中文摘要：

基于分数阶四元数傅里叶变换（Fr QFT）和遗传算法,提出了一种新的彩色图像自适应水印算法.首先,依据直接从彩色载体图像提取的纹理、边缘和色调掩蔽特性,将图像块分为3种不同类型;不同类型块采用不同的Richard逻辑曲线确定水印嵌入强度,并采用遗传算法从不可见性和鲁棒性2个方面优化各Richard逻辑曲线参数;最后,根据由优化的Richard逻辑曲线确定的自适应水印嵌入强度,通过量化索引调制算法和冗余嵌入策略将水印自适应嵌入到彩色载体图像的Fr QFT系数中.实验测试结果表明,所提算法在不可见性和鲁棒性2个方面均优于现有传统算法和基于四元数的算法.

英文摘要：

A newcolor image adaptive watermarking algorithm is proposed based on the fractional quaternion Fourier transform（ Fr QFT） and the genetic algorithm. First,the image blocks are classified into three types according to the masking properties of texture,edge and color tone directly extracted from the color host image. The adaptive watermarking strength value of each block is determined by the corresponding Richard curve. And the parameters of the Richard curves are optimized by the genetic algorithm with the consideration of the invisibility and the robustness. Finally,according to the adaptive watermarking strength values decided by the optimized Richard curves,the watermarks are inserted into the Fr QFT coefficients of the color host image by using the quantization index modulation algorithm and the redundant embedding strategy. The experimental results demonstrate that the proposed algorithm outperforms some existing conventional algorithms and some existing quaternion-based algorithms in terms of the invisibility and the robustness.