基于小波域分形变换的图像水印技术

为了提高图像水印的鲁棒性和不可见性,结合小波变换和分形变换,提出了一种基于小波域内分形变换的图像数字水印方法。首先对图像进行小波变换,结合图像空域分形编码思想把图像的小波系数分成域子树和值子树两类,然后利用分形仿射变换选出具有相似性的域子树,将其作为水印的嵌入树,结合人类视觉系统的JND模型实现水印的嵌入和提取,最后针对该方法进行了JPEG压缩、剪切、滤波、添加噪声、旋转等相关实验,结果表明,该方法具有安全可靠、鲁棒性和不可见性好等优点,具有创新,可行性强。

Image Watermarking Method Based on Fractal Transform in DWT Domain

In order to improve the robustness and invisibility of image watermark,a kind of the image watermarking method based on the fractal transforms in discrete wavelet transform domain is proposed in this paper.Firstly,it applies the DWT transform to the entire image and divides the discrete wavelet coefficients into domain sub-trees and the range sub-trees based on the image spatial fractal coding,then selects the similar domain trees by the fractal affine transforms and regards them as the embedded trees,which the watermark are embedded into and extracted from by the JND model of the human visual system.Finally,it can be treated by many correlative experiments such as JPEG compress,cropping,filtering,adding noises,and rotation.The experimental results show the method is secure,robust,invisible,novel and feasible.