【摘要】 以图像作水印且提取时不需要原图像的数字水印技术面临许多挑战,因而,有关这种技术的研究文献很少。该文首次提出了一种基于遗传算法和Opt-rec多小波、利用奇偶性嵌入灰度图像的公开水印新技术。Opt-rec多小波具有对称性、正交性、在眼0,1演有限支撑、无边界失真,对前置滤波器选取具有任意性,因而Opt-rec多小波比普通小波具有更为广泛的应用前景。选择适应度函数,在适当的约束条件下,通过遗传算法,对不同的图像自适应地得到Opt-rec多小波变换的前置滤波器和后置前置滤波器;将灰度水印图像分解成位图,宿主图像进行一层多小波分解,每个低频系数嵌入1比特水印信息;若嵌入“1”,使对应的低频系数四舍五入为奇数,嵌入“0”,则使其为偶数,相反亦可。该算法提取的水印无失真,可以改善水印系统不可感知性和不可统计性。实验结果表明,该方法抗剪切攻击能力较强,但其抵抗噪声、压缩等处理的能力较差。更多还原

【Abstract】 A new approach to blind digital watermarking based on the DMWT is presented in this paper.A prefilter can be constructed through genetic algorithms according to fitness function for different images.A watermark image is decomposed to bit maps.One level DMWT is realized by using the prefilter and opt-rec multiwavelet.The watermark bit maps are embedded in low frequency parts.″0″ or ″1″ of the watermark bit maps is represented by even or odd number respectively,and vice versa.This method can keep good perceptual transparency,and make no distortion of the extracted watermark.The experiment results have shown that this proposed approach has the desired properties such as invisibility,reliable detection,and robustness against cropping operation.更多还原