基于小波系数块能量分析的自适应数字水印算法

Adaptive digital watermarking algorithm based on energy analysis of wavelet coefficients block

为增强水印的鲁棒性,提出一种基于小波变换的改进数字水印算法。该算法将宿主三级小波变换后的第三级细节子图分别分割成互不重叠的系数块,进而对各块能量进行统计分析以确定更适于水印嵌入的块,最后结合人类视觉系统的掩蔽特性,在所选块的最大系数上实现水印的自适应嵌入。理论分析与仿真结果表明应用本算法实现的水印具有更好的鲁棒性和不可见性。

To enhance the robustness of watermark, an improved digital watermarking algorithm based on wavelet transform was proposed. The third level detail sub-images decomposed the original image using three levels DWT（ Discrete Wavelet Transform） were divided into non-overlap blocks. Then the blocks, which were more adaptable to embed watermark, were selected by block energy analysis. At the end, combining with the properties of human visual system, the watermark was adaptively embedded into the largest coefficients which belonged to the selected blocks, Theoretical analysis and experiment results show that the watermark generated with the proposed algorithm is imperceptible and more robust.