Bangladesh National ID Card OCR Extractor

A robust API for extracting information from Bangladesh National ID Cards using OCR technology. This service provides a secure, rate-limited REST API that processes images and extracts key information such as name, date of birth, and ID number.

📋 Features

• Robust Text Extraction: Uses EasyOCR with specialized patterns for Bangladesh ID cards
• High Accuracy: Multiple pattern matching algorithms to handle various ID card formats
• Secure API: Token-based authentication and request rate limiting
• Cross-Platform: Works on both Windows and Linux environments
• Field Validation: Validates extracted information against provided data
• Resource Management: Efficient cleaning of temporary files
• Comprehensive Logging: Detailed logs for debugging and auditing

🔧 Requirements

• Python 3.8+ (tested on Python 3.12 and 3.13)
• Flask web framework
• OpenCV for image processing
• EasyOCR for text extraction
• Storage space for model files (~100MB)

⚙️ Installation

Common Setup (All Platforms)

1. Clone the repository:

   git clone https://github.com/yourusername/nid-ocr-extractor.git
   cd nid-ocr-extractor

2. Create environment file:

   # Copy example environment file
   cp .env.example .env
   
   # Generate secure tokens and update .env file
   python -c "import secrets; print(f'SECRET_KEY={secrets.token_hex(32)}')"
   python -c "import secrets; print(f'AUTH_TOKEN={secrets.token_hex(16)}')"

Windows Setup

1. Create and activate virtual environment:

   python -m venv win_venv
   win_venv\Scripts\activate

2. Install dependencies:

   pip install -r requirements.txt
   
   # Windows needs python-magic-bin instead of python-magic
   pip uninstall -y python-magic
   pip install python-magic-bin

Linux Setup

1. Create and activate virtual environment:

   python -m venv venv
   source venv/bin/activate

2. Install system dependencies:

   For Debian/Ubuntu:

   sudo apt-get update
   sudo apt-get install -y libgl1-mesa-glx libglib2.0-0 libsm6 libxext6 libxrender-dev

   For Arch Linux:

   sudo pacman -Syu
   sudo pacman -S mesa glib2 libx11 libxext libxrender

3. Install Python dependencies:

   pip install -r requirements.txt

🚀 Usage

Starting the Server

# Start the Flask server
python app.py

By default, the server runs on http://localhost:5000.

Testing with the Client

The repository includes a client script for testing the API:

# Basic usage with default settings
python client.py --token YOUR_AUTH_TOKEN

# Specify a custom image
python client.py --image path/to/id/image.jpg --token YOUR_AUTH_TOKEN

# Compare with known data
python client.py --name "John Doe" --dob "15 Mar 1985" --token YOUR_AUTH_TOKEN

API Endpoints

GET /

Health check endpoint that confirms the API is running.

POST /process_image

Processes an ID card image and extracts information.

Request Headers:

• X-API-Token: Your authentication token from .env file

Form Data:

• image: The image file (JPEG, PNG)
• Name (optional): Name for comparison
• Date of Birth (optional): Date of birth for comparison

Response:

{
  "Name": "MD SAMIM MIA",
  "Date of birth": "07 Jun 1972",
  "ID Number": "9116217028",
  "Full extracted text": "...",
  "similarity": {
    "status": "no_comparison_data_provided"
  }
}

⚠️ Common Issues and Troubleshooting

Windows Issues

1. libmagic not found error:

   ImportError: failed to find libmagic
   

   Solution: Replace python-magic with python-magic-bin:

   pip uninstall -y python-magic
   pip install python-magic-bin

2. DLL load failed error:

   ImportError: DLL load failed while importing cv2
   

   Solution: Reinstall OpenCV:

   pip uninstall -y opencv-python
   pip install opencv-python

Linux Issues

1. OpenGL/libGL.so.1 error:

   ImportError: libGL.so.1: cannot open shared object file
   

   Solution: Install required libraries:

   # For Ubuntu/Debian
   sudo apt-get install -y libgl1-mesa-glx
   
   # For Arch Linux
   sudo pacman -S mesa

2. Permission denied for cache directory:

   PermissionError: [Errno 13] Permission denied: 'cache'
   

   Solution: Check permissions:

   chmod 750 cache

🛠️ Configuration

The application uses environment variables defined in .env for configuration:

Variable	Description	Default
SECRET_KEY	Secret key for Flask	Generated value
AUTH_TOKEN	API authentication token	Generated value
RATE_LIMIT	Max requests per window	10
RATE_LIMIT_WINDOW	Rate limit window in seconds	60
MAX_CONTENT_LENGTH	Max allowed file size in bytes	5MB (5242880)
CACHE_DIR	Directory for temporary files	cache

🔒 Security Notes

1. Always use a strong, randomly generated AUTH_TOKEN
2. The API implements rate limiting to prevent abuse
3. Temporary files are automatically deleted after processing
4. Input validation helps prevent malicious uploads
5. Security headers mitigate common web vulnerabilities

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🙏 Acknowledgments

• EasyOCR for the OCR engine
• Flask team for the web framework
• OpenCV contributors for image processing capabilities

---

Note: This software is intended for legitimate identity verification purposes. Please ensure compliance with local data protection and privacy regulations when handling personal identification information.