📦 Huffman Image Compressor (C++ & Qt)

📌 Project Overview

This project is a Lossless Image Compression Tool capable of shrinking file sizes by 40-50% without losing any visual data. It implements the Huffman Coding Algorithm from scratch using C++.

The tool is specifically optimized for PGM (Portable Gray Map) images, commonly used in medical imaging (DICOM), and features a user-friendly Qt GUI for easy encoding/decoding operations.

⚙️ Key Features

• Core Algorithm:
  • Implements Greedy Strategy using Min-Heap (Priority Queue) to build the Optimal Huffman Tree.
  • Generates variable-length binary codes based on pixel frequency (frequent pixels = shorter codes).
• Serialization: Saves the compressed data along with the Huffman Tree structure (Header) to allow perfect reconstruction.
• Qt GUI:
  • Visualize compression ratio.
  • Toggle between Compress/Decompress modes easily.
• Performance: Optimized C++ file I/O for handling large raw image binaries.

🛠️ Technical Implementation

The system relies on advanced Data Structures:

1. Frequency Map: Hash map to count pixel occurrences.
2. Priority Queue: To select the two smallest probability nodes iteratively.
3. Binary Tree: To generate unique prefix codes (0/1 paths).
4. Bit Manipulation: Packing bits into bytes for physical storage.

🚀 How to Build & Run

Prerequisites

• C++ Compiler (GCC/Clang)
• Qt Creator (or Qt 5.x Libraries)

Steps

1. Clone the Repository:

   git clone [https://github.com/mariamashraf731/Huffman-Image-Compressor.git](https://github.com/mariamashraf731/Huffman-Image-Compressor.git)

2. Open in Qt Creator:
   • Open src/gui/GUI.pro.
   • Configure Project & Build.
3. Run:
   • Load a .pgm image to compress.
   • Or load a .enc file to decompress.

📄 Documentation

For the mathematical proof and algorithmic details, check the Final Report.