🧠 Sudoku Solver Web App

A web-based application to recognize, generate, and solve Sudoku puzzles using image processing (OCR), Backtracking algorithms, and Flask for the backend API. Users can upload an image of a Sudoku puzzle, generate new puzzles of varying difficulty, or solve manually entered ones.

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🚀 Features

• ✅ Upload a Sudoku image and auto-recognize the grid using OpenCV and Tesseract OCR
• ✅ Generate valid Sudoku puzzles (easy, medium, hard)
• ✅ Solve any valid Sudoku grid using a backtracking algorithm
• ✅ Clean and modular backend using Flask

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🛠️ Tech Stack

• Backend: Python, Flask
• Image Processing: OpenCV, Pytesseract, PIL (Pillow)
• Sudoku Logic: Numpy-based grid manipulation, AI solver & generator
• Frontend: HTML/CSS/JavaScript

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📁 Project Structure

├── app.py                 # Flask main application
├── recognizer.py          # Handles OCR and Sudoku grid recognition from images
├── solver.py              # Sudoku solver using backtracking
├── generator.py           # Sudoku puzzle generator with difficulty levels
├── templates/             # HTML templates (e.g., index.html)
├── static/
│   ├── styles/            # CSS files
│   └── scripts/           # JavaScript files
├── uploads/               # Temporary upload folder (auto-created)
├── requirements.txt       # Python dependencies
└── README.md              # You're here

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🧩 Setup Instructions

1. 🔧 Install System Dependencies

Ensure you have Python 3.7+ installed.

You also need Tesseract-OCR installed on your system:

Windows:

• Download from: https://github.com/tesseract-ocr/tesseract
• After installation, optionally configure the path in recognizer.py:

# pytesseract.pytesseract.tesseract_cmd = r'C:\Program Files\Tesseract-OCR\tesseract.exe'

Linux (Ubuntu):

sudo apt update
sudo apt install tesseract-ocr

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2. 🐍 Create Virtual Environment (Recommended)

python -m venv venv
source venv/bin/activate  # On Windows: venv\Scripts\activate

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3. 📦 Install Python Dependencies

pip install -r requirements.txt

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4. ▶️ Run the App

python app.py

Then visit: http://127.0.0.1:5000

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✅ Dependencies (requirements.txt)

Flask
numpy
opencv-python
pytesseract
Pillow

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💡 Future Improvements

• Add support for mobile camera capture
• Improve OCR digit recognition with CNN
• Track solving steps visually

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📄 License

This project is open-source and available under the MIT License.

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Made with 🧠, 🐍, and ❤️ for Sudoku enthusiasts!