关键词: 通信技术, 数字水印, 码分多址, Turbo码, 线性最小均方误差估计

Abstract:

A high capacity and robust digital watermarking scheme based on Code Division Multiple Access (CDMA) is proposed. This scheme can solve several watermarking problems. The interference among the groups with the same access is decreased by the construction of a group matrix with the sorted sequence. The problem that the Peak Signal to Noise Ratio (PSNR) value of the original image will decease greatly if a large image watermarking image is embedded in can be solved by adaptively adjusting the final encoded watermarks. The MAI can be eliminated by using the Linear Minimum Mean Square Error Estimation (LMMSEE) while the influence of the noise is not increased. Experiment results show that the proposed digital watermarking scheme and methods have the following advantages: the capacity is much high, the distortion of the watermarked image is imperceptible, the security of the watermarking is good, the watermarking has good robust performance resistance to interference noise and other attacks in common image operations.

Key words: communication, digital watermarking, code division multiple access(CDMA), Turbo code, linear minimum mean square error estimation