Unlock the Power of Optical Character Recognition with a Telegram Chatbot

Getting Started

We’ll use the following modules to build our bot:

• Telegraf: A Telegram bot framework for Node.js
• Node-Tesseract-OCR: A Node.js wrapper for the Tesseract OCR API
• Node-FFmpeg: A FFmpeg module for Node.js
• Dotenv: A module for loading environment variables from a.env file
• Axios: A promise-based HTTP client for Node.js

Understanding Our Bot Logic

Our bot will have two independent scenes: imageScene and videoScene. The imageScene will handle extracting text from images, while the videoScene will handle extracting text from frames in videos.

Creating Our Working Directory

mkdir ocr-bot
cd ocr-bot
npm init -y
npm install telegraf node-tesseract-ocr node-ffmpeg dotenv axios

Registering Our Bot

To register our bot, we’ll need to contact the BotFather, a bot that helps create new bot accounts and manage existing ones. Follow the instructions to create a new bot account and obtain an access token.

Creating the Main File

const { Telegraf } = require('telegraf');
const dotenv = require('dotenv');

dotenv.config();

const bot = new Telegraf(process.env.BOT_TOKEN);

//... (rest of the code)

Creating the Image Scene

const { WizardScene } = require('telegraf');
const fileManager = require('./fileManager');
const ocr = require('./ocr');

const imageScene = new WizardScene('imageScene',
async (ctx) => {
//... (rest of the code)
}
);

Creating the Video Scene

const { WizardScene } = require('telegraf');
const fileManager = require('./fileManager');
const ocr = require('./ocr');

const videoScene = new WizardScene('videoScene',
async (ctx) => {
//... (rest of the code)
}
);

Creating the File Manager

const axios = require('axios');
const fs = require('fs');
const path = require('path');

const downloadFile = async (fileUrl, fileUniqueId) => {
//... (rest of the code)
};

const deleteFile = async (filePath) => {
//... (rest of the code)
};

Creating the OCR File

const tesseract = require('node-tesseract-ocr');
const ffmpeg = require('fluent-ffmpeg');

const extractText = async (imagePath) => {
//... (rest of the code)
};

const videoOCR = async (videoPath, frame) => {
//... (rest of the code)
};

Running Our Bot

node main.js

Open your Telegram client and add the bot that you’ve created. Start a conversation with it by sending /start or clicking the start button if available. Click the “Extract from 🖼️” button to enter the imageScene, and then send an image to extract text from it. Repeat the process for the videoScene.