DCT Image Compression with Progressive Decoding

This repository contains a Java implementation of a Discrete Cosine Transform (DCT) based image compression algorithm with support for progressive decoding simulation. The algorithm mimics the compression techniques used in standard compression algorithms like JPEG and MPEG.

Features

• DCT-based coder-decoder for compressing images
• Support for baseline and progressive delivery modes
• Simulation of decoding using both baseline and progressive modes with latency control

Usage

To use the program, compile and run the Java file with the following command:

javac MyProgram.java
java MyProgram InputImage quantizationLevel DeliveryMode Latency

• InputImage: Path to the input image file (RGB format).
• quantizationLevel: A factor that affects compression (0 to 7).
• DeliveryMode: 1 for baseline, 2 for progressive using spectral selection, 3 for progressive using successive bit approximation.
• Latency: Latency in milliseconds for simulating data delivery during decoding.

Example Invocations

1. Baseline mode with no quantization and no latency:

java MyProgram Example.rgb 0 1 0

2. Baseline mode with quantization level 3 and latency of 100ms:

java MyProgram Example.rgb 3 1 100

3. Progressive mode using spectral selection with quantization level 1 and latency of 100ms:

java MyProgram Example.rgb 1 2 100

Implementation Details

• Encoder: Breaks the RGB image into 8x8 blocks, performs DCT on each block, quantizes the coefficients, and outputs the compressed data.
• Decoder: Dequantizes the coefficients, performs inverse DCT, and reconstructs the image.
• Progressive Decoding: Simulates sequential, spectral selection, and successive bit approximation modes with latency control.

Requirements

• Java Development Kit (JDK)
• Java IDE (optional)