MATLAB Implementation of Digital Watermarking Techniques

This document provides reference implementations for digital watermark embedding techniques in MATLAB. The code demonstrates three primary methods: checksum-based verification that adds integrity protection through hash calculations, LSB substitution that modifies the least significant bits of pixel values for invisible embedding, and patchwork algorithms that use statistical properties for robust watermarking. Each implementation includes detailed comments explaining the core algorithms and parameter configurations. Additionally, the codebase contains modules for calculating signal-to-noise ratio (SNR) to evaluate watermark visibility impact, and reversible watermark removal functions that demonstrate proper extraction procedures. The SNR calculation employs standard image processing metrics to quantify embedding distortion, while the removal scripts show how to reverse embedding operations while preserving original content quality. All functions are structured with clear input/output parameters and include error handling for practical deployment scenarios.