基于三元数极谐-Fourier矩和混沌映射的立体图像零水印算法

Stereo image zero-watermarking algorithm based on ternary polar harmonic Fourier moments and chaotic mapping

立体图像因其强烈的沉浸感,近年来受到广泛关注,与之对应的立体图像的版权保护问题日趋紧迫.目前绝大多数用于图像版权保护的水印算法都是针对平面图像的,用于立体图像的水印算法较少.即使是立体图像水印算法,大部分算法未能很好体现和保留左右视角分量内部的特定联系,因而说必然影响算法的鲁棒性.本文提出面向立体图像的三元数极谐-Fourier矩(ternary polar harmonic Fourier moments,TPHFM),并基于此和混沌映射,提出一种鲁棒立体图像零水印算法.首先使用线性和非线性混合耦合时空混沌系统对原始二值logo图像进行混沌化,然后计算原始立体图像的TPHFM并选择适用于零水印算法的精确矩,然后计算精确矩的幅值来构造二值特征图像并使用Sine映射和Cosine映射对其进行置乱,最后将置乱的二值特征图像与二值混沌logo图像进行异或操作得到构造的零水印图像.仿真实验表明,本文算法对常规图像处理和几何攻击均具有较好的鲁棒性,并优于三元数圆谐-Fourier矩(ternary radial harmonic Fourier moments,TRHFM)算法和其他零水印算法.

In recent years, stereo images have attracted extensive attention because of their strong immersion,and the corresponding copyright protection of stereo images is becoming increasingly urgent. At present, most of the watermarking algorithms for image copyright protection are aimed at planar images, and there are few watermarking algorithms for stereo images. Moreover, most of＇ the existing stereo image watermarking algorithms are not very good at reflecting and retaining the specific relationship between the left and right views of the stereo images, which will inevitably affect the robustness of the algorithm. In this paper, ternary polar harmonic Fourier moments（TPHFM） for stereo images is proposed and based on this and chaotic mapping, a robust stereo image zero-watermarking algorithm is presented. First, mixed linear-nonlinear coupled map lattice is used to make the original binary logo image chaotic. Next, the TPHFM of the original stereo image is computed and accurate moments for the zero-watermarking algorithm are selected. Then, the binary feature image is constructed using the accurate moments, and scrambled using Sine mapping and Cosine mapping. Finally, a zero-watermark image is generated using the exclusive-or on the scrambled binary feature image and the chaotic binary logo image.Experimental results show that the proposed zero-watermarking algorithm is excellently robust against common image processing attacks and geometric attacks, and is superior to ternary radial harmonic Fourier moments（TRHFM）-based algorithm and other zero-watermarking algorithms.