基于混合进制系统与像素差异的无损水印算法

Lossless watermarking algorithm based on multiple-base notational system and pixel difference

为解决当前水印技术主要是将相同的水印容量嵌入到图像中的每个像素值,使其水印容量较小,以及抗失真性能不佳的不足,设计混合进制系统与像素差异的数据水印算法。将载体图像分割为非重叠子块,计算每个子块的像素差值;引入混合进制系统,获取不同的基数;根据像素差值,定义基数选择规则;考虑人眼视觉特性,设计像素区间自适应调整机制,改进diamond编码技术,完成水印信息的嵌入;建立水印信息提取机制,复原水印。实验结果表明,与当前数据水印算法相比,所提算法具有理想的不可感知性,以及更大的水印容量与更低的失真度。

To solve the defect such as big distortion of watermark extraction quality induced by embedding the same watermark capacity into each pixel value in the image in current image watermarking technology,the lossless image watermarking algorithm based on multiple-base notational system and pixel difference was proposed.The pixel difference of each sub block was calculated by dividing the cover image into non-overlapping subblocks.The different base was got by introducing the multiple-base notational system.Bases selection rules corresponding were defined according to pixel difference of subblocks.The two boundary constraints were designed by considering the human visual characteristics.The watermark information extraction mechanism was designed to recover the watermark data.Experimental results show that the proposed algorithm has greater watermark capacity and lower distortion compared with the current image watermarking algorithm.