Analysis of Capacity for Time-varying Watermark Channel with Side-information
Zhou Si-qing · Jisuanji gongcheng · 2007
n the study of digital watermark channel capacity,the known probability distribution is supposed for watermark attack channel,but it is not always true,for example channel estimation errors,scaling and geometrical transformations etc.This paper proposes mathematical model for time-varying watermark channel with side information,composed of the deterministic and the random components of the time-varying attack.Minimal assumptions are made regarding the probability distributions of the watermark channel.Lower and upper bounds on the mutual information between the received signal and the cover signal allows to estimate capacity of watermark channel.Therefore,simple additive Gaussian noise channel model is not sufficient to describe the watermark channel.The theoretical results is valid by numerical simulate.