一种基于小波系数边信息的鲁棒水印算法

为了实施图像的版权保护，提出了一种基于小波系数幅值关系的盲水印算法。原始图像通过三级小波分解得到小波系数，算法在密钥的控制下，伪随机地选择中频子带中两块共8个系数组成一组。通过小幅度量化来加强每组数据中两块系数幅值的大小关系特征，利用这组系数的特征作为边信息和水印信息生成密钥、嵌入水印。保存密钥，并在密钥的控制下提取水印。实验结果表明，该算法不仅能有效抵抗JPEG压缩、低通滤波、高斯噪声和几何攻击，而且水印图像的PSNR可以保持在50 dB以上。

Blind robust watermark algorithm based on side-information of wavelet coefficients

In order to protect this copyright of the image, this paper presented a blind robust watermark algorithm based on the wavelet coefficients magnitude relationship. Transformed the host image into wavelet coefficients using the 3-level DWT, divided two blocks of the middle frequency band in DWT into a group of 8 wavelet coefficients in a pseudorandom manner using a key. Then embedded 1 bit watermark information in a group. Generated a secret key by magnitude relationship characteristic of two blocks and watermark. Saved the key and used to extract watermark. The experimental results show that the proposed algorithm is quite effective against JPEG compression, low-pass filtering, Gaussian noise and geometric attacks and the PSNR of watermark image is above 50 dB.