):
For a basic overview of the functions, including the pros/cons of different approaches, see the intro. Check out the docs for a full explanation of the API.
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
Major changes in v2
Upgrade to tesseract v4.1.1 (using emscripten 1.39.10 upstream)
Support multiple languages at the same time, eg: eng+chi_tra for English and Traditional Chinese
Supported image formats: png, jpg, bmp, pbm
Support WebAssembly (fallback to ASM.js when browser doesn't support)
React Native is not supported as it does not support Webassembly.
Disclaimer: These examples are now several years old and use old versions of both Tesseract.js and the relevant frameworks. Users are encouraged to use the latest version of Tesseract.js rather than the versions used in these examples. For users that update these examples (or make new ones), please consider contributing through a PR.
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.dev.js and worker.dev.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
Support this project with your organization. Your logo will show up here with a link to your website. [Contribute]
FAQs
Pure Javascript Multilingual OCR
The npm package tesseract.js receives a total of 124,219 weekly downloads. As such, tesseract.js popularity was classified as popular.
We found that tesseract.js demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago.It has 4 open source maintainers collaborating on the project.
Package last updated on 03 Jun 2023
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