DCT Digital Watermarking Algorithm

This documentation presents my graduation project focusing on digital watermarking algorithms. The algorithm employs sophisticated techniques to embed hidden information within digital images, serving crucial applications in copyright protection, authentication, and digital media溯源. The implementation involves complex mathematical operations and algorithmic steps, primarily utilizing Discrete Cosine Transform (DCT) for frequency domain analysis. The core process includes: partitioning the host image into blocks, applying DCT to transform spatial data into frequency coefficients, modifying selected mid-frequency coefficients to embed watermark data (using quantization index modulation or similar techniques), and performing inverse DCT to reconstruct the watermarked image. Key functions typically implemented include: - dct2() for 2D Discrete Cosine Transform - Watermark embedding function manipulating DCT coefficients - Extraction algorithms for watermark recovery - PSNR calculation for quality assessment The algorithm maintains visual quality while embedding robust watermark data through strategic coefficient selection in DCT domain. This approach ensures the embedded information survives common image processing operations while remaining imperceptible to human observers. I hope this technical exploration of DCT-based digital watermarking proves insightful and valuable for researchers and practitioners in digital media security.