基于离散余弦变换彩色图像的数字水印研究

Study on color image digital watermarking based on discrete cosine transform

为了在彩色图像中嵌入彩色数字水印,同时保持原始彩色图像的完整性及健壮性,提出基于空间域和频率域间转换,配合RGB色彩系统,利用离散余弦变换将图像的空间域表示转换为频率域,将彩色数字水印频域系数经适当处理后嵌入图像的低频部分,使嵌入的彩色数字水印能抵抗各种图像处理时的破坏。实验结果表明:应用该方法嵌入彩色数字水印,不仅不破坏原始彩色图像品质,而且能抵抗外界的破坏,成功取回所嵌信息。

Color digital watermark embedded in color images has becoming a hot topic in current study on how to maintain the integrity and robustness of the original color image. Based on transitions between the spatial and frequency domain, combined with RGB color system, a method is proposed so that it transforms the spatial domain into frequency domain by discrete cosine transform method, and embeds the frequency domain coefficients of color digital watermark into lower frequency part of images after proper processing. In this way, the embedded color watermark can resist any kinds of image destructions. The experimental results show that applying the proposed method to embed color digital watermark is not only harmless to the quality of the original color image, but also resistant to outer destructions, in which way the embedded information can be successfully retrieved.