彩色图像YC_bC_r域自适应数字水印算法

Adaptive Color Image Watermark Algorithm Based on YC_bC_r

提出了一种用MATLAB实现的彩色图像水印算法。利用彩色图像在YCbCr域内对色差分量的DCT系数的改变加入水印,将色差分量矩阵进行8×8分块,根据每个小块内边缘点的密度将所有小块分成两类,不同类的小块分别按照不同的拉伸因子,加入水印信息。由于水印加入过程中考虑到人类视觉系统的纹理掩蔽功能,使得添加的水印具有自适应性。经试验测试,提出的算法实现的水印对于诸如JPEG压缩、放大缩小等常见的图像处理和噪声干扰具有很好的稳健性。

A new way of embeding digital watermark in color image by MATLAB was presented. The digital watermark was hided by the modification of DCT coefficient of chromatism in the YC_bC_r, the matrix of chromatism was disparted into 8×8 blocks, which were divided into two types by the density of edge point, then the watermark components with different strength were hided into the blocks according to the classification.Watermark has adaptive property due to shelter function of the human visual system. The experimental results show that the watermark generated with the proposed algorithm is invisible and robust to against noise and image processing techniques such as JPEG compaction,enlarge and reduce.