窄色域抗打印扫描全息水印算法

目的为了提升水印抗打印扫描攻击的鲁棒性,提出一种窄色域抗打印扫描全息水印算法。方法制作打印机的ICC特性文件,应用特性文件转换宿主图像到CMYK颜色模式,从而获得适应该设备的窄色域,将制成全息图的水印嵌入到宿主图像的DWT域内。结果实验表明,该算法经历打印扫描后可顺利提取水印,且打印扫描后获得的水印图像保真度较高。与在RGB颜色模式中嵌入水印相比,该算法水印的鲁棒性和宿主图像的保真度均具有明显优势;相较于嵌入水印到默认转换的CMYK颜色模式,鲁棒性相当,该算法宿主图像的保真度具有明显优势。结论该窄色域算法可提升打印扫描过程中颜色传递的一致性,结合全息图不可撕毁的优势权衡了鲁棒性与保真度的关系,该算法有益于数字水印在防伪印刷领域的应用。

Holographic Watermarking Algorithm for Print-and-Scan Process in Narrow Colour Gamut

The work aims to propose a holographic watermarking algorithm for print-and-scan process in narrow color gamut, so as to enhance the robustness of watermark against print-and-scan attacks. The ICC device profile of printer was generated and used to convert the host image into CMYK color space, in order to obtain the narrow color gamut suitable for the device, and the watermarks in the hologram were embedded into DWT domain of the host images. The experiments showed that, after the print-and-scan process, the watermarks could be smoothly extracted by the proposed algorithm with high fidelity of watermarked images. Besides, compared with the watermark embedded in RGB color space, the proposed algorithm showed advantages in watermark robustness and host image fidelity. Compared with CMYK color space with embedded watermark from default conversion, the proposed algorithm showed clear advantage in host image fidelity with basically same robustness. The proposed narrow gamut algorithm can improve the consistency of color transfer in the print-and-scan process and balance the relation between robustness and fidelity with the advantage of hologram integrity. Therefore, the proposed algorithm is conducive to the application of digital watermarking in the anti-counterfeit printing.