Image Closed Loop Digital Watermarking Technique
闭环图象数字水印技术

Combining the embedding process with the performance analysis, this paper presents a new image digital watermarking technique, the closed loop digital watermarking in order to make the technique more robust and utility, and gives an implementation approach in wavelet domain. The embedding process is modified continuously according to the results of the performance analysis of watermarking embedding process. If the watermarking can not meet the requirements of detection process or the embedded watermark renders visual artifact of image, the embedded intensity of watermark or watermark itself is modified so as to obtain optimal embedding effect. The convergence of the closed loop techniques is proved. In the performance analysis, the distribution of likelihood function is analyzed, and the mean and the variance of likelihood function in two hypothesis tests and their relationship are deduced. The probabilities of false alarm and detection are also given which are used as the performance measures for the closed loop system. The conclusions are approved by experimental results that this closed loop watermarking technique takes advatage of traditional methods.