Implementation of Image Digital Watermarking Embedding and Extraction Using DWT

This MATLAB project implements image digital watermarking embedding and extraction using Discrete Wavelet Transform (DWT). The program includes both the watermark image and original image files for comprehensive testing. The implementation involves embedding the watermark image into the original image to provide protection and authentication capabilities. DWT serves as a fundamental image processing technique that transforms images into the frequency domain for effective watermark manipulation. The core algorithm operates through multi-level wavelet decomposition, where the watermark is strategically embedded in the low-frequency subbands (LL coefficients) to ensure robustness and visibility. During embedding, the program performs DWT decomposition on the original image, modifies the appropriate coefficients with watermark data, and reconstructs the watermarked image using inverse DWT. For extraction, the algorithm processes the watermarked image by applying the same DWT decomposition and retrieving the watermark information from the previously modified coefficients. Key functions include wavelet decomposition using 'dwt2', coefficient modification with scaling factors, and image reconstruction via 'idwt2'. The implementation incorporates error checking and quality metrics to evaluate watermark visibility and extraction accuracy. This program demonstrates significant practical value for digital watermarking research and applications, providing a foundation for copyright protection, content authentication, and tamper detection in digital images.