The Study of Digital Watermarking and Image Hiding Techniques

• Main Authors: Wen-Yi Yang, 楊文懿
• Other Authors: Cheng-Fa Tsai
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/60306176735899474912

碩士 === 國立屏東科技大學 === 資訊管理系 === 93 === Abstract： As rapid evolution of Internet technology, the transmission of digital multimedia become easier and fast. So, how to protect the security of information transmission and make sure the completeness of copyright are becoming popular search subject in recent year. Information hiding technology provide good way to solve the kind of problem. In general, information hiding technology divide into two type applications. One can apply for copyright protection, we call it as digital watermarking. The robustness of the embedded watermark is the major consideration. The other can apply for secret communication, we call it as steganography. The steganographic image quality and embedding capacity of the cover-image are the focus of attention. Hence, concerning this problem we propose good approach for digital watermarking and image steganography individual. In the digital watermarking topic, our method located frequency domain to process image information. The watermarking method combines the discrete cosine transform (DCT) and singular value decomposition (SVD) to be presented. First we compute color cover-image DCT coefficient by DCT and obtain coefficient’s singular value after decomposing coefficient . Then the watermark need to be embedded into singular value. After experimental test proved that the quality of watermarked cover-image is better than other method and the robustness of embedding watermark is high. In the image steganography topic, our method located spatial domain to process image information. Cover-image and secret-image are color image which been proposed in our approach. We utilize the edge detection method to distinguish edge blocks and smooth blocks. As human eyes are less sensitive to modification in the edge block and more sensitive to modification in the smooth block. We embed the secret message into cover-image mobility. It means we embed more message in edge block than smooth block. Our approach may reduce the distortion of stego-image and the capacity of embed message is quite obviousness. The experimental result showed the above method we propose could be ensure successfully for the copyright protection, secret information communication and data management.