Digital Image Watermarking Technology Based on DWT

This MATLAB source code implements digital image watermarking technology based on Discrete Wavelet Transform (DWT). The code includes complete watermark embedding and extraction functionalities, demonstrating excellent performance results. This technology enables the embedding of watermark information into digital images to protect copyright and ensure image integrity. The implementation utilizes DWT transformation to embed watermarks into different frequency components of the image, significantly improving watermark invisibility and robustness against various attacks. The algorithm works by decomposing the host image into multiple frequency subbands (LL, LH, HL, HH) using wavelet transforms, then strategically inserting watermark data into selected subbands to balance visibility and robustness. During the extraction process, the code accurately recovers the original watermark from the watermarked image and restores it to its original quality level. The extraction algorithm reverses the embedding process by applying inverse DWT and employing correlation-based detection methods to precisely retrieve the hidden watermark data. Key functions in the implementation include: - dwt2() for forward discrete wavelet transform - idwt2() for inverse wavelet reconstruction - Coefficient modification algorithms for watermark embedding - Correlation calculation for watermark detection This DWT-based digital image watermarking MATLAB source code serves as a valuable tool for protecting digital image copyright and maintaining content integrity, particularly suitable for applications requiring robust watermarking solutions with good perceptual quality preservation.