A communication system model for digital image watermarking problems

The Internet has become the main media for sharing multimedia data, such as images, video, and audio. The ease of making exact copies of the multimedia data has urged the need for copyright protection. Digital watermarking is one of the ways to protect the copyright of the multimedia data, by embedding information of the owner or the intended user to the multimedia data. Prior work on digital watermarking has mainly focused on realizations of the techniques. In this paper, we analyze the digital watermarking problems in a theoretical point of view. More specifically, we explain performance issues in digital watermarking problems by digital communication theory. Capacity, imperceptibility, and robustness are all included in this framework. An adaptive-coding-rate watermarking scheme based on spread spectrum communications is designed for verifying the proposed framework.