基于小波变换的静态图像数字水印研究

Research on digital watermark of static image based on wavelet transform

通常静态图像经过离散余弦(DCT)小波变换后,纹理及边缘的特征主要集中在高频子带LH,HL和HH上,经过一般的图像处理以后,高频上的信息容易丢失。在嵌入的水印信息量较少的情况下,可以把水印信息嵌入到低频系数上,使人眼不易察觉,增强了水印的鲁棒性。实验表明,该算法有良好的不可感知性和强健的鲁棒性。

Usually a static image is transformed by discrete cosine （DCT）, while texture and edge features concentrates in the high frequency subbands LH, HL and HH. The high-frequency information is easy to lose after a general image processing. This paper advised to embed the watermark information into the low-frequency coefficients in case of less embedded informa tion. It is invisible for human eyes, greatly enhancing the robustness of watermark. The experiments show that the algorithm has good imperceptibility and strong robustness.