线性内插在DCT域数字水印中的应用分析与改进

Application Analysis and Improvement for Linear Interpolation Watermark in DCT Domain

线性内插水印算法原理简单、隐蔽性好、水印容量大。首先全面分析了DCT域线性内插水印算法的误差,指出线性内插方法用于空间域水印时误差最大值为8,用于变换域水印时误差最大值可能大于8。然后据此对一种基于线性内插的DCT域水印算法进行了改进,优化了水印信号拆分方法。实验结果证实改进后的算法明显消除了原始算法中存在的较大误差值集中现象,取得了较好效果。

The linear interpolation watermark algorithm＇s principle is simple, confidentiality is fine and the watermark capacity is big. First the error analysis of linearity interpolation watermark algorithm in DCT domain is introduced. Pointed out when the linear interpolation method uses in spatial domain watermark the erroneous maximum value is 8, when uses in transforms domain watermark the erroneous maximum val- ue possibly being bigger than 8. Then made the improvement in which mainly optimized the watermark sig- nal splitting method to a linear interpolation DCT watermark algorithm. The experimental result confirmed the improvement algorithm obviously eliminated the centralism phenomenon of big erroneous value which in the primitive algorithm exists, has obtained good effect.