基于小波变换和HVS的图像数字水印的研究

Research of Digital Image Watermarking

在经典Barni算法的基础上,本文提出了一种改进的图像水印算法。本算法有如下改进点:(1)选择JND值较大的块作为水印嵌入块,保证了水印嵌入强度,从而实现了较好的鲁棒性;(2)根据不同的图像特性选取嵌入因子,保证了不可见性;(3)水印嵌入在小波系数的中低频部分,进一步提高了鲁棒性。实验结果证明本文算法比Barni算法有明显的性能提高。

An improved image watermarking scheme based on the classic Barni＇ s scheme is proposed. There are some improvements in this algorithm： （1）Watermarks were embedded into the blocks with great value of JND to satisfy good robustness; （2）The embedding factors were determined along with different characteristics of image to satisfy imperceptibility; （3） Watermarks were imbedded into low wavelet coefficients or mean wavelet coefficients, so as to catch better robustness. Experimental results show this scheme has better performance than Barni’s scheme.