一种新的小波域正交数字水印方案

提出一种基于人眼视觉模型、 小波变换和正交向量的数字水印方案. 首先对原始图像进行8×8的分块, 然后对每小块进行小波变换, 进而对水印图像进行调制, 并加入到原始图像中, 形成带水印图像, 最后进行小波反变换得到含有水印的图像. 在水印检测过程中, 根据实际需要提出了非盲水印和盲水印两种检测方案. 根据正交向量的特点通过假设检验的方 法提取水印. 实验表明, 这种方法能有效检测出水印图像, 并对常见的水印攻击（如裁剪、 JPEG压缩等）具有良好的鲁棒性, 尤其对信号增强或减弱抗攻击性强.

A New DWT Orthogonal Digital Watermarking Algorithm

This paper presents a new perceptual digital watermarking scheme based on human vision system, discrete wavelet transform and orthogonal vector. The original gray image is first divided into 8×8 blocks, and then 8×8 blocks are permuted. A 1 level digital wavelet transform (DWT) is applied to each 8×8 block. Each watermark bit is modulated by orthogonal vector, then the watermark is added to the original image.Finally the IDWT is performed to form the watermarked image. In the watermarking detection process, two detection algorithms are proposed. By hypothetical testing, the watermark can be extracted exactly. The experimental results show that the proposed technique successfully survives image processing operations, image cropping, and the Joint Photographic Experts Group (JPEG) lossy compression. Especially, the scheme is robust towards image sharping and image enhancement.