MATLAB-Based Digital Watermark Embedding Using DCT Algorithm

This MATLAB program implements digital watermark embedding for images using Discrete Cosine Transform (DCT) technology. The program employs DCT algorithms to embed digital watermarks into images, serving to protect copyright and ensure image integrity. Digital watermarking represents a covert technique that embeds information into images without compromising visual quality. Through DCT transformation, the program performs frequency-domain analysis and processing, enabling effective watermark embedding. Key implementation features include: DCT coefficient modification in middle-frequency bands for robustness, watermark bit encoding using quantization index modulation, and inverse DCT (IDCT) reconstruction for watermarked image generation. The program includes complete DCT/IDCT transformation modules for pre-processing and post-processing operations, allowing frequency-domain manipulation before watermark insertion and image reconstruction afterward. Algorithm implementations utilize MATLAB's dct2() and idct2() functions for efficient block-based DCT processing, with configurable parameters for watermark strength and location selection.