Digital watermarking in the generalized discrete cosine transform domain.

摘要

In recent years, advances in digital technologies have created significant changes in the way we reproduce, distribute, and market intellectual property (IP). However, the lowered cost of reproduction, storage, and distribution provides opportunities for large-scale commercial violation. In a world where piracy is growing, the rights of IP owners need to be protected. As a result, digital watermarking is now a commonly used method of protecting the ownership of someone's intellectual property. Digital watermarking can be generally defined as embedding additional information, called a watermark or signature, into an original digital object (often called a cover object) that can be detected and extracted later to make an assertion about the object. The most interest for us is digital watermarking used for protection of digital images. In this thesis, we explore digital watermarking in the generalized discrete cosine transform (GDCT) domain and compare the results with the well explored technique in the discrete cosine transform (OCT) domain. The original images and the resulting watermarked images when no attack is imposed, as well as with some attacks being applied after the process of watermarking are included. These attacks are important for checking the robustness of the embedded watermark. Statistical properties of watermarked images are also discussed.