目的 设计一种适用于彩色打印扫描图像的鲁棒性盲水印算法。 方法 结合四元数傅里叶变换及离散小波变换的优点，提出了一种双变换域全息水印算法。利用四元数傅里叶变换及离散小波变换，将全息水印信息分散嵌入到彩色宿主图像 3 个色彩分量的低频小波系数区域，而不引起大的图像失真，同时，算法实现了盲提取。 结果 算法满足不可见性要求，同时打印扫描实验证明，该算法具有抵抗打印扫描攻击的能力。 结论 结合四元数傅里叶变换及离散小波变换的双变换域水印算法，保留了 2 种变换域在处理彩色图像中的优点，在应用于打印扫描彩色图像时，效果比现有算法更好。

To design a robust blind watermarking scheme that is suitable for print-and-scan color image, a dual-transform domain watermarking algorithm was put forward based on discrete wavelet transform (DWT) and quaternion discrete Fourier transform (QDFT). Digital hologram watermarking information was scattered and imbedded into the low-frequency part of three color components of the color host image without visible distortion. Meanwhile the algorithm was blindly extracted. Experiment results showed that the proposed algorithm met the invisibility requirements and was resistant to printing-and-scanning attack. The dual-transform domain watermarking algorithm based on discrete wavelet transform and quaternion discrete Fourier transform retains the advantages of two transform domains in processing of color image, and has better performance in the field of print-and-scanning color image.