一种网格编码的数字水印算法

An image digital watermarking technique based on trellis code

根据信道载体内容构造网格状态阵,用状态阵元素做密钥种子,随机产生网格规则,采用该规则确定水印信息穿越该网格状态阵的路径,形成参考模板;设计信息编码方案,对参考模板编码映射形成信息模板,强化水印信息能量,降低遭受攻击的概率;对信息模板加奇偶校验码,形成附加模板。考虑人类视觉和离散小波变换特点,把附加模板嵌入载体图像的细节子带中,对水印化图像进行加噪、剪切和旋转等攻击,算法仍能成功地提取水印且误码率很低。

This paper proposes an image digital watermarking scheme based on trellis coding. First, a trellis state matrix is built according to original image content, and trellis rules are randomly generated by a state value of the matrix.Second,digital watermark is mapping into a reference model with the trellis rules, and the reference model is mapping into an information model according to a set trellis coding scheme.Third,an additive model is formed by embedding odd - even check - out code into the information model. Finally, the additive model is embedded into the low frequency domain of the original image based on discrete wavelet transform（DWT）and Human Visual System（HVS）. Digital watermark is successfully pick- upped from the watermarked image which may be undergone tamper attacked.The experimental results are excellent and the wrong： code rate is very low.