Coefficient selection methods for scalable spread spectrum watermarking

With the increasing use of mobile and internet technology as a means of content distribution, we see a move towards scalable content distribution mechanisms, which allow the adaptation of content to the requirements of the target system. Adequate protection of scalable content requires the adoption of scalable watermarking algorithms. Many of the existing algorithms are based on the spread spectrum techniques, first presented in a watermarking context by Cox et al. [2]. The various algorithms often use quite different methods for coefficient selection, resulting in different watermark properties. We examine the effect of the coefficient selection method on watermark scalability by considering the quality and resolution scalability of seven simple selection methods when used as part of a spread spectrum watermarking algorithm.