基于多描述编码和小波变换的数字图像水印算法

A Novel Image Watermarking Algorithm Based on Multiple Description Coding and Wavelet Transform

为保证数字图像水印的鲁棒性、安全性以及嵌入容量,结合加密技术与图像压缩编码技术,提出了一种基于多描述编码和小波变换的加密数字水印技术.该技术采用密钥1对需要隐藏的水印图像进行多描述编码,并将编码转换为格雷码,然后将宿主图像色彩分量变换为差值图像,最后在频域内采用密钥2进行小波变换,以交互块跳频的方式完成水印信息的嵌入.理论分析和仿真实验均表明,这种数字水印技术有较大的嵌入容量,同时对常见的图像处理操作具有较强的鲁棒性,能够提高水印的安全性及抗剪裁攻击性能.

Combining encryption with image compression, a new image watermarking teclanlque based on the multiple description coding and wavelet transform is proposed to maintain the robustness, safety and embedding capacity of digital image watermarking. The watermarking images to be hided are transformed into Gray code after coded by multiple description coding algorithm using security key No. 1. The color components of a host image are transformed to a difference image. The Gray code is embedded into the host image by inter-block frequency- hopping spread spectrum and security key No. 2 finally. Theoretical analysis and numerical simulations show that the proposed algorithm has high embedding capacity and is more robust to common image processing. The security and the ability to resist cropping attack can also be enhanced at the same time using the proposed method.