Watermarking On Image And Graphics

With the rapid development of web technology and multimedia technology, digital watermarking has been widely used in areas such as copyright protection, data tracking and monitoring, multimedia authentication. For different applications, researchers have proposed various schemes and watermarking algorithms. Based on the actual application of watermarking, this dissertation focuses on the application of watermarking technology on multimedia authentication; digital map and 3D model copyright protection. Through detailed analysis and discussion of the researches of theses three domains, this dissertation has proposed the following original watermarking algorithm and solution schemes:For the application of semi-fragile watermarking algorithm on multimedia authentication, the main contributions of this dissertation include:(1) Through analyzing MHB algorithm, it is discovered that the generating part and embedding part of the authentication code could be completely separated, and the embedding process is independently taken in bits, so every embedding bit has no connection with any other bits, which results in that the attacker could alter an embedding block without affecting other embedding blocks and the change of the embedding block will not influence the authentication results. So, this dissertation has improved MHB algorithm, constructed a interdependent policy, making not only the authentication code and embedding blocks interdependent, but also the interdependent between embedding blocks, and realized a secure sub-block dependent semi-fragile digital watermarking algorithm. It is theoretically proved that the algorithm enhanced the security against tampering attack, while experimental results has shown that for JPEG compression with quality factor Q≥50, the algorithm is robust and is sensitive to other malicious attacks.(2) Since the application of digital signature on multimedia authentication has some drawbacks, such as the signature could be readily deleted and the lossy compression could results in signature loss, this dissertation proposes a scheme of the application of semi-fragile watermarking on the integrality and authenticity of multimedia information. A web-secured transaction model is constructed with encryption technology, information hiding technology and semi-fragile watermarking algorithm integrated, systematically expounded the model composition, authentication process, and formally proved the security of the model. This dissertation also...