Watermark Embedding and Extraction in Discrete Cosine Transform Domain with Attack Testing

This MATLAB-based implementation provides comprehensive watermarking operations in the Discrete Cosine Transform (DCT) domain, featuring efficient embedding and extraction capabilities along with attack testing modules. The code utilizes block-based DCT processing where watermark information is embedded in selected mid-frequency coefficients to balance visibility and robustness. Key functions include DCT coefficient quantization, watermark bit encoding using amplitude modulation, and extraction through inverse quantization and correlation detection. The attack testing suite evaluates robustness against common image processing operations including JPEG compression, Gaussian noise addition, filtering operations, and geometric transformations. Each module follows modular programming principles with clearly defined input/output parameters, making integration into existing systems straightforward. You can readily adapt this implementation for copyright protection applications or digital watermarking research by modifying parameters such as embedding strength, DCT block size, and watermark pattern design. The code provides a solid foundation for developing custom watermarking solutions with configurable robustness characteristics. The implementation demonstrates practical applications of DCT-domain signal processing and error correction techniques in digital watermarking systems. We hope this implementation serves as a valuable resource for your image protection and watermarking research projects. The commented code structure facilitates understanding of the underlying algorithms and enables straightforward extension for specialized requirements.